Re: [OSPF] OSPF Hybrid Broadcast and P2MP Interface Type

Aton,

> -----Original Message-----
> From: Anton Smirnov [mailto:asmirnov@cisco.com] 
> Sent: Thursday, December 09, 2010 4:58 PM
> To: Jeffrey (Zhaohui) Zhang
> Cc: ospf@ietf.org
> Subject: Re: [OSPF] OSPF Hybrid Broadcast and P2MP Interface Type
> 
>    Hi Jeffrey,
> 
> > We developed the solution for a real network situation

It is difficult to go into too much details, but there are real examples of true-broadcast radio networks where the bw/delay is different between different pairs of radios.

> 
> It's a bit hard to see value of the proposal without knowing 
> more about
> possible network scenarios where this solution may be applicable.
> Situations when cost to each neighbor is different usually 
> mean that L2
> paths to them are different. Bunch of separate L2 connections are
> grouped together and presented to OSPF on L3 as single multiaccess
> interface - but underneath it is L2 point-to-multipoint network. So
> saying that Hello packet propagation is more optimal is not true -
> replication is just moved from OSPF to lower level.

Even so you still have the benefit of reduced number of adjacencies.

> 
> Thinking of network solutions which could benefit from assigning
> different cost to each neighbor I come up with things like VPLS, Metro
> Ethernet. May be fixed radio networks. But these all are L2 p2mp
> networks. Multiaccess is just emulated and benefits of using it are
> ephemeral.

Multiacess could be emulated in such a way that minimum replication happens - in that case the benefit is real.

The key is that the lower layer is presented to L3 as multi-access and we could/should take advantage of it.

Thanks.

Jeffrey

> 
> Anton
> 
> 
> On 11/22/2010 05:36 PM, 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
> > _______________________________________________
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> > OSPF@ietf.org
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> 