Subject: [MMUSIC] Question about ICE: Checks Schedule

From: woo johnman <[email-masked]>
Date: Tue, 8 Nov 2011 08:59:07 +0800

Hi,Experts:

I got such a question when i read the ICE standard.

At 5.7.4, It says:

"

 2.  The agent examines the check list for the first media stream (a
       media stream is the first media stream when it is described by
       the first m line in the SDP offer and answer).  For that media
       stream:

       *  For all pairs with the same foundation, it sets the state of
          the pair with the lowest component ID to Waiting.  If there is
          more than one such pair, the one with the highest priority is
          used.
 "

At 5.8. it says:

"

   o  Find the highest-priority pair in that check list that is in the
      Waiting state.

   o  If there is such a pair:

      *  Send a STUN check from the local candidate of that pair to the
         remote candidate of that pair.  The procedures for forming the
         STUN request for this purpose are described in Section 7.1.2.

      *  Set the state of the candidate pair to In-Progress.

   o  If there is no such pair:

      *  Find the highest-priority pair in that check list that is in
         the Frozen state.

      *  If there is such a pair:

         +  Unfreeze the pair.

         +  Perform a check for that pair, causing its state to
            transition to In-Progress.

"

As my understanding, clause 5.7.4 can be considered as the initialization
stage of the ICE check procedure expressed at clause 5.8.

The question is why the criterion of waiting pair selection is a little
different at the two stage.

At initliazation, it uses  'foundation' and 'component ID' to deduce the
waiting pair,But at runtime  it mainly uses 'priority' .

I think the later is simple and nice. Can the same criterion be used at two
stage?

Thanks in advance!

---

From: woo johnman <[email-masked]>
Date: Tue, 8 Nov 2011 09:48:56 +0800

Hi,Experts:

At 5.7.4, It says:

"

At 5.8. it says:

"

         +  Unfreeze the pair.

"

Thanks in advance!