3Com 3C905B-TX NICs cannot connect to Cisco Catalyst 2950 Switches

[szeshiong.lee]

Hi All,

Symptom: A few Cisco Catalyst 2950 switches installed into an existing network. All users migrated to the new switches. Most users have no problems with connecting to the "new" network. However, users using 3C905B-TX NICs do not have network connectivity. The LEDs on the switches show GREEN, giving the false impression that a connection has been established. However, there is no network connectivity, and tests conducted with PING returned "Request timed out".

What I've tried: Verified that it's not a cable issue. Verified that it's not a port issue. Upgraded one of the switches to the latest version of IOS available for download "12.1(9)EA1". Enabled 'port fast'. Upgraded NICs drivers to the lastest version. Verified that it is not a NIC issue as they can connect to a 'dumb' hub. Manually configured the network speed for the switch port and NIC.

All of the above actions did not seem to solve the problem. Wonder if any of you have a similar experience. Any help or suggestion will be deeply appreciated.

Thanks in advance

SzeShiong Lee

[medic]

You mention you manually set the port speed on both ends. Did you also manually set the duplex as well?

[szeshiong.lee]

Yes, I did. The switch port and NICs were manually configured to run at 100Mbps, Full Duplex. However, that did not help with the situation.

Thanks

[c.finn]

Hi SzeShiong,

I am using 2950s with 3C905B-TX NICs successfully. Could the problem be your cabling? I have seen situations where older Cat.5 UTP will work fine for 10 meg, half duplex but not for 100 meg connections. I would suggest setting both ends to 10 meg, half duplex to see if that works.

One other tip: If you're systems are running off a Microsoft OS, make sure that you use 3COMs DOS utility to configure the EEPROM on the NIC to be the desired speed/duplex.

Regards,

Colin

[o.hassairi]

make show interface fastethernet x/y and be sure protocol is up.

then see if there are input/output errors.

make sure too u don't have VLANs...

[szeshiong.lee]

Hi,

The interfaces are up. There are no errors. And the only VLAN I have is the default VLAN1. No other VLANs are configured.

The switches that I'm using are new, and I am experiencing this problem with default settings that came with the switch.

Regards,

SzeShiong

[szeshiong.lee]

Hi Colin,

Thanks for your valid suggestions. I think the cabling should not be the source of the problem as I'm using newly installed Cat 5e cables. However, I do have to admit that all this time I was trying to set the speed to 100Mbps Full Duplex and has yet tried the lower speed settings.

I'll try to manually configure the switch port and NIC to the lower speed setting and see if I can get a connection. I think your second suggestion regarding the 3Com DOS utility may be valid also. I'll try to do that as well if the speed setting fails.

Thanks again,

SzeShiong

[c.finn]

...one other thought... do you use any 'port security' commands on your switches?

[szeshiong.lee]

I did not change anything from the default settings. I'm assuming that the default does not have any port security settings enabled.

[wvaux]

One thing you can try if you haven't already is hard code the speed and duplex on the ports of the switch along with the NIC card. Another thing you may want to look at is that if the switch is set to auto auto it will only auto sense half duplex. You may want to check that out as well.