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Dialogic® SS7 Protocols 
MTP3 Programmer’s Manual
2 
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The names of actual companies and products mentioned herein are the trademarks of their respective owners. 
Publication Date: August 2007 
Document Number: 05-2471-002, Issue 7
Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
3 
Contents 
1 Introduction.............................................................................................................5 
1.1 Applicability.......................................................................................................5 
1.2 Related Information............................................................................................5 
2 Functional Overview.................................................................................................6 
2.1 MTP3 Module Overview........................................................................................6 
2.2 Module Configuration..........................................................................................6 
2.3 Feature Overview................................................................................................7 
2.4 General Description.............................................................................................7 
3 Message Reference...................................................................................................9 
3.1 Protocol Requests from User Part to MTP3..............................................................9 
3.1.1 API_MSG_TX_REQ  – MTP Transfer Request................................................10 
3.2 Protocol Indications from MTP3 to User Part..........................................................11 
3.2.1 API_MSG_RX_IND – MTP Transfer Indication..............................................12 
3.2.2 MTP_MSG_PAUSE – MTP Pause Indication..................................................13 
3.2.3 MTP_MSG_RESUME – MTP Resume Indication.............................................14 
3.2.4 MTP_MSG_STATUS – MTP Status Indication................................................15 
3.3 Layer Management Requests Sent to MTP3...........................................................16 
3.3.1 MTP_MSG_ACT_LS – Activate Link Set Request...........................................17 
3.3.2 MTP_MSG_DEACT_LS – Deactivate Link Set Request...................................18 
3.3.3 MTP_MSG_ACT_SL – Activate Signaling Link Request...................................19 
3.3.4 MTP_MSG_DEACT_SL – Deactivate Signaling Link Request...........................20 
3.3.5 MTP_MSG_INHIB_SL – Inhibit Signaling Link Request..................................21 
3.3.6 MTP_MSG_UNINHIB_SL – Uninhibit Signaling Link Request..........................22 
3.3.7 MTP_MSG_SLTC_START – Signaling Link Test Request.................................23 
3.3.8 MTP_MSG_SRT_START – Start SRT Request (Japan)....................................24 
3.4 Management Indications Issued by MTP3 to Layer Management...............................25 
3.4.1 MTP_MSG_LINK_INHIB – Signaling Link Inhibited Indication.........................26 
3.4.2 MTP_MSG_LINK_UNINHIB – Signaling Link Uninhibited Indication.................27 
3.4.3 MTP_MSG_INHIB_DENIED – Signaling Link Inhibit Denied Indication.............28 
3.4.4 MTP_MSG_UNINHIB_FAIL – Signaling Link Uninhibit Failure Indication...........29 
3.4.5 MTP_MSG_SRT_RESULT – SRT Result Indication (Japan)..............................30 
3.5 Management Requests Sent to MTP3....................................................................31 
3.5.1 MTP_MSG_RESET – MTP3 Module Reset Request.........................................33 
3.5.2 MTP_MSG_CONFIG – MTP3 Module Configuration Request............................34 
3.5.3 MTP_MSG_CNF_LINKSET – Link Set Configuration Request...........................38 
3.5.4 MTP_MSG_CNF_LINK – Signaling Link Configuration Request........................40 
3.5.5 MTP_MSG_CNF_ROUTE – Route Configuration Request................................42 
3.5.6 MTP_MSG_CNF_TIMERS – MTP3 Timer Configuration Request.......................44 
3.5.7 MTP_MSG_TRACE_MASK – MTP3 Trace Mask Configuration Request...............45 
3.5.8 MTP_MSG_END_LINKSET – Link Set End Request........................................48 
3.5.9 MTP_MSG_END_LINK – Signaling Link End Request.....................................48 
3.5.10 MTP_MSG_END_ROUTE – Route End Request.............................................49 
3.5.11 MTP_MSG_GARBAGE – Clear Garbage Request...........................................50 
3.5.12 MTP_MSG_UPDATE_L4 – Update Level 4 Request........................................51 
3.5.13 MTP_MSG_R_LK_STATUS – Read Link Status Request..................................52 
3.5.14 MTP_MSG_R_RT_STATUS – Read Route Status Request...............................54 
3.5.15 MTP_MSG_R_SP_STATS – Read Signaling Point Statistics Request.................56 
3.5.16 MTP_MSG_R_RT_STATS – Read Route Statistics Request..............................57 
3.5.17 MTP_MSG_R_LS_STATS – Read Link Set Statistics Request..........................58 
3.5.18 MTP_MSG_R_LK_STATS – Read Link Statistics Request................................59 
3.5.19 GEN_MSG_MOD_IDENT – Read Module Version Request..............................60 
3.6 Management Indications Issued by MTP3..............................................................61 
3.6.1 MGT_MSG_MTP_EVENT – MTP3 Q.752 Event Indication...............................62 
3.6.2 MGT_MSG_EVENT_IND – Error Indication..................................................63 
3.6.3 MGT_MSG_TRACE_EV – Trace Event Indication...........................................65 
3.7 Message Summary Table....................................................................................66 
4 Internal Interfaces..................................................................................................68 
4.1 Primitives Issued by MTP3 to MTP2......................................................................68
4 
Contents 
4.2 Primitives Received by MTP3 from MTP2................................................................68 
4.3 Messages Exchanged Between MTP3 and Timer Services.........................................69 
4.4 Messages Exchanged Between MTP2 and MTP3 On-board........................................69 
Glossary...................................................................................................................70 
Figures 
1 MTP3 Context Diagram...............................................................................................8 
Tables 
1 Message Summary Table...........................................................................................66 
Revision History 
Note: The latest released issue of this guide can be found at: 
http://www.dialogic.com/support/helpweb/signaling 
Issue No. Part No. Date Description of Changes 
7 05-2471-002 19-Apr-07 
Changed to Dialogic format. 
Changes to Message Format in Section 3.2.4, “MTP_MSG_STATUS” on 
page15. 
Changes to tx_pool_size in Section 3.5.2, “MTP_MSG_CONFIG” on 
page34. 
6 05-2471-001-01 07-Jul-05 
Support for additional link and route status queries added using messages: 
MTP_MSG_R_RT_STATUS, MTP_MSG_R_LK_STATUS and 
MTP_MSG_UPDATE_L4. 
Support for Japan specific Signaling Route Test (SRT) added using 
messages: MTP_MSG_SRT_START and MTP_MSG_SRT_RESULT. 
Support for dynamic configuration changes added using the messages: 
MTP_MSG_END_LINKSET, MTP_MSG_END_LINK and 
MTP_MSG_END_ROUTE. 
5 Not Applicable 26-Nov-97 
Module enhanced to support Alternative Routing. Format of link set and 
route configuration messages modified (while maintaining backward 
compatibility). 
Link set configuration enhanced so that each link set can (if required) have 
a different local point code and use a different sub-service field setting. 
Management Inhibiting now supported. 
Minor typographical corrections including mnemonics for many message 
types. 
4 Not Applicable 08-Jun-95 
Name changed from Level 3 Programmer’s Manual to MTP3 Programmer’s 
Manual. 
ANSI and 24-bit point code options added. module_id no longer required in 
configuration message. Level 2 instance number added. 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
Chapter 1:  Introduction 
Signaling System Number 7 (SS7), as defined by the ITU-T and other national standards bodies, defines a 
Message Transfer Part (MTP) for the reliable transfer of messages between different nodes within a telephony 
network. MTP is conceptually sub-divided into three layers: MTP1, MTP2 and MTP3. 
The Signaling Network Functions of the MTP are known as MTP Level 3 (MTP3), as specified in ITU-T 
Recommendation Q.704, ANSI T1.111.4, and are used by many other national and international standards 
bodies. The Signaling Network Functions ensure a reliable transfer of the signaling messages even in the 
event of failures of signaling links or nodes within the signaling network. 
MTP3 uses the services offered by the underlying protocol module (for example, MTP2 or M2PA) to achieve 
point-to-point communication with peer MTP3 implementations. 
This manual gives an overview of the operation of the MTP3 module and defines the structure of all 
messages that can be sent to the module or issued by the module. 
1.1 Applicability 
This manual relates to the MTP3 software implementation used on Dialogic® SS7 products. It is applicable to 
MTP3 host-based software and to board-based MTP3 software running on the following Dialogic® boards: 
•SS7HD 
•SPCI4 
•SPCI2S 
The manual is intended for use by developers who are using SS7 board-level products and wish to use some 
or all of the features of the message-based interface to the MTP3 module. Users of the s7_mgt configuration 
utility should note that the s7_mgt utility generates the configuration messages detailed in this document 
based on the content of a configuration file therefore, there is no need for the user to generate configuration 
messages. 
This manual is not intended for use with the following Dialogic® SS7 products: 
•SS7G21 
•SS7G22 
Users of these Dialogic® products should refer to the appropriate product documentation. 
This document describes the interface to the MTP3 module including full details of all run-time configuration 
options. It applies to revisions of the MTP3 module commencing with a major revision number of 5 (for 
example, Version 5.00). The module version can be read using the GEN_MSG_MOD_IDENT message 
described later in this manual. 
1.2 Related Information 
Refer to the following documents for related information: 
•Software Environment Programmer’s Manual – U10SSS 
•MTP2 Programmer’s Manual – 05-2331 
•M2PA Programmer’s Manual – 05-2407 
•ITU-T Recommendations Q.704, Q.707 – Message Transfer Part 
•ITU-T Recommendation Q.752 – Monitoring and Measurements 
•ANSI T1.111.4 – Message Transfer Part 
For more information on Dialogic® SS7 products and solutions, visit 
http://www.dialogic.com/support/helpweb/signaling/.
6 
Chapter 2 Functional Overview 
Chapter 2:  Functional Overview 
2.1 MTP3 Module Overview 
The MTP3 module is an implementation of the ITU-T Signaling System Number 7 (SS7), Message Transfer 
Part (MTP) level 3. It implements the Signaling Message Handling and Signaling Network Functions from 
Q.704, the Signaling Link Test Control from Q.707 and Monitoring and Measurement Reporting from Q.752. 
The MTP3 module can also be configured at run-time to operate in accordance with ANSI T1.111. 
The MTP3 module provides the user with sufficient level 3 functionality to implement a Signaling Point (SP) 
equipped with multiple link sets, each containing up to 16 signaling links and connecting to multiple 
destinations either directly or via Signaling Transfer Points (STPs). It supports load sharing within a link set 
and the full changeover and changeback procedures to ensure that, in the event of a link failure, traffic is 
transferred to an alternative link in the link set. The module also supports the use of Alternative Link Sets 
allowing each destination to be reached by two Alternative Routes. These link sets can be configured as 
“preferred” and “secondary” link sets or as equal priority, in which case, load sharing across the link sets is 
supported. In the event of a link set failure or recovery, the Forced Rerouting and Controlled Rerouting 
procedures are invoked. 
Messages can be sent to adjacent signaling points using the associated mode of signaling or via signaling 
transfer points to any remote signaling point using the quasi-associated mode. Received messages destined 
for the signaling point are presented to the appropriate User Part module, which is provided by the user. The 
user can activate and deactivate each signaling link set or individual links, inhibit and uninhibit individual 
links and enable the Signaling Link Test (SLT) procedure in accordance with ITU-T Recommendation Q.707. 
The module also supports comprehensive event reporting and measurements in accordance with ITU-T 
Q.752. 
In addition to protocol-related functions, the MTP3 module contains a number of features to assist the user 
when developing an application. These features include the ability to trace any primitive message received 
by or issued from the MTP3 module to a management module where it can be recorded or presented to the 
user. In this way, the user can debug the application without ever needing to gain detailed knowledge of the 
internal operation of the MTP3 module. 
2.2 Module Configuration 
Each link set is uniquely identified by a link set identifier (linkset_id) with a value in range of 0to one less 
than the number of link sets supported. Each link within the module is uniquely identified by a link identifier 
(link_id) with a value in the range of 0 up to one less than the number of links supported. In all message 
exchanges with the management module, each link is considered to belong to a link set and references to 
the link are made using the link set identifier (linkset_id) and the link reference (link_ref), which has a 
value in the range of 0 to one less than the maximum configured number of links in a link set. 
The MTP3 module is configured for operation in conjunction with up to 16 user part modules that lie above 
the MTP3 module in the protocol stack, and one or more level 2 modules that lie below the MTP3 module in 
the protocol stack. 
Management functions should be provided by a management module that is responsible for correctly 
configuring the MTP3 module, activating and deactivating the links and recording or presenting the trace 
messages and event indications to the user. 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
2.3 Feature Overview 
Features of the MTP3 module include: 
•Software implementation of ITU recommendation Q.704 
•Software implementation of ANSI T1.111.4. 
