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Github Action edited this page Jun 10, 2024 · 1 revision

RT-7.5: BGP Policy - Match and Set Link Bandwidth Community

Summary

Configure bgp policy to match, add and delete statically configured BGP link bandwidth communities to routes based on a prefix match.

Testbed type

Procedure

  • Testbed configuration - Setup external BGP sessions and prefixes.

    • Generate config for 2 DUT and ATE ports where:
      • DUT port 1 to ATE port 1 EBGP session.
      • DUT port 2 to ATE port 2 IBGP session.
    • Configure dummy accept policies and attach it to both sessions on DUT.
      • Create a /routing-policy/policy-definitions/policy-definition/policy-definition named 'allow_all' with the following statements
        • statement[name='allow-all']/
          • actions/config/policy-result = ACCEPT_ROUTE
      • Use /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/apply-policy/config/import-policy to apply the policy on the DUT bgp neighbor to the ATE port 1.
    • Configure ATE port 1 with a BGP session to DUT port 1.
      • Advertise ipv4 and ipv6 prefixes to DUT port 1 using the following communities:
        • prefix-set-1 with 2 ipv4 and 2 ipv6 routes without communities.
        • prefix-set-2 with 2 ipv4 and 2 ipv6 routes with communities [ "100:100" ].
        • prefix-set-3 with 2 ipv4 and 2 ipv6 routes with extended communities [ "link-bandwidth:100:0" ].
    • Configure Send community knob to IBGP neigbour to advertise the communities to IBGP peer
      • use /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/config/send-community.

  • RT-7.5.1 - Validate bgp sessions and traffic

    • For IPv4 and IPv6 prefixes:
      • Observe received prefixes at ATE port-2.
    • Generate traffic from ATE port-2 to ATE port-1.
    • Verify traffic is received on ATE port 1 for advertised prefixes. routes.

  • RT-7.5.2 - Validate adding and removing link-bandwidth ext-community-sets using OC model release 3.x

    • Configure the following extended community sets on the DUT: (prefix: routing-policy/defined-sets/bgp-defined-sets/ext-community-sets/ext-community-set)

      • Create an ext-community-set named 'linkbw_0' with:
        • ext-community-member = [ "link-bandwidth:100:0" ]
      • Create an ext-community-set named 'linkbw_1M' with members as follows:
        • ext-community-member = [ "link-bandwidth:100:1M" ]
      • Create an ext-community-set named 'linkbw_2G' with members as follows:
        • ext-community-member = [ "link-bandwidth:100:2G" ]
      • Create an community-set named 'regex_match_comm100' with members as follows:
        • community-member = [ "^100:.*$" ]
      • Create an ext-community-set named 'linkbw_any' with members as follows:
        • ext-community-member = [ "^link-bandwidth:.:.$" ]
      • Create an ext-community-set named 'linkbw_any_0' with members as follows:
        • ext-community-member = [ "^link-bandwidth:.*:.0" ]

    • Create a /routing-policy/policy-definitions/policy-definition/policy-definition named 'set_linkbw_0' with the following statements

      • statement[name='zero_linkbw']/
        • actions/bgp-actions/set-ext-community/reference/config/ext-community-set-refs = 'linkbw_0'
        • actions/bgp-actions/set-ext-community/config/options = ADD
        • actions/bgp-actions/set-community/config/method = REFERENCE
        • actions/config/policy-result = NEXT_STATEMENT
      • statement[name='accept_all_routes']/
        • actions/config/policy-result = ACCEPT_ROUTE

    • Create a /routing-policy/policy-definitions/policy-definition/policy-definition named 'not_match_100_set_linkbw_1M' with the following statements

      • statement[name='1-megabit-match']/
        • conditions/bgp-conditions/match-community-set/config/community-set = 'regex_match_comm100'
        • conditions/bgp-conditions/match-community-set/config/match-set-options = INVERT
        • actions/bgp-actions/set-ext-community/reference/config/ext-community-set-refs = 'linkbw_1M'
        • actions/config/policy-result = NEXT_STATEMENT
      • statement[name='accept_all_routes']/
        • actions/config/policy-result = ACCEPT_ROUTE

