[c-nsp] Cisco 3012 IBM Blade Switch Configurations?

ChrisSerafin chris at chrisserafin.com
Wed Feb 18 11:06:50 EST 2009


What MST config do you suggest and on what if not all of the switches?

The docs from Cisco go into crazy configurations, and I only need basic 
STP functions: 2 core switches with an etherchannel link from each of 
them to each blade switch.




David Hughes wrote:
>
> On 17/02/2009, at 5:21 AM, ChrisSerafin wrote:
>
>> That brings up a good point about STP. If I have 1 etherchannel going 
>> from each switch blade to each upstream switch, will the switches 
>> detect the loops or do I need to manually configure this? Thanks for 
>> your comments!
>
> The blade switches operate as separate switches and can be viewed as 
> if they were your normal 29xx or 35xx access switch depending on the 
> CIGESM you buy (well, with a couple of caveats about their management 
> interfaces).  If the switches are connected to your network via a 
> single etherchannel then there's no possibility of a loop - other than 
> a mis-configured etherchannel.  You don't get loops but you don't get 
> any redundancy at the network layer.  In this setup I assume you are 
> using some form of NIC teaming and failover on the blades themselves 
> for redundancy.  That's not going to pick up a failed uplink on your 
> primary switching path as most teaming drivers only look at link state 
> on the NIC.
>
> If you are following a "normal" dual attached model where each access 
> switch (be it a top of rack switch or a blade switch module) is 
> uplinked to 2 different switches then you get link redundancy but 
> naturally need STP.  If you are running dense virtualisation or vm 
> server farms then the STP you should be running is MST.
>
>
> Thanks
>
> David
> ...
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