26 May
2011
26 May
'11
12:44 p.m.
On 5/25/11 9:33 PM, Daniel-Constantin Mierla wrote:
[...]
PS. Guys, before implementing SIP-related RFC N, where N is greater
than 4000, wait until RFC N+3000 is published to see if there will be
one obsoleting it. If not, you may be safe investing time in it.
on the other hand,
I think MSRP didn't bring much value, just another
type of stream out of signaling channel. I am not that familiar with
MSRP to know really if there are real benefits, but sending instant
messaging over SIP was there from beginning and rather simple without
other components that introduce new points of failure.
Reducing the number of optional headers will make the messages also
quite small. As for path optimization, initial request creating the
dialog could get only record-routes from the SIP hops that are intended
to stay in the path (like the relay).
For file transfer, clunking the content and sending over several
requests (again with minimum number of headers) with proper cseq
incrementation will be a straightforward implementation.
SIP can be used in very simple ways, without new types of protocols and
communication channels...
Cheers,
Daniel
On 5/25/11 1:00 PM, Iñaki Baz Castillo wrote:
--
Daniel-Constantin Mierla
http://www.asipto.com
Hi, for those interested in MSRP protocol
(instant message sessions
and file transfer for SIP) there are bad news:
Even if there are already clients and servers (MSRP relays o IM
conference servers) implementing the MSRP protocol (RFC 4975 and 4976)
the SIMPLE WG will publish a new draft [*] that breaks these RFC's
just to satisfy big vendors interested in deploying MSRP capable
SBC/ALG boxes (so instead of solving NAT issues with MSRP relays as
RFC 4976 states, they want it to be fixed in the router by doing ugly
ALG, or in a SBC). This is terrible because all the MSRP devices
should implement this new draft in order to interoperate (no backward
compatibility at all). The draft also breaks the security defined in
RFC 4975 (for example, TLS name based authentication cannot work
anymore).
For further information I recommend reading these two posts:
http://blog.tekelec.com/blog/bid/29816/More-on-MSRP-Session-Match-Extension
http://blog.tekelec.com/blog/bid/33138/MSRP-Session-Match-Backwards-Compati…
and also these very *hot* mail threads in the SIMPLE maillist:
http://www.ietf.org/mail-archive/web/simple/current/msg09227.html
http://www.ietf.org/mail-archive/web/simple/current/msg09229.html
[*] http://tools.ietf.org/html/draft-ietf-simple-msrp-sessmatch-11