    • Create a /routing-policy/policy-definitions/policy-definition/policy-definition named 'match_100_set_linkbw_2G' with the following statements

      • statement[name='2-gigabit-match']/
        • conditions/bgp-conditions/match-community-set/config/community-set = 'regex_match_comm100'
        • conditions/bgp-conditions/match-community-set/config/match-set-options = ANY
        • actions/bgp-actions/set-ext-community/reference/config/ext-community-set-refs = 'linkbw_2G'
        • actions/config/policy-result = NEXT_STATEMENT
      • statement[name='accept_all_routes']/
        • actions/config/policy-result = ACCEPT_ROUTE

    • Create a /routing-policy/policy-definitions/policy-definition/policy-definition named 'del_linkbw' with the following statements

      • statement[name='del_linkbw']/
        • actions/bgp-actions/set-ext-community/config/options = 'REMOVE'
        • actions/bgp-actions/set-ext-community/config/method = 'REFERENCE'
        • actions/bgp-actions/set-ext-community/reference/config/ext-community-set-refs = 'linkbw_any'
        • actions/config/policy-result = NEXT_STATEMENT
      • statement[name='accept_all_routes']/
        • actions/config/policy-result = ACCEPT_ROUTE

    • Create a /routing-policy/policy-definitions/policy-definition/policy-definition named 'match_linkbw_0_remove_and_set_localpref_5' with the following statements

      • statement[name='match_and_remove_linkbw_any_0']/
        • conditions/bgp-conditions/match-ext-community-set/config/community-set = 'linkbw_any_0'
        • actions/bgp-actions/set-ext-community/reference/config/ext-community-set-refs = 'linkbw_any_0'
        • actions/bgp-actions/set-ext-community/config/method = 'REFERENCE'
        • actions/bgp-actions/set-ext-community/config/options = 'REMOVE'
        • actions/bgp-actions/config/set-local-pref = 5
        • actions/config/policy-result = NEXT_STATEMENT
      • statement[name='accept_all_routes']/
        • actions/config/policy-result = ACCEPT_ROUTE

    • For each policy-definition created, run a subtest (RT-7.8.3.x-<policy_name_here>) to

      • Use gnmi Set REPLACE option for:

        • /routing-policy/policy-definitions to configure the policy
        • Use /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/apply-policy/config/import-policy to apply the policy on the DUT bgp neighbor to the ATE port 1.

      • Verify expected communities are present in ATE.

      • Verify expected communities are present in DUT state.

        • Do not fail test if this path is not supported, only log results
        • /network-instances/network-instance/protocols/protocol/bgp/rib/afi-safis/afi-safi/ipv4-unicast/neighbors/neighbor/adj-rib-in-post/routes/route/state/ext-community-index
        • /network-instances/network-instance/protocols/protocol/bgp/rib/afi-safis/afi-safi/ipv6-unicast/neighbors/neighbor/adj-rib-in-post/routes/route/state/ext-community-index

      • Expected community values for each policy

        set_linkbw_0 not_match_100_set_linkbw_1M
        prefix-set-1 [ "link-bandwidth:100:0" ] [none]
        prefix-set-2 [ "100:100", "link-bandwidth:100:0" ] [ "100:100" ]
        prefix-set-3 [ "link-bandwidth:100:0" ] [ "link-bandwidth:100:0" ]
        match_100_set_linkbw_2G del_linkbw rm_any_zero_bw_set_LocPref_5
        prefix-set-1 [ none ] [none] [none]
        prefix-set-2 [ "100:100", "link-bandwidth:100:2000000000" ] [ "100:100" ] [ "100:100" ]
        prefix-set-3 [ "link-bandwidth:100:0" ] [ none ] [ none ], localpref=5

