08-22-2010 12:40 AM - edited 03-03-2019 06:01 AM
Hello,
Today I have plugged in a new Cisco 2901 ISR G2 router into a Cisco 2950 switch.
On router side, the interfaces were hard coded to 100/Full and on the switch side all set to Auto.
On router, the commands SHOW IP INTERFACE G0/0 and G0/1
shows speed as 100 and Duplex as Full.
However on the switch SHOW INTERFACE STATUS
shows a-half and 10mbps.
Is it a normal behaviour?I feel in this case, the router too should have shown speed as 10mpbs and duplex as half.
Now on the switch I have hardcoded the speed/duplex to 100/Full.
Solved! Go to Solution.
08-22-2010 04:58 PM
Hello,
Yes. You need to make sure that the effective speed/duplex settings are
supported by both ends. If there is a mismatch, you will start seeing
CRC-Errors and collisions.
Regards,
NT
08-22-2010 02:27 AM
Hello,
Since you have set the speed/duplex to 100/full on the router, it shows what
is configured. On the 2950, since it tried to negotiate and did not succeed,
it reverted to the default value. Please try setting speed/duplex settings
to auto on both devices and see if that helps. (It is especially helpful if
you have gig interface on one end and fastethernet on the other).
Regards,
NT
08-22-2010 06:03 AM
How can I confirm the effective speed/duplex settings on the router itself?
Is it always by verifying on both the devices(switch and router)?
08-22-2010 08:21 AM
Hello,
Typically, when you set it to auto negotiate, they negotiate to a value that
is supported by both hardware. Please take a look at the following links:
http://www.dell.com/content/topics/global.aspx/power/en/ps1q01_hernan?c=us&c
s=555&l=en&s=biz
http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note0918
6a00800a7af0.shtml#auto_neg_valid
Hope this helps.
Regards,
NT
08-22-2010 04:41 PM
Thank You for the links.
However inorder to confirm the effective speed/duplex settings, do I always need to confirm on both the end(switch and router)?
08-22-2010 04:58 PM
Hello,
Yes. You need to make sure that the effective speed/duplex settings are
supported by both ends. If there is a mismatch, you will start seeing
CRC-Errors and collisions.
Regards,
NT
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