NDN-FCH (Find Closest Hub)

NDN-FCH (Find Closest Hub) is a geolocation service application for the Named Data Networking (NDN) network. It aims to provide end hosts connecting to the NDN hub network with the ability to quickly locate the NDN hub closest to their current location.

Protocol Description

NDN-FCH is an HTTP-based service with a very simple API.

• Requesting an NDN hub based on IP-location inference using MaxMind GeoLite2 City database

  Input: GET request /[?k=N][&cap=wss]

  Parameters:

  • k (value 1 to 10, default 1) to request k closest hubs.
  • cap=wss to request a hub capable of secure WebSockets.

  Output: a comma-separated list of hostnames of the closest NDN hubs

  Example:

    client
       |                                              http://ndn-fch.named-data.net
       |      (a) GET / HTTP/1.0                                    |
       | -------------------------------------------------------->  |
       |                                                           ...
       |      HTTP 200    "spurs.cs.ucla.edu"                       |
       | <--------------------------------------------------------  |
       |                                                            |
  
      ...                                                          ...
  
       |                                                            |
       |      (b) GET /?k=3 HTTP/1.0                                |
       | -------------------------------------------------------->  |
       |                                                           ...
       |      HTTP 200    "spurs.cs.ucla.edu,aleph.ndn.ucla.edu,ndnhub.ics.uci.edu"
       | <--------------------------------------------------------  |
       |                                                            |
  

• Requesting an NDN hub based on explicit location

  Input: GET request /?lat=LATITUDE&lon=LONGTITUDE[&k=N]

  Parameters:

  • lat (from -90 to +90) latitude of the location
  • lon (from -180 to +180) longitude of the location
  • k (value 1 to 10, default 1) to request k closest hubs.

  Output: a comma-separated list of hostnames of the closest NDN hubs

  Example:

    client
       |                                              http://ndn-fch.named-data.net
       |                                                            |
       |      (c) GET /?lat=20.222&lon=163.55 HTTP/1.0              |
       | -------------------------------------------------------->  |
       |                                                           ...
       |      HTTP 200    "133.9.73.66"                             |
       | <--------------------------------------------------------  |
  
      ...                                                          ...
  
       |                                                            |
       |      (b+c) GET /?lat=20.222&lon=163.55&k=3 HTTP/1.0        |
       | -------------------------------------------------------->  |
       |                                                           ...
       |      HTTP 200    "133.9.73.66,133.1.17.51,203.253.235.168" |
       | <--------------------------------------------------------  |
  

Deployment Instructions

Prerequisites

• Python 3
• pip
• virtualenv

Creating python environment and dependency installation

virtualenv .python
source .python/bin/activate
pip install -r requirements.txt
deactivate

Configuration

cp config.dist.py config.py
## edit config.py

Database download

To manually download geo-ip mapping and hub position databases:

./manage.py update_geodb
./manage.py update_hubs

These databases need to be periodically refreshed, e.g., using a daily/weekly cronjob

# update geoip database weekly
0 22 * * 1    /path/to/ndn-fch/manage.py update_geodb && touch /path/to/ndn-fch/app.wsgi

# update hubs information daily
0 23 * * *    /path/to/ndn-fch/manage.py update_hubs && touch /path/to/ndn-fch/app.wsgi

Run the Application

./manage.py runserver

So access the application at the address (http://localhost:5000/)

Want to specify a different port?

$ ./manage.py runserver -h 0.0.0.0 -p 8080

Configure mod_wsgi apache module

<VirtualHost *:80>
    ServerAdmin [email protected]
    ServerName ndn-fch.example.comf

    WSGIProcessGroup ndn-fch.example.com
    WSGIDaemonProcess ndn-fch.example.com processes=2 threads=15 display-name=%{GROUP}

    WSGIScriptAlias / /path/to/ndn-fch/app.wsgi

    <Directory /path/to/ndn-fch>
        Order deny,allow
        Allow from all
    </Directory>
</VirtualHost>