RVS4000 multicast freeze

Unanswered Question
Nov 9th, 2009

Hi all,

I have a problem with %subj% -- I'm trying to pass IPTV (IP multicast) from WAN to local network, the router is configured as gateway, with firewall and IPS switched off and with multicast passthrough switched on. On the client side I'm using VLC.

After reboot, VLC is able to play any multicast stream for about 30 seconds. After that time, packets coming from router stop (I examined this using WireShark). Sometimes, the receiving continues after another approx 30 seconds, but it stops again and forewer. If I switch streams (if I use another IP multicast address) before the first 30 seconds elapse, I can keep multicasting alive for longer time.

Do you have any hint? Now it is a big problem for me, is not there some new FW being prepared (I have



I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
David Carr Tue, 11/10/2009 - 07:54

Martin what kind of internet connect do you have connecting to the rvs4000?  What is your mtu settings set for?

martin.kolarik@... Tue, 11/10/2009 - 08:15

Hi David,

my internet connection is DHCP (bound to MAC). The provider runs local metropolitan network (optic fibers), inside which it multicasts UDP streams. So data flows not from internet, but from provider's network. Of course, from router point of view (and from its WAN address point of view) it is "from internet".

MTU is set on WAN side to "Auto".

Thank you,


martin.kolarik@... Tue, 11/10/2009 - 11:52

Hi David,

I do not suppose, that my solution will be widely accepted :-), but when new FW will be released, it can be patched that way. So, I logged in (using telnet) and I examined firewall tables.

Normally, when LAN client joins multicast stream, router adds the particular multicast address into FORWARD iptables chain. This results to behavior described in my first post.

Now, not normally :-), if I add whole multicast scope ( to both FORWARD and INPUT chains, everything WORKS! I expect router's FW to do the job itself (this or other way), because the solution is not stable (first router reboot kills it).

Please, tell me, if there is another solution, which I could preferably use.

Thank you,


David Carr Wed, 11/11/2009 - 07:41

Yeah at the moment I am not sure of any work around or fix.  I personally have never ran into this issue.  If you would like to call the SBSC at 866-606-1866 and get a documented case started with them, they can do some troubleshooting with you and see if they can get it resolved for you.  I Hope this helps.