Solved: Catalyst 3750 Stack vs. Individual Catalyst 3750

satish_zanjurne · ‎11-22-2009

Hi,

Which of the topology attached in picture is recommended ?

TOPOLOGY A : Catalyst 3750 stack with port-channel to access switch

TOPOLOGY B : Catalyst 3750 without stack ,. ( STP running )

Leo Laohoo · ‎11-23-2009

In my humble opinion, if your stack of 3750 (topology A) is properly cabled up then you can enjoy 32Gb, half-duplex backplane. With Topology B, your main switch only talks in 2 Gb.

I would go for Topology A because this is better suited for a 3750.

Another thing is the configuration. In Topology B, you configure three switches while you only configure two switches with Topology A.

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Leo Laohoo · ‎11-23-2009

Whatever floats your boat. If I ever saw two separate switches that has a potential for stacking, I will. I have heard of good arguments as to why these should not be stacked but it all depends entirely upon you.

STP will still be there.

If the switch master in a stack of two (or more, for example) fails, the 2nd one will immediately take-over. The config is shared between all of the stack members anyway.

View solution in original post

hobbe · ‎11-24-2009

As a general rule I would stack the switches.

Stacking switches gives a couple of advantages such as faster backbone between the switches, redundancy for broken powersupplys, easier management, trunking servers to different hardware and so on.

However that said there is a thing you should ask yourself before stacking.

Stacking binds the two or more switches together as a logical unit.

That means that if you for some reason need to restart the switch it will be offline for more or less 3.5 minutes.

Reasons for restarts includes but are not limited to:

IOS Upgrades (planned)

Software error resulting in a crash

Reloads issued by operator.

Problems affecting the ip stack of the switch stack (wrong ios, configuration errors cpu or memory problems)

Or just the in general, shit happens.

If you can not ever have the switches lost for 3.5 minutes for some reason then maybe a different aproach is advisable.

Fx it might be better to look at a meshed solution (traditional switch design).

But if you have those demands then it might be a better solution to have several stacks with 3750E and a redundant design

Expensive?! Absolutely, but it keeps the network up and about.

HTH and good luck

View solution in original post

Leo Laohoo · ‎11-23-2009

In my humble opinion, if your stack of 3750 (topology A) is properly cabled up then you can enjoy 32Gb, half-duplex backplane. With Topology B, your main switch only talks in 2 Gb.

I would go for Topology A because this is better suited for a 3750.

Another thing is the configuration. In Topology B, you configure three switches while you only configure two switches with Topology A.

satish_zanjurne · ‎11-23-2009

Hi leolaohoo

Thanks for your answer, so what do you suggest is it good practice to convert the 2 individual catalyst 3750 in a stack , wherever i see the scope ? and this will eliminate need of STP as well !!!

Now if we take specific example, will it be good to terminate 2 links from 2 different service provide on such stacks

Site 1 : First stack link A on stack member 1

link B on stack member 2

Site 2 : Second stack link A on stack member 1

link B on stack member 2

Do you see any risk involved in such termination of the links ( in case stack fails where one switch is failed and other is not able to become master ) ?

Leo Laohoo · ‎11-23-2009

Whatever floats your boat. If I ever saw two separate switches that has a potential for stacking, I will. I have heard of good arguments as to why these should not be stacked but it all depends entirely upon you.

STP will still be there.

If the switch master in a stack of two (or more, for example) fails, the 2nd one will immediately take-over. The config is shared between all of the stack members anyway.

hobbe · ‎11-24-2009

As a general rule I would stack the switches.

Stacking switches gives a couple of advantages such as faster backbone between the switches, redundancy for broken powersupplys, easier management, trunking servers to different hardware and so on.

However that said there is a thing you should ask yourself before stacking.

Stacking binds the two or more switches together as a logical unit.

That means that if you for some reason need to restart the switch it will be offline for more or less 3.5 minutes.

Reasons for restarts includes but are not limited to:

IOS Upgrades (planned)

Software error resulting in a crash

Reloads issued by operator.

Problems affecting the ip stack of the switch stack (wrong ios, configuration errors cpu or memory problems)

Or just the in general, shit happens.

If you can not ever have the switches lost for 3.5 minutes for some reason then maybe a different aproach is advisable.

Fx it might be better to look at a meshed solution (traditional switch design).

But if you have those demands then it might be a better solution to have several stacks with 3750E and a redundant design

Expensive?! Absolutely, but it keeps the network up and about.

HTH and good luck

satish_zanjurne · ‎11-24-2009

Thanks Guys , those are helpful comments...

Due to budget constraints , i need to go with single stacks, otherwise i will prefer traditional network design(mesh) with multiple stacks.

Leo Laohoo · ‎11-24-2009

Thanks for the rating!

Stacking also minimizes cost to fibre optic modules and cables.

Are you using Layer 3? If you are only interested in Layer 2 switches that can potentially be stacked then you should look at the 2975.

Cisco Catalyst 2975 Switch with LAN Base Software Data Sheet
https://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps10081/data_sheet_c78-502660.html