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Create numerous BGP sources with a single router

Sometimes you need numerous BGP sources in your lab, but have only a fixed number of routers. Although you could introduce an extra BGP source with Quagga running on Linux (or use tricks to generate more than one BGP source on a single Linux host), it’s usually best if you could avoid the introduction of extra devices in your lab.

Recent releases of Cisco IOS provide a perfect solution: you can run as many BGP instances as you wish on a single router (each one in its own VRF) and use the BGP Support for Dual-AS Configuration to replace actual AS number with the desired one.

Read the whole article in the CT3 wiki


  1. Hi,

    IIRC what you can't do (and which was what I needed ofcourse), was to replace the router's AS num, with that of the peer's. i.e. fake iBGP peering with peer instead of eBGP. shame...

  2. Your memory is perfect. Quagga to the rescue :)
  3. Hello Ivan,

    Many Cisco docs mention ROUTEM as a BGP speaker and/or client simulator. Do you have more info about it? How is it available?

    Thanks, Jon
  4. @Jon: I have no information on ROUTEM. It could be an internal testing tool, but I don't see a great need for it (apart from stress testing, but if you're interested in that, you could easily write your own BGP source in PERL).
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