Solved: Benefits of stacking switches

[speederpro4]

Hello all,

I'm wondering about the benefits of stacking switches. Our company has two HP Procurve 2650 and one HP 2824 switch. The cost on them are like >$2000 each. The only extra function that I see on these switches is its ability to stack. I'm curious as to whether the benefits of stacking really outweight the cost?

We still have many users on a 10MB switch. I want to upgrade them but not sure if benefit of stacking is going to help them at all. I know these users are hungry for bigger bandwidth as our data transfer usage is very high within company.

Can anyone help me make a better decision? I know I can get a gigabit switch with link aggregation for less than 1/2 the price of these HP Procurve stackable switches.

My understanding of stacking is that it makes all three switches like 1 big switch. Or am I wrong? Currently, our user is only two hopes away from our gateway and servers. That is most user can reach our server/gateway by the third hop (asumming the three switches as 1 hop).

 

[JohnWill]

They take less space and look neat in the rack.

 

[zx10guy]

You are correct about the concept of stacking switches. The reason stacking switches is better than just doing link aggregation/Etherchannel is because of what you said. There is a specific type of cable used to link the switches together. The link is always greater than throughput of a LAG group to connect the switches. Many switches I've worked with have a limitation of 8 ports in a LAG group. So that means you're limited to 8 Gbps. Also, it's a bit unwieldy to have 8 cables coming off a switch connecting to another device. To illustrate the speed difference with a stacking bus on a stackable switch, I dug up specs on two stackable switches from two different manufacturers.

Cisco's 3750 switch is stackable and has a 32 Gbps bus. I've used these switches at work before. The cabling is included and linking switches is pretty straight forward.

Netgear's GS748TS has a stacking bus capable of 20 Gbps.

So as you can see, there is a significant advantage in using a stacking bus when available. Why is this a nice feature if you can spring for it? Well, you can add additional switches to your stackable switch(es) and still be able to manage them as one single switch. Let me say this feature is extremely useful when you have to manage a few switches in a business environment. Stackable switches also allow you to have the expansion capability of a chassis based switch solution like a Cisco Catalyst 4500/6500 switch without having to pay the higher premium to get into one.

 

[speederpro4]

Thanks, I will have to do more research on those Cisco switches and see if HP has similar ones. I like to buy the same switches so I only have to learn how to manage one switch.

 

[zx10guy]

HP does have stackable switches too.

One other thing I forgot to mention, stacked switches are somewhat redundant. Meaning that if one switch in the stack dies out, it doesn't take down the rest of the switch stack as a new "master" switch would be elected. The only loss of service will be the affected devices plugged into the failed switch.