08-15-2007 02:06 PM - edited 03-03-2019 06:20 PM
Client/server environment. Server is connected to a Cisco hub. I took traces and I see about 150 packets retransmitted by the server side. Client displays 14 packets retransmitted. Performance is lower than expected. The server network interface card is logging Tx errors.
Questions:
Does the retransmission could be generated by a busy hub?
I know that errors in interfaces can be caused by a faulty port, bad cable or speed/duplex mismatch.
Someone claimed that a busy, congested hub could be capable of generating such errors and retransmissions. Can someone confirm that claim?
08-15-2007 02:22 PM
Hi,
yes to all questions.
08-15-2007 02:23 PM
The tx errors you are seeing on the client/server may be a result of high number of collisions on the LAN. That's definitely possible with a hub in place as it would generate large amount of broadcasts during busy traffic periods. Try replacing the hub with a switch to break the collision domain and the errors might cease.
HTH
Sundar
08-15-2007 02:40 PM
Positive. The errors went away once I put the switch in place.
Note that I set the switch port to 100Mbs full-duplex and the server side NIC to 100Mbs full-duplex.
Out of pure curiosity, is there any way I that could determine whether the errors were generated just because the hub was busy, or perhaps there was a negotiation issue? Very curious about that...
08-15-2007 02:43 PM
The hub must have been busy at that time. But, I just want to emphasize that wasn't the reason why you saw those errors. It's due to the fact the hub indiscriminately sends out the broadcast out every port and that would have resulted in more collisions of ethernet frames due to the half-duplex nature of the ports.
HTH
Sundar
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