Switch performance?

[Ares2600]

I'm hoping someone with more experience might be able to help me. I'm shopping for hardware for a (rather large) project and trying to make a switch choice... here are the requirements:

48 ports
10/100/1000
FAST

Literally that's it. It doesn't have to be fancy and doesn't need any advanced features.. This is a short term project. We're going to buy a few of them and then be done with them. The biggest concern is that they're fast. We're looking at 42 connections to each switch running at nearly line speed. My first reaction was Cisco, but I'm surprised at my findings and hoping to get your opinions.

Cisco just released these beasts, boasting line speed on every port:

http://www.cisco.com/en/US/pro...t0900aecd8017a72e.html

But it seems that 3com has this, which from a 'specs' perspective has an even faster switching rate. so fast that I can't even see how it would ever be exercised with only 48 ports. (136 Gbps switching capacity.. even at full duplex that's faster than line speed)

http://www.3com.com/products/e...rchase&sku=3CR17662-91

As expected the 3com is like 1/3 the price of the Cisco. Am I paying for features on the Cisco? Can the 3com actually be faster for that much less money?

I'm a software/systems guy and while I can deal with the more reasonable stuff just fine these big network appliances are a bit foreign to me.

Any thoughts would be great.

 

[Homerboy]

I mean.... good question

 

[jlazzaro]

the Cisco 4948 is a L2-4 switch. if you dont know what that is, chances are you dont need it.

"fast" is a relative term (along with our friend "good"). switches dont use processors, but switching fabric to "switch" data from one port to another. most any switch on today's market will deliver wire-speed performance...you'd be hard pressed to notice a throughput difference running a standard 1500-byte ethernet MTU. latency, or delay is another factor, but of less concern if you're not running time-sensitive applications / signaling.

personally, not a big fan of 3Com. i would look into basic L2 switches from either Cisco or HP...

 

[Homerboy]

personally, not a big fan of 3Com. i would look into basic L2 switches from either Cisco or HP...

Says the guy with a ASCII Cisco logo in his sig

 

[Ares2600]

Okay.. I AM a little embarassed that I didn't think of the L2-4 issue when comparing costs. I definitely don't need an L2-4. I'll narrow my search on the cisco side. Truthfully I started the search through marketing emails, so it was directed in that way.

My main concern is being able to get nearly line speed on all ports at once. This project is like a benchmark. I've got a two tier setup (a few middleware machines to a big fat database) and a whole bunch of driver machines. I need a switching fabric that will allow for nearly all the ports to talk to the others at nearly 1Gbps on each port. I'm not uplinking at all between switches. The traffic will stay within the switch itself. Latency is a concern as well, though I'm not sure if even 'bad' latency would be noticed on the scales that my final latency measurements would be in.

If you were to solve my above problem, essentially need to really light up the switching fabric of a 48-port gigabit switch, would you expect most of them to perform similarly?

 

[spidey07]

Something from foundry/extreme should be fine.

A cisco 3750 is not going to cut it for you. Also, the cisco 4948 has been out for a few years, it's not a new product.

 

[Ares2600]

Shows what my site network guy knows. Hence the AT inquiry. =)

Thoughts on that 3Com?

 

[spidey07]

Avoid 3com at all costs.

Also, forgot about the cisco 3750-e. Throw that in with foundry and extreme and you will have what you need to be looking at.

 

[nightowl]

Given what you are looking for, I would go with the Cisco 4948 (low latency). Also, I can almost guarantee you that you do not need a wire rate switch. You are going to have over-subscription on the host side.

 

[spidey07]

Originally posted by: nightowl
Given what you are looking for, I would go with the Cisco 4948 (low latency). Also, I can almost guarantee you that you do not need a wire rate switch. You are going to have over-subscription on the host side.

Grid computing says otherwise. You must treat "the network" like a bus in this regard.

I've taken cisco 6509 blades to their knees with this kind of stuff. Even on the same blade.

This is where foundry/extreme excel. Cisco has never been best in the perfomance category.

 

[nightowl]

Spidey, most grid computing has some sort of over-subscription built in as well, even with the very largest clusters on the Top 500. Also, when I refer to over-subscription there is more than just the network, there is also the host as well as I mentioned before. If you have a cluster of 128 hosts, you do not have 127 NICs in it. Chances are each host has only 1 or 2 interfaces. Right there, with multiple hosts talking to one host you have the possibility for over-subscription.

Also, I am sure that you can bring any line card or switch to its knees given the right combination of traffic. Out of curiosity, which line card was it in the 6500 (DFC?) and what was the scenario?

 

[spidey07]

65xx blades, engineering/materials analysis jobs.

cisco is finally waking up to the 'stop oversubscribing your blades' mentality.

 

[nightowl]

Ah, with 65xx blades they are very much over-subscribed.