3750 stacking question

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Sep 11th, 2008
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I plan to stack two 3750s soon. My goal is to work with our server admin to team the NICs on the servers and configure an ether channel on the 3750s, and connect each server to both of the 3750s in the stack. We currently have this running fine on a 4510 but the servers have both NICs connected to the same switch. I know when you stack the 3750 is creates one logical switch. So does anyone know if i will run into any problems configuring LACP on the servers, Teaming the NIC's and ether channel on the 2 3750s?

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satish_zanjurne Thu, 09/11/2008 - 07:33
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yes !!!

you are right, by creating stack you will make it logically one switch.So it is the same case with old 4510.

So if server has 2 NIC's then,

using 2 3750 , make it them as 2 access switches , do teaming with each NIC connected to each 3750.

And etherchannel between 2 3750, is standard way, so make it put them in "ON" mode.

HTH...rate if helpful..

cowetacoit Thu, 09/11/2008 - 07:43
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ok, so i can configure LACP on the broadcom software, connect each NIC to each 3750, configure the ports as access ports, and configure ether channel on those two switch ports. I believe on the the 4510 i configured Port-Channel load-balance src-mac. does this sound like the correct config for the 3750 stack? I heard of stories where the switch learns the same MAC from two different switchports and it can have mac-address-table problems.

satish_zanjurne Thu, 09/11/2008 - 07:46
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you want etherchannel between HOST & 3750 ??

cowetacoit Thu, 09/11/2008 - 07:48
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I want my servers to connect to 2 3750's in a stacked configuration running LACP for redundancy and load balancing.

cowetacoit Thu, 09/11/2008 - 08:41
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I'm not sure if you were implying i ether channel the 2 3750's but stacking will give you 32gps instead of 2 gig ether channel.

satish_zanjurne Thu, 09/11/2008 - 11:32
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But then stacking is still, single logical unit.

32Gbps you are getting in backplane or the fabric of switch.

What about teaming ? Are you going to connect both NIC's to onse switch ( stack ) ??

cowetacoit Thu, 09/11/2008 - 12:08
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right....the whole point of stacking those 3750's is to make one large switch and so you can have redundant connections. So as i mentioned the plan is to have 2 NIC's in a server, stack 2 3750's, plug each NIC into a seperate physical 3750 (stack), team the NIC's and then create a port channel for the server connections on the 3750. Are you telling me this will not work?

When you stack 3750's, the stack operates at 32gbps.

MUHAMMAD SHAHEEN Fri, 09/12/2008 - 04:00
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Hi Michael,

you are on the right track, thats how i have at few locations and it works fine.

you should see no problems !!!



cowetacoit Fri, 09/12/2008 - 05:18
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ok great. i guess my main concern was wanting to run LACP on the servers but i thought i read that you couldn't use LACP on a stack of 3750s. I'm confident this will work though, just wanted some reassurance.


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