Hi Jeffrey,

please see inline:

On 23.11.2010 19:29, Jeffrey (Zhaohui) Zhang wrote:
Peter,

I think I understand the potential issue you mentioned, but not quite clear 
about your solution.

The draft mentions that the metrics could be dynamically learned if the 
underlying network support it (in that case the l2 and l3 should match). 
However that is outside the scope the draft, which assumes that the metrics is 
obtained by some means. Indeed if it is statically configured then the operator 
needs to be careful.

dynamically updating L3 metrics based on the L2 topology is a problem of it own. The consequence is that L2 network changes that mostly used to be hidden to the L3 now becomes propagated to the L3 network.


You mentioned creating p2p l2 connections. Does that mean there will be 
correponding l3 p2p interfaces? If yes isn't it no longer a bcast/p2mp hybrid? 
If not can you elaborate?

yes, some form of a sub-interface using the VLAN technology. That is typically a p2p connection between the two OSPF speakers.

thanks,
Peter

Thanks.
Jeffrey

-----Original Message-----
From: Peter Psenak [mailto:[email protected]]
Sent: Tuesday, November 23, 2010 1:11 PM
To: Jeffrey (Zhaohui) Zhang
Cc: [email protected]
Subject: Re: [OSPF] OSPF Hybrid Broadcast and P2MP Interface Type

Hi Jeffrey,

one potential issue with this approach is the possible suboptimal
traffic path if the L3 p2p topology created as you described do not
match the L2 forwarding topology. With large L2 domains it may be be
nontrivial to assign L3 metric correctly so that the L2/L3
forwarding match.

One possible method to address the problem in hand is to create p2p
connections between the routers via the L2 domain, using dedicated
VLANs. This way the L2 forwarding is forced to match the L3
p2p topology.

thanks,
Peter

On 22.11.2010 17:36, Jeffrey (Zhaohui) Zhang wrote:
Hi,

I presented the draft
http://www.ietf.org/draft-nsheth-ospf-hybrid-bcast-and-p2mp-01
.txt in Beijing (slides
http://www.ietf.org/proceedings/79/slides/ospf-9.ppt) and it
was deferred to the mailing list on whether the problem is
worth the working group effort (some who reviewed the draft
agreed that the proposed solution is reasonable for the problem).

I'd like to request folks to review the draft/slides and
voice your opinion. We developed the solution for a real
network situation and would like to see that it gets
consensus and standardized so that more operators/vendors can
benefit from this.

Thanks.
Jeffrey
_______________________________________________
OSPF mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/ospf





_______________________________________________
OSPF mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/ospf

Reply via email to