Core Switch, Help choosing!

[sport404]

Hey guys, so my new building is going to be 5 floors with a wiring closest on each floor. Each floor is going to have 2 3560E 48 port switches. Each floor will have fiber runs to the main data center floor. My question is what type of cisco switch should I be looking at the deals with the fiber runs and is layer 3 so I can use that for routing instead of a regular router?

Thanks!

 

[chipk]

Cisco's "core" devices are typically the 4500 or 6500, depending on the size of the network. I would think the 4500 would do for you (480 ports total on your 3560s - will most of those be used?)

http://www.cisco.com/en/US/products/hw/switches/index.html

 

[sport404]

No not all ports will be used to begin with. We have somewhat of a grant so we are trying to get stuff in place now and be prepared for future growth in the next year or so.
I guess my question would be on the 4500 is that it appears to have so many connections in the picture. Is this device just modular and I buy what i need for it? What is the common thing for connecting in fiber runs?

Thanks!!!

 

[chipk]

Yes, that's correct. I imagine you're getting SFP modules with those 3560s, so something like the WS-X4448-GB-SFP would be what you want. You probably want everything dual-homed, and that would require 20 ports for what you've got, and the next smallest module is 18 ports. Here's where you can look at the above model:

http://www.cisco.com/en/US/products/hw/modules/ps2710/products_data_sheet0900aecd802109ea.html

The problem is the next smallest module only has 18 ports, so you'd either be looking at single-homing all your switches, or going with a redundant configuration in your core (2 4503s with 1 18 port SFP module each). Not sure what your budget is or other constraints, but have you considered redundancy in your core?

You can't really go with any smaller switch that I'm aware of because you need something modular that can handle the fiber connections. You could go with the lowest-end 4500 (4503).

 

[sport404]

I know each floor had multimode duplex fiber runs. The second switch on each floor will just connect into the first switch. I am new to fiber, so this help clarify things? We also have backup fiber runs going up to the data center as well. I was wondering about redundancy but wasn't sure which method was best

Thanks

 

[chipk]

So, my understanding is that you have 2 3560s in each closet, and what you are saying is that the 2nd 3560 does not connect directly to the core, but through the other 3560 (a sort of daisy-chain)?

This isn't really an ideal configuration. If I were you, I'd dual-connect each 3560 back to the core, especially if you have the fiber available.

 

[sport404]

Not sure if I can swing that many fiber runs due to the cost. Whats wrong with the daisy connection? SFP port to another SFP port?

Thanks

 

[chipk]

It's not that you can't do it, it's just not ideal. What you've got is a 3560 switch with 48 ports that is designed as an access switch. When you daisy-chain another 3560 off of that, you're essentially doubling the load on the switching fabric. You don't have a huge network, so maybe this won't be a problem. Maybe it wouldn't be a problem even if your port density was 100%, but it's just not ideal. What I would be more concerned about is how many single points of failure you have.

 

[sport404]

Would you have any other suggestions for closet switches? Need to be 48 port and 1gig ports and fiber connections Any other model more suitable for this situation?

Thanks again

 

[chipk]

No, those are the best switches for your situation, and you may never see any problems at all.

 

[techcontroller]

There are other alternatives that you could use if you wanted to cut cost. You can look into purchasing the Catalyst 3550 series switches. I work with and troubleshoot as well as configure and maintain these switches every day. They are rather cheap in comparison to the 3560s.

Is there a specific reason you have to have a 3560?? You could also purchase a 2960g for almost half the price of a 3560. That's a 48 port switch with gig ports on it. It all depends on what you plan to use it for I suppose. That, or the switches are already bought, and in that case..please ignore. lol

 

[chipk]

You're right tech - but sport404 requires fiber (5 connections, I believe) to the core, and I can't recall if there's a 3550/3560 that has 5 modular ports. I'll have to look that up.

 

[techcontroller]

Maybe I am looking at this wrong. I was thinking that he was going to have two switches per closet, each switch going back the the distrobution switch. If that is the case, he would just daisy chain one 3550 off the other, then run the main access switch to the distro switch on the data center floor. I don't see why he would need 5 connections on one switch if he is using a 4500 as the distro switch. Here is what I am looking at...

http://i48.photobucket.com/albums/f208/Gehennas/5floors.jpg

You can either connect the 3550s via multimode fiber and Gbics (expensive way) or by GigaStack. GigaStacks are not the best way, but it works, and I have not had any SERIOUS issues with them. It's just another way to cut costs. The only fiber that would necessary would be connecting the 1st switches to the distro switch.

 

[chipk]

Yeah, 5 connections on the 4500...

You've got 5 closets going back to the datacenter, that's 5 fiber connections...

 

[texnut]

Hey - I just finished specing out a similar if not exact situation as yours and here is what I did:
(Except I only have to deal with two floors, the data center and the floor where our offices are).

WS-C3560G-24TS-S (24 GigE w/ 4 SFP ports) as my distribution switch.

Office floor gets:
WS-C3560-48PS-S (48 10/100 Power over Ethernet w/ 2 SFP ports)
WS-C3560-24PS-S (24 10/100 Power over Ethernet w/ 2 SFP ports).

I've got an SFP short wave module populated in the distribution switch and a SFP module populate in the 48 port access switch. I then have the 24 port daisyed off of teh 48 port.

Should work out to be just fine!

 

[sport404]

Tech Controller has my situation exactly right. I was looking at the 2960's but can they handle a fiber connection?? Thats why I was drawn towards the 3000 series. To be honest I reall don't know much about how fiber connections work. How does a dual multimode fiber run connect into a switch, what are my connection options?

Thanks!

 

[wybnormal]

Fiber connections are very easy to use and offer the advantages of never being out of style. Who remembers trying to upgrade the copper cable plant from CAT3 to CAT5 only to see CAT5E show up? Fiber is fiber for the most part unless you plan to extend your demarc or IDF out about 2-3 kilometers. Then it gets fun.

Anyways.. multimode is cheap, 62.5 is the normal size you want (But Netapps want to see 50micron but work with 62.5). You want to see two PAIRs pulled in, one lit up and one dark but terminated for failover. Or have both lit up if you have the ports and let spanning tree sort it out or use channeling to pair them together. Once you have fiber in place, you really do not need to worry about your main data runs again in the long term future.

Cisco uses two styles of GBICs for fiber, an older larger BIC and a newer one called SFP which is much smaller and uses a different connector. Always have a couple of spares as they do burn out. But there are "Cisco" branded GBICs coming out of Asia on eBay that are very cheap so you really can afford the spares. I put Cisco in quotes because even when I look at them very closely, I can not tell if they are real or not but they work.

With respect to the switch fabric load on a 3500 series switch, they have very high speeds. I run over 70 servers and two Netapps with 8Tbs on them and 4 64Bit SQL boxes hammering away on 4 3560s chained together plus the users. Not ideal by any means but the switches are not the bottleneck and the stats prove it. You would be hardpressed to pass that much data to overwhelm the switching fabric.

The break even point a few years ago for the chassis solution vs the stackables was 350-400 ports. That probably has changed some as the prices of the stackables has really fallen alot in the past two years relative to feature sets. The chasis does off real reduntency like dual RSMs which is much better than trying to use HSRP or the like on the stackables.

MikeS

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