•Support for 24-bit point codes (China) 
•Support for Japan specific extensions 
•Run-time selection between ITU, ANSI, China and Japan operation 
•Run-time selection of point code size 14-bit, 16-bit or 24-bit 
•Support for dual-operation, where two instances of MTP3 cooperate to form a single local point code 
•Support for Alternative Routing and Combined Link Sets 
•Support for Signaling Link Test 
•Support for Monitoring and Measurements in accordance with ITU-T Q.752 
•Message-based interface 
•Comprehensive trace options for selectively reporting to system management each primitive issued to, 
or received by, the MTP3 module 
2.4 General Description 
The interface to the MTP3 module is entirely message-based, using the structured messages documented in 
the Software Environment Programmer’s Manual. The MTP3 module is capable of working in conjunction with 
board-based MTP2 implementations running on multiple boards and host-based M2PA implementations. 
Figure1 provides an overview of the MTP3 module showing the various interfaces. 
8 
Chapter 2 Functional Overview 
Figure 1. MTP3 Context Diagram 
API_MSG_TX_REQ 
MTP_MSG_RESET 
MTP_MSG_CONFIG 
MTP_MSG_CNF_LINKSET 
MTP_MSG_CNF_LINK 
MTP_MSG_CNF_ROUTE 
MTP_MSG_CNF_TIMERS 
MTP_MSG_TRACE_MASK 
MTP_MSG_END_LINKSET 
MTP_MSG_END_LINK 
MTP_MSG_END_ROUTE 
MTP_MSG_GARBAGE 
MTP_MSG_UPDATE_L4 
MTP_MSG_R_LK_STATUS 
MTP_MSG_R_RT_STATUS 
MTP_MSG_R_SP_STATS 
MTP_MSG_R_RT_STATS 
MTP_MSG_R_LS_STATS 
MTP_MSG_R_LK_STATS 
GEN_MSG_MOD_IDENT 
MGT_MSG_EVENT_IND 
MGT_MSG_TRACE_EV 
MGT_MSG_MTP_EVENT 
API_MSG_RX_IND 
MTP_MSG_PAUSE 
MTP_MSG_RESUME 
MTP_MSG_STATUS 
MTP3 
Module 
API_MSG_TX_REQ 
SS7_MSG_START 
SS7_MSG_STOP 
SS7_MSG_EMGCY 
SS7_MSG_EMGCY_CLRD 
SS7_MSG_RTV_BSNT 
SS7_MSG_RTVL_REQ 
SS7_MSG_FLUSH 
SS7_MSG_CONTINUE 
API_MSG_RX_IND 
SS7_MSG_IN_SVC 
SS7_MSG_OUT_SVC 
SS7_MSG_REM_PR_OUT 
SS7_MSG_REM_PR_OK 
SS7_MSG_RXD_BSNT 
API_MSG_RTVD_MSG 
SS7_MSG_RTVL_COMPL 
MTP_MSG_RTVL_NOT_POS 
MTP_MSG_LINK_CONG 
MTP_MSG_LINK_UNCONG 
MTP_MSG_FLUSH_ACK 
TIM_MSG_KEEP_TIME 
SS7_MSG_TM_EXP 
User Part 
Interface 
Management 
Interface 
System 
Services 
MTP2 
Interface 
MTP_MSG_ACT_LS 
MTP_MSG_DEACT_LS 
MTP_MSG_ACT_SL 
MTP_MSG_DEACT_SL 
MTP_MSG_INHIB_SL 
MTP_MSG_UNINHIB_SL 
MTP_MSG_SLTC_START 
MTP_MSG_SRT_START 
MTP_MSG_LINK_INHIB 
MTP_MSG_LINK_UNINHIB 
MTP_MSG_INHIB_DENIED 
MTP_MSG_UNINHIB_FAIL 
MTP_MSG_FOR_USP 
MTP_MSG_SRT_RESULT 
Layer Management 
Interface
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
Chapter 3:  Message Reference 
This section describes the individual messages and associated parameters that may be sent to MTP3 or 
generated by MTP3. The interface is message-based, using messages of type MSG as defined in the 
Software Environment Programmer’s Manual. 
These messages are used for the primitive protocol interface with layer 4 User Part module, the primitive 
protocol interface with the MTP3 layer management module and for the non-primitive interface to 
management for the purposes of configuring and managing the MTP3 module. 
The messages are grouped into the following categories: 
•Protocol Requests from User Part to MTP3 
•Protocol Indications from MTP3 to User Part 
•Layer Management Requests Sent to MTP3 
•Management Indications Issued by MTP3 to Layer Management 
•Management Requests Sent to MTP3 
•Management Indications Issued by MTP3 
3.1 Protocol Requests from User Part to MTP3 
Primitive protocol requests are sent from the User Part (for example, ISUP, SCCP etc.) to MTP3 in accordance 
with the published protocol specifications. 
This section of the manual is applicable only to users intending to write their own User Part implementation. 
When using a User Part from the Dialogic® SS7 product range, the messages for this interface are 
implemented within the User Part module and the user should consult the User Part documentation, which 
details the format of the messages that should be sent from the application to the User Part module. 
Currently, only the following protocol request is sent from the User Part to MTP3: 
•API_MSG_TX_REQ  – MTP Transfer Request 
When sending a protocol request to MTP3, the user should ensure that the message is sent to the correct 
module_id and the correct instance of the MTP3 module (if multiple instances are in use, for example, on 
different boards). 
The default module_id for MTP3 is MTP_TASK_ID (0x22). However, host-based MTP3 is capable of running 
at different module IDs and this can be useful for example where multiple MTP3 modules are running on a 
single host. The user should ensure that the correct MTP3 module ID is written to the hdr->dst field of the 
message. 
Typically, it is appropriate to set the instance value to 0 using the GCT_set_instance() library function. 
However, if separate MTP3 instances are running on multiple boards, it is necessary to set the instance to the 
board ID on which the target MTP3 is running. 
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Chapter 3 Message Reference 
3.1.1 API_MSG_TX_REQ  – MTP Transfer Request 
Synopsis 
Message issued by the User Part (for example, ISUP, SCCP etc.) to MTP3 to invoke the Message Transfer 
Request service for transmission to the network. 
Message Format  
Message Header 
Field Name Meaning 
type API_MSG_TX_REQ (0xcf00) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len Number of octets in Message Signal Unit (MSU) 
Parameter Area 
OFFSET SIZE NAME 
0 len 
MSU data in binary format commencing with the Service Indicator 
Octet (SIO). The following information is contained in this field: 
• Originating Point Code 
• Destination Point Code 
• Signaling Link Selection 
• Service Information Octet 
• User Data 
The data should be formatted since it is sent to the network 
commencing with the SIO. The format depends on the point code size 
currently in use. 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
3.2 Protocol Indications from MTP3 to User Part 
Protocol primitive indications are issued by MTP3 to the appropriate User Part module(s) as configured on a 
per Service Indicator (SI) basis in the module configuration message (user_id field). These indications are 
in accordance with the published protocol specifications. 
Note: This section of the manual is applicable only to users intending to write their own User Part 
implementation. When using a User Part from the Dialogic® SS7 product range, the messages for 
this interface are received and processed by the User Part module and the user should consult 
the User Part documentation, which details the format of the messages that are sent from the 
User Part to the application. 
The User Part module is responsible for releasing all messages sent to it by MTP3. 
The following protocol indications are issued by MTP3 to the User Part: 
•API_MSG_RX_IND – MTP Transfer Indication 
•MTP_MSG_PAUSE – MTP Pause Indication 
•MTP_MSG_RESUME – MTP Resume Indication 
•MTP_MSG_STATUS – MTP Status Indication 
12 
Chapter 3 Message Reference 
3.2.1 API_MSG_RX_IND – MTP Transfer Indication 
Synopsis 
Message issued to the User Part by MTP3 to indicate reception of a Message Signal Unit (MSU) from the 
network. 
Message Format  
Message Header 
Field Name Meaning 
type API_MSG_RX_IND (0x8f01) 
id 
The use of this field is controlled by the setting of bit 0 in the 
ext_options field of the module configuration message. 
• If bit 0 of ext_options is set to 0, this field contains the User Part 
Reference (or Service Indicator). This is primarily useful for 
backward compatibility. 
• If bit 0 of ext_options is set to 1 (recommended for all new 
designs), this field provides an indication of the MTP Label Format 
used in the parameter area as follows: 
0 – MTP label contains 14-bit point codes 
1 – MTP label contains 24-bit point codes 
2 – MTP label contains 16-bit point codes 
src MTP3 module ID 
dst User part module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len Number of octets in MSU 
Parameter Area 
Offset Size Name 
0 len 
MSU data in binary format commencing with the Service Indicator 
Octet (SIO). The following information is contained in this field: 
• Originating Point Code 
• Destination Point Code 
• Signaling Link Selection 
• Service Information Octet 
• User Data 
The data is formatted since it was received from the network 
commencing with the SIO. The format depends on the point code size 
currently in use. 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
3.2.2 MTP_MSG_PAUSE – MTP Pause Indication 
Synopsis 
This primitive is issued by MTP3 to indicate to the user part the total inability of providing MTP service to the 
specified destination. 
Message Format  
Message Header 
Field Name Meaning 
type MTP_MSG_PAUSE (0x8403) 
id User Part Reference 
src MTP3 module ID 
dst User Part module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len 4 
Parameter Area 
Offset Size Name 
0 4 Affected destination point code 
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Chapter 3 Message Reference 
3.2.3 MTP_MSG_RESUME – MTP Resume Indication 
Synopsis 
This primitive is issued by MTP3 to indicate to the user the total ability of providing MTP service to the 
specified destination. 
Message Format  
Message Header 
Field Name Meaning 
type MTP_MSG_RESUME (0x8404) 
id User Part Reference 
src MTP3 module ID 
dst User Part module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len 4 
Parameter Area 
Offset Size Name 
0 4 Affected destination point code 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
3.2.4 MTP_MSG_STATUS – MTP Status Indication 
Synopsis 
This primitive is issued by MTP3 to indicate to the user part the partial inability of providing the MTP service 
to the specified destination. This may be due to signaling network congestion or due to unavailability of the 
remote user part. 
Message Format  
Message Header 
Field Name Meaning 
type MTP_MSG_STATUS (0x8405) 
id User Part Reference 
src MTP3 module ID 
dst User Part module ID 
rsp_req 0 
hclass 0 
status 
One of the following: 
• 1 = Remote User Unavailable 
• 2 = Signaling Network Congestion 
err_info 0 
len 6 or 8 
Parameter Area 
Offset Size Name 
0 4 Affected destination point code 
4 2 
Congestion status (if status = 0x02). 
This field is set to the current congestion level in the range 0 to 3, 
where 0 means no congestion and 3 means maximum congestion. 
Many networks use only a single level of congestion (that is, 1). 
6 2 
Unavailabilty cause (if status = Remote User Unavailable(1)) 
The unavailabilty cause may be one of the following: 
0 = Unknown 
1 = Unequipped User 
2 = Inaccessible User
16 
Chapter 3 Message Reference 
3.3 Layer Management Requests Sent to MTP3 
Protocol management primitives are sent from Layer Management to MTP3 in accordance with published 
MTP3 recommendations. The primitive names are closely aligned with the terminology used in ITU-T 
Recommendation Q.704. 
The layer management primitives allow the user to activate and deactivate signaling links, inhibit and 
uninhibit signaling links and request manual signaling link tests to be performed. 
The full list of layer management requests sent to MTP3 includes: 
•MTP_MSG_ACT_SL – Activate Link Set Request 
•MTP_MSG_DEACT_SL – Deactivate Link Set Request 
•MTP_MSG_INHIB_SL – Inhibit Signaling Link Request 
•MTP_MSG_UNINHIB_SL – Uninhibit Signaling Link Request 
•MTP_MSG_SLTC_START – Signaling Link Test Request 
•MTP_MSG_SRT_START – Start SRT Request (Japan) 
When sending layer management requests to MTP3, the user should ensure that the message is sent to the 
correct module_id, the correct instance of the MTP3 module (if multiple instances are in use – for example 
on different boards) and to the correct id. 
The default module_id for MTP3 is MTP_TASK_ID (0x22). However, host-based MTP3 is capable of running 
at different module IDs and this can be useful, for example, where multiple MTP3 modules are running on a 
single host. The user should ensure that the correct MTP3 module ID is written to the hdr->dst field of the 
message. 
Typically, it is appropriate to set the instance value to 0 using the GCT_set_instance() library function; 
however, if separate MTP3 instances are running on multiple boards, it is necessary to set the instance to 
the board_id on which the target MTP3 is running. 
Since links are identified in terms of linkset_id and link_ref, the hdr->id field for all layer management 
requests should be set to (linkset_id * 256) + link_ref. 
The hdr->rsp_req field may be used optionally to request a confirmation. If requested, the MTP3 module 
confirms acceptance of the primitive by sending the message back to its originator with bit14 cleared in the 
type field of the message. This mechanism is described in detail in the Software Environment Programmer’s 
Manual. 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
3.3.1 MTP_MSG_ACT_LS – Activate Link Set Request 
Synopsis 
This primitive is used by management to request the MTP3 module to activate all the links in a linkset. 
Note: The preferred mechanism of link activation is to use instead the MTP_MSG_ACT_SL message to 
activate individual signaling links. 
