Stackable between different Switch 3750 models ?!?!?

[graziosicarlo]

Hi  all,

i have two switch 3750 but with different features

• 3750E-24TD-E ( switch with all 24 port 1 GB and  10GB features embedded)

       IOS Version 12.2(44r)SE3 .System image file is "c3750e-universalk9-mz.122-55.SE1

• 3750G-24TS-E  (switch with all 24  port 1 GB + 4 SFP port)

       IOS Version 12.1(14r)EA1a . System image file is "c3750-advipservicesk9-mz.122-25.SEB1

Do you know if is possible to connect in stackacble these 2 different 3750 models ??

thanks a lot  in advance for your answers

Carlo

[Shashank Singh · Accepted solution]

Hi Carlo,

The switches cannot be connected as a stack unless they run the same IOS major version. I would recommend to upgrade them to exactly same version(122-55.SE1) and then they can be stacked.

Regards,

Shashank

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[Shashank Singh · Accepted solution]

Hi Carlo,

The switches cannot be connected as a stack unless they run the same IOS major version. I would recommend to upgrade them to exactly same version(122-55.SE1) and then they can be stacked.

Following link is helpful

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750e_3560e/software/release/12.2_46_se/configuration/note/swactivn.html#wp144864

Regards,

Shashank

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[graziosicarlo]

HI Shashank and thanks a lot for your quickly answer :-)

If i'll upgrade both 3750 ( 3750E and 3750G) to the same major IOS version  CAN  I stack them with the owner cables ???

thanks again

Carlo

[Shashank Singh]

Hi Carlo,

Yes the regular stack cable should be good enough to stack them.(http://tinyurl.com/4kkpedw)

Hope this helps.

Shashank

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[sdheer · Accepted solution]

Hi Carlo,

When a 3750E is connected to a 3750G stack there are 3 things to be considered:

 

1)       Destination Stripping in stackwise plus as compared to Source stripping in
stackwise –  When you combine the 2 technologies they negotiate to the lower one, so in
your case, all the 5 switches including the 3750E would run in stackwise mode, that is
they would do source stripping = No effect in the performance.

2)       Local Switching in stackwise plus as compared to no local switching in 3750E –
When combined together the 3750G would not perform local switching while the 3750E would
retain the local switching feature = Marginal increase in performance.

3)       2 line rate 10G ethernet ports per 3750E supported in stackwise plus - This
feature cannot really be utilized in your case since you have only 1 3750E, but as it is
since you would combine this with the stackwise 3750, this feature would not be supported.

 You will need to satck the switches with the stack cables.

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[graziosicarlo]

Hi Swati and thanks,

you say:

3)  2 line rate 10G ethernet ports per 3750E supported in stackwise plus - This
feature cannot really be utilized in your case since you have only 1 3750E, but as it is
since you would combine this with the stackwise 3750, this feature would not be supported.

So what does this mean? that  if i have a stack with one 3750E and with one  3750G  i cant use the 2 line rate 10 GB ports ??? Help me to understand better this .....

[Shashank Singh · Accepted solution]

Hi Carlo,

3750E is a line rate non blocking switch which means that the uplinks are not oversubscribed. This means that every uplink on this switch has a dedicated controller chip which makes it perform better in case of congestion on the uplinks.

On other models of 3750 switches, the uplinks are oversubscribed which means that one controller chip controls more than one interfaces which degrades performance in case load increases beyond a point.

With 3750E stacked with non 3750E switch, the uplinks will not operate at line rate. This means that the performance on the 3750E uplinks will be equivalent to that on a normal 3750 switch. But this impact will be seen only if the load on all the uplinks is very high.

Cheers

Shashank

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[graziosicarlo]

""With 3750E stacked with non 3750E switch, the uplinks will not operate  at line rate. This means that the performance on the 3750E uplinks will  be equivalent to that on a normal 3750 switch. But this impact will be  seen only if the load on all the uplinks is very high.""

OK,

i could have problem ONLY in case  the load on all the uplinks is very high.  BUT i CAN use the two  10GB interfaces with 10GB links perfomance  rate ?!?!

when you say: 3750E uplinks will  be equivalent to that on a normal 3750 switch dont mean that my 3750E have a 1 GB link rate .....i hope ...

Carlo

[Shashank Singh · Accepted solution]

Hi Carlo,

The 10 gig uplinks will operate at 10 gig only even the switches are stacked and definitely not fall to 1 gig The impact is not even visible unless you use all the uplinks on the switch to the maximum of their capacity.

Cheers

Shashank

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[graziosicarlo]

Whauuu Shashank......... what a fright !

I have understood that my 3750E  10 GB ports  when were in stack ALWAYS had 1 GB line rate .... same the other 3750G ..........

thansk again ;-)

[Shashank Singh]

hahaha   trust me..its not all that bad!!!

[Ton V Engelen]

Hi,

when i stacked E switches with G switches, i needed a universal firmware version for the 3750E switch

In my case i used

c3750-ipbasek9-mz.122-50.SE2.bin for the 3750G switches

and

c3750e-universalk9-mz.122-50.SE2.bin for the 3750E switches

to stack them.