Re: Keeping up data channel

On Wed, Jun 13, 2012 at 9:45 PM, Adam Bergkvist <adam.bergkvist@ericsson.com
> wrote:

> On 2012-06-13 15:36, SUN Yang wrote:
>
>>
>>
>> On Wed, Jun 13, 2012 at 4:15 AM, Stefan Hakansson LK
>> <stefan.lk.hakansson@ericsson.**com <stefan.lk.hakansson@ericsson.com>
>> <mailto:stefan.lk.hakansson@**ericsson.com<stefan.lk.hakansson@ericsson.com>>>
>> wrote:
>>
>>    On 06/12/2012 07:36 AM, Harald Alvestrand wrote:
>>
>>        On 06/11/2012 03:58 PM, Markus.Isomaki@nokia.com
>>        <mailto:Markus.Isomaki@nokia.**com <Markus.Isomaki@nokia.com>>
>> wrote:
>>
>>            Hi,
>>
>>            In today's WebRTC meeting a discussion came up on how costly
>>            it is
>>            to keep an unused data channel connected.
>>
>>            As long as we are using UDP, it is extremely costly for
>> cellular
>>            connected mobile devices. In many networks keep-alives at least
>>            every 30 seconds are neeed to keep the UDP flow alive.
>>
>>        We also have to send something every 30 seconds to keep the
>>        consent-to-receive alive in the case of media (and to maintain NAT
>>        mappings). So as long as a PeerConnection remains unclosed, I think
>>        we should assume that a packet will be sent every 30 seconds.
>>
>>
>>    I agree, and I also think this is more of a PeerConnection than a
>>    data channel issue.
>>
>>    I think we need to make developers close the PeerConnection when it
>>    is not needed. A way to promote this would of course be to make
>>    PeerConnection set up fast.
>>
>> Why set up PeerConnection fast means closing PeerConnection when not
>> needed?
>>
>
> It just a guess of how developers will behave. If it takes long to setup a
> PeerConnection it's likely that developers won't close it unless they're
> sure that it won't be used again. If it's quick and easy to setup again,
> they might consider closing it.
>
> /Adam

got it. thanks.

In another scenario:

I think if user have a conference call with 5 friends using webrtc, and
suddenly offline due to some problem, then restore requested by user, so
the browser will restart the 5 PeerConnections with his 5 friends, and
prepare to handle stream distribution to them via 5 mediastream constructed
with the same mediastreamtrack used by firest mediastream, and handle the
incoming 5 video/audio streams.

In fact it is really some time for browser to restore. all these in
conference call scenario.


-- 
Yang
Huawei