Subject: [GROW] BGP Monitoring Protocol

From: "UTTARO, JAMES, ATTLABS" <[email-masked]>
Date: Wed, 8 Apr 2009 10:12:39 -0400

"o  Peer Distinguisher (8 bytes): Routers today can have multiple
      instances (example L3VPNs).  This field is present to distinguish
      peers that belong to one address domain from the other.

      If the peer is a "Global Instance Peer", this field is zero
      filled.  If the peer is a "L3VPN Instance Peer", it is set to the
      route distinguisher of the particular L3VPN instance that the peer
      belongs to."
 
I was a bit confused about the "L3VPN Instance Peer". What does it mean
to set the Peer Distinguisher to the Route Distinguisher of the L3VPN
instance that the peer belongs to? Are you assuming that the RD is
different for every instantiation of the VPN on each PE? It is possible
that the same RD is used across all PEs that a VPN belongs to.
 
Jim Uttaro

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From: Robert Raszuk <[email-masked]>
Date: Wed, 08 Apr 2009 08:12:02 -0700

Hi Jim,

 > I was a bit confused about the "L3VPN Instance Peer". What does it
 > mean to set the Peer Distinguisher to the Route Distinguisher of the
 > L3VPN instance that the peer belongs to?

EBGP session you are monitoring will belong to either global table or 
some VRF on a given PE. Adding RD makes it easier to find out which VRF 
given routes belong. If the session is to the global table the field 
will be zero.

 > Are you assuming that the RD is different for every instantiation of
 > the VPN on each PE? It is possible that the same RD is used across all
 > PEs that a VPN belongs to.

There is no need to make such assumption. The addition of the RD should 
be used at the management station along with Peer BGP ID which would 
then used in tuple identify PE/VRF for a given session.  Peer BGP ID is 
already part of BMP header.

Cheers,
R.

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From: "UTTARO, JAMES, ATTLABS" <[email-masked]>
Date: Wed, 8 Apr 2009 11:38:49 -0400

-----Original Message-----
From: Robert Raszuk [mailto:[email-masked]] 
Sent: Wednesday, April 08, 2009 11:12 AM
To: UTTARO, JAMES, ATTLABS
Cc: [email-masked]
Subject: Re: [GROW] BGP Monitoring Protocol

Hi Jim,

>>already part of BMP header.

My thinking is that the management station cannot use the RD as the
method to uniquely identify a VPN/VRF across all PEs. For VPNA Each PE
participating in VPNA may use a unique RD. This method is quite useful
for convergence, and load balancing. If ISPs can configure RDs as unique
per VPN per PE per VRF or common then how can RD make it easier to
determine eBGP sessions belonging to a specific VPN. I agree that it
will identify per VRF but is this useful without the VPN context?

Cheers,
R.

> I was a bit confused about the "L3VPN Instance Peer". What does it
mean