New "channels" feature in future version of Bird?

[Jan Matejka]

Hi!

First of all, thank your for your question. It's good to know that the
rework is really watched by the community.

> I am very curious about the new "channels" feature from the int-new
> branch.
> 
> I understand it is supposed to replace import and export filters by
> connecting protocols to routing tables.  What is the motivation for this
> change, and how does it work from a high-level perspective?  Will it be
> part of Bird 2?

Import and export filters should stay as they were before. The
"channels" feature is just an internal abstraction layer between routing
tables and protocols. It was the best way chosen by us to allow
protocols connect to several tables at once, like multiprotocol BGP.

In the configuration, the only change worth mentioning is that your old
config

protocol bgp { table t1; import ...; export ...; igp table it; ... }

should change to something like

protocol bgp {
ipv4 { table t1; import ...; export ...; };
ipv6 { table t2; import ...; export ...; };
vpn4 { ... };
igp ipv4 table it4;
igp ipv6 table it6;
...
}

No replacing of filters is planned for the integrated version, at least
in near future.

If one of our crazy ideas comes true, we may add Lua as a possible
language to write filters in (in several years' perspective) and maybe
also deprecate the current, then-legacy filter language in far future.

MQ