Subject: Re: Aggregation problem for I-PMSI in MVPN

From: Lizhong Jin <[email-masked]>
Date: Fri, 30 Jul 2010 19:02:06 +0800

Hi Rahul, Ben,
What I mentioned at the session has been discussed on list before, but not
ended. Before moving forward the status of
draft-ietf-l3vpn-2547bis-mcast-bgp-08, I strongly suggest to resolve this
technical issue.

The draft-jin-mpls-mldp-leaf-discovery-01 does not intend to solve above
aggregation problem. The leaf discovery mechanism is intent to allow L3VPN
Multicast to aggregate mLDP based P2MP LSP which is setup by other
applications, e.g, static or mLDP inband signaling.

This is more like the situation of P2P LSP which can be used for aggregation
for various application. For example, LDP based IP prefix LSP can be used
for aggregation for PW, L3VPN and L2VPN. This should be also the case for
multicast LSP, which can reduce the forwarding state for P routers. This is
a very important issue for MPLS multicast. And the current problem is that
mLDP based P2MP LSP can not be aggregated by various applications, because
of leaf initiated nature of mLDP. That's what the leaf discovery want to
solve.

Does the above decription make sense?

BR
Lizhong Jin

=====================================================
Date: Fri, 18 Jun 2010 11:53:55 +0800
From: [email-masked]
Subject: Re: Aggregation problem for I-PMSI in MVPN
To: [email-masked]
Cc: [email-masked], [email-masked],      Yakov Rekhter
       <[email-masked]>,    [email-masked],
       [email-masked],  [email-masked], [email-masked],
       [email-masked]
Message-ID:
       <[email-masked]
Content-Type: text/plain; charset="us-ascii"
OK, now I see two solutions:
A: Setting the Leaf Information Required flag to 1 in the PMSI Tunnel
attribute of its intra-as I-PMSI A-D route; (Yakov suggested)
B: Delete I-PMSI A-D route suppression rule to section 9.1.1 of
draft-ietf-l3vpn-2547bis-mcast-bgp-08 where already describes some
suppression rules of intra-as I-PMSI A-D. (Eric suggested)
I add another option, named C:
C: Let other independent mLDP leaf discovery mechanism to solve this
problem.
It would be appreciated if there are any other comments from the WG, and
decide which option is most optimized.
BR
Lizhong

Eric Rosen <[email-masked]>
2010-06-17 22:36
Please respond to
[email-masked]

To
[email-masked]
cc
[email-masked], [email-masked], [email-masked], Yakov
Rekhter <[email-masked]>, [email-masked],
[email-masked], [email-masked], [email-masked]
Subject
Re: Aggregation problem for I-PMSI in MVPN

> I think it is a bit difficult to ensure such "fact" as you described in
a
> mvpn network.
On the contrary, an operator would have to go to considerable trouble to
get
himself into a situation like this.  If you want each PE to auto-discover
all the other PEs in the same MVPN, you shouldn't suppress the I-PMSI A-D
routes!  That is, if you go to the trouble of explicitly turning off the
auto-discovery mechanisms, you shouldn't then complain that auto-discovery
isn't working.