Add support for Large BGP Community

[job]

Can GoBGP implement support for https://tools.ietf.org/html/draft-heitz-idr-large-community ? The Large BGP Community is a very straightforward, easy to implement type of BGP Community.

Inter-op testing can be done with ExaBGP, the latest release supports Large BGP Community. Information about Large BGP Community is tracked here http://largebgpcommunities.net/implementations/

[pavel-odintsov]

Hello!

I'm also interested in this feature so much! I'll be happy to help with test and API integration as usual :)

[ishidawataru]

Hi, added the feature by this commit (a3ccd8e).

you can try like

% gobgp global rib add -a ipv4 10.0.0.0/24 large-community 100:100:100
% gobgp global rib add -a ipv4 10.0.0.0/24 large-community 100:100:100,200:200:200

[job]

Very cool! I'll do some testing against ExaBGP and report back on the interoperability.

Please make sure that if the IETF specification changes (for instance changes the Attribute codepoint) GoBGP can change accordingly. This is easiest accomplished by keeping the Large Community feature in a separate branch until the standardisation process is finished.

[job]

Dear @ishidawataru ,

Can you provide me with answers to these questions for the implementation report at https://trac.tools.ietf.org/wg/idr/trac/wiki/draft-ietf-idr-large-community%20implementations ?

• Can receive and display Large Communities with Routes?
• Do GoBGP aggregate routes with multiple Large Communities, removing duplicates?
• Can GoBGP match Large Communities using the 3 decimal uint32 representation?
• Can GoBGP Set/delete Large Communities using the 3 decimal uint32 representation?
• Separator used in the textual representation?
• Treat-as-withdraw when a route contains a Large Community attribute of invalid length?
• Are there any restrictions on the value of Global Administrator field?

[pierky]

As of my findings, I try to answer some of your questions. Any corrections, suggestions and comments are welcome.

Can receive and display Large Communities with Routes?

Yes.

Can GoBGP match Large Communities using the 3 decimal uint32 representation?
Can GoBGP Set/delete Large Communities using the 3 decimal uint32 representation?

Not yet: a feature request is tracked on #1133 and it's already on devs' todo list. Currently it can only set large communities via CLI.

Separator used in the textual representation?

:

Are there any restrictions on the value of Global Administrator field?

No: tested with some reserved values (65535:1:1 and 4294967295:4294967295:4294967295)

[job]

I think this one is done now?

[pierky]

Support has been added but I think there are a couple of things to improve, unless I missed something.

• Duplicate Large Communities handling: Duplicate Large Communities handling #1143 (comment)
• Malformed large BGP communities attributes handling: Malformed large BGP communities attributes handling #1147

[pavel-odintsov]

Any updates, guys? :) I really want to add this shiny option in FastNetMon's GoBGP plugin!

[fujita]

@pavel-odintsov except for handing bad messages, GoBGP supports this feature. Already good enough for FastNetMon?

[fujita]

Please create a new issue if there is something to improve about Large BGP Community in GoBGP.