Re: [MMUSIC] FW: I-D Action: draft-schwarz-sdp-for-gw-01.txt

Christian Groves <> Fri, 04 April 2014 01:43 UTC

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Subject: Re: [MMUSIC] FW: I-D Action: draft-schwarz-sdp-for-gw-01.txt
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Hello Albrecht,

Thanks for submitting the draft. I support the addition of the extra 
<proto> codepoints for scenarios where a gateway performs application 
agnostic inter working. In general the background to H.248/Megaco usage 
of SDP is good but I'm not sure if the reasons for the new codepoints 
are documented sufficiently in the draft.

Some specific comments below:
Clause 1.4 Scope: I propose to word this slightly differently to 
indicate the scope is the collection of SDP codepoints for GCPs in order 
to identify additional ones that REQUIRE registration with IANA.

Clause 4: There appears to be some duplication in the headings, i.e. 4 
and 4.5. Perhaps also "<proto> element" needs to be removed from the 
title of heading 4 as clause 4.4 covers the <type> element?

Clause 4.1 Purpose, Last Para: To me this is the reason for the entire 
draft. The draft has cataloged how SDP is used by GCPs(H.248/Megaco) 
however hasn't really gone into much depth on why the additional 
codepoints are needed. Perhaps a paragraph for each additional codepoint 
could be added indicating where it is used/needed?

Clause 4.4: I think the draft could indicate that H.248 uses the 
<attrtype> values as defined on the IANA registry and no additional IANA 
registrations are required.

Clause 5.1: I think it would be good to note that this has already been 
registered with IANA.

Clause 7.1: TCP/TLS is already registered. See RFC4572 clause 4. However 
I'm not sure that in the case of agnostic interworking that the MUST 
indicated in that clause (/An 'm' line that specifies 'TCP/TLS' MUST 
further qualify the protocol using a fmt identifier to indicate the 
application being run over TLS./) applies.

I've also noticed some other minor editorial issues that i'll forward to 
you off-line.

Regards, Christian

On 27/03/2014 8:48 PM, Schwarz, Albrecht (Albrecht) wrote:
> fyi, this is a spin off activity from
> 	draft-ietf-mmusic-udptl-dtls
> in order to define additional codepoints as required for DTLS security session termination (so called end-to-access edge security mode) and DTLS transparent forwarding (e.g. as part of end-to-end security mode) in middleboxes.
> -Albrecht
> -----Original Message-----
> From: I-D-Announce [] On Behalf Of
> Sent: Donnerstag, 27. März 2014 10:03
> To:
> Subject: I-D Action: draft-schwarz-sdp-for-gw-01.txt
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
>          Title           : SDP codepoints for gateway control
>          Author          : Albrecht Schwarz
> 	Filename        : draft-schwarz-sdp-for-gw-01.txt
> 	Pages           : 12
> 	Date            : 2014-03-27
> Abstract:
>     SDP is used in many signalling protocols at call control level (such
>     as SAP, SIP, BICC), bearer control level (such as RTSP, IPBCP) and
>     gateway control level (such as H.248/MEGACO, MGCP). Scope of this RFC
>     is related to gateway control specific SDP usage. Gateway control
>     protocols do usually NOT define and introduce any new SDP parameters,
>     however, gateway control protocols need specific SDP parameter values
>     in addition to SDP usage at call or bearer control level. Such SDP
>     codepoints are collected by this RFC with the purpose of registration
>     with IANA.
> The IETF datatracker status page for this draft is:
> There's also a htmlized version available at:
> A diff from the previous version is available at:
> Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at
> Internet-Drafts are also available by anonymous FTP at:
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