From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Fw: [Bridge] IGMP snooping not filtering multicast messages Date: Wed, 8 Jun 2011 08:44:34 -0700 Message-ID: <20110608084434.28bfc18c@nehalam.ftrdhcpuser.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Herbert Xu Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:59399 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756597Ab1FHPoq (ORCPT ); Wed, 8 Jun 2011 11:44:46 -0400 Sender: netdev-owner@vger.kernel.org List-ID: Begin forwarded message: Date: Tue, 31 May 2011 19:48:52 +0200 (CEST) From: "maxd@inwind.it" To: bridge@lists.linux-foundation.org Subject: [Bridge] IGMP snooping not filtering multicast messages Hi. I have a partial mesh network composed by Linux nodes. Each linux node may have up to 4 ethernet interfaces, which are exploited to create point-to-point connections with other linux nodes. I have bridged the ethernet interfaces in each node, so that the whole network, which is physically composed by a set of network segments, appears as a single layer-2 domain. I have enabled spanning tree to avoid loops. In this scenario, I would like to exploit the IGMP snooping functionality, but it seems that it is not working properly. I am using iperf to set a multicast source (iperf client) and a few multicast sinks in the network (iperf servers). I am using tcpdump, instead, to check where multicast messages are received. What I notice is that there is apparently no filtering of the multicast messages, that are always flooded in the network. I tried to repeat the test varying the multicast address (paying attention not to get reserved addresses), with and without multicast clients set, with the multicast_router option set to 1 (default) and to 0. To double check that IGMP is working, I have also tried to disable it; the only difference I see is that tcpdump does not show IGMP query messages when the IGMP snooping is disabled. So, I am wondering if the IGMP snooping implementation currently available can deal with my scenario. In particular, I would stress the following points that I think might be relevant: -I have no multicast router in my network (it looks like a single stand-alone lan) -Each node acts as a bridge, so I have multiple bridges in my network, connected each other. Any idea would be greatly appreciated! Massimiliano _______________________________________________ Bridge mailing list Bridge@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/bridge