4006 known issues with port speed/duplex negotiation

[kimlong]

Hi,

We have a sporadic problem with a 4006 that seems to be happening mostly

with Windows98 clients. When we use a Fluke to test the lines, dhcp works

great (a little slow) but we pull an address and successfully ping. The cable

is testing fine with no issues. However, when the customer attempts to login

they are not successful. Since it's 98, the systems are older, too. We are also

aware of the Windows ip autoconfig problem where an ip is arbitrarily assigned

if a dhcp request takes too long and it doesn't seem to be that.

I know in the past (like maybe 3 years ago) Cisco suggested static configurations for the port and duplex options on the switch. But since

that time, the current thought is to set everything to 'auto'. This particular

switch has the speed set but not the duplex. The swtich is running 5.5(16)

Should having the speed but not the duplex configured make a difference?

Thanks in advance.

[lgijssel]

As far as I know autonegotiation is not directly related to the OS that one uses. It has more to do with the chipsets on the network cards.

Today, it's not an issue anymore but perhaps with older equipment it is.

Autonegotition only operates correctly when both sides are set to AUTO.

So it's either fully AUTO or completely fixed. (both sides identical settings)

Configuring a either fixed speed or duplex on one side causes autoneg. to fail.

[kimlong]

Yup, I understand that it's the chipset but Windows98 is indicative of

how old these machines are. I'm going to set everything to auto

and see if that helps.

[t.baranski]

Is Portfast enabled?

Either way, I'd suggest leaving both speed and duplex on auto.

[kimlong]

Yes, portfast is enabled. I am going to set everything to auto

today and see if that makes a difference.

Thank you for your help.

[vincent-n]

Don't worry so much about the duplex or speed setting. The problem you have is a combination of Win98 and the "portfast" feature on the switch port. My recommendation to fix the problem is to simply enable "potrfast" on the PC ports and leave the speed/duplex settings as auto. To test a connection (for duplex and speed), simply run an FTP server and start FTPing from the PCs. On the 4006 (also assuming on same VLAN), the transfer speed should be > 3Mb/sec. If it gets lower than this then you most likely to have a speed/duplex problem. Also looking at the FCS error counts on the interface will also tell you the same problem.