SPA2102 and multicast

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May 6th, 2009
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I have a partner in the DTV business who complain that the SPA2102 bugs their multicast transmissions through sending a ethernet PAUSE fram when receiving multicast in a rate it cannot handle although the SPA2102 is not (or at least should not) be interested in the transmission. Some channels work OK (those with lower bitrate) but channels with higher bitrate cause trouble. This is probably du to limited throughput in the SPA2102 where the low bitrate channels are just under the limit and the high-bitrate multicasts are just over that same limit. According to the same partner, turning of multicast in the SPA2102 does not rid the problem.

Are there any known issues with behavior when the SPA2102 is in the same LAN as a multicast transmission?


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Alberto Montilla Wed, 05/06/2009 - 06:59
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Dear Gustav;

SPA2102 is not designed for IPTV traffic. The issue the partner is experiencing is normal.

Our suggestion is to go for the WRP400 which can process IPTV streams, including IGMP proxy/snooping.

The only option I would try with SPA2102 (if not possible to exchange it by WRP400) is to change networking mode from router (NAT) to bridge. This will allow more throughput, although there is no guarantee of supporting IPTV streams. Of course this has some implications on IP address assignments (your ISP connection would need then to support several IP addressed).


gustavolsson Wed, 05/06/2009 - 07:09
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Hi Alberto and thanks for your answer!

Please note that this problem occurs when the SPA2102 is connected to the same switch as the IPTV receiver. The IPTV receiver is not in the ethernet-side of the spa2102 but in the same switch, ie. the multicast traffic is never passing through the spa2102. As:


                                 /----- (SPA2102)

(multicaster) ------- (switch) -|

                                 \----- (IPTV receiver)

Should the scenario above work or is it still limited by the SPA2102 not designed for multicast?


Alberto Montilla Thu, 05/07/2009 - 10:13
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Umm...It should work

Could you please send me the router configuration?

(Go to router->admin->advance and save the html page)

Meanwhile, I would suggest the routing mode to Bridge. This should solve the issue I believe.


mschellong Fri, 06/26/2009 - 08:25
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Hello  everyone,

I have the same problem in our network with same network scheme like Gustav.

Solution with changing lan interface form router to bridge is not working.

10 mbps plus mcast stream causes totaly collapse video.

Alberto Montilla Mon, 06/29/2009 - 06:30
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Dear Sirs;

We would need to see the traces. This issue may be an issue of the router which is sending (although not subscribed) the traffic through all LAN ports. The SPA2102 may be sending the pause because it cannot handle such amount of throughput.



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