Re: [PWE3] CEP IESG comments

[Carlos Pignataro <[e-mail]>]

Ron,

One quick question: The IANA Considerations section (Section 14) reads:

14.  IANA Considerations

   IANA considerations for pseudo-wires are covered in [PWE3-IANA].  CEP
   does not introduce additional requirements from IANA.

However, [PWE3-IANA] defines the "MPLS Pseudowire Type" [RFC4446] of
"SONET/SDH Circuit Emulation over Packet (CEP)", but not the
corresponding "L2TPv3 Pseudowire Type":
http://www.iana.org/assignments/l2tp-parameters

Also, in the signaling sections 11.X, I was wondering if the "CEP/TDM
Payload Bytes" and "CEP/TDM Bit Rate" interface parameter sub-TLVs
defined in [RFC4446] correspond to the "TDM PW AVP" definitions in
Section 2.1 of draft-ieft-l2tpext-tdm-02 when used over L2TPv3 (and
therefore a reference and brief description would be needed)
http://tools.ietf.org/html/draft-ieft-l2tpext-tdm-02#section-2.1
and the "CEP Options" interface parameter sub-TLV does not have an
equivalent L2TPv3 AVP.

Thanks,

--Carlos.

On 11/10/2006 12:21 PM, Ron Cohen allegedly said the following:
> Hi,
> 
> Please find below resolutions to several comments raised during the IESG
> review of the SONET PW draft (draft-ietf-pwe3-sonet-13.txt). Please let
> us know of any objections or comments to these resolutions. 
> 
> The modifications are:
> 
> 1. Limiting the draft scope to transport of CEP over MPLS and L2TP.
> Transport over UDP/IP will be left out of scope of this draft.
> 
> One comment concerned the security mechanims needed to support UDP/IP.
> To address this we need to include a detailed description of the use of
> IPsec, including the mechanisms needed to exchange keys. As far as the
> authors have been able to determine, there is no planned use of CEP over
> UDP/IP. The authors therefore recommend limiting the draft scope to
> transport of CEP over MPLS and L2TP. Transport over UDP/IP will be left
> out of scope of this draft and the associated sections removed from the
> text.
> 
> 2. Clarification on the use of RTP for CEP. Clarifications include
> 
> - Add the following sentence:
> 
>      Although CEP MAY employ an RTP
>      header when explicit transfer of timing information is
>      required, this is purely formal reuse of the header format.
>      RTP mechanisms, such as header extensions, CSRC list, padding, 
>      RTCP, RTP header compression, SRTP, etc. are not applicable to
> pseudowires.  
> 
> - Change Figure 1 to indicate RTP header location between CEP header and
> SONET fragement. 
>   This is consistent with L2TP and MPLS PSN encapsulation of other TDM
> drafts. 
> 
>                 +-----------------------------------+
>                 |   PSN and Multiplexing Layer      |
>                 |             Headers               |
>                 +-----------------------------------+
>                 |           CEP Header              |
>                 +-----------------------------------+
>                 |           RTP Header              |
>                 |           (RFC3550)               |
>                 +-----------------------------------+                |
> |
>                 |                                   |
>                 |           SONET/SDH               |
>                 |            Fragment               |
>                 |                                   |
>                 |                                   |
>                 +-----------------------------------+
> 
>                    Figure 1: Basic CEP Packet
>  
> 
> 3. Clarifications on security section that include adding the following
> sentences:
> 
>     Although CEP MAY employ an RTP header when explicit transfer of
> timing information 
>     is required, SRTP [RFC3711] mechanisms are not a substitute for PW
> layer security.
> 
>     CEP transport over L2TPv3 is subject to the security considerations
> discussed in 
>     section 4.1.3 of [LT2Pv3]. In particular, CEP over L2TP may be
> secured using IPsec
>     as described in [RFC3193].
> 
> 
> If this approach is acceptable to the working group we will forward the
> changes to the RFC editor.
> 
> Best
> Ron (on behalf of CEP Authors)
> 
> Ron Cohen
> Resolute Networks
> 
> 
> _______________________________________________
> pwe3 mailing list
> [e-mail]
> https://www1.ietf.org/mailman/listinfo/pwe3
> 

-- 
--Carlos Pignataro.
Escalation RTP - cisco Systems

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