Re: [MMUSIC] Questions about ICE candidates with BUNDLE - suggested text

[Roman Shpount <[e-mail]>]

On Mon, Feb 22, 2016 at 5:10 AM, Christer Holmberg <
[e-mail]> wrote:

> Assuming we will only associated ICE candidates to the “m=” line
> associated with the offerer/answerer BUNDLE-tag, below is a first suggested
> of modified ‘ICE Considerations’ text:
>
>
>
> -----------------------
>
>
>
> 11.  ICE Considerations
>
>
>
> 11.1.  General
>
>
>
>    This section describes how to use the BUNDLE grouping extension
>
>    together with the Interactive Connectivity Establishment (ICE)
>
>    mechanism [RFC5245].
>
>
>
>    The generic procedures for negotiating usage of ICE using SDP,
>
>    defined in [I-D.ietf-mmusic-ice-sip-sdp], also apply to usage of ICE
>
>    with BUNDLE, with the following exceptions:
>
>
>
>    o  When BUNDLE addresses for a BUNDLE group have been selected for
>
>       both endpoints, ICE connectivity checks and keep-alives only need
>
>       to be performed for the whole BUNDLE group, instead of per bundled
>
>       "m=" line.
>
>
>
>    o  Among bundled "m=" lines with which the offerer has associated a
>
>       shared address, the offerer only associates ICE-related media-
>
>       level SDP attributes with the "m=" line associated with the
>
>       offerer BUNDLE-tag.
>
>
>
>    o  Among bundled "m=" lines with which the answerer has associated a
>
>       shared address, the answerer only associates ICE-related media-
>
>       level SDP attributes with the "m=" line associated with the
>
>       answerer BUNDLE-tag.
>
>
>
>    Support and usage of ICE mechanism together with the BUNDLE extension
>
>    is OPTIONAL.
>
>
>
> 11.2.  SDP Offer/Answer Procedures
>
>
>
> 11.2.1.  General
>
>
>
>    When an offerer associates a unique address with a bundled "m=" line
>
>    (excluding any bundle-only "m=" line), it MUST also associate unique
>
>    ICE candidates to the "m=" line, according to the procedures in
>
>    [I-D.ietf-mmusic-ice-sip-sdp].
>
>
>
>    An offerer MUST NOT associate ICE candidates with a bundle-only "m="
>
>    line with a zero port value.
>
>
>
>    NOTE: The bundle-only "m=" line, if accepted by the answerer, will
>
>    inherit the candidates associated with the selected offerer BUNDLE
>
>    address.  An answerer that does not support BUNDLE would not accept a
>
>    bundle-only "m=" line.
>
>
>
>    When an offerer or answerer associates a shared address (i.e. a
>
>    previously selected BUNDLE address) with one or more bundled "m="
>
>    lines, the offerer (or answerer) MUST only associate SDP 'candidate'
>
>    attributes with the "m=" line associated with the offerer BUNDLE-tag
>
>    (or the answerer BUNDLE-tag) address).  The offerer or answerer MUST
>
>    NOT associate 'candidiate' attributes with any other bundled "m="
>
>    line to which the offerer (or answerer) associates a shared address.
>
>    This also apply to any other ICE-related media-level SDP attribute.
>
>
>
>    NOTE: The following ICE-related media-level SDP attributes are
>
>    defined in [I-D.ietf-mmusic-ice-sip-sdp]: 'candidiate', 'remote-
>
>    candidates', 'ice-mismatch', 'ice-ufrag', 'ice-pwd', and 'ice-
>
>    pacing'.
>
>
>
> 11.2.2.  Generating the Initial SDP Offer
>
>
>
>    When an offerer generates an initial offer, it associates unique ICE
>
>    candidates with the bundled "m=" lines, according to Section 11.2.1.
>
>
>
> 11.2.3.  Generating the SDP Answer
>
>
>
>    When an answerer generates an answer that contains a BUNDLE group,
>
>    the answerer MUST only associate SDP 'candidate' attributes (and
>
>    other ICE-related media-level SDP attributes) with the "m=" line
>
>    associated with the answerer BUNDLE-tag.
>
>
>
> 11.2.4.  Offerer Processing of the SDP Answer
>
>
>
>    When an offerer receives an answer, if the answerer supports and uses
>
>    the ICE mechanism and the BUNDLE extension, the offerer MUST
>
>    associate the same ICE candidates, associated with the "m=" line
>
>    representing the offerer BUNDLE address (selected by the answerer),
>
>    with each bundled "m=" line.
>
>
>
> 11.2.5.  Modifying the Session
>
>
>
>    When an offerer generates a subsequent offer, it associates unique or
>
>    shared ICE candidates with the bundled "m=" lines, according to
>
>    (Section 11.2.1).
>
>
>
I am not 100% sure about what exactly is meant by ICE candidate being
associated with an m= line. Does this mean ICE candidate is created for
this m= line and "candidate" SDP attribute is included in this m= line?

Overall the text is good, but I would explicitly replace "ICE candidates"
with "ICE candidates or any other ICE-related media-level SDP attributes"
to avoid any potential confusion. This will also make the phrase "This also
apply to any other ICE-related media-level SDP attribute" unnecessary.
_____________
Roman Shpount