03-21-2010 05:26 AM - edited 03-04-2019 07:52 AM
Hi there,
We are running 2 switches at different locations:
2950G ISO 12.1(22)EA4
3524XL IOS 12.0(5)
Between them are 2 100Mbps LanX lines with 2 different providers.
The etherchannel seems to come up OK, but only one of the lines is used. I cannot see the other ends of the etherchannel setup via CDP.
My questions are:
1. Is CDP required for this to work?
2. If not, is it difficult to make it work without CDP?
3. If it does work without CDP, does that compromise the complete functionality of the setup?
Thanks for any help you can offer.
Frank
03-21-2010 05:47 AM
Hello Frank,
>> but only one of the lines is used.
unfortunately C2950 supports etherchannels only in this limited way with second link that is only an hot standby.
They provide redundancy but not load sharing over the bundle.
We had even opened a Cisco service request when we have seen this on a C2950LRE but we had this feedback.
It is not a question of CDP but of switch real capabilities
>> I cannot see the other ends of the etherchannel setup via CDP.
this depends from service provider configuration if they use 802.1 Q inQ tunneling they need to enable L2 tunneling protocol in order to carry CDP frames over the point to point service.
see
as you can see transport of CDP, VTP and STP can be enabled by service provider or not
Hope to help
Giuseppe
03-21-2010 04:35 PM
Thanks for the answer. I find that odd. I found a number of example configs involving 2950 and none of them mentioned that limitation.
Is there a table somewhere that lists various switches and what they can and can't do with Etherchannel? I tried searching but had no luck.
Frank
03-22-2010 01:17 PM
Would a 2900XL do the trick? or is it always better if the switches match?
Thanks
03-23-2010 08:07 AM
Hello Frank,
who is on the other side of the bundle is not a problem
I couldn't find an exact reference but as I wrote we got this answer in a Cisco TAC Service Request for 2950 LRE
Hope to help
Giuseppe
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