[Sipconnectit] NENAi3 handling of REFER.
andrew.hutton at siemens-enterprise.com
Wed Mar 21 10:40:45 EDT 2012
During the workshop I did take an action to have a closer look at NENAi3 with regard to any possible incompatibility with the SIPConnect due to the use of REFER
Having had another look at NENi3 I am not sure that there really is a problem. In NENAi3 08-003 it seems clear to me that the intention is that Border Control Function (i.e. B2BUA) , which is at the ingress of the ESInet, is meant to terminate the REFER in the case when the remote party does not support REFER. The problem is that the NENA 08-003 spec has some holes with regard to specifying this.
Section 126.96.36.199 of the spec states "If the calling device supports REFER, the REFER can be sent to the calling device to transfer a call. Section 5.8 discusses the problem of a calling device that is unable to support a REFER transaction."
However section 5.8 actually only covers the case when the calling device does not support replaces but it does recommend that the BCF terminates the REFER in this case.
Having spoken to Brian Rosen about this at the last IETF meeting he was of the opinion that it is the role of the BCF to terminate the REFER when the remote UA does not support REFER. So I think the problem is with the NENA spec and not with SIPConnect1.1. I can talk to Brian again next week at the IETF to see if NENA can somehow clarify this.
Would be interested in other opinions on this.
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