Patch to reveal more information in SHOW ROUTE

[Andrew Francis]

Hi,


Twitch's network operations department uses BIRD as a centralized looking
glass. It's a BGP route reflector that is peered with all our border
routers. Staff use the route reflector to inspect how a destination network
can be reached from our different points-of-presence.


Some peers will advertise the same IP as part of different prefix lengths,
likely due to aggregation or filtering. For instance, one provider
advertises 117.120.24.0/22 to us, but all others only advertise a /21.


Querying SHOW ROUTE on the looking glass shows the /22 on one border
router, and hides the /21's. This makes sense as a routing decision from
the location of the looking glass, but doesn't give us the global
visibility we want.


I have a patch which adds an option to SHOW ROUTE to reveal all prefixes,
regardless of length / best-match, covering a particular IP.


This produces tons of output. I am also working on an option to print the
single best prefix for each unique BGP.next_hop / BGP.originator_id. This
gives us exactly what we want: the route taken to a particular IP from each
border router.


Would the community be interested in integrating this feature? If so, I'll
start the process here to get a patch released publicly.


Thanks


Andrew Francis   |   *Twitch* <http://www.twitch.tv/>   |   Engineering
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