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(a)fib.upc.edu>
Copies to: udpcast(a)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(a)fib.upc.edu>
To: udpcast(a)udpcast.linux.lu, Daniel Sanchez
Dorado <dani(a)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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Michael D. Setzer II - Computer Science Instructor
Guam Community College Computer Center
mailto:mikes@kuentos.guam.net
mailto:msetzerii@gmail.com
http://www.guam.net/home/mikes
Guam - Where America's Day Begins
G4L Disk Imaging Project maintainer
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Michael D. Setzer II - Computer Science Instructor
Guam Community College Computer Center
mailto:mikes@kuentos.guam.net
mailto:msetzerii@gmail.com
http://www.guam.net/home/mikes
Guam - Where America's Day Begins
G4L Disk Imaging Project maintainer
http://sourceforge.net/projects/g4l/
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http://setiathome.berkeley.edu (Original)
Number of Seti Units Returned: 19,471
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