Message Format 
Description 
On receipt of this message, MTP3 attempts to activate all links in the link set. Receipt of a confirmation 
message does not imply that the link set is available for use, merely that MTP3 is attempting to bring the link 
into service. The user part should determine availability of a signaling relation using the MTP PAUSE and MTP 
RESUME indications. 
The user can determine the current state of individual signaling links on demand using the 
MTP_MSG_R_LK_STATUS message. 
Message Header 
Field Name Meaning 
type MTP_MSG_ACT_LS (0xc30e) 
id linkset_id * 256 
src Originating module ID 
dst MTP3 module ID 
rsp_req Sending layer’s bit set if response required 
hclass 0 
status 0 
err_info 0 
len 0
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Chapter 3 Message Reference 
3.3.2 MTP_MSG_DEACT_LS – Deactivate Link Set Request 
Synopsis 
This primitive is used by management to request the MTP3 module to deactivate all the links in a link set. 
Note: The preferred mechanism of link deactivation is to use instead the MTP_MSG_DEACT_SL 
message to deactivate individual signaling links. 
Message Format 
Description 
On receipt of this message, MTP3 attempts to deactivate all links in the link set. 
Message Header 
Field Name Meaning 
type MTP_MSG_DEACT_LS (0xc30f) 
id linkset_id * 256 
src Originating module ID 
dst MTP3 module ID 
rsp_req Sending layer’s bit set if response required 
hclass 0 
status 0 
err_info 0 
len 0 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
3.3.3 MTP_MSG_ACT_SL – Activate Signaling Link Request 
Synopsis 
This primitive is used by management to request the MTP3 module to activate the specified single link within 
a link set. 
Message Format 
Description 
On receipt of this message, MTP3 attempts to activate the specified link in the link set. Receipt of a 
confirmation message does not imply that the link is available for use, merely that MTP3 is attempting to 
bring the link into service. The user part should determine availability of a signaling relation using the MTP 
PAUSE and MTP RESUME indications. 
The user can determine the current state of a signaling link on demand using the MTP_MSG_R_LK_STATUS 
message. 
Message Header 
Field Name Meaning 
type MTP_MSG_ACT_SL (0xc30a) 
id (linkset_id * 256) + link_ref 
src Originating module ID 
dst MTP3 module ID 
rsp_req Sending layer’s bit set if response required 
hclass 0 
status 0 
err_info 0 
len 0
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Chapter 3 Message Reference 
3.3.4 MTP_MSG_DEACT_SL – Deactivate Signaling Link Request 
Synopsis 
This primitive is used by management to request the MTP3 module to deactivate the specified link within a 
link set. 
Message Format 
Description 
On receipt of this message, MTP3 attempts to deactivate the specified link in the link set. 
Message Header 
Field Name Meaning 
type MTP_MSG_DEACT_SL (0xc30b) 
id (linkset_id * 256) + link_ref 
src Originating module ID 
dst MTP3 module ID 
rsp_req Sending layer’s bit set if response required 
hclass 0 
status 0 
err_info 0 
len 0
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3.3.5 MTP_MSG_INHIB_SL – Inhibit Signaling Link Request 
Synopsis 
This primitive is used to request the MTP3 module to invoke management inhibiting on the specified link 
within a link set. 
Message Format 
Description 
On receipt of this message, MTP3 attempts to execute the Management Inhibiting function. For Management 
Inhibiting to succeed, there must be alternative available links to reach all destinations that can be accessed 
over the link. 
If the procedure is successful, MTP3 stops sending traffic over the link. 
If the procedure is not successful, the MTP3 module issues a message to management 
(MTP_MSG_INHIB_DENIED) indicating that the requested operation has failed. 
The user can determine the current state of a signaling link (including whether it is currently inhibited) on 
demand using the MTP_MSG_R_LK_STATUS message. 
Message Header 
Field Name Meaning 
type MTP_MSG_INHIB_SL (0xc310) 
id (linkset_id * 256) + link_ref 
src Originating module ID 
dst MTP3 module ID 
rsp_req Sending layer’s bit set if response required 
hclass 0 
status 0 
err_info 0 
len 0
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Chapter 3 Message Reference 
3.3.6 MTP_MSG_UNINHIB_SL – Uninhibit Signaling Link Request 
Synopsis 
This primitive is used to request MTP3 to remove the management inhibit condition for the specified link 
within a link set. 
Message Format 
Description 
On receipt of this message, MTP3 attempts to execute the Management UnInhibiting function. If the 
procedure is not successful, the MTP3 module issues a message (MTP_MSG_UNINHIB_FAIL) to management 
indicating that the requested operation has failed. 
The user can determine the current state of a signaling link (including whether it is currently inhibited) on 
demand using the MTP_MSG_R_LK_STATUS message. 
Message Header 
Field Name Meaning 
type MTP_MSG_UNINHIB_SL (0xc311) 
id (linkset_id * 256) + link_ref 
src Originating module ID 
dst MTP3 module ID 
rsp_req Sending layer’s bit set if response required 
hclass 0 
status 0 
err_info 0 
len 0 
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3.3.7 MTP_MSG_SLTC_START – Signaling Link Test Request 
Synopsis 
This primitive is used by management to manually request that a signaling link test be carried out in 
accordance with Q.707 on the specified link. 
Message Format 
Description 
Receipt of this message causes a Signaling Link Test to be carried out on the specified link. This test is in 
addition to the periodic test that is carried out automatically by the module (when configured accordingly). 
Typically, this message is not used when the periodic Signaling Link Test is enabled. 
Message Header 
Field Name Meaning 
type MTP_MSG_SLTC_START (0xc30c) 
id (linkset_id * 256) + link_ref 
src Originating module ID 
dst MTP3 module ID 
rsp_req Sending layer’s bit set if response required 
hclass 0 
status 0 
err_info 0 
len 0
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Chapter 3 Message Reference 
3.3.8 MTP_MSG_SRT_START – Start SRT Request (Japan) 
Synopsis 
Primitive issued by user (or management) to MTP3 requesting that a Japan-specific Signaling Route Test 
(SRT) be started on the specified signaling link. 
Message Format  
Description 
This primitive is issued by the user to request that a Signaling Route Test be started on the specified link 
towards the specified DPC. 
The MTP3 module generates the message and sends it to the network. It also starts an internal timer 
(Designated in JT-Q.707/NTT-Q.707 as Timer T10) while waiting for a response. If a successful response is 
not received, MTP3 generates a second SRT message, restarts the timer, and waits for the response. 
On receipt of the response, or failure of the SRT, MTP3 sends an MTP_MSG_SRT_RESULT message to the 
user indicating the result of the test. 
Message Header 
Field Name Meaning 
type MTP_MSG_SRT_START (0xc317) 
id (linkset_id * 256) + link_ref 
src Originating module ID 
dst MTP3 module ID 
rsp_req Sending layer’s bit set if response required 
hclass 0 
status 0 
err_info 0 
len 4 
Parameter Area 
Offset Size Name 
0 4 DPC – Destination Point Code for SRT message 
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3.4 Management Indications Issued by MTP3 to Layer Management 
Protocol management primitives are sent by MTP3 to Layer Management in accordance with published MTP3 
recommendations. The primitive names are closely aligned with the terminology used in ITU-T 
Recommendation Q.704. 
The full list of management indications that can be issued by MTP3 includes: 
•MTP_MSG_LINK_INHIB – Signaling Link Inhibited Indication 
•MTP_MSG_LINK_UNINHIB – Signaling Link Uninhibited Indication 
•MTP_MSG_INHIB_DENIED – Signaling Link Inhibit Denied Indication 
•MTP_MSG_UNINHIB_FAIL – Signaling Link Uninhibit Failure Indication 
•MTP_MSG_SRT_RESULT – SRT Result Indication (Japan) 
Messages are sent to the module_id configured as the Management module ID (mgmt_id) in the MTP3 
module configuration message (MTP_MSG_CONFIG), except in the case of the MTP_MSG_SRT_RESULT 
message where the result is sent to the module that originally requested the SRT. 
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Chapter 3 Message Reference 
3.4.1 MTP_MSG_LINK_INHIB – Signaling Link Inhibited Indication 
Synopsis 
This primitive is used to indicate to management that a link has been inhibited. 
Message Format 
Description 
This message is issued to management whenever a signaling link becomes inhibited. This may be due to 
local inhibiting or remote inhibiting. 
The user can determine the current state of a signaling link (including whether it is currently inhibited) on 
demand using the MTP_MSG_R_LK_STATUS message. 
Message Header 
Field Name Meaning 
type MTP_MSG_LINK_INHIB (0x8380) 
id (linkset_id * 256) + link_ref 
src MTP3 module ID 
dst Management module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len 0 
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3.4.2 MTP_MSG_LINK_UNINHIB – Signaling Link Uninhibited Indication 
Synopsis 
This primitive is used to indicate to management that a link has been uninhibited. 
Message Format 
Description 
This message is issued to management whenever a signaling link that has been inhibited becomes 
uninhibited. 
The user can determine the current state of a signaling link (including whether it is currently inhibited) on 
demand using the MTP_MSG_R_LK_STATUS message. 
Message Header 
Field Name Meaning 
type MTP_MSG_LINK_UNINHIB (0x8381) 
id (linkset_id * 256) + link_ref 
src MTP3 module ID 
dst Management module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len 0
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Chapter 3 Message Reference 
3.4.3 MTP_MSG_INHIB_DENIED – Signaling Link Inhibit Denied Indication 
Synopsis 
This primitive is used to indicate to management that an inhibit request has been denied. 
Message Format 
Description 
This message is issued to management whenever an attempt at inhibiting a signaling link fails. 
Message Header 
Field Name Meaning 
type MTP_MSG_INHIB_DENIED (0x8382) 
id (linkset_id * 256) + link_ref 
src MTP3 module ID 
dst Management module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len 0 
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3.4.4 MTP_MSG_UNINHIB_FAIL – Signaling Link Uninhibit Failure Indication 
Synopsis 
This primitive is used to indicate to management a failure to uninhibit a link. 
Message Format 
Description 
This message is issued to management whenever an attempt at uninhibiting a signaling link fails. 
Message Header 
Field Name Meaning 
type MTP_MSG_UNINHIB_FAIL (0x8383) 
id (linkset_id * 256) + link_ref 
src MTP3 module ID 
dst Management module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len 0
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Chapter 3 Message Reference 
3.4.5 MTP_MSG_SRT_RESULT – SRT Result Indication (Japan) 
Synopsis 
Primitive issued by MTP3 to notify the result of a (Japan-specific) Signaling Route test to the user. 
Message Format 
Description 
This primitive is issued by MTP3 to the user to convey the result of a Signaling Route Test (SRT) on the 
specified link. 
Note: The message is sent to the module_id that requested the original SRT (unlike other 
management indications that are sent to the management module established at configuration 
time). 
Message Header 
Field Name Meaning 
type MTP_MSG_SRT_RESULT (0x8321) 
id (linkset_id * 256) + link_ref 
src MTP3 module ID 
dst User module ID (Taken from original SRT request) 
rsp_req 0 
hclass 0 
status 
Result of the SRT: 
• 0 = Success 
• 1 = Failure (T10 Expiry) 
• 2 = Failure (Incorrect Test Pattern) 
• 3 = Failure (SRA received on wrong link) 
• 5 = Failure (SRT aborted internally) 
Other values reserved for additional failure reasons. 
err_info 0 
len 0 
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3.5 Management Requests Sent to MTP3 
In addition to the protocol primitives defined for the MTP3 to User Part interface and the MTP3 to Layer 
Management Interface, the MTP3 module supports a non-primitive interface for configuration and 
management. 
The non-primitive interface is used to support requests by the user for initialization, configuration and 
diagnostic purposes and to allow MTP3 to report protocol-based and software error events to the local 
system management module. 
This section describes the formats of all the messages used in the non-primitive interface. 
The full list of management requests available to send to MTP3 includes: 
•MTP_MSG_RESET – MTP3 Module Reset Request 
•MTP_MSG_CONFIG – MTP3 Module Configuration Request 
•MTP_MSG_CNF_LINKSET – Link Set Configuration Request 
•MTP_MSG_CNF_LINK – Signaling Link Configuration Request 
•MTP_MSG_CNF_ROUTE – Route Configuration Request 
•MTP_MSG_CNF_TIMERS – MTP3 Timer Configuration Request 
•MTP_MSG_TRACE_MASK – MTP3 Trace Mask Configuration Request 
•MTP_MSG_END_LINKSET – Link Set End Request 
•MTP_MSG_END_LINK – Signaling Link End Request 
•MTP_MSG_END_ROUTE – Route End Request 
•MTP_MSG_GARBAGE – Clear Garbage Request 
•MTP_MSG_UPDATE_L4 – Update Level 4 Request 
•MTP_MSG_R_LK_STATUS – Read Link Status Request 
•MTP_MSG_R_RT_STATUS – Read Route Status Request 
•MTP_MSG_R_SP_STATS – Read Signaling Point Statistics Request 
•MTP_MSG_R_RT_STATS – Read Route Statistics Request 
•MTP_MSG_R_LS_STATS – Read Link Set Statistics Request 
•MTP_MSG_R_LK_STATS – Read Link Statistics Request 
•GEN_MSG_MOD_IDENT – Read Module Version Request 
When sending layer management requests to MTP3, the user should ensure that the message is sent to the 
correct module_id, the correct instance of the MTP3 module (if multiple instances are in use, for example, 
on different boards) and to the correct id. 
