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Designing a Remote LAN

If I have a new site with about 500 users, that may grow to about 700 in the next few years, which LAN switches and WAN routers/L3 switches can I use?

Now, before you say anything, I KNOW this is a very broad question and there are a lot of different designs and approaches one can take. What I am asking for is ONE from each engineer who answers this post.


Users access:

*email over the WAN.

*Internet access over the WAN (through the DC). Business is NOT e-commerce, so there isnt THAT much business-related Internet traffic.

*There are