Re: [mpls-tp] [mpls] WG LC draft-lm-pwe3-mpls-tp-gal-in-pw-00.txt

[Luca Martini <[e-mail]>]

Greg ,
Some

On 02/18/11 11:15, Greg Mirsky wrote:
> Dear Luca,
> I see at least two issues:
>
>     * use of GAL for PW, in my view, is another VCCV CC type that has
>       to be negotiated as described in RFC 5085.
>
These are valid points, but this document in question does not define,
not discussed VCCV.
We have since posted a draft that proposes a new VCCV mode , and we
welcome comments regarding that document.
(draft-nadeau-pwe3-vccv-2-01.txt)

>     * use of GAL creates ambiguous situation when PW CW is used. The
>       benefit from extending GAL in PW, as I see, is for PWs that are
>       not required to use PW CW. That might be a good enough reason to
>       update RFC 5586 as proposed in the document but we must address
>       use cases of GAL in PWs that require presence PW CW. If we
>       prohibit or even discourage use of GAL for these PWs that have
>       PW VCCV as native Associated Channel, then architecture of ACh
>       for MPLS-TP PW not simplified as result of adopting the proposal.
>
> Regard
Greg,
The GAL is basically a notifier that the packet following the end of the
MPLS label stack, is explicitly defined as a G-ACH format.
Normally the packet would be decoded as an IP packet , unless the last
label on the stack indicated otherwise.

The GAL can certainly be applied  to a PW OAM packet on a PW that uses
the CW, and this document does not define that , nor restricts it.

The scope of this document is limited to removing an unnecessary
restriction in rfc5586, hence  this comment not applicable to this document.

Thanks.
Luca

> s,
> Greg
>
> On Fri, Feb 18, 2011 at 7:46 AM, Luca Martini <[e-mail]
> <mailto:[e-mail]>> wrote:
>
>     Greg,
>
>     Sorry, but I do not remember the point you mention.
>     Can you explain again here ?
>     Thanks.
>     Luca
>
>
>     On 02/17/11 23:47, Greg Mirsky wrote:
>     > Dear Authors and All,
>     > prior to the meeting in Bejing and acceptance of this proposal as WG
>     > document Luca and I agreed that use of GAL with PW VCCV presents a
>     > problem.
>     > I was not attending the IETF-79, nor I found discussion of this
>     issue
>     > in the minutes. I think that this issue should be specified,
>     > explained. In my view, this document updates not only RFC 5586
>     > but RFC 5085 too.
>     >
>     > Regards,
>     > Greg
>     >
>     > Comment to draft-lm-pwe3-mpls-tp-gal-in-pw-00.txt
>     >
>     > On Sat, Oct 30, 2010 at 10:14 AM, Luca Martini
>     <[e-mail] <mailto:[e-mail]>
>     > <mailto:[e-mail] <mailto:[e-mail]>>> wrote:
>     >
>     >     Greg,
>     >
>     >     You are correct , the proposed update does not propose any
>     changes
>     >     to VCCV.
>     >     However the problem with vccv is not as simple as to ask for
>     a new
>     >     code point from IANA.
>     >     Given the good amount of discussion on this point, we should
>     >     probably have a discussion in Beijing.
>     >
>     >     Luca
>     >
>     >
>     >
>     >     On 10/29/2010 05:07 PM, Greg Mirsky wrote:
>     >>     Dear Authors,
>     >>     I think that proposed update of the Section 4.2. RFC 5586
>     makes it possible
>     >>     to use GAL on MPLS-TP PW that uses Control Word. I consider
>     it to be
>     >>     conflict between PW VCCV CC types because use of GAL is not
>     negotiated
>     >>     through PW VCCV negotiation. To avoid such situation I propose:
>     >>
>     >>        - in Section 5 request IANA to assign new CC Type "MPLS
>     Generic
>     >>        Associated Channel Label"
>     >>        - assign precedence to new CC Type that affects Section
>     7 RFC 5085
>     >>
>     >>     Regards,
>     >>     Greg
>     >>
>     >>
>     >>
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