Cisco Switch, Broadcom NICs, Random Network Semi-dropping.

'ello folks...

So here's the situation. I'm in a company where roughly 100 workstations, 15 printers, and 8 servers all drain into one closet in which we have a series of 3 Cisco 3500 XL switches (I forget exact model at the moment). The switches are chained together via GBICs with copper firewire. The workstations in the building are almost all using Broadcom NetXtreme Gigabit Ethernet cards (HP machines). At completely random intervals, a machine will drop part way off the network - for example, it will be able to ping servers A, B, and C, but not D, E, F. All servers are running fine and everyone else is doing beautifully. If I go to the switches and change the port the workstation is connected on, it can then see all the servers. If I plug a different machine into the original "problem" port, the new machine can access everything just fine.

Any ideas? The ports on the switch are all auto-negotiate. The NICs are all auto-negotiate. The network cables shouldn't be the issue - it happens with new and old cords.

We never had this problem until we moved to the Cisco switches. Before this, we had the same network setup, but with 3Com switches.

I'm at a loss to what this could be. Any suggestions would be great!

Cheers, - Teros

Reply to
Loading thread data ...

Is the workstations and servers connected to the same switch? If not maybe an issue with the trunk between the switches, do a sh int0/X to get counter stats for the port. Also it is recommended that you hard code speed and duplex settings instead of using the auto negotiate settings.

Post a sh int 0/X also what version of IOS are you running do a sh ver and post it.

Reply to
Chad Mahoney

We also have the same problem with (mainly) 5000 Cisco chassis but others as well. What seems to happen is when auto-neg is on the duplex often gets mismatched. I guess the card or the switch tries to transmit at the same time as receive and packets are discarded. Auto neg should be hardware controlled and was developed as NWAY a long time ago---but Cisco seems to have got it all wrong! Other switches seem to be very happy at auto (3com, Netgear).

It's VERY inconvenient & time consuming to have to hard code - some devices may only have 10MB (eg. printers) and it's not following the design. Also in theory if the cable is dodgy the speed should be able to step down to 10MB

Reply to
David Wood

and if you look on the circuit board of some 5000 series cards you will see that the Ethernet chipset are Broadcom!

Reply to
Martin Kayes Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.