[c-nsp] IOS XR BFD

[Nick 'tarantul' Novikov]

On Sun, Jul 5, 2009 at 12:40 AM, Pavel Lunin<plunin at senetsy.ru> wrote:
> Nick, folks are telling clever things.
>
> It is not BGP's deal anyway to control reachability. It's an IGP's task, as
> well as the best path calculating. Just let IGP carry loopback /32 prefixes,
> then run iBGP on them, not on subifs. iBGP's job is to carry routes
> regardless of the topology state.

Ok. Example of physical topology:
http://pastebin.ca/1484472
All physical links protected by IS-IS.
RR* routers can't keep full BGP table and for this reason ASBR*
announce 0/0 route only. If I configure BGP session between ASBR* and
use for it lo0 interfaces I will have a loop. Do not you think?


> This sort of design is a standard for some last two decades, so it's at
> least strange to go a different way. Moreover I can imagine an only reason
> why you can't run IGP --  a lack of control plane resources. I hope it's not
> you case (with IOS XR, huh :), otherwise static routes will save you (does
> IOS XR support BFD for them? :)

So fsck... No. IOS XR can't. If I configure (X.X.X.X - subif BGP
neighbor, not lo0 address)
router static
 address-family ipv4 unicast
  X.X.X.X/32 Null0
 !
!
BGP session don't drop!
In old school IOS a similar construction works great.



-- 
tarantul
Dios es Amor