need SOHO design advice

[WannaFly]

opps, submitted twice....

 

[MichaelD]

Bump for an interesting thread.

 

[Garion]

I've been reading this thread for a bit, and thought I'd throw my two cents in..

One thing you haven't mentioned is the planned growth of your company. Do you think it will double in size over the next few years?

Later 3 switching is an incredibly cool technology when used appropriately. It also makes your network much more complicated - You've got a bunch of different subnets that you need to administer, you've got to including the routing in your troubleshooting, etc. Plus, you do take a minor performance hit.

I usually try to keep a subnet network under about ~150 hosts. With only 70 machines, plus assorted printers, servers, etc. you'll probably be looking at around 90 de vices, well under my 150 max.

Ask yourself this - What does L3 switching really buy you? You get the ability to segment each department into VLANS, but that really doesn't do much for you, from a functional perspective, unless you plan on writing access lists and filtering traffic between VLANS.

Networking is complicated enough without making it more complex than it needs to be. One of the very fundemental rules of what we do is to keep it simple. That makes it supportable, hence stable.

What you guys are proposing is a great network, but I think it might be overkill. You'd likely do just fine with a pair of 48-port Layer2 switches uplinked together, one with a few extra gig ports for your servers, if you're sure you need it. (Most servers really don't need gigabit bandwidth unless they serve a lot of really big files).

- G

 

[cmetz]

WannaFly, call Extreme and ask, but last time I checked you can't get copper gigabit connections on the 48Si - there is no small form factor mini-GBIC for copper yet. It's a bummer. You could get a media converter, but it'll probably be cheaper to get SX fiber boards for your file server. Watch out for the same issue when connecting dumb L2-only switches to the gig port (though, on EBay, gig fiber + a bunch of 10/100 copper switches are cheap right now, 'cause people don't much want them anymore).

Garion,
>Plus, you do take a minor performance hit.

Any L3 switch on which there is a measurable performance hit for doing L3 switching vs. doing Ethernet MAC switching, frankly, sucks. The two operations should be the same from the hardware's perspective.

The main reason to use L3 switching and VLANs here is that WannaFly has a chance now to do an every-station reconfiguration, and probably won't get that chance again. If he thinks he might want subnets - to separate traffic, to make ACLs easier, etc. - he better do 'em now. Otherwise, he'll have to go renumbering later, reconfiguring a whole lot of stations, and that gets ugly. If all he's doing is statically routing between VLANs on an L3 switch, this is as simple and easy as routing gets. Is it as easy as having everything in one big Ethernet? No. But it's not much worse.

 

[Garion]

Originally posted by: cmetz
WannaFly, call Extreme and ask, but last time I checked you can't get copper gigabit connections on the 48Si - there is no small form factor mini-GBIC for copper yet. It's a bummer. You could get a media converter, but it'll probably be cheaper to get SX fiber boards for your file server. Watch out for the same issue when connecting dumb L2-only switches to the gig port (though, on EBay, gig fiber + a bunch of 10/100 copper switches are cheap right now, 'cause people don't much want them anymore).

Garion,
>Plus, you do take a minor performance hit.

Any L3 switch on which there is a measurable performance hit for doing L3 switching vs. doing Ethernet MAC switching, frankly, sucks. The two operations should be the same from the hardware's perspective.

The main reason to use L3 switching and VLANs here is that WannaFly has a chance now to do an every-station reconfiguration, and probably won't get that chance again. If he thinks he might want subnets - to separate traffic, to make ACLs easier, etc. - he better do 'em now. Otherwise, he'll have to go renumbering later, reconfiguring a whole lot of stations, and that gets ugly. If all he's doing is statically routing between VLANs on an L3 switch, this is as simple and easy as routing gets. Is it as easy as having everything in one big Ethernet? No. But it's not much worse.

Actually, moving a PC betweeen VLANS shouldn't involve any work at all, assuming you're using DHCP correctly. You can just change your lease time to be very low and then move the VLANS overnight. When users come in the next morning, their leases should have expired and been renewed with the new info. At worst, it's a reboot. Only work is moving printers and other devices with static IP's.

- G

 

[cmetz]

Garion, that's the theory with DHCP. It's never worked nearly that well in practice when I've tried it.

 

[Garion]

With a bit of pre-planning, it works very well, in my experience. My current company has migrated tens of thousands of back office users with this method, and it's been pretty clean. The only catch that we've found have been IP-based printing to LAN printers, which needs to be changed. A good argument for DNS!

- G

 

[WannaFly]

Well now that there has been an argument presented, I must decide wether it is a good idea to goto VLANs with L# switching now, or just use L2 switches. I am not sure if the company will go for the idea of all the initial testing that will have to be done with VLANs (testing DHCP, DNS, printing, file sharing etc), but i definately want to get some experiance doing so. I have written my draft proposal and have included using VLANs in it, but like I said, i'll have to give it alot of thought. Especially because i am not familiar with how windows 200 will handle DHCP/DNS with VLANs. Everyone has been so helpful and given me plenty of information to look up, now i get to start testing with it. Anyone know if theres a CHEAP L3 switch i could get ahold of to do some testing at home?

 

[cmetz]

Garion, I think our different experiences directly lead to our different opinions. That's okay, the poster gets two viewpoints to consider.

WannaFly, see if you can find a used Extreme or Foundry box on EBay. Some of the Cisco switches are also L3 switches, but Cisco plays very fast and loose with terminology there and so many of the switches they claim are L3 switches really aren't (software IP forwarding, or otherwise bad performance). No matter how you do it, though, I think you're going to find that L3 switches cost more.

Actually, if all you want is VLANs and static routing and basic ACLs, you might be able to get away with an older-generation Extreme or Foundry switch for your network (EBay or otherwise). However, for all the vendors, having an old-gen box that doesn't run modern software inevitably means you're missing out on a lot of features, and you'll end up finding some or other feature you wish you had but isn't in the old software. (an example being the ability to ssh into the box, rather than telnet)

 

[WannaFly]

I am going to keep an eye out for an older(cheap) L3 switch to do some testing with. Still havent made the decision if i am going to go with VLANs or not. It seems that as it is, there will be over 100 jacks installed. So now its time to weigh the pros and the cons. Thanks for all the help, i am sure i will be posting later with a few more questions