will the old WS-C3750G-48TS-(S or E) works with the new replacement

[reycapoy]

Hello,

    Situation: Currently WS-C3750G-48TS-(S or E) switches are on stack. Now these units will soon EOL on Jan. 30, 2013 and Cisco recommends that

WS-C3750X-48T-S or WS-C3750X-48T-E will be used.

   The question is: Will the new SKU works together in a stack with the old ones?  Will there be no changes on the type of stacking cable to be used?

Thanks,

[Leo Laohoo · Accepted solution]

The question is: Will the new SKU works together in a stack with the old ones? 

If you are NOT getting the 3750X-24S, then the answer is "YES".  You must also consider that in order for the 3750X to work with the 3750/3750G in a single stack, you'll need to upgrade the IOS of the 3750/3750G to the minimum IOS level of the 3750X.  I believe the minimum level is 12.2(55)SE1.

You will NOT be able to upgrade the 3750/3750G stack to 12.2(58)SE or 15.0(1)SE or 15.0(2)SE if your current 3750/3750G has a flash memory of 24 mb or less. 

 Will there be no changes on the type of stacking cable to be used?

Stacking cable shape will be the same.  The older 3750/3750G has a backplane speed of 8 Gbps (full duplex) but the 3750X has a backplane speed of 32 Gbps (full duplex).  When a 3750X joins a stack with a lower backplane speed, then the 3750X will "down speed" the backplane speed accordingly.

[reycapoy]

Hi loalaohoo,

    Thank you so much for the quick reply.

Best Regards,

[reycapoy]

Hi loalaohoo,

   Follow up question only. What if a WS-C3750X-48T-S to be stacked with the WS-C3750G-48TS-S, or WS-C3750G-48TS-E with WS-C3750X-48T-E. Same procedure will apply?

Thanks,

[Leo Laohoo · Accepted solution]

What if a WS-C3750X-48T-S to be stacked with the WS-C3750G-48TS-S, or WS-C3750G-48TS-E with WS-C3750X-48T-E. Same procedure will apply?

Same thing.

Read the Release Notes for IOS version for 12.2(55)SE and go down to Supported Hardware.  This table will tell you what is the minimum IOS level for each specific model.

You will NOT be able to downgrade the IOS of the 3750X's minimum IOS level so you will need to upgrade the IOS level of your older 3750/3750G.

[reycapoy]

Hi leolaohoo,

   Thanks.

[Joseph W. Doherty · Accepted solution]

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Posting

As Leo has described, with some restrictions, you can mix and match original 3750 series and 3750-X series in same stack.  As Leo also touched upon, original and -X series (also E series) stack ring has more bandwidth (i.e. 2x) which you lose in a mixed stacked.  Also lost, the -X series (also E series) stack reverts from StackWise+ to StackWise, which doesn't use the stack ring as cleverly (StackWise floods all member switch traffic to stack ring and source switch removes traffic; StackWise+ only places non-local member unicast traffic on stack ring and destination member removes it).

Mixed stacks are also more difficult to upgrade their IOS as they run different images.

3750-X (also 3750-E) fabric and forwarding performance support all ports at wire-rate, original 3750Gs do not.

Lastly, 3750-X also support StackPower.

For these reasons, I often recommend not mixing the original StackWise 3750 series with later 3750 StackWise+ in the same stack, although, again, they often can work together.

[reycapoy]

Hi Joseph,

    Thanks for the advise.