        • LocalPreference The prefixes of "prefix-set-3" matching policy "rm_any_zero_bw_set_LocPref_5" should have Local Preference value 5.
          All other prefixes, Local Preference should be none or 100 (standard default).
          For all other policies, Local Preference should be none or 100 (standard default)

        • Regarding prefix-set-3 and policy "nomatch_100_set_linkbw_2G"

          • prefix-set-3 is advertised to the DUT with community "link-bandwidth:100:0" set.
          • The DUT evaluates a match for "regex_nomatch_as100". This does not match because the regex pattern does not include the link-bandwidth community type.
          • Community linkbw_2G should be added.

        • Regarding policy-definition "match_linkbw_0_remove_and_set_localpref_5"

          • The link-bandwidth value 0 is interpreted by some implementation as weight "0" in WCMP group. In these implementations the remaining members distribute traffic according to weights.
          • Other implementations consider value 0 invalid or not having link-bandwidth. These implementations create ECMP group with all routes including this one, and ignores link-bandwidth of all members - distribute traffic equally.
          • This policy intention is to overcome this implementation difference, by deprefering (LocPref) routes with link-bandwidth 0 (only this routes) to prevent them becoming part of multipath, and remove link-bandwidth community so route will not be treated with WCMP behavior.

OpenConfig Path and RPC Coverage

The below yaml defines the OC paths intended to be covered by this test. OC paths used for test setup are not listed here.

paths:
  ## Config Parameter Coverage
  ## Configuration to enable advertise communities to bgp peer
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/config/send-community:
  ## Policy for community-set configuration
  /routing-policy/defined-sets/bgp-defined-sets/ext-community-sets/ext-community-set/config/ext-community-set-name:
  /routing-policy/defined-sets/bgp-defined-sets/ext-community-sets/ext-community-set/config/ext-community-member:
  ## Policy action configuration
  /routing-policy/policy-definitions/policy-definition/config/name:
  /routing-policy/policy-definitions/policy-definition/statements/statement/config/name:
  /routing-policy/policy-definitions/policy-definition/statements/statement/actions/config/policy-result:
  /routing-policy/policy-definitions/policy-definition/statements/statement/actions/bgp-actions/set-ext-community/config/options:
  /routing-policy/policy-definitions/policy-definition/statements/statement/actions/bgp-actions/set-community/config/method:
  /routing-policy/policy-definitions/policy-definition/statements/statement/actions/bgp-actions/set-ext-community/reference/config/ext-community-set-refs:
  /routing-policy/policy-definitions/policy-definition/statements/statement/actions/bgp-actions/config/set-local-pref:
  ## Policy for community-set match configuration
  /routing-policy/policy-definitions/policy-definition/statements/statement/conditions/bgp-conditions/match-ext-community-set/config/ext-community-set:
  /routing-policy/policy-definitions/policy-definition/statements/statement/conditions/bgp-conditions/match-ext-community-set/config/match-set-options:
  ## Policy attachment point configuration
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/apply-policy/config/import-policy:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/apply-policy/config/export-policy:
  /network-instances/network-instance/protocols/protocol/bgp/peer-groups/peer-group/apply-policy/config/import-policy:
  /network-instances/network-instance/protocols/protocol/bgp/peer-groups/peer-group/apply-policy/config/export-policy:
  ## Telemetry Parameter Coverage
  /network-instances/network-instance/protocols/protocol/bgp/rib/afi-safis/afi-safi/ipv4-unicast/neighbors/neighbor/adj-rib-in-post/routes/route/state/ext-community-index:
  /network-instances/network-instance/protocols/protocol/bgp/rib/afi-safis/afi-safi/ipv6-unicast/neighbors/neighbor/adj-rib-in-post/routes/route/state/ext-community-index:
rpcs:
    gnmi:
        gNMI.Subscribe:

Minimum DUT Required

vRX - Virtual Router Device

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