Subject: [Ice] 5245bis: NOMINATED vs SELECTED

From: Christer Holmberg <[email-masked]>
Date: Fri, 18 Nov 2016 12:07:51 +0000

Section 2.6 says:

   "Consequently, ICE assigns one of the agents in the role of the
   CONTROLLING AGENT, and the other of the CONTROLLED AGENT.  The
   controlling agent gets to nominate which candidate pairs will get
   used for media amongst the ones that are valid.

   When nominating, the controlling agent lets the checks continue until
   at least one valid candidate pair for each media stream is found.
   Then, it picks amongst those that are valid, and sends a second STUN
   request on its NOMINATED candidate pair, but this time with a flag
   set to tell the peer that this pair has been nominated for use.  This
   is shown in Figure 4.

   <picture>

   Once the STUN transaction with the flag completes, both sides cancel
   any future checks for that media stream.  ICE will now send media
   using this pair.  The pair an ICE agent is using for media is called
   the SELECTED PAIR."

Now, if I understand the text above correctly, the only difference between NOMINATED and SELECTED is that SELECTED means that the nomination STUN transaction has succeeded.

However, e.g., in section 5.1.3.4 is the following text:

      "Completed:  In this state, ICE checks have produced nominated pairs

      for each component of the media stream."

Q1: Shouldn't a check list be placed in Completed state once the nomination procedure has actually succeeded, i.e., one ICE checks has produced SELECTED pairs? In addition, due to the previous nomination changes, I don't think a check list is Completed just because a pair is nominated.

Q2: Is there a need to separate between NOMINATED and SELECTED? Especially with the removal of aggressive nomination, there may be multiple NOMINATED pairs.

Regards,

Christer

Completed:  In this state, ICE checks have produced nominated pairs

      for each component of the media stream.

---

From: Christer Holmberg <[email-masked]>
Date: Fri, 18 Nov 2016 14:45:09 +0000

Hi,

I need to re-formulate my previous e-mail.

First, the text in Section 2.6 that I referenced needs to be modified, due to the removal of aggressive nomination.

At least the following sentence I think shall be modified, as it suggests (at least in my reading) that media cannot be sent before nomination:

OLD:

   "The controlling agent gets to nominate which candidate pairs will get
   used for media amongst the ones that are valid."

NEW:

   "The controlling agent gets to nominate which candidate pairs will get
   used for media amongst the ones that are valid. Before the controlling
   agent nominates a pair media can be sent on any valid candidate pair."

My questions slightly modified:

Q1: Shouldn't a check list be placed in Completed state once the nomination procedure has actually succeeded, i.e., one ICE checks has produced SELECTED pairs?

I removed Q2, because it is not important at this point.

Regards,

Christer

From: Ice [mailto:[email-masked]] On Behalf Of Christer Holmberg
Sent: 18 November 2016 14:08
To: [email-masked]
Subject: [Ice] 5245bis: NOMINATED vs SELECTED

Section 2.6 says:

   <picture>

Regards,

Christer