Re: [mpls] Thanks for comments on draft-akiya-mpls-lsp-ping-reply-mode-simple

Hi Loa,

Thanks for comments.

> "If the IP path is there, use that! It will always work"

Yes, that's a good comment from Curtis. There's one thing that I'd like to point out.

Multisegment-Pseudowire over TP was a scenario where I was scratching my head few months ago. Initiating TP segment could have IP routes (TP in IP based domain), but next TP segment may not have IP routes (IP in IP-less domain). So the "If the IP path is there ..." is something which initiator does not always have knowledge of. In this case, using Reply Mode of IP can cause responder to drop the request. Same problem as using Reply Mode 4/5 but not having paths corresponding to Reply Mode 4/5 at responder.

The question is whether standard should have pre-defined preference or not, I'd like to wait for more comments.

Thanks,
Nobo

> -----Original Message-----
> From: Loa Andersson [mailto:loa@pi.nu]
> Sent: Thursday, November 07, 2013 12:22 PM
> To: Nobo Akiya (nobo); mpls@ietf.org
> Cc: draft-akiya-mpls-lsp-ping-reply-mode-simple@tools.ietf.org
> Subject: Re: [mpls] Thanks for comments on draft-akiya-mpls-lsp-ping-
> reply-mode-simple
> 
> Folks,
> 
> <chair hat off>
> 
> 
> 
> On 2013-11-07 00:02, Nobo Akiya (nobo) wrote:
> 
> <snip>
> 
> >
> > B. For pre-defined preference Reply Mode:
> >
> > Current proposed order:
> >    1. control-channel
> >    2. reverse-lsp
> >    3. IP path
> >
> > That was what author felt as a reasonable order
> based on input from some, at the time of writing the draft.
> However, we would like to seek for further input from others in the WG,
> particularly from operators. Thanks!
> 
> I can understand why we came up with with this order of preference; I can
> also understand the logic behind what Curtis said "If the IP path is there, use
> that! It will always work"
> 
> However thinking about it I'm more and more convinced that the order of
> preference need to established not as something that is once and for all
> fixed by the standard. I think that the operator would benefit from be able
> to decide the order of preference at configuration time.
> 
> /Loa
> 
> </chair hat off>
> 
> >
> > -Nobo
> >
> > _______________________________________________
> > mpls mailing list
> > mpls@ietf.org
> > https://www.ietf.org/mailman/listinfo/mpls
> >
> 
> --
> 
> 
> Loa Andersson                        email: loa@mail01.huawei.com
> Senior MPLS Expert                          loa@pi.nu
> Huawei Technologies (consultant)     phone: +46 739 81 21 64