[AVT] WGLC comments on draft-ietf-avt-ports-for-ucast-mcast-rtp-11: Part 6: Resend behavior

[Magnus Westerlund <[e-mail]>]

Hi,

In Section 4, there is some statement about resending. I want to come to
some conclusion on this topic that was brought up before.

The basic issue is the question on how one detects packet loss for RTCP.
There is no other mechanism than detecting lack of response / action
from the corresponding peer.

The issue I have is that the RTT + server delay in responding can easily
be many times the minimal sending interval that RTCP configure to serve
even 1 mbit/s stream. Thus the formulation in the draft:

"When a client sends a
   Port Mapping Request or Token Verification Request message but it
   does not receive a response back from the server (either a Port
   Mapping Response or Token Verification Failure message), it MAY
   resend its request by following the timer rules defined for RTCP
   feedback messages in Section 3.5 of [RFC4585] as a good practice."

Might not be sufficient. Because the issue is how one detects the packet
loss and how quickly the packet is considered lost.

Cheers

Magnus Westerlund

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