Cisco3500 Possible to change duplex?

[pdecker]

I have a 2621 router and two workstations connected to a Cisco3550 24 FX switch. Everything for my purposes works fine. However, when I console into the switch this message comes up every 30 seconds or so:

%CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on FastEthernet0/24
(not half duplex), with secure_router FastEthernet0/1 (half duplex).

And likewise when I console into router I get about the same message, (except with the order reveresed of course since its the router talking not the switch).

To me this seems obvious enough, the switch fastethernet is configured at full duplex, and the router fastethernet at half duplex. So I tried to just change the router fastethernet to operate in full duplex mode. But once I change it, the router fastethernet imeadiately goes down, and I cant get it back up unless I change the duplex back to half (or auto).

Is there a way to change the SWITCH mode to half duplex? Or should I do something else? Im not familiar with the commands of the cisco switch (I've learned all this stuff in a matter of two days

Once again, the network is up and running to the extend I need it, but its always a little uncomfortable to have an error message continually strobing your console.

Thanks for any help

 

[baddos]

under the interface, use the "duplex" command.

 

[pdecker]

The duplex command is available under the interface on the 2621 Router, however on the 3550-24-FX switch the duplex command is not available. Here is the type from the switch:

secure_switch#config
Configuring from terminal, memory, or network [terminal]? t
Enter configuration commands, one per line. End with CNTL/Z.
secure_switch(config)#interface fastethernet0/24
secure_switch(config-if)#duplex ?
% Unrecognized command

Here is my IOS version from sh ver :
IOS (tm) C3550 Software (C3550-I9Q3L2-M), Version 12.1(11)EA1

I would have thought that duplex would have been available in the switch, but as you can see, it wasnt, at least not accessed the same way as in the router. Is it available somewhere else?

 

[Degg]

the command should be 'duplex full', its reversed.

Degg
Network Administrator

 

[pdecker]

Still can't find it. I am searching in the interface config of the fastethernet port. When I do a ? the first few possible commands show as :

arp Set arp type (arpa, probe, snap) or timeout
bandwidth Set bandwidth informational parameter
carrier-delay Specify delay for interface transitions
cdp CDP interface subcommands
channel-group Etherchannel/port bundling configuration
default Set a command to its defaults
delay Specify interface throughput delay
description Interface specific description
dot1x IEEE 802.1X subsystem
exit Exit from interface configuration mode
flowcontrol Configure flow operation.
help Description of the interactive help system

Apparently there is no "duplex" command available in this interface config mode. I am trying to change the duplex mode on the switch, not the router. Any more suggestions of how to do this?

 

[pplewis]

Maybe you need to set the 'speed' before the duplexity command becomes available?

 

[jwi71]

FX ports only run in full duplex. You cannot select half, that is why the duplex command isnt available.

J