Greetings,
I'm troubleshooting an application problem in which I think that Ethernet flow control may be a contributing factor.
I think my switch may be sending PAUSE messages to particularly talkative hosts because I'm seeing brief (sub-second) stoppages in the multicast data streams coming from these hosts at the instant that a new multicast sender / receiver box joins the lan. Link establishment, IGMP host report and new (S,G) happen more or less simultaneously.
All of my talkative hosts stop transmitting for about the same duration and at precisely the same time.
Anyhoo, I don't *know* that Ethernet flow control is the problem, but it is enabled for RX and TX on both ends of each host-switch link.
So, the question is this: Will I see the PAUSE frames when I run tcpdump on the hosts in question, or are those flow control frames a special case handled only by the NIC, and which won't make it up to tcpdump?
I'm running tcpdump in promiscuous mode on each of these hosts. I have never observed a pause frame in the tcpdump output. The boxes are running linux 2.4.something.
Many thanks!
/chris