Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) Circuit Emulation Service over MPLS (CEM) Encapsulation
draft-malis-sonet-ces-mpls-09

[Ballot discuss]
There are a number of features of SONET that are not mentioned (e.g. payload scrambling). Although they have little impact on the CEM, the lack of inclusion could cause an implementor to be confused. A short section, paragraph would suffice to state that certain SONET options have no impact on CEM.

[Ballot comment]
From the Gen-ART Review by Suresh Krishnan.

  Section 5.4.2 says:
  >
  > As discussed in section 6.2, a CEM de-packetizer MAY or MAY NOT
  > support re-ordering of mis-ordered packets. "
  >
  The term MAY NOT is not defined in RFC 2119.  The use here is confusing.
  Section 6.2 does not contain any such discussion either. I recommend a
  corrected reference and "MAY".

IANA Last Call comments:

Upon approval of this document, the IANA will make the following
changes in "Pseudo Wires Name Spaces (PWE3)" registry located at
http://www.iana.org/assignments/pwe3-parameters
sub-registry "MPLS Pseudowire Types Registry" (PW Types)

OLD:
PW type Description Reference
------- ----------------------------------------------------------- ---------
0x0008 SONET/SDH Circuit Emulation Service Over MPLS Encapsulation [CEM]

NEW:
PW type Description Reference
------- ----------------------------------------------------------- ---------
0x0008 SONET/SDH Circuit Emulation Service Over MPLS Encapsulation
[CEM,RFC-malis-sonet-ces-mpls-09]

We understand the above to be the only IANA Action for this document.

-------- Original Message --------
Subject: draft-malis-sonet-ces-mpls-08.txt
Date: Thu, 12 Jul 2007 14:27:28 +0200
From: Mark Townsley
To: Malis, Andrew G. , pwe3-chairs@tools.ietf.org


Andy,

I just reviewed this document, and am prepared to issue the LC for
publishing as Historic. I have two concerns. First, it seems that the
CEM header does not follow the "first nibble set to zero" which could of
course confuse ECMP implementations. I think it may be worth pointing
this out via a reference to RFC 4928. Something in Section 4 that looks
like:

Note: Setting the R bit to 1 violates the Best Current Practice defined
in RFC 4928 when operating on MPLS networks. In this situation, MPLS
networks could mistake a CEM payload as the first nibble of an IPv4
packet, potentially causing misordering of packets on the pseudowire in
the presence of MPLS ECMP in the MPLS network.

Second, you have this in the document...
> 10. IANA Considerations
> 
>    IANA has already allocated the PWE3 PW Type value 0x0008 for this
>    specification; however, the current entry in the IANA database
>    requires a correction. The entry should properly say:
> 
> 0x0008 SONET/SDH Circuit Emulation Service Over MPLS Encapsulation [CEM]
> 
>    And the CEM reference should say:
> 
> [CEM]  "SONET/SDH Circuit Emulation Service over MPLS (CEM)
>        Encapsulation", draft-malis-sonet-ces-mpls-07.txt
>        (work in progress)

It looks to me like 0x0008 was assigned to CEP, as referenced in RFC
4446 and RFC 4842. If CEM is also using this, we have more of a problem
than simply a typo here.

- Mark

From: "Andrew G. Malis" :

I would like to request that draft-malis-sonet-ces-mpls-07.txt be
published as a historical RFC. Mark Townsley will be the shepherding
AD.  This draft documents the IANA assignment of PWE3 PW type 0x0008,
and points to RFC 4842 as the standards-track protocol for this
application.