Hello, I'm the network administrator at the Barcelona School of Informatics, in Barcelona, Spain. We are testing a spanish deployment tool, Opengnsys, that uses udpcast for massive file distribution, via multicast. In our tests, we have found that udpcast floods our network with multicast traffic, and this is a big problem for us. We have other multicast products for many years, like Rembo, and there is no problem about flooding.
We have been sniffing and analyzing udpcast protocols, and we think that the problem is in the IGMP signaling. We haven't capture any IGMP packet. We have analyzed the source code, and we haven't been able to locate any reference to IGMP. Usually, the standard solution is generating an IGMP-Group Specific query, to subscribe the receiver to the group. With this step, you join a multicast group. Then, when the sender broadcast the multicast traffic, the network is capable to switch the packets only to the subscribed ports.
We have found, that our switches, are not capable of locate multicast receivers PCs, because they don't see the IGMP packet. IGMP snooping is enabled, and it allows the switches identify multicast, but, it doesn't work.
These are our testing scripts:
RECEIVER: ./udp-receiver --file /tmp/dst.iso --interface eth0 --nokbd
SENDER: ./udp-sender --file /tmp/wi7_pr64_000.iso --full-duplex --interface eth0 --autostart 30 --nokbd
Sender and receiver are Linux machines, in the same subnet, without any kind of firewalls. The file arrives fine, but, the multicast traffic floods other ports. The switch involved is a cisco C3560G-48PS, with igmp snooping enabled, and there is multicast enabled router (Cisco 3750G-48TS) for querier in this VLAN. Our switches don't make any IGMP-snoop link.
Any idea?
Thanks in advance.