Determine difference between 2 BGP feeds

John Kristoff jtk at ultradns.net
Tue Apr 18 20:36:07 UTC 2006


On Tue, 18 Apr 2006 16:13:12 -0400 (EDT)
Scott "Tuc" Ellentuch at T-B-O-H <ml at t-b-o-h.net> wrote:

> 	Is there a utility that I can use that will pull the
> routes off each router (Foundry preferred), and then compare 
> them as best it can to see why there is such a difference? 

I don't know anything about foundry, but if you can simply display
the routing table from a terminal, you can go the hacky unix cli
tool way.  For example, use 'script' to log your terminal session
to a file, then presuming you can show the route table and each
route includes a 'via upstream-address-line' line for each route
(completely untested and I'm sure someone could come up with
something much simpler and better):

  grep 'via upstream?' script > upstream?
  perl -ne 'print "$1\n" if /(\d{1,3}(?:\.\d{1,3}){3}\/\d{1,3})/' upstream? |
     sort > upstream?.sored
  comm -23 upstream1.txt upstream2.txt
  comm -13 upstream1.txt upstream2.txt

John



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