Patch to reveal more information in SHOW ROUTE
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
As an option to "show route", I would use this. Thanks, Chris On Thu, 22 Jan 2015, Andrew Francis wrote:
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
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 23.1.2015 06:40, Andrew Francis wrote:
Hi,
Hi Andrew, thank you for your e-mail. But isn't this command doing what you require: bird> show route where 192.168.168.168 ~ net ? Ondrej
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 <http://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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Thanks Ondrej, That query does seem to return all the routes of interest, but it takes a long time (many seconds per query). I'm guessing it's not FIB accelerated? One of the things we're doing is script-driven bulk data collection, so we probably want something faster. (We have about 50 million routes.) Thanks Andrew Francis | *Twitch* <http://www.twitch.tv/> | Engineering | 415 430 8612 On Fri, Jan 23, 2015 at 3:09 AM, Ondrej Filip <feela@network.cz> wrote:
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On 23.1.2015 06:40, Andrew Francis wrote:
Hi,
Hi Andrew, thank you for your e-mail. But isn't this command doing what you require:
bird> show route where 192.168.168.168 ~ net
?
Ondrej
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 <http://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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On Fri, Jan 23, 2015 at 09:16:59PM -0800, Andrew Francis wrote:
Thanks Ondrej,
That query does seem to return all the routes of interest, but it takes a long time (many seconds per query). I'm guessing it's not FIB accelerated?
That is true, "show route where 192.168.168.168 ~ net" just applies filter (where ...) to all routes. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santiago@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."
participants (4)
-
Andrew Francis -
Chris Caputo -
Ondrej Filip -
Ondrej Zajicek