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Re: [rtcweb] RTP Usage: Is RTP Retransmission REQUIRED or RECOMMENDED

"Fabio Pietrosanti (naif)" <lists@infosecurity.ch> Wed, 27 June 2012 17:04 UTC

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Sender: Fabio Pietrosanti <naif@infosecurity.ch>
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Date: Wed, 27 Jun 2012 19:04:53 +0200
From: "Fabio Pietrosanti (naif)" <lists@infosecurity.ch>
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Cc: rtcweb@ietf.org
Subject: Re: [rtcweb] RTP Usage: Is RTP Retransmission REQUIRED or RECOMMENDED
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On 6/27/12 6:19 PM, Cameron Byrne wrote:
> I think Bernard noted this as well, but it is not so much buffer
> bloat... but the issue is indeed latency, not loss.  Consequently,
> re-transmission not productive.
> 
> On Wed, Jun 27, 2012 at 12:42 AM, Fabio Pietrosanti (naif)
> <lists@infosecurity.ch> wrote:
>> If you use RTP over a Mobile Networks subject to strong packet loss
>> (especially 3G or area plenty of many mobile devices), the RTP
>> retransmission became a requirement.
>>
> 
> Please cite the packet loss you are referring to.

My company does Mobile VoIP Clients for Blackberry, Nokia S60, iPhone,
Android and i know that Packet Loss is the *major cause of bad quality*
reported by my customer.

Given empirical practical experience i have from my customer:
 - In crowded areas in 3G
 - Within certain building (both 2G and 3G)

I don't know which kind of retransmission schemas you are referring to,
but i am sure that packet loss of UDP packets in a mobile network exists
and it's a concrete issue.

Fabio

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