Subject: [siprec] Comments on extensions for recordiing-aware UAs

From: "Elwell, John" <[email-masked]>
Date: Fri, 20 May 2011 17:50:36 +0200

1. In section 6.2 of draft-portman-siprec-protocol-04, there is a record-aware option tag. It states:
"When a user agent inserts a Supported header field with the option
   tag record-aware, the UAS may provide recording indications through
   the media level SDP.  The UAS may also at the same time provide
   recording indications through traditional means such as playing a
   tone inband."
This seems to imply that the use of "traditional means" might not be necessary if the UA sends this option tag in Supported. The problem is, the a=record attribute in 6.1 only conveys the fat that a medium is being recorded and might not convey the full semantics that an announcement might convey. Therefore it might be dangerous to skip the "traditional means". Perhaps we need some different or additional wording, and perhaps something in the Security Considerations section.

2. In section 6.3, for a=recordpref, I think we need an additional value "nopreference", which should also be the default value.

John (as individual)