Cisco 2950's: FULL DUPLEX

[Smooth23]

Hello,

How do I configure all ports on a Cisco 2950 48 port switch to Full duplex?

I have Cisco Network Assistant installed and can see how I change each port individulay but not how to change all ports on the switch.

Can this be done?

I have three 2950’s all with GBIC connections and one CAT6 to another area. So 3 x 48ports and 1 x 24 port.

Looking forward to hearing from someone.

 

[leedsit]

The way I do it would be

config t
interface range fastethernet 0/1 - 48
duplex full
end



LEEroy
MCNE6,CCNA2,CWNA, Project+

 

[Smooth23]

Hmm, so there's no way of accomplishing this in Network assistant manager?

It's just tat i'm too familiar with cmd line stuff...

 

[leedsit]

Hi,

sorry, not too familar with NAM.

LEEroy
MCNE6,CCNA2,CWNA, Project+

 

[Smooth23]

No worries, thanks anyway.

 

[JOAMON]

The default is for Auto. Why would you need to hard set to full duplex? I have only ever had to mess with the speed and duplex when connecting to an old 10-base-t device then had to set the port to 10 half duplex.

 

[JOAMON]

I recall reading someing on CNA and it was related to the smartport section and then in the device setup tab I believe there is a way to build a Cisco global macro and apply to the interfaces. Take a visit to Cisco and take a look at that.

 

[JOAMON]

See if the following link us helpful

http://www.cisco.com/en/US/products...figuration_guide_chapter09186a00802c2fb4.html

 

[Smooth23]

Joamon,

Yeah, all the ports are displayed as AUTO, so is this ok? I mean what will determine whether or not a computer/printer will run in full or half duplex? I guess it will be the NIC and what that supports!!!

Will the switch always attempt to use FD, then if the network device cannot support it, use HD?

Thansk

 

[JOAMON]

Most fast ethernet NIC will run at 100 full when connected to a switch port in auto. I usally like to lock in the setting for older 10-base-t devices as 10 half to avoid any problems. Some routers have ethernet ports that only have a max speed of 10 but can operate in full duplex. I like to port match these as well. If you think you have any mis-match in CNA go to reports, views, system messages and look for anything that says duplex mis-match.

 

[jdeisenm]

I've seen a bad windows driver or a windows nic set to something other than auto cause a switch port defined as auto to go to half/100. When I ran a Sh int fa0/x, I would see collisions and errors, and of course the negotiated speed. In my environment, older hp printers and terminal servers run at half/10.

 

[LincolnIT]

Typically, if there is a duplex/speed misconfiguration on a port it will show excessive collisions. Unless you know something is setup manually (e.g. an older HP printer with JetDirect), then just leave it on a-duplex and a-speed and monitor the ports for collisions. If you see a port with excessive collisions, determine the proper setting and apply it to the switch.

 

[ADB100]

If you hard-code the speed and duplex on one end of a link (Host or Switchport) you MUST hard-code the other as well. If you don't you will have a duplex mismatch - i.e. one end full-duplex and the other half-duplex. Unless you have devices that can't auto negotiate I would leave them alone. Some older NIC's (5+ years) may have problems with duplex negotiation but its very rare.
Problems usually arise when 'clever' server guys hard-code their server NIC's and then complain to the network guys when backups take forever...

HTH

Andy

 

[chieftan]

Your network Layer 2 device will always negotiate at the slower speed and duplex of the two devices.

 

[voltron1011]

We usually keep our ports at auto, however there are a few Sun devices that are really particular about being set to Full-100 (both side, obviously).

 

[tharder]

I suggest leaving them set to AUTO. If you think there are problems, type> "show int count err" and you'll see errors on any of the culprits. Adjust as required.....

We have some old 2500 series routers with 10mb/half interfaces. They negotiate correctly but CDP gets annoyed when it doesn't see both sides of the connection set the same and generated a lot of speed/duplex mismatch messages.

 

[Smooth23]

Hey all,

I'm going to leave the ports as AUTO as suggested by many.

Thanks for all the responses, very useful indeed.

 

[jneiberger]

Good move. I'll belatedly add my recommendation to leave switchports and devices set to AUTO. You should only try hard-setting speed and duplex when autonegotiation fails, which is almost always caused by a bad NIC or bad driver.