The default module_id for MTP3 is MTP_TASK_ID (0x22). However, host-based MTP3 is capable of running 
at different module IDs and this can be useful for example where multiple MTP3 modules are running on a 
single host. The user should ensure that the correct MTP3 module ID is written to the hdr->dst field of the 
message. 
Typically, it is appropriate to set the instance value to 0 using the GCT_set_instance() library function. 
However, if separate MTP3 instances are running on multiple boards, it is necessary to set the instance to 
the board_id on which the target MTP3 is running. 
Care should be taken to correctly populate the hdr->id field as different messages require different 
parameters. In particular, messages relating to links and link sets should be expressed as: (linkset_id * 
256) + link_ref. 
The hdr->rsp_req field may optionally be used to request a confirmation. If requested, the MTP3 module 
confirms acceptance of the primitive by sending the message back to its originator with bit14 cleared in the 
type field of the message. This mechanism is described in detail in the Software Environment Programmer’s 
Manual. Messages intended to read back information from MTP3 must use this mechanism, otherwise MTP3 
will not respond to the request. 
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Chapter 3 Message Reference 
The MTP3 module returns a confirmation message containing a status value taken from the following table: 
Mnemonic Value Description 
SUCCESS 0 Success 
MTP_BAD_PRIM 0x51 Invalid or unexpected message 
MTP_BAD_ID 0x58 Invalid ID in header 
MTP_GARBAGE 0x65 Failed to clear garbage queue, (in which case, it is necessary to 
send another MTP_MSG_GARBAGE message at a later time)
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3.5.1 MTP_MSG_RESET – MTP3 Module Reset Request 
Synopsis 
Message used to initialize or to re-initialize the MTP3 module. 
Message Format 
Description 
This message is used to initialize the MTP3 module. All messages received by the module before the first 
MTP_MSG_RESET message are discarded. Subsequent MTP_MSG_RESET requests cause all system 
resources requested by the MTP3 module to be released and the module to be reset to its idle state. 
Whenever the module is reset, it must subsequently be configured (using the MTP_MSG_CONFIG, 
MTP_MSG_CNF_LINKSET, MTP_MSG_CNF_LINK and MTP_MSG_CNF_ROUTE requests) before attempting to 
activate signaling links. 
Message Header 
Field Name Meaning 
type MTP_MSG_RESET (0x7300) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 0 
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Chapter 3 Message Reference 
3.5.2 MTP_MSG_CONFIG – MTP3 Module Configuration Request 
Synopsis 
This message is used to configure the MTP3 module. It must be issued after an MTP_MSG_RESET request 
and before any MTP_MSG_CNF_LINKSET requests are issued. 
Message Format  
Parameters 
•options 
This field is a 16-bit field used to convey various run-time options to the module, as shown in the 
following table (refer also to the ext_options field that conveys additional run-time options): 
Message Header 
Field Name Meaning 
type MTP_MSG_CONFIG (0x7303) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 40 
Parameter Area 
Offset Size Name 
0 2 options - Run-time options 
2 1 module_id – Reserved, should be set to 0 
3 1 mngt_id- Module ID of management module 
4 2 tx_pool_size - Transmit pool size 
6 2 timer_res – Reserved, must be set to 1 
8 4 point_code – Default Local Point code for MTP3 
12 2 num_links - Total number of links 
14 2 num_linksets Total number of link sets 
16 1 ssf – Default Sub-Service field value 
17 5 Reserved for future use, must be set to zero 
22 2 ext_options – Extended run-time options 
24 16 user_id - Module ID for each of the 16 user parts 
Bit Meaning 
0 
This bit is set to disable the discrimination function. Typically, only MSUs with a destination 
point code equal to the point code of the signaling point are distributed to the user parts. 
However, if this bit is set, ALL received MSUs are passed to the user parts. 
• 0 – Normal setting, message discrimination enabled as per protocol specification 
• 1 – Disable discrimination 
1 
This bit is set to disable the Sub-Service Field (SSF) discrimination function. Typically, only 
MSUs with a SSF matching the SSF supplied in the configuration message are accepted for 
distribution to the user parts. However, if this bit is set, the SSF is not examined by the 
discrimination function. 
• 0 – Normal setting, SSF discrimination enabled as per protocol specification 
• 1 – Disable SSF discrimination 
2 
This bit is used to control the buffer format used by MTP3 for MTP Transfer Requests and 
Indications. This field should be set as follows, depending on the MTP3 implementation in 
use: 
• For Host-based MTP3, set this bit to 1 
• For SS7HD-based MTP3 (ss7.dc4), set this bit to 1 
• For SSPCI4 / SPCI2S based MTP3 (ss7.dc3), set this bit to 0 
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•mngt_id 
The module identifier of the management module to which trace messages and event notifications are 
sent. 
•tx_pool_size 
This parameter is used to set the size of an internal pool of buffers used for generation of MTP3 
messages for transmission to the network. This parameter should be set to the following fixed values 
depending on the specific MTP3 implementation in use: 
•timer_res 
This parameter is reserved for future use and should always be set to 1. 
•point_code 
The default local point code of the signaling point (SP) which should lie in the range of 0 to 16383 (for 
14-bit point codes) and in the range of 0 and 16777215 (for 24-bit point codes). 
The user can specify the local point code on a per-link set basis if required, allowing MTP3 to connect to 
more than one network where each network uses a different point code numbering scheme. This is 
achieved using the local_pc parameter in the link set configuration message which overrides the 
point_code parameter. 
3 
This bit is used to determine the behavior when an MSU is received from the network for a 
User Part that is not currently configured. The module can either discard the message with 
no further action or issue a User Part Unavailable message back to the network. 
• 0 – Discard the message 
• 1 – Issue a User Part Unavailable message 
5 
This bit is set to disable operation of Management Inhibiting functionality. When set, any 
attempt to inhibit a signaling link (either locally or remotely is denied). When clear, 
Management Inhibiting Functionality operates normally. 
• 0 – Normal setting, enable Management Inhibiting support 
• 1 – Disable Management Inhibiting support 
6 
This bit is used to disable the Signaling Route Set Test mechanism. Typically, when a remote 
signaling point becomes unavailable, a periodic Signaling Route Set Test message is issued in 
order to ensure that subsequent availability of the signaling point is detected. Setting this bit 
allows the sending of this message to be disabled. 
• 0 – Normal setting, enable Signaling Route Set Test 
• 1 - Disable Signaling Route Set Test 
8 
This bit is used to select between ITU and ANSI operation. 
• 0 - ITU (CCITT) operation 
• 1 - ANSI operation 
NOTE: For correct ANSI operation, the user should always set bits 9, 10 and 11, as well as 
bit8. 
9 
This bit is used to select between 14/16-bit point codes and 24-bit point codes. It must 
always be set to 1 when the ANSI option is selected. 
• 0 – Use 14-bit or 16-bit point codes (depending on the setting of ext_options bit 4) 
• 1 – Use 24-bit point codes 
10 
This bit is used to enable Multiple Congestion States operation. It should always be set when 
ANSI option is selected. 
• 0 - Disable Multiple Congestion States 
• 1 - Enable Multiple Congestion States 
11 
This bit is used to enable Multiple Message Priority operation. It should always be set when 
ANSI option is selected. 
• 0 - Disable Multiple Message Priority operation 
• 1 - Enable Multiple Message Priority operation 
Others All other bits are reserved for future use and must be set to zero. 
MTP3 Implementation tx_pool_size 
Host-Based MTP3 0 
SS7HD (ss7.dc4) 0 
SPCI4 / SPCI2S (ss7.dc3) 20 
Bit Meaning
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Chapter 3 Message Reference 
•num_links 
The total number of signaling links to be supported by the signaling point. This is a run-time setting and 
should be in the range of 1 and the maximum number of links supported by the implementation. If it is 
known at configuration time that the system requires less than the maximum number of links, 
num_links should be set accordingly to achieve slight performance benefits. 
•num_linksets 
The number of link sets to be supported by the signaling point. This is a run-time setting and should be 
in the range of 1 and the compile-time maximum number of link sets. If it is known at configuration time 
that the system requires less than the maximum number of link sets, num_linksets should be set 
accordingly to achieve slight performance benefits. 
•ssf 
The default value to be used in the Sub-Service Field (SSF) of all Message Signal Units (MSUs) 
originating from within the MTP3 module. The valid range is 0 to 15. This parameter is also used in the 
discrimination function. The user can override this parameter by specifying a per-link set SSF value if 
required. 
Note: When using ANSI operation, the two least significant bits of the ssf parameter must always be 
set to 1 for correct operation. 
•user_id 
An array of module identifiers for each of the 16 possible User Parts. These are the modules to which the 
MTP3 module distributes received messages for this signaling point. The value for any User Parts not 
implemented should be set to zero. The values for the user parts handled by MTP3 (0, 1 and 2) is 
typically set to zero to allow these messages to be handled internally by MTP3.  
•ext_options 
This field is used in addition to the options field to convey “extended” run-time options to the module as 
shown in the following table: 
user_id Suggested Setting 
user_id[0] This parameter is typically set to zero so that Signaling Network Management 
messages are processed by MTP3. 
user_id[1] This parameter is typically set to zero so that Signaling Network Test & 
Maintenance messages are processed by MTP3. 
user_id[2] This parameter is typically set to zero so that ANSI format Signaling Network 
Test & Maintenance messages are processed by MTP3. 
user_id[3] If SCCP is in use, this parameter should be set to the module ID of the SCCP 
module. Otherwise, it should be set to zero. 
user_id[4] If TUP is in use, this parameter should be set to the module ID of the TUP module. 
Otherwise, it should be set to zero. 
user_id[5] If ISUP is in use, this parameter should be set to the module ID of the ISUP 
module. Otherwise, it should be set to zero. 
user_id[x] If Service Indicator x is in use, this parameter should be set to the module ID of the 
appropriate User Part module. Otherwise, it should be set to zero. 
Bit Meaning 
0 
This bit is used to control the usage of the hdr->id field of MTP Transfer Indication 
messages. 
• 0 – The id field contains the User Part Reference (or Service Indicator), this is 
primarily useful for backward compatibility. 
• 1 - The id field provides an indication of the MTP Label Format used in the parameter 
area. This is the recommended setting for all new designs. 
1 
This bit controls how received Transfer Controlled and Signaling Route Set Congestion 
Messages that are not destined for the local point code are processed. 
• 0 – Normal operation; messages are discarded. 
• 1 – Messages are sent to fixed module_id 0x0a. 
2 
This bit controls MTP3 operation on detection of Remote Processor Outage (RPO). 
• 0 – On detection of RPO, the signaling link is taken out of service and restoration 
commences. This setting is useful for backward compatibility. 
• 1 – Normal setting; RPO is handled in accordance with the ITU-T 1992 (and later) 
recommendations. 
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3 
This bit is used when MTP3 is operating in dual mode to control which bit of the Sub-Service 
Field is used to flag messages that have been received by one MTP3 and are being conveyed 
to the dual module over the inter-MTP3 link set. 
• 0 – Normal setting; sub-Service Field bit 2 is modified. 
• 1 – Alternative setting; sub-Service Field bit 0 is modified. 
4 
This bit is used to select between 14-bit point codes and 16-bit point codes. It is only 
significant when 24-bit point codes are NOT selected (refer to the options parameter). 
• 0 – Use 14-bit point codes 
• 1 – Use 16-bit point codes 
5 
This bit is used to activate Japan-specific MTP3 operation. 
• 0 – Normal setting; Japan-specific functionality is disabled 
• 1 – Japan-specific functionality is enabled 
NOTE: For correct Japan-specific operation, the user should also select 16-bit point codes 
by setting bit 4 as well as bit 5. 
6 
This bit is used to control the handling of received Route Set Test Messages. It should only be 
set if bit 1 is also set. 
• 0 – Normal operation; Route Set Test messages processed by MTP3 
• 1 – Route Set Test Messages not processed by MTP3, but passed directly to 
module_id0x0a 
Others All other bits are reserved for future use and must be set to zero. 
Bit Meaning
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Chapter 3 Message Reference 
3.5.3 MTP_MSG_CNF_LINKSET – Link Set Configuration Request 
Synopsis 
This message is used to configure each link set within the signaling point. It must be issued after a 
MTP_MSG_CONFIG request and before any MTP_MSG_CNF_LINK requests are issued for links within the link 
set. 
This message may also be used to modify existing link sets. If the number of links in the link set needs to be 
increased or decreased, then this message may be used with the MTPLSF_RECFG option (bit 2 of the flags 
field). First, all links in the link set must be ended. Then, with the reconfigure option set and all other 
parameters unchanged from when the link set was first configured, the new number of links in the link set 
may be set. 
