Re: [GROW] Peer-groups in BMP adj-rib-out (was Re: I-D Action: draft-ietf-grow-bmp-adj-rib-out-00.txt)

[Jeffrey Haas <[e-mail]>]

On Thu, Jul 13, 2017 at 01:27:38PM +0000, Jakob Heitz (jheitz) wrote:
> What is this "approximate state"?
> Why does a sample peer not give you approximate state?

You just gave multiple examples of when the peer might not be good enough.
I'm unclear why you're asking the question.

Simple examples:
Basic ibgp, no policy.  Monitoring the rib-out per group is likely good
enough.  Same for reflection.  Likely the same for ebgp confederation peer.

Basic ibgp for L3VPN.  Monitoring the rib-out per group is probably good
enough, even with rt-constrain.  Can you tell which peers got the update or
not?  Not with the encoding discussed.  But you can tell what the state
advertised is.  But in such cases you're really better off looking at rib-in
state on the receiver anyway.

For ebgp in the same peer group?  Possibly good enough as long as you don't
care about the per-nexthop or potentially community changes.  If the ebgp
peers are also yours to monitor, the rib-in is sufficient.  If they're not,
then go per-peer.

> Why does loc-rib not give you approximate state?

Because it doesn't give you the results of export policy on your peer group?
(Otherwise we wouldn't be discussing a rib-out feature...)

-- Jeff