On 14 Dec 2012 at 13:09, Daniel Sanchez Dorado wrote:
Date sent: Fri, 14 Dec 2012 13:09:42 +0100 From: Daniel Sanchez Dorado dani@fib.upc.edu Copies to: udpcast@udpcast.linux.lu Subject: Re: [Udpcast] IGMP missing
Yes, IGMP Snooping is enabled, but IGMP Snooping only works if the sender sends a IGMP Membership to the multicast group. A switch is not able to detect multicast traffic directly, because it's a layer 2 device. IGMP Snooping feauture allows a switch, (layer 2) detect a IGMP (layer 3) packet, but not the multicast traffic directly.
I have checked-out the tunning list. His hints are fantastic to constraint the flow, but i am trying to avoid it.
Thank you very much!
This IGMP Membership looks interesting, but was wondering what switches or do all switches support it? Did look for code example to implement it, but did see full examples yet. I've got old 3com switches in my classroom, and they have to have the Storm setting turned off or they shutdown a udpcast session.
El 13/12/2012 12:28, Michael D. Setzer II escribió:
Did you check out the Tuning hints on this page.
http://www.udpcast.linux.lu/hints.html
IGMP snooping is suppose to be enable.
On 12 Dec 2012 at 16:50, Daniel Sanchez Dorado wrote:
Date sent: Wed, 12 Dec 2012 16:50:26 +0100 From: Daniel Sanchez Dorado dani@fib.upc.edu To: udpcast@udpcast.linux.lu, Daniel Sanchez Dorado dani@fib.upc.edu Subject: [Udpcast] IGMP missing
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.
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