Re: [MMUSIC] Fwd: New Version Notification for draft-reddy-mmusic-ice-happy-eyeballs-04.txt

["Prashanth Patil (praspati)" <[e-mail]>]

Hi Ari,

On 1/10/14 9:30 PM, "Ari Keränen" <[e-mail]> wrote:

>Hi,
>
>I read the latest draft and have a few questions. In Section 3 the draft
>says:
>
>>    ICE [RFC5245] section 4.1.2 states that the formula in section
>>    4.1.2.1 SHOULD be used.  Failing to do so may lead to ICE taking
>>    longer to converge as the checklist no longer will be coordinated.
>>    Therefore responsiveness of ICE candidate checks are improved when
>>    both sides support Happy-Eyeballs, both sides have the same number of
>>    candidate pairs, and both sides use the same Happy Eyeballs promotion
>>    algorithm.
>
>Do you mean the checklist is no longer coordinated (i.e., matching on
>both sides) if all those requirements aren't fulfilled? That sounds a
>bit strange but that's the impression I got from the text.
>
>Also, if there is no coordination/signaling between the endpoints, what
>are the odds they'd end up using the same promotion algorithm?
>
>>    If each ICE agent uses a different algorithm to promote IPv4
>>    candidates, ICE connectivity checks will be as responsive as the
>>    least aggressive algorithm.
>
>What is "least aggressive algorithm"?

Since there is no signaling between the end points, each end point could
promote IPv4 to different positions in the checklist. Based on candidate
pair priority = 2^32*MIN(G,D) + 2*MAX(G,D) + (G>D?1:0), the end point that
has promoted IPv4 in the least aggressive fashion i.e. IPv4 lower in its
list when compared to the other end point, will influence the candidate
priority pairing due to (2^32*MIN(G,D)) in the formula.


Thanks,
Prashanth

>
>
>Cheers,
>Ari
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