[rtcweb] JSEP issue regarding TRANSPORT/IDENTICAL mux category attributes

[Christer Holmberg <[e-mail]>]

Hi,

I have found an issue in JSEP.

Section 5.2.1 says:


   "Each m= section, provided it is not marked as bundle-only, MUST
   generate a unique set of ICE credentials and gather its own unique
   set of ICE candidates.  Bundle-only m= sections MUST NOT contain any
   ICE credentials and MUST NOT gather any candidates.”

…and:

   "[I-D.ietf-mmusic-sdp-mux-attributes] groups SDP attributes into
   different categories.  To avoid unnecessary duplication when
   bundling, Section 8.1 of [I-D.ietf-mmusic-sdp-bundle-negotiation]
   specifies that attributes of category IDENTICAL or TRANSPORT should
   not be repeated in bundled m= sections."


First, the two paragraphs contradict each other, because the ICE credentials (SDP ‘ice-ufrag’, ice-pwd’ etc attributes) are of TRANSPORT category.

Second, according to BUNDLE, IDENTICAL/TRANSPORT category attributes are not duplicated if the m- section 1) contains a shared address (BUNDLE address) or 2) is bundle-only.
If the m- line contains a unique address, which is common in the initial offer, attributes need to be associated with each m- line. However, the text does not address that.

I think the easiest way to fix it is by simply s/“specifies that attributes”/ “specifies WHEN attributes”.

…and change “should not” to “must not”.

Regards,

Christer