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3750 stack

What is the recommended maximum number of 3750s to place in a stack, and what performanc

e issues can I expect to see (CPU, memory, SNMP drops, etc.,) as that number is approached?

Thank you.

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8 REPLIES

Re: 3750 stack

What is the recommended maximum number of 3750s to place in a stack, and what performanc

e issues can I expect to see (CPU, memory, SNMP drops, etc.,) as that number is approached?

Thank you.

Hi,

Up to nine separate switches can be joined together through their StackWise ports.

One of the switches controls the operation of the stack and is called the stack master. The stack master and the other switches in the stack are stack members. The stack members use the Cisco StackWise technology to behave and work together as a unified system. Layer 2 and Layer 3 protocols present the entire switch stack as a single entity to the network.

StackWise Plus technologies deliver advanced performance for voice, video, and Gigabit Ethernet applications.

Problem can be faced is a break in any one of the cables will result in the stack bandwidth being reduced to half of its full capacity. Subsecond timing mechanisms detect traffic problems and immediately institute failover. This mechanism restores dual path flow when the timing mechanisms detect renewed activity on the cable.

Hope to help !!

If helpful do rate the post

Ganesh.H

New Member

Re: 3750 stack

Followup question: How can I remotely determine whether my StackWise cabling is redundant?

Thank you.

Re: 3750 stack

Followup question: How can I remotely determine whether my StackWise cabling is redundant?

Thank you.

Within microseconds of a breakage of one part of the path, all data is switched to the active half of the bidirectional path.

For more information check out the below link hope that help !!

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps5023/prod_white_paper09186a00801b096a.html

If helpful do rate the post

Ganesh.H

New Member

Re: 3750 stack

I guess I wasn't clear enough. I want to add additional switches to my stack, but need to first confirm that the StackWise cabling is redundant, or else I run the risk of isolating part of the stack when I disconnect the StackWise cables to insert the new switch into the stack.  How is this determined via CLI?

Thank you.

New Member

Re: 3750 stack

Kenneth

here is what I think you are asking.

This command shows if you are uning the full 32Gb of the stackwise cables

sh switch stack-ring speed

Stack Ring Speed        : 32G
Stack Ring Configuration: Full
Stack Ring Protocol     : StackWise

New Member

Re: 3750 stack

You can build your connection list by doing a show switch neighbors.  Especially with three switches you can easily build a quick drawing showing you if you will break something.

Show switch detail might also do the trick.


James

New Member

Re: 3750 stack

Hi,

if your confident that the switches have been stacked correctly, I simply use (see below )before I swap out or add devices.

3560-Stack#show switch stack-ports
  Switch #    Port 1       Port 2
  --------    ------       ------
    1           Ok           Ok
    2           Ok           Ok
    3           Ok           Ok
    4           Ok           Ok

Lee

Hall of Fame Super Gold

Re: 3750 stack

In paper Cisco recommends no more than 9 (including the master).  In practice, I'd recommend no more than 7 (including the master).

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