[SR-Users] Need help understanding/separating signaling from media

[Alex Balashov]

It is indeed not generally recommended, due to the extremely real-time, delay-sensitive nature of media and the way VMs can subject a user space process like rtpproxy to distorted I/O scheduling and timing.

However, this seems to be less of a problem as virtualisation evolves closer and closer "to the metal", and in any case is unlikely to be an issue for relatively small numbers of concurrent calls, on a non-oversubscribed hypervisor. 

Still, it is not recommended from a "best practical" point of view, definitely not. 

Grant Bagdasarian <GB at cm.nl> wrote:

>Hello Alex,
>
>Thank you for the explanation. It's clear to me now. 
>One more thing, I've read that it's not recommended to have media being
>handled by virtual servers, is this also the case when using rtpproxy?
>We are using VMWare for virtualization.
>
>Regards,
>
>Grant
>
>________________________________________
>Van: sr-users-bounces at lists.sip-router.org
>[sr-users-bounces at lists.sip-router.org] namens Alex Balashov
>[abalashov at evaristesys.com]
>Verzonden: maandag 28 januari 2013 17:11
>Aan: sr-users at lists.sip-router.org
>Onderwerp: Re: [SR-Users] Need help understanding/separating signaling
>from media
>
>Hi Grant,
>
>On 01/28/2013 11:03 AM, Grant Bagdasarian wrote:
>
>> I think that the RTP Proxy module does precisely this, but what I
>> still don’t understand is how the rtp stream is passed between these
>> two agents for each call.
>
>The Kamailio 'rtpproxy' module goes out to the rtpproxy service[1] and
>asks it to engage the call, saying: "Can you please allocate and
>provide
>me with a pair of ports for each end of this call?"  The rtpproxy
>process answers, and Kamailio then writes the IP and ports provided by
>rtpproxy into the SDP of both the requests and replies involved in
>setting up the call.
>
>The result is that as far as both UAs are concerned, rtpproxy is their
>endpoint, and they will send media to it.  Kamailio instructs rtpproxy
>to bridge both streams.
>
>When the call is torn down, Kamailio tells rtpproxy to disengage and
>deallocate the bridge mapping for those streams.
>
>-- Alex
>
>[1] Which may be running on the same host, or may be running on another
>host, in a distributed fashion.  Kamailio talks to rtpproxy through
>rtpproxy's UDP control socket, and more than one rtpproxy may be used,
>both for failover and round-robin load distribution.  This is readily
>baked into the rtpproxy module.
>
>--
>Alex Balashov - Principal
>Evariste Systems LLC
>235 E Ponce de Leon Ave
>Suite 106
>Decatur, GA 30030
>United States
>Tel: +1-678-954-0670
>Web: http://www.evaristesys.com/, http://www.alexbalashov.com/
>
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-- 
Sent from my mobile, and thus lacking in the refinement one might expect from a fully-fledged keyboard. 

Alex Balashov - Principal 
Evariste Systems LLC 
235 E Ponce de Leon Ave 
Suite 106 
Decatur, GA 30030 
United States
Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com/