Subject: [mpls-tp] change subject if appropriate - 2nd wg last call on draft-ietf-mpls-tp-gach-gal

From: Martin Vigoureux <[email-masked]>
Date: Wed, 25 Feb 2009 13:30:06 +0100

all,

in case the discussion does not directly concern the gal/gach draft
could you modify the subject line of the e-mail thread,
it will help in keeping track of the LC comments.
thanks for your cooperation.

-m

---

From: <[email-masked]>
Date: Wed, 25 Feb 2009 15:48:05 -0000

Point take Martin thanks....but I would say this much of discussion is
indirectly germane to this draft, as the draft has already made specific
assumptions about how the DP OAM and CP/MP encapsulations work (though
this has never been formally announced yet), and I disagree with some of
this.  For example, I strongly believe that DP OAM for defect
detection/handling should *not* be indicated by the GAL....that should
only be used by CP/MP protocols.

regards, Neil
> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Martin Vigoureux
> Sent: 25 February 2009 12:30
> To: [email-masked]
> Subject: [mpls-tp] change subject if appropriate - 2nd wg 
> last call ondraft-ietf-mpls-tp-gach-gal
> 
> all,
> 
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> mpls-tp mailing list
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---

From: Martin Vigoureux <[email-masked]>
Date: Wed, 25 Feb 2009 17:24:42 +0100

Neil,

I understand, this is why I have said *directly*.
Yet, I do not think the draft has made any assumption,
it builds onto the requirements doc.

regards,
-m

---

From: "BOCCI Matthew" <[email-masked]>
Date: Wed, 25 Feb 2009 17:33:18 +0100

Neil,

What exactly is your concern here? Is it that, by adding a GAL to the
label stack, the label stack is not identical between OAM and user plane
packets? Even so, they should still be switched in an identical manner
at intermediate LSRs and will still fate-share. 

This architecture was discussed in the JWT report and the MPLS-TP
framework (draft-ietf-mpls-tp-framework-00.txt), both of which have been
around for quite a while now.

Cheers,

Matthew

> [mailto:[email-masked]] On Behalf Of [email-masked]
> Sent: 25 February 2009 15:48
> To: VIGOUREUX MARTIN; [email-masked]
> Subject: Re: [mpls-tp] change subject if appropriate - 2nd wg 
> last callondraft-ietf-mpls-tp-gach-gal
> 
> Point take Martin thanks....but I would say this much of 
> discussion is indirectly germane to this draft, as the draft 
> has already made specific assumptions about how the DP OAM 
> and CP/MP encapsulations work (though this has never been 
> formally announced yet), and I disagree with some of this.  
> For example, I strongly believe that DP OAM for defect 
> detection/handling should *not* be indicated by the 
> GAL....that should only be used by CP/MP protocols.
> 
> regards, Neil
> > Subject: [mpls-tp] change subject if appropriate - 2nd wg last call 
> > ondraft-ietf-mpls-tp-gach-gal
> > 
> > all,
> > 
> > could you modify the subject line of the e-mail thread, it 
> will help 
> > in keeping track of the LC comments.

---

From: <[email-masked]>
Date: Wed, 25 Feb 2009 17:02:29 -0000

Note subject line changed:

Thanks Matthew,  I thought I had already explained them.....but in
summary I have 2 principle concerns:

1	The first relates to the role PWs should play in MPLS-TP as a
*transport network*.  I will not repeat the detail here, save to note
that:
-	PWs have no need to exist in MPLS-TP, and we for sure must not
create another layer network out of them like is happening in MPLS, ie
MS-PWs.
-	It is not clear to me at all why the CW is needed, even as
adaptation (though it can hardly be described as good adaptation)....and
this is something I want to pick up later as/when we on to discuss this
aspect of the DP, but it is germane to the next point on where the OAM
indicate flag should be.

2	The second relates to the OAM that is used for defect
detection/handling in the DP.  We should strive to ensure that DP OAM
and traffic look as alike as possible in order to ensure that the OAM
really mimics the traffic to the best possible extent.  If you add a GAL
then the labelled header increases by 1 for OAM wrt traffic and other
header fields will also change.

Further, from a pure architectural perspective we should try and keep
all DP components well separated from CP/MP components (this has some
relationship to security too).  So I would have a special label that is
only used by CP/MP components and not DP components...and defect
detection/handling OAM is a DP component.

Coming back to the OAM indicate aspect, we only need 1 bit to indicate
that the payload is OAM and not traffic.  Where we find that bit from is
dependent on what happens in and immediately after the last normal
forwarding header....which is why we need to understand just exactly
what is being proposed for the DP and why, eg CW...why needed in
MPLS-TP?...why not just have some PID function either in the last header
(S=1 indicates this and is essentially what John/I suggested) or
immediately following the last header?  The OAM indicate flag should lie
here somewhere, not under the GAL IMO.

I feel sure you must agree that these are the correct architectural aims
we should have for MPLS-TP.

regards, Neil

> From: BOCCI Matthew [mailto:[email-masked]] 
> Sent: 25 February 2009 16:33
> To: Harrison,N,Neil,CXM R; VIGOUREUX MARTIN; [email-masked]
> Subject: RE: [mpls-tp] change subject if appropriate - 2nd wg