Subject: [siprec] FW: Remote recording - RTC-Web client acting as SIPREC session recording client

From: "Elwell, John" <[email-masked]>
Date: Tue, 23 Aug 2011 10:02:22 +0200

Would SIPREC folks please note that there is considerable discussion ongoing on the RTCWEB mailing list concerning whether an RTC-Web client needs to support SRC functionality.
http://www.ietf.org/mail-archive/web/rtcweb/
In particular, the message below attempts to summarize the discussion to date. If you have views, please use the RTCWEB mailing list.

John

> -----Original Message-----
> From: Elwell, John 
> Sent: 23 August 2011 08:59
> To: [email-masked]; [email-masked]
> Subject: Remote recording - RTC-Web client acting as SIPREC 
> session recording client
> 
> There has been some discussion recently on remote recording, 
> mixed to some extent with discussions on local recording and 
> with mailbox, but I would like to focus on remote recording 
> and try to summarize.
> 
> First, some background on the IETF SIPREC WG. This is 
> specifying support for SIP-based session recording, whereby a 
> Session Recording Client (SRC) on the path of a call 
> (communication session) can forward media and metadata to a 
> session recording server (SRS) or recording device. In 
> conventional SIP terms, the SRC can exist at an endpoint of 
> the communication session being recorded (i.e., at a SIP UA), 
> or at a B2BUA that has access to the media as well as the 
> signalling. Very often in a contact centre, there are 
> mandatory requirements for recording some or all 
> communication sessions, and often calls are routed through a 
> B2BUA that also provides the SRC. So in this case there is no 
> responsibility on SIP UAs to support SRC functionality, and 
> no issues of additional bandwidth on the device's access. 
> However, it is anticipated in SIPREC that in some deployments 
> UA-located SRCs will be used. How a UA is organized 
> internally to provide SRC functionality is not standardized.
> 
> So the question for RTC-Web is whether a SIP UA implemented 
> as an RTC-Web client can provide SRC functionality, i.e., 
> support remote recording. An RTC-Web SIP UA is implemented by 
> a combination of functionality running on the web server, 
> functionality running in client side script (JS) and 
> functionality embedded in the browser. The amount of 
> functionality needed in the browser and needing to be exposed 
> at the browser API in support of SRC will depend to some 
> extent on how much core functionality goes into the browser, 
> in particular whether the browser implements SIP or not. Some 
> of the functions noted to date include:
> - ability to take a copy of streams sent to / received from 
> the remote party and send them, in real-time, to a remote 
> recording device (SRS);
> - possible need to mix the copied streams before sending 
> (e.g., mix the sent and received audio streams)
> - possible need to use a different codec or other parameters 
> when sending to the SRS;
> - possible need to use a different encryption/integrity 
> context when sending to the SRS;
> - possible need to insert tones / announcements into the 
> original media path being recorded;
> - possible need to support SDP enhancements for indicating 
> media that are being recorded or preferences for which media 
> are being recorded;
> - possible need to support SIP enhancements for indicating 
> SRC/SRS capability and recording awareness (if SIP is 
> implemented in browser);
> - possible need to support the sending of metadata to the SRS 
> (if SIP is implemented in browser).
> 
> Clearly there would be a fairly big hurdle for browsers to 
> support SRC functionality. But without this, RTC-Web clients 
> would not be suitable for use in environments where remote 
> recording is required and calls are not forced through some 
> middlebox that provides SRC functionality.
> 
> John
> 
> John Elwell
> Tel: +44 1908 817801 (office and mobile)
> Email: [email-masked]
> http://www.siemens-enterprise.com/uk/
> 
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