LAN down when transfering big file

[y.wong]

Hi.

I've a LAN using 6 cat 3550 in cascaded stack connection. But whenever a big file is transferred to a port on another switch in the same VLAN, the entire LAN down.

Some details

- Using Gigastack GBIC in auto duplex mode (half)

- 14 VLAN

- storm-control enabled in all interfaces

- no spanning tree enabled (tried to enable but doesn't help)

- vtp pruning enabled

- IOS C3500XL Ver12.0(5.2)XU, Maintenance interim software.

- 8 + 1 MB RAM

Any help appreciated. Thanks

YH

[smif101]

Are you stating that the GBIC is auto negoitationg to half-duplex? If so change that to full-duplex right away. None of your ports should be in half-duplex. That will tie up the whole link when downloading because only one side can trasmit at a time.

Jason Smith

www.smif101.com

[y.wong]

Yes. They auto negotiate to half-duplex. I suppose it is the default for cascaded stack configurations, as stated below. When I force them to full-duplex, the connection came down.

http://www.cisco.com/en/US/products/hw/modules/ps872/products_module_installation_guide_chapter09186a008007d1f6.html#xtocid15

Big file transfer between ports in the same switch is ok.

I am thinking to change to a star configuration, so that GE connection would be full duplex. Would that help?

Pls help.

[aashish.c]

Hi

YES, by default in stacking design using Gigastack Gbic ports will only work at HALF duplex, never at full and you cant make them run at full duplex.

In this acse when you star a trabsfer of big file from 1 switch to another then what exactly happens. does the port shut down, or switch hangs up ??

Kindly check the following :

1. capture the logs from the source switch and destination switch.

2. check the errors like input, output, collisions etc.

3. on Gig ports of switches whiare connecting to other switches, apply the following command :

switch(config-if)#switchport nonegotiate

There would be lot of collisions on Gig ports because of half duplex, but check these things and also paste the output here.let me know the result.

Thanks and Regards

Aashish