Message Format  
Parameters 
•adj_pc 
The adjacent point code, that is, the point code of the signaling point at the other end of all signaling 
links within the link set. 
•target_cnt 
This field is reserved for future use and should always be set to zero. 
•num_links 
The number of signaling links that are allocated to the link set. 
Note: Each of these links requires its own configuration message be issued to the module. 
•sls_bits 
The number of bits from the SLS field to use for load sharing. This should range from 0 to 4. The least 
significant bits of the SLS are used for load sharing. Typically, this should be set to 4. 
Message Header 
Field Name Meaning 
type MTP_MSG_CNF_LINKSET (0x7310) 
id linkset_id * 256 
src Sending module ID 
dst MTP3 module ID 
rsp_req used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 16 
Parameter Area 
Offset Size Name 
0 4 adj_pc - Point code of the adjacent signaling point 
4 2 target_cnt- Reserved; set to zero 
6 2 num_links- Number of links allocated to the link set 
8 2 flags - Run-time options 
10 1 sls_bits - Number of sls bits to use for load sharing within the link set 
11 1 ssf – Per link set Sub-Service-Field 
12 4 local_pc – Per-link set local point code 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
•ssf 
The value to be used in the Sub-Service Field (SSF) of all Message Signal Units (MSUs) related to this 
link set originating from within the MTP3 module. The valid range is 0 to 15. The parameter is also used 
in the discrimination function. 
This field allows the user to specify the SSF on a per-link set basis (instead of using the default SSF 
specified in the global configuration message). If the user wishes to specify a per-link set SSF value, bit 
1 of the flags field in this message must also be set. 
Note: When using ANSI operation, the two least significant bits of the ssf parameter must always be 
set to 1 for correct operation. 
•local_pc 
The local point code of the signaling point as seen by the network connected to this link set. This should 
lie in the range of 0 to 16383 (for 14-bit point codes) and in the range of 0 and 16777215 (for 24-bit 
point codes). 
This field allows the user to specify the local point code on a per-link set basis (instead of using the 
default point_code specified in the global configuration message). When a per-link set local point code 
is specified, the user must also set bit 0 in the flags field of the link set configuration message. 
•flags 
This field is a 16-bit field containing run-time configuration options for the link set as follows: 
Bit Meaning 
0 
This bit is used to determine whether or not the user has supplied a per-link set local 
point code for this link set. If not, the point_code parameter from the global 
configuration message is used instead. 
• 0 - Use the per module (default) point_code as the local point code 
• 1 - Use the local_pc parameter as the local point code for this link set 
1 
This bit is used to determine whether or not the user has supplied a per-link set sub- 
service-field (SSF) for this link set. If not, the ssf parameter from the global 
configuration message is used instead. 
• 0 - Use the per-module (default) SSF for this link set 
• 1 - Use the per-link set ssf parameter for this link set 
2 
This bit must be set to 1 when the message is being used to modify the existing link set 
configuration. 
• 0 – Normal setting; used when link set is first configured 
• 1 – Reconfiguration; used when the link set is being modified 
15 
This bit is used to indicate that the link set is the inter-MTP3 link set connecting 
together the two halves when operating in a dual MTP3 configuration. 
• 0 – Normal setting 
• 1 – This link set is the inter-MTP3 link set in a dual configuration 
Other bits All other bits are reserved for future use and must be set to zero. 
40 
Chapter 3 Message Reference 
3.5.4 MTP_MSG_CNF_LINK – Signaling Link Configuration Request 
Synopsis 
This message is used to configure each link within the signaling point. It must be issued after the 
MTP_MSG_CNF_LINKSET request that configures the link set in which the link exists. 
Message Format  
Parameters 
•link_id 
The link identifier used to uniquely identify the link within the MTP3 module. The valid range is from 0 to 
one less than the number of links supported. 
•slc 
The Signaling Link Code (SLC) that distinguishes this link from others in the link set. This is typically the 
same as link_ref. 
•lower 
The module ID of the level 2 module for this link. Typically, this is set to the MTP2 moduleID. 
•l2_llid 
The logical link ID of the signaling link within the level 2 module. This is the value that is used in the id 
field of messages issued by MTP3 to MTP2. 
•l2_inst 
The instance number of the MTP2 module. This is used to determine to which MTP2 module messages for 
this link should be sent. This allows for multiple instances of the MTP2 module, each running on a 
separate board. 
Message Header 
Field Name Meaning 
type MTP_MSG_CNF_LINK (0x7311) 
id (linkset_id * 256) + link_ref 
src Sending module ID 
dst MTP3 module ID 
rsp_req used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 16 
Parameter Area 
Offset Size Name 
0 2 link_id - link_id of the link within the SP 
2 1 slc- Signaling link code for the link (SLC) 
3 1 lower- Module ID of lower layer (for example, MTP2) 
4 2 l2_llid - Logical link ID of the level 2 link 
6 2 flags - Link-specific flags (see below) 
8 2 l2_inst - Level 2 module instance number 
10 6 Reserved for future use; must be set to zero. 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
•flags 
This field is a 16-bit field containing run-time configuration options that may be used to modify the 
operation of the signaling link depending on local requirements. The following flags are defined: 
Bit Meaning 
0 
This bit is set to override automatic internal selection of the proving period during link 
alignment. 
• 0 – Normal setting; proving period is in accordance with the SS7 protocol 
• 1 – Proving period is controlled by bit 3 as detailed below 
1 
This bit is set to cause a Signaling Link Test to be successfully carried out on link 
activation before marking the link as available. If it is not set, the link is marked as 
available as soon as the link is IN SERVICE at level 2. 
• 0 - Do not carry out SLT on activation 
• 1 - Carry out SLT on activation 
2 
This bit is set to cause a periodic Signaling Link Test to be carried out while a link is in 
service. In the event that the test fails, the link is marked as unavailable and 
restoration commences. This option is only valid if bit 1 is also set. 
• 0 - Do not conduct periodic SLT 
• 1 - Conduct periodic SLT 
3 
This bit is only significant when bit 0 is set to cause fixed selection or for Normal or 
Emergency proving periods during link alignment. 
• 0 – Always use Emergency proving period during link alignment 
• 1 – Always use Normal proving period during link alignment 
Other bits All other bits are reserved for future use and must be set to zero. 
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Chapter 3 Message Reference 
3.5.5 MTP_MSG_CNF_ROUTE – Route Configuration Request 
Synopsis 
This message is used to add a route to the MTP3 routing table. It should be issued once for each route. The 
message specifies which link set or link sets are to be used to reach the destination point code and whether 
or not to invoke load sharing across the link sets. 
When modifying an existing Route, different link sets may be configured and the LSH option may be enabled 
or disabled. 
Message Format  
Parameters 
•dpc 
The destination point code, that is, the point code of the remote signaling point for which this message is 
configuring routing data. It may be either an adjacent point code or a point code accessible via an 
adjacent Signaling Transfer Point (STP). 
Note: A route configuration message must be issued for each adjacent signaling point, even if no user 
part messages are sent to the adjacent signaling point. 
•norm_ls 
The linkset_id of the normal link set used to reach the specified destination. This may be any of the 
following options: 
—a) The only link set used to reach the destination. 
—b) The preferred link set used to reach the destination. 
—c) One of a pair of links sets forming a combined link set. 
In the latter two cases, a second link set must also be specified. 
•second_ls 
The linkset_id of an optional second link set used to reach the specified destination. This may be either 
of the following options: 
—a) The secondary link set used to reach the destination only on failure of the preferred link set. 
—b) One of a pair of link sets forming a combined link set over which load sharing takes place. 
When a second link set is specified, the user must also set bit 0 in the flags field of this message. 
Message Header 
Field Name Meaning 
type MTP_MSG_CNF_ROUTE (0x7312) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 32 
Parameter Area 
Offset Size Name 
0 4 dpc - Destination Point Code 
4 1 norm_ls - linkset_id of normal link set 
5 1 second_ls - linkset_id of optional link set 
6 2 Reserved for future use, must be set to zero. 
8 2 flags - run time options (see below) 
10 2 up_enable - User part enable mask 
12 20 Reserved for future use, must be set to zero.
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
•up_enable 
A 16-bit field used to identify the user parts that are supported over this route. The bits are labelled 0 to 
15 and for each user part supported, the bit corresponding to the Service Indicator for that user part 
should be set. For example, to support just ISUP messages, the ISUP Service Indicator is 5; therefore, 
bit 5 should be set. Consequently, a up_enable value of 0x0020 is appropriate in this case. 
•flags 
A 16-bit field containing run-time configuration options for the route as follows: 
Bit Meaning 
0 
This bit is used to determine whether or not the user has supplied a second link set 
parameter for this route. 
• 0 - Only a single link set is specified 
• 1 - Two link sets are specified for this route 
1 
This bit is used to determine whether or not to load share messages across the two link 
sets. It is only used when two link sets are specified for the route. When set, the MTP3 
module load shares messages for the destination equally across each of the two 
specified link sets. Otherwise, the MTP3 module considers the normal link set to be the 
preferred link set and only uses the second link set in the event of failure of the normal 
link set. 
• 0 – Disable load sharing, that is, use preferred and secondary link sets 
• 1 – Enable load sharing across the two link sets 
2 
This bit can be used to mark the route as a “default” route that is used by MTP3 to 
carry traffic to any destinations that are not explicitly configured using route 
configuration messages. 
• 0 – Normal operation 
• 1 – This route is a default route permitted to carry traffic for any unknown DPC 
3 
This bit is used in conjunction with bit 2 to control the behavior of default routes. 
• 0 – Normal operation. If the route is a default route, it is only used to carry traffic 
when the configured dpc is determined accessible in accordance with normal 
signaling route accessibility procedures. 
• 1 – Pseudo DPC operation. The route is considered available to carry traffic as soon 
as either link set is accessible. MTP3 does not generate Route Set Test messages or 
expect Transfer Allowed messages for this “default” route. 
4 
This bit is used to control the behavior in the event that the destination becomes 
inaccessible over all link sets within the route. 
• 0 – Normal operation. The destination is declared inaccessible and any buffered 
messages are discarded. 
• 1 – An internal 10 second timer is run during which time messages continue to be 
buffered (subject to capacity), allowing for potential recovery of the route. If the 
route recovers during this time, buffered messages are transmitted. On expiry of 
the timer, any buffered messages are discarded. 
5 
This bit allows the user to disable the Route Set Test (RST) procedure for this route. 
0 – Normal operation; generate RST messages 
1 – Disable RST; do not generate RST messages 
15 
This bit must be set to 1 when the message is being used to modify the existing route 
configuration. 
• 0 – Normal setting; used when the route is first configured 
• 1 – Reconfiguration; used when the route is being modified 
Other bits All other bits are reserved for future use and must be set to zero. 
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Chapter 3 Message Reference 
3.5.6 MTP_MSG_CNF_TIMERS – MTP3 Timer Configuration Request 
Synopsis 
This message is used to configure the MTP timer values to values other than their default values. The 
message can be issued at any time after the MTP_MSG_CONFIG message. The new timer values take effect 
when the timer is next started. 
Message Format  
Message Header 
Field Name Meaning 
type MTP_MSG_CNF_TIMERS (0x7317) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 64 
Parameter Area 
Offset Size Name 
0 2 version; must be set to zero 
2 2 Timer T1 
4 2 Timer T2 
6 2 Timer T3 
8 2 Timer T4 
10 2 Timer T5 
12 2 Timer T6 
14 2 Timer T7 
16 2 Timer T8 
18 2 Timer T9 
20 2 Timer T10 
22 2 Timer T11 
24 2 Timer T12 
26 2 Timer T13 
28 2 Timer T14 
30 2 Timer T15 
32 2 Timer T16 
34 2 Timer T17 
36 2 Timer T18 
38 2 Timer T19 
40 2 Timer T20 (ITU) 
42 2 Timer T21 
44 2 Timer T22 (ITU) or T20 (ANSI) 
46 2 Timer T23 (ITU) or T21 (ANSI) 
48 2 Timer T24 
Offset Size Name 
50 2 SLTC Timer T1 
52 2 SLTC Timer T2 
54 2 Timer T101 
56 8 Reserved for future use, must be set to zero.
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3.5.7 MTP_MSG_TRACE_MASK – MTP3 Trace Mask Configuration Request 
Synopsis 
Set the MTP3 module’s event masks for tracing (input and output) messages to the management module on 
a per-primitive basis and reporting Q.752 events on a per-event basis. The fields in the masks are defined 
below. 
Message Format  
Parameters 
•op_evt_mask 
The output event trace mask. This is a 32-bit value with bits set to 1 to cause a trace message to be sent 
to the system management module whenever a message is issued by MTP3 for the events indicated. 
 31     30     29     28     27     26     25     24 
+------+------+------+------+------+------+------+------+ 
|   0  |   0  |   0  |   0  |   0  |   0  |   0  |   0  | 
|      |      |      |      |      |      |      |      | 
+------+------+------+------+------+------+------+------+ 
 23     22     21     20     19     18     17     16 
+------+------+------+------+------+------+------+------+ 
|   0  |   0  |   0  |FLUSH | CONT |MSGFOR|UNINH_|INHIB_| 
|      |      |      |      |      |USP   |FAIL  |DENIED| 
+------+------+------+------+------+------+------+------+ 
 15     14     13     12     11     10      9      8 
+------+------+------+------+------+------+------+------+ 
|LINK_ |LINK_ |LPO_  |LPO   |RTVL_ |RTV_  |L2_   |L2_EM | 
|UNINH |INHIB |RECOV |      |REQ   |BSNT  |NO_EM |      | 
+------+------+------+------+------+------+------+------+ 
 7      6      5      4      3      2      1      0 
+------+------+------+------+------+------+------+------+ 
|L2_   |L2_   |TX_REQ|   0  |STATUS|RESUME|PAUSE |TFR_  | 
|STOP  |START |      |      |      |      |      |IND   | 
+------+------+------+------+------+------+------+-----------+ 
where: 
—FLUSH = Flush Request 
—CONT = Continue Request 
—MSGFORUSP = Message for unknown destination point code indication 
—UNINH_FAIL = MTP Uninhibit Failed Indication 
—INHIB_DENIED = MTP Uninhibit Denied Indication 
—LINK_UNINH = MTP Link Uninhibited Indication 
Message Header 
Field Name Meaning 
type MTP_MSG_TRACE_MASK (0x5316) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 24 
Parameter Area 
Offset Size Name 
0 4 op_evt_mask - Output event trace mask 
4 4 ip_evt_mask - Input event trace mask 
8 4 q791_evt_mask - Q.752 (previously Q.791) event trace mask 
12 12 Reserved for future use; must be set to zero. 
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Chapter 3 Message Reference 
—LINK_INHIB = MTP Link Inhibited Indication 
—LPO_RECOV = Local Processor Recovered Indication 
—LPO = Local Processor Outage Indication 
—RTVL_REQ = Retrieval Request 
—RTV_BSNT = Retrieve BSNT Request 
—L2_NO_EM = Emergency Ceases Indication 
—L2_EM = Emergency Indication 
—L2_STOP = Stop Request 
—L2_START = Start Request 
—TX_REQ = Message for Transmission Request 
—STATUS = MTP Status Indication 
—RESUME = MTP Resume Indication 
—PAUSE = MTP Pause Indication 
—TFR_IND = MTP Transfer Indication 
•ip_evt_mask 
The input event trace mask. This is a 32-bit value with bits set to 1 to cause a trace message to be sent 
to the system management module on receipt of messages indicating the events shown. 
 31     30     29     28     27     26     25     24 
+------+------+------+------+------+------+------+------+ 
|   0  |   0  |   0  |   0  |   0  |   0  |   0  |   0  | 
| |      |      |      |      |      | 
+------+------+------+------+------+------+------+------+ 
 23     22     21     20     19     18     17     16 
+------+------+------+------+------+------+------+------+ 
|   0  |FLUSH |RTVL_ |BSNT_ |LINK_ |LINK_ |UNINH_|INHIB_| 
|      |ACK   |NOTPOS|NOTRTV|UNCONG|CONG  |LINK  |LINK  | 
+------+------+------+------+------+------+------+------+ 
 15     14     13     12     11     10      9      8 
+------+------+------+------+------+------+------+------+ 
|DEACT_|ACT_  |   0  |START_|DEACT_|ACT_  |RTVL_ |RTVD_ | 
|LKSET |LKSET |      |SLTC  |LINK  |LINK  |CMPL  |MSG   | 
+------+------+------+------+------+------+------+------+ 
 7      6      5      4      3      2      1      0 
+------+------+------+------+------+------+------+------+ 
|BSNT_ |L2_RPO|L2_RPO|L2_OUT|L2_IN |TM_EXP|RX_IND|TFR_  | 
|IND   |_CLRD |      |_SVC  |_SVC  |      |      |REQ   | 
+-------+------+------+------+------+------+------+-----------+ 
where: 
—FLUSH_ACK = Flush Ack Indication 
—RTVL_NOTPOS = Retrieval Not Possible Indication 
—BSNT_NOTRTV = BSNT Not Retrievable Indication 
—LINK_UNCONG = Link Uncongested Indication 
—LINK_CONG = Link Congested Indication 
—UNINH_LINK = Uninhibit Link Request 
—INHIB_LINK = Inhibit Link Request 
—DEACT_LKSET = Deactivate Link Set Request 
—ACT_LKSET = Activate Link Set Request 
—START_SLTC = Start Signaling Link Test Request 
—DEACT_LINK = Deactivate Link Request 
—ACT_LINK = Activate Link Request 
—RTVL_CMPL = Retrieval Complete Indication 
—RTVD_MSG = Retrieved Message Indication 
—BSNT_IND = BNST Indication 
—L2_RPO_CLRD = Remote Processor Outage Cleared Indication 
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Dialogic® SS7 Protocols MTP3 Programmer’s Manual Issue 7 
—L2_RPO = Remote Processor Outage Indication 
—L2_OUT_SVC = Out Of Service Indication 
—L2_IN_SVC = In Service Indication 
—TM_EXP = Timer Expiry Indication 
—RX_IND = Received Message Indication 
—TFR_REQ = MTP Transfer Request 
•q791_evt_mask 
The event mask that determines which Monitoring and Measurement events are generated by MTP3. This 
is a 32-bit value with bits set to 1 to cause protocol events to be reported to management in accordance 
with ITU-T Q.752 (previously Q.791). When enabled, events are reported using the 
MGT_MSG_MTP_EVENT message. 
Note: Typically these events should be enabled for normal operation; take care not to inadvertently 
clear these fields when sending this message to MTP3. 
 31     30     29     28     27     26     25     24 
+------+------+------+------+------+------+------+------+ 
|   0  |   0  |   0  |   0  |   0  |   0  |   0  |   0  | 
|      |      |      |      |      |      |      |      | 
+------+------+------+------+------+------+------+------+ 
 23     22     21     20     19     18     17     16 
+------+------+------+------+------+------+------+------+ 
|   0  |   0  |   0  |   0  |   0  |   0  |   0  |AJSP_ | 
|      |      |      |      |      |      |      |OK    | 
+------+------+------+------+------+------+------+------+ 
 15     14     13     12     11     10      9      8 
+------+------+------+------+------+------+------+------+ 
|AJSP_ |DEST_ |DEST_ |TFA_  |TFP_  |LS_   |LS_   |CONG_ | 
|LOST  |OK    |LOST  |SENT  |SENT  |OK    |LOST  |DIS   | 
+------+------+------+------+------+------+------+------+ 
 7      6      5      4      3      2      1      0 
+------+------+------+------+------+------+------+------+ 
|CONG_ |CONG  |RPO_  |RPO   |REST  |CB    |CO    |  0   | 
|CLR   |      |CLR   |      |      |      |      |      | 
+------+------+------+------+------+------+------+------+ 
where: 
—AJSP_OK = Adjacent SP accessible 
—AJSP_LOST = Adjacent SP inaccessible 
—DEST_OK = Destination available 
—DEST_LOST = Destination unavailable 
—TFA_SENT = Transfer Allowed broadcast 
—TFP_SENT = Transfer Prohibited broadcast 
—LS_OK = Link Set recovered 
—LS_LOST = Link Set failure 
—CONG_DIS = MSU(s) discarded due to congestion 
—CONG_CLR = Congestion cleared 
—CONG = Signaling link congested 
—RPO_CLR = Remote processor outage cleared 
—RPO = Remote processor outage 
—REST = Link restoration commenced 
—CB = Changeback 
—CO = Changeover 
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Chapter 3 Message Reference 
3.5.8 MTP_MSG_END_LINKSET – Link Set End Request 
Synopsis 
Message sent to MTP3 to remove a link set that has previously been configured. Prior to ending a link set, all 
signaling links must also be removed and all routes using the link set must be ended or modified not to use 
it. 
Message Format 
3.5.9 MTP_MSG_END_LINK – Signaling Link End Request 
Synopsis 
Message sent to MTP3 to remove a signaling link that has previously been configured. 
Message Format 
Message Header 
Field Name Meaning 
type MTP_MSG_END_LINKSET (0x7323) 
id linkset_id * 256 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 0 
Message Header 
Field Name Meaning 
type MTP_MSG_END_LINK (0x7324) 
id (linkset_id * 256) + link_ref 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 0
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3.5.10 MTP_MSG_END_ROUTE – Route End Request 
Synopsis 
Message sent to MTP3 to remove a route from the routing table. 
Message Format  
Parameters 
•dpc 
The destination point code for which the route is being removed. 
Message Header 
Field Name Meaning 
type MTP_MSG_END_ROUTE (0x7325) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 0 
Parameter Area 
Offset Size Name 
0 4 dpc – Destination point code 
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Chapter 3 Message Reference 
3.5.11 MTP_MSG_GARBAGE – Clear Garbage Request 
Synopsis 
This message is used to clear the MTP3 module’s garbage queue. When the module is reset, it may not be 
possible to release all frames from the transmit pool as some may still require confirmation from the lower 
layers. When this happens, the frame is appended to the modules, garbage queue and a message is sent to 
management. The MTP_MSG_GARBAGE request can be used by management to attempt to clear the 
garbage queue, freeing the memory for use by other modules. 
Note: The garbage queue is only used on certain board-based MTP3 implementations (that is, SPCI4, 
and SPCI2S). It is not used for host-based implementations or on the Dialogic® SS7HD board. 
Message Format 
Message Header 
Field Name Meaning 
type MTP_MSG_GARBAGE (0x731d) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 0 
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3.5.12 MTP_MSG_UPDATE_L4 – Update Level 4 Request 
Synopsis 
Message sent to MTP3 to request the broadcast of current route status to all user parts for a specified 
destination. 
Message Format  
Description 
This message is sent to the MTP3 module to request that all user parts are notified of the current route 
status for the given destination using the normal MTP PAUSE, MTP RESUME and MTPSTATUS primitives. 
The message is intended for use after new routes have been configured or following additional user part 
configuration on a live system (for example, the addition of a new ISUP circuit group). It allows the user to 
ensure that the user part is updated with the current accessibility of the destination. 
The confirmation message indicates success or failure in the status field of the header (success=0). 
Parameters 
•dpc 
The destination point code for which a status broadcast is requested. 
Message Header 
Field Name Meaning 
type MTP_MSG_UPDATE_L4 (0x731f) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Used to request a confirmation 
hclass 0 
status 0 
len 4 
Parameter Area 
Offset Size Name 
0 4 dpc 
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Chapter 3 Message Reference 
3.5.13 MTP_MSG_R_LK_STATUS – Read Link Status Request 
Synopsis 
The message is used by (any) external module to request on-demand from MTP3 the per-link availability 
status of a signaling link. 
Note: This is the preferred method of reading link status as it does not require the application to track 
status indications to know the current status. 
Message Format  
Parameters 
•link_id 
The MTP3 global link ID written into the response for convenience. 
•availability 
Coded as follows: 
•state_flags 
Contains a number of individual flags that allow the user to determine the reason for link unavailability. It 
is coded as follows:  
Message Header 
Field Name Meaning 
type MTP_MSG_R_LK_STATUS (0x6322) 
id (linkset_id * 256) + link_ref 
src Sending module ID 
dst MTP3 module ID 
rsp_req Must be used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 8 
Parameter Area 
Offset Size Name 
0 2 link_id 
2 1 availability 
3 1 Reserved for future use; currently set to zero 
4 2 state_flags 
6 2 transient_flags 
Value Mnemonic Description 
0 MTPLKAV_UNAVAILABLE Unavailable; the link is not available to carry signaling traffic 
1 MTPLKAV_AVAILABLE Available; the link is available to carry signaling traffic 
Bit Mnemonic Description 
0 MTPLKSF_FAILED The link is out of service at MTP2 (either due to failure, deactivation or 
SLT failure). 
1 MTPLKSF_INHR The link is Remotely Inhibited. 
2 MTPLKSF_INHL The link is Locally Inhibited. 
3 MTPLKSF_BLKR The link is (Remotely) Blocked (that is, a Remote Processor Outage 
condition currently exists). 
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•transient_flags 
Contains a number of individual flags that provide additional information on the current internal 
operating state of the link. These conditions are all transient conditions that only last for a few seconds. 
The field is coded as follows: 
Bit Mnemonic Description 
0 MTPLKTF_CO_IN_PROG Changeover in progress. 
1 MTPLKTF_CB_IN_PROG Changeback in progress. 
2 MTPLKTF_LIN_IN_PROG Local link inhibit in progress. 
3 MTPLKTF_UNH_IN_PROG Link uninhibit in progress. 
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Chapter 3 Message Reference 
3.5.14 MTP_MSG_R_RT_STATUS – Read Route Status Request 
Synopsis 
Message issued to MTP3 to request current route status for a given destination. 
Message Format  
Description 
This message is sent to the MTP3 module to request the current accessibility of a destination (route). The 
sending module must fill in the dpc parameter and set the remainder of the parameter area to zero before 
sending the message to MTP3. The sending module must also set its response required bit in the rsp_req 
field of the message header. The response includes: 
•Current route accessibility (Unavailable or Available) 
•Current route congestion status (0, 1, 2 or 3) 
•Individual link set accessibility (Unconfigured, Unavailable or Available) of the DPC over each link set 
The confirmation message indicates success or failure in the status field of the header (success=0) and fills 
in the remaining fields of the parameter area. 
The message may be sent by any module, but is intended for use by the system management module in 
response to a request from the user for route status information. 
Parameters 
•dpc 
The destination point code for which status is requested. 
•route_status 
The current overall accessibility of the specified destination. Values taken from the table shown below. 
•route_cong 
The current congestion status of the route in the range 0 to 3, when multiple congestion levels are used 
or 0 to 1 when a single congestion level is used. 0 indicates no congestion. 
Message Header 
Field Name Meaning 
type MTP_MSG_R_RT_STATUS (0x631e) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Must be used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 20 
Parameter Area 
Offset Size Name 
0 4 dpc 
4 4 Reserved; must be set to zero 
8 1 route_status 
9 1 route_cong 
10 2 Reserved; must be set to zero 
12 1 ls0_status 
13 3 Reserved; must be set to zero 
16 1 ls1_status 
17 3 Reserved; must be set to zero 
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•ls0_status 
Current accessibility of the destination over the first link set of the route. Values taken from the table 
shown below. 
•ls1_status 
Current accessibility of the destination over the second link set of the route. Values taken from the table 
shown below. 
Mnemonic Value Meaning 
MTPACCESS_UNAVAIL_0 0 Unavailable – Not configured 
MTPACCESS_UNAVAIL_1 1 Unavailable – Normal, unspecific 
2 to 7 Unavailable – Reserved for future specific meanings 
MTPACCESS_AVAIL_8 8 Available – Normal, unspecific 
9 to 15 Available – Reserved for future specific meanings 
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Chapter 3 Message Reference 
3.5.15 MTP_MSG_R_SP_STATS – Read Signaling Point Statistics Request 
Synopsis 
This message is used by management to request that the module produces a report in accordance with ITU- 
T Q.752 of the statistics relating to the signaling point as a whole. The statistics are written into the 
parameter area and the message is returned to the sender. The internal statistics can be reset by setting 
status = 1 or left unchanged if status = 0. 
Message Format  
Message Header 
Field Name Meaning 
type MTP_MSG_R_SP_STATS (0x6318) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Must be used to request a confirmation 
hclass 0 
status 0 - Read statistics without modification. 
1 - Read and reset statistics. 
err_info 0 
len 8 
Parameter Area (Written by MTP3 in Response) 
Offset Size Name 
0 4 version - set to zero 
4 4 Number of MSUs for which no outgoing route was available 
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3.5.16 MTP_MSG_R_RT_STATS – Read Route Statistics Request 
Synopsis 
The message is used by management to request that the module produces a report in accordance with ITU- 
T Q.752 of the statistics relating a particular route. The statistics are written into the parameter area and the 
message is returned to the sender. The internal statistics can be reset by setting status = 1 or left unchanged 
if status = 0. The dpc field in the parameter area must be initialized by the sending module. 
Message Format  
Message Header 
Field Name Meaning 
type MTP_MSG_R_RT_STATS (0x6319) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Must be used to request a confirmation 
hclass 0 
status 0 - Read statistics without modification. 
1 - Read and reset statistics. 
err_info 0 
len 16 
Parameter Area 
Offset Size Name 
0 4 dpc - (initialized by sender) 
4 4 version - set to zero 
8 4 Number of times the route has been unavailable 
12 4 Duration of route unavailable 
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Chapter 3 Message Reference 
3.5.17 MTP_MSG_R_LS_STATS – Read Link Set Statistics Request 
Synopsis 
The message is used by management to request that the module produces a report in accordance with ITU- 
T Q.752 of the statistics relating to a particular link set. The statistics are written into the parameter area 
and the message is returned to the sender. The internal statistics can be reset by setting status = 1 or left 
unchanged if status = 0. 
Message Format  
Message Header 
Field Name Meaning 
type MTP_MSG_R_LS_STATS (0x631a) 
id linkset_id * 256 
src Sending module ID 
dst MTP3 module ID 
rsp_req Must be used to request a confirmation 
hclass 0 
status 0 - Read statistics without modification 
1 - Read and reset statistics 
err_info 0 
len 16 
Parameter Area 
Offset Size Name 
0 4 version - set to zero 
4 4 Duration of link set unavailable 
8 4 Number of times the adjacent SP has been inaccessible 
12 4 Duration of adjacent SP inaccessible 
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3.5.18 MTP_MSG_R_LK_STATS – Read Link Statistics Request 
Synopsis 
The message is used by management to request that the module produces a report in accordance with ITU- 
T Q.752 of the statistics relating to a particular link. The statistics are written into the parameter area and 
the message is returned to the sender. 
Message Format  
Message Header 
Field Name Meaning 
type MTP_MSG_R_LK_STATS (0x631b) 
id (linkset_id * 256) + link_ref 
src Sending module ID 
dst MTP3 module ID 
rsp_req Must be used to request a confirmation 
hclass 0 
status 0 - Read statistics without modification 
1 - Read and reset statistics 
err_info 0 
len 68 
Parameter Area 
Offset Size Name 
0 4 version - set to zero 
4 4 Number of changeover attempts for the link 
8 4 Duration of link unavailability (for any reason) 
12 4 Duration of link inhibition due to local action 
16 4 Duration of link inhibition due to remote action 
20 4 Duration of unavailability due to link failure 
24 4 Duration of link unavailability due to RPO 
28 4 Number of local management inhibit 
32 4 Number of local management uninhibit 
36 4 Number of SIO/SIF octets transmitted 
40 4 Number of MSUs transmitted 
44 4 Number of SIF/SIO octets received 
48 4 Number of MSUs received 
52 4 Congestion indications 
56 4 Duration of link congestion 
60 4 MSUs discarded due to congestion 
64 4 Number of congestion events resulting in loss of MSUs 
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Chapter 3 Message Reference 
3.5.19 GEN_MSG_MOD_IDENT – Read Module Version Request 
Synopsis 
Request the module type and software issue number. 
Message Format  
Message Header 
Field Name Meaning 
type GEN_MSG_MOD_IDENT (0x6111) 
id 0 
src Sending module ID 
dst MTP3 module ID 
rsp_req Must be used to request a confirmation 
hclass 0 
status 0 
err_info 0 
len 28 
Parameter Area (Written by MTP3 Module in Response) 
Offset Size Name 
0 2 type – Reserved for future use 
2 1 maj_rev - Major revision number 
3 1 min_rev - Minor revision number 
4 24 text – Null terminated string giving textual module identity. “SS7 
MTP3” 
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3.6 Management Indications Issued by MTP3 
Management indications are sent to the user nominated management module to advise of events occurring 
within the MTP3 module such as protocol events, diagnostic traces or error indications. 
The full list of management indications available to be sent from MTP3 includes: 
•MGT_MSG_MTP_EVENT – MTP3 Q.752 Event Indication 
•MGT_MSG_EVENT_IND – Error Indication 
•MGT_MSG_TRACE_EV – Trace Event Indication 
Management indications are sent to the management module as configured in the mgmt_id field of the 
MTP_MSG_CONFIG message. 
The user can select, using trace masks, which events to report and disable the remainder. 
The use of the hdr->id field is detailed on a per-message basis in this section. 
The receiving module is responsible for releasing the message using the relm() library function.
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Chapter 3 Message Reference 
3.6.1 MGT_MSG_MTP_EVENT – MTP3 Q.752 Event Indication 
Synopsis 
This message is used by level 3 to notify management of various protocol events in accordance with ITU-T 
Q.752. Notification of individual events can be enabled or disabled using the MTP_MSG_TRACE_MASK 
message. 
Message Format  
The EVENT_CODE coding and the meaning of the event specific parameters are given in the following table: 
Message Header 
Field Name Meaning 
type MGT_MSG_MTP_EVENT (0x0301) 
id 0 
src MTP3 module ID 
dst Management module ID 
rsp_req 0 
hclass 0 
status EVENT CODE (see below) 
err_info Timestamp 
len Either 0, 1, 2 or 4 
Parameter Area 
Offset Size Name 
0 len Event specific parameters 
Value Mnemonic Parameter Description 
1 MTPEV_CO link Changeover 
2 MTPEV_CB link Changeback 
3 MTPEV_REST link Restoration commenced 
4 MTPEV_RPO link Remote processor outage 
5 MTPEV_RPO_CLR link Remote processor outage cleared 
6 MTPEV_CONG link Signaling link congestion 
7 MTPEV_CONG_CLR link Congestion cleared 
9 MTPEV_LS_LOST link set Link set failure 
10 MTPEV_LS_OK link set Link set recovered 
13 MTPEV_DEST_LOST point code Destination unavailable 
14 MTPEV_DEST_OK point code Destination available 
15 MTPEV_AJSP_LOST link set Adjacent SP inaccessible 
16 MTPEV_AJSP_OK link set Adjacent SP accessible 
link is indicated as (linkset_id * 256) + link_ref, (size = 2). 
link set is indicated as linkset_id, (size = 1). 
point code is a 4 byte value, (size = 4).
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3.6.2 MGT_MSG_EVENT_IND – Error Indication 
Synopsis 
This message is used by level 3 to advise management of errors or events occurring within the MTP3 
module. 
Message Format 
The error_code in the status field is coded as shown in the following table: 
Message Header 
Field Name Meaning 
type MGT_MSG_EVENT_IND (0x0008) 
id 0 (unless shown below) 
src MTP3 module ID 
dst Management module ID 
rsp_req 0 
hclass 0 
status error_code (see below) 
err_info Timestamp 
len 0 
Value Mnemonic ID Description 
0x52 MTP_POOL_EMPTY 0 
Indicates that MTP3 has attempted to allocate a message 
buffer from its internal pool, but the pool is empty. When 
this happens, MTP3 continues to activate a normal 
(external) message buffer so there is no impact on 
operation and no messages are lost. 
0x53 MTP_TX_FAIL 0 MTP3 failed to send an MSU to lower layer. This indicates that an internal call to the GCT_send() function has 
failed. 
0x54 MTP_LEN_ERR 0 MSU too long for buffer. This can only happen if the user tries to send an MSU that is physically too long to fit into 
an internal buffer. 
0x55 MTP_SLT_FAIL link_id 
Signaling link test failure. This event is logged on the 
second expiry of the Signaling Link Test Control timer as a 
result of not receiving a valid Signaling Link Test 
Acknowledgement (SLTA) message. This may be due to 
configuration error (opc, dpc, ssf, slc) or may be as a 
result of incorrect physical connections (for example, loop 
back in place or wrong timeslot in use). 
0x56 MTP_BAD_DPC 0 
Message received for unknown destination. This event can 
only occur when operating in dual MTP3 mode. It occurs if 
a message is received from the other MTP3 for passing on 
to the network, but the DPC has not been configured. 
0x57 MTP_TALLOC_ERR 0 Failed to allocate a buffer to send a message to the lower layer. The message is discarded. Under normal usage, this 
event should not occur. 
0x59 MTP_MALLOC_ERR 0 
Failed to allocate an internal buffer during Changeback 
process. In the unlikely event that this event occurs, the 
changeback operation is completed using the time- 
controlled diversion. However, this event indicates that the 
system has run out of messages, so unpredictable 
operation may result. 
0x5a MTP_BSNT_FAIL link_id 
MTP3 failed to receive a BSNT from MTP2 during a 
changeover cycle. This may be as a result of a failure of 
the MTP2 board. MTP3 uses the Emergency Changeover 
procedure. 
0x5b MTP_RTV_FAIL link_id 
MTP3 failed to retrieve some or all messages from the 
MTP2 transmission buffer during Changeover. This may be 
as a result of a failure of the MTP2 board. MTP3 discards 
any retrieved messages. 
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Chapter 3 Message Reference 
0x5c MTP_BAD_FSN link_id 
Erroneous FSN in COA. This indicates that MTP2 was 
unable to complete message retrieval using the received 
FSN and potentially some messages are discarded during 
changeover. Recovery should be automatic. 
0x5d MTP_BAD_COO link_id A Changeover message was received after changeover had completed. This can happen under different network 
failure scenarios and is of no real consequence. 
0x5e MTP_SNMM_ERR 0 Internal software error. Please report through normal 
support channel. 
0x5f MTP_SLTM_ERR 0 Internal software error. Please report through normal 
support channel. 
0x60 MTP_NO_COA link_id 
Failed to receive COA. MTP3 Timer T2 expired while 
awaiting a Changeover Ack from the remote end. This is 
an informational message, Changeover continues 
following timer expiry. Persistent receipt of this message 
may be an indication of a configuration mismatch with the 
remote end. 
0x61 MTP_NO_CBA link_id 
Failed to receive CBA. MTP3 Timer T5 expired prior to 
receipt of all Changeback Ack messages. This is an 
informational message, Changeback continues using the 
time-controlled method and no resulting impact on 
operation occurs. 
0x66 MTP_TIM_ERR tim_ref 
Attempt to re-use active timer resource (message ID is set 
to the timer reference). This indicates an internal software 
error and should be reported through the normal support 
channel. 
0x67 MTP_RRT_OVRFLW 0 
Messages discarded due to overflow of Re-Routing buffer. 
MTP3 has discarded messages during forced or controlled 
rerouting as a result of an excessive number of messages 
queued internally. Operation resumes normally, although 
some messages are lost. 
0x68 MTP_FLUSH_FAIL link_id Failed to receive Flush Ack from MTP2. This condition could 
occur if the board on which MTP2 is running has failed. 
0x69 MTP_FLUSH_L2 link_id 
MTP2 transmission buffer flushes (due to RPO). 
Unacknowledged messages in the MTP2 transmission 
buffer have been flushed out due to the excessive duration 
of the RPO condition. 
0x70 MTP_SRT_FAIL link_id Signaling Route Test (SRT) Failure (Japan specific). The user is notified of the failure reason in the 
MTP_MSG_SRT_RESULT message. 
0x71 MTP_SRT_RETRY link_id Signaling Route Test (SRT) Retry (Japan specific). MTP3 is 
repeating an SRT as the first attempt was not successful. 
Value Mnemonic ID Description
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3.6.3 MGT_MSG_TRACE_EV – Trace Event Indication 
Synopsis 
The MTP3 module may be configured to report to management each primitive issued or received. This is 
useful for trace and diagnostic purposes. The MTP3 event masks are used to enable and disable tracing on a 
per-primitive basis for each link. The traced primitives are reported as event indications as shown below. 
Message Format  
Message Header 
Field Name Meaning 
type MGT_MSG_TRACE_EV (0x0003) 
id 0 
src MTP3 module ID 
dst Management module ID 
rsp_req 0 
hclass 0 
status 0 
err_info 0 
len 18 + length of traced data 
Parameter Area 
Offset Size Name 
0 1 source module id 
1 1 destination module id 
2 2 id 
4 2 type 
6 2 status 
8 4 timestamp 
12 4 pointer to the message being traced 
16 2 data length 
18 0 to 280 data - Data taken from the payload of a traced transmit or receive 
frame or the contents of the MSG parameter area 
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Chapter 3 Message Reference 
3.7 Message Summary Table 
Table1 lists, by message type, all the messages defined in this manual. 
Table 1. Message Summary Table 
Message 
Type Mnemonic Description 
0x0003 MGT_MSG_TRACE_EV Trace Event Indication 
0x0008 MGT_MSG_EVENT_IND Error Indication 
0x0301 MGT_MSG_MTP_EVENT MTP3 Q.752 Event Indication 
0x1316 Confirmation of MTP_MSG_TRACE_MASK 
0x2111 Confirmation of GEN_MSG_MOD_IDENT 
0x2318 Confirmation of MTP_MSG_R_SP_STATS 
0x2319 Confirmation of MTP_MSG_R_RT_STATS 
0x231a Confirmation of MTP_MSG_R_LS_STATS 
0x231b Confirmation of MTP_MSG_R_LK_STATS 
0x231e Confirmation of MTP_MSG_R_RT_STATUS 
0x2322 Confirmation of MTP_MSG_R_LK_STATUS 
0x3300 Confirmation of MTP_MSG_RESET 
0x3303 Confirmation of MTP_MSG_CONFIG 
0x3310 Confirmation of MTP_MSG_CNF_LINKSET 
0x3311 Confirmation of MTP_MSG_CNF_LINK 
0x3312 Confirmation of MTP_MSG_CNF_ROUTE 
0x3316 Confirmation of MTP_MSG_GARBAGE 
0x3317 Confirmation of MTP_MSG_CNF_TIMERS 
0x331f Confirmation of MTP_MSG_UPDATE_L4 
0x3323 Confirmation of MTP_MSG_END_LINKSET 
0x3324 Confirmation of MTP_MSG_END_LINK 
0x3325 Confirmation of MTP_MSG_END_ROUTE 
0x5316 MTP_MSG_TRACE_MASK MTP3 Trace Mask Configuration Request 
0x6111 GEN_MSG_MOD_IDENT Read Module Version request 
0x6318 MTP_MSG_R_SP_STATS Read Signaling Point Statistics Request 
0x6319 MTP_MSG_R_RT_STATS Read Route Statistics Request 
0x631a MTP_MSG_R_LS_STATS Read Link Set Statistics Request 
0x631b MTP_MSG_R_LK_STATS Read Link Statistics Request 
0x631e MTP_MSG_R_RT_STATUS Read Route Status Request 
0x6322 MTP_MSG_R_LK_STATUS Read Link Status Request 
0x7300 MTP_MSG_RESET MTP3 Module Reset Request 
0x7303 MTP_MSG_CONFIG MTP3 Module Configuration Request 
0x7310 MTP_MSG_CNF_LINKSET Link Set Configuration Request 
0x7311 MTP_MSG_CNF_LINK Signaling Link Configuration Request 
0x7312 MTP_MSG_CNF_ROUTE Route Configuration Request 
0x7316 MTP_MSG_GARBAGE Clear Garbage Request 
0x7317 MTP_MSG_CNF_TIMERS MTP3 Timer Configuration Request 
0x731f MTP_MSG_UPDATE_L4 Update Level 4 Request 
0x7323 MTP_MSG_END_LINKSET Link Set End request 
0x7324 MTP_MSG_END_LINK Signaling Link End Request 
0x7325 MTP_MSG_END_ROUTE Route End Request 
0x830a Confirmation of MTP_MSG_ACT_SL 
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0x830b Confirmation of MTP_MSG_DEACT_SL 
0x830c Confirmation of MTP_MSG_SLTC_START 
0x830e Confirmation of MTP_MSG_ACT_LS 
0x830f Confirmation of MTP_MSG_DEACT_LS 
0x8310 Confirmation of MTP_MSG_INHIB_SL 
0x8311 Confirmation of MTP_MSG_UNINHIB_SL 
0x8317 Confirmation of MTP_MSG_SRT_START 
0x8321 MTP_MSG_SRT_RESULT SRT Result Indication 
0x8380 MTP_MSG_LINK_INHIB Signaling Link Inhibited Indication 
0x8381 MTP_MSG_LINK_UNINHIB Signaling Link Uninhibited Indication 
0x8382 MTP_MSG_INHIB_DENIED Signaling Link Inhibit Denied 
0x8383 MTP_MSG_UNINHIB_FAIL Signaling Link Uninhibit Failure Indication 
0x8403 MTP_MSG_PAUSE MTP Pause Indication 
0x8404 MTP_MSG_RESUME MTP Resume Indication 
0x8405 MTP_MSG_STATUS MTP Status Indication 
0x8f00 Confirmation of API_MSG_TX_REQ 
0x8f01 API_MSG_RX_IND MTP Transfer Indication 
0xc30a MTP_MSG_ACT_SL Activate Signaling Link Request 
0xc30b MTP_MSG_DEACT_SL Deactivate Signaling Link Request 
0xc30c MTP_MSG_SLTC_START Signaling Link Test Request 
0xc30e MTP_MSG_ACT_LS Activate Link Set Request 
0xc30f MTP_MSG_DEACT_LS Deactivate Link Set Request 
0xc310 MTP_MSG_INHIB_SL Inhibit Signaling Link Request 
0xc311 MTP_MSG_UNINHIB_SL Uninhibit Signaling Link Request 
0xc317 MTP_MSG_SRT_START Start SRT Request (Japan) 
0xcf00 API_MSG_TX_REQ MTP Transfer Request 
Table 1. Message Summary Table (Continued) 
Message 
Type Mnemonic Description
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Chapter 4 Internal Interfaces 
Chapter 4:  Internal Interfaces 
The MTP3 module interfaces with the lower layer protocol layer (for example, MTP2) and system services for 
timer tick information. Detailed knowledge of these interfaces is not required in order to use the MTP3 
module, however, for completeness the messages and message types used on these interfaces are detailed 
in this chapter. 
4.1 Primitives Issued by MTP3 to MTP2 
4.2 Primitives Received by MTP3 from MTP2 
Message 
Mnemonic Message Type Brief Description of Internal Use 
API_MSG_TX_REQ 0xcf00 Send a Message Signal Unit (MSU) to MTP2 for 
transmission 
SS7_MSG_START 0xc204 Starts the MTP2 Initial Alignment procedure 
SS7_MSG_STOP 0xc205 Takes a link out of service 
SS7_MSG_EMGCY 0xc207 Notifies MTP2 of an Emergency condition 
SS7_MSG_EMGCY_CLRD 0xc208 Cancels a previous Emergency request 
SS7_MSG_RTV_BSNT 0xc209 Requests BSNT from MTP2 
SS7_MSG_RTVL_REQ 0xc20a Requests retrieval of unacknowledged messages 
SS7_MSG_FLUSH 0xc212 Flushes messages from the transmission and 
retransmission buffers during periods of processor outage 
SS7_MSG_CONTINUE 0xc211 Resumes normal operation following processor outage 
Message 
Mnemonic MessageType Brief Description of Internal Use 
API_MSG_RX_IND 0x8f01 Message Signal Unit (MSU) received from the network 
SS7_MSG_IN_SVC 0x8303 In Service indication 
SS7_MSG_OUT_SVC 0x8304 Out of Service indication 
SS7_MSG_REM_PR_OUT 0x8305 Remote Processor Outage indication 
SS7_MSG_REM_PR_OK 0x8306 Remote Processor Outage cleared indication 
SS7_MSG_RXD_BSNT 0x8307 BSNT indication form MTP2 
API_MSG_RTVD_MSG 0x8f08 Retrieved message 
SS7_MSG_RTVL_COMPL 0x8309 Retrieval complete indication 
MTP_MSG_RTVL_NOT_POS 0x8315 Retrieval not possible indication 
MTP_MSG_LINK_CONG 0x8312 Link congestion indication 
MTP_MSG_LINK_UNCONG 0x8313 Link congestion cleared indication 
MTP_MSG_FLUSH_ACK 0x8316 Flush acknowledgement indication 
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4.3 Messages Exchanged Between MTP3 and Timer Services 
4.4 Messages Exchanged Between MTP2 and MTP3 On-board 
In addition, three internal messages are used as part of the on-board interface between MTP2 and MTP3 to 
convey message for transmission to MTP2, to convey received indications to MTP3 and to transfer retrieved 
messages from MTP2 to MTP3. These messages are not passed off board so the user does not need to use 
these messages. For completeness they are also listed below: 
Message 
Mnemonic Message Type Brief Description of Internal Use 
SS7_MSG_TM_EXP 0xc002 Periodic 100ms timer expiry indication sent to MTP3 
TIM_MSG_KEEP_TIME 0x7006 Message sent by MTP3 to initialize timer services 
Message 
Mnemonic MessageType Brief Description of Internal Use 
SS7_MSG_TX_REQ 0xc000 Sends a Message Signal Unit (MSU) to MTP2 for 
transmission 
SS7_MSG_RX_IND 0x8001 Indication of a received MSU from MTP2 to MTP3 
SS7_MSG_RTVD_MSG 0x8301 Message sent by MTP2 to return retrieved messages to 
MTP3 
70 
Glossary 
Glossary 
DPC Destination Point Code 
M2PA MTP2 Peer to Peer Adaptation Layer. A SIGTRAN protocol used to replicate the services 
offered by MTP2 while using IP as a transport protocol. 
MTP Message Transfer Part. Layers 1 to 3 of the SS7 protocol stack broadly equivalent to the 
Physical, Data Link and Network layers in the OSI protocol stack. See also MTP1, MTP2, 
and MTP3. 
MTP1 Message Transfer Part Level 1. An SS7 stack layer that defines the physical and electrical 
characteristics of the signaling links of the SS7 network. Signaling links use DS0 
channels and carry raw signaling data at a rate of 48, 56 or 64 kbps. 
MTP2 Message Transfer Part Level 2. An SS7 stack layer that provides link-layer functionality. 
Ensures that two end points of a signaling link can reliably exchange signaling messages. 
It provides error checking, flow control and sequence checking. 
MTP3 Message Transfer Part Level 3. An SS7 stack layer that provides network-layer 
functionality. Ensures that messages can be delivered between signaling points across 
the SS7 network regardless of whether the signaling points are directly connected. It 
provides node addressing, routing, alternate routing and congestion control. 
MSU Message Signal Unit. A data unit that carries signaling information for call control, 
transaction processing, network management and maintenance. Typically, the MSU is 
carried in the Signaling Information Field (SIF) of SS7 messages. 
SLT Signaling Link Test 
SRT Signaling Route Test 
SS7 Signaling System Number 7 
SSF Sub-Service Field 
STP Signaling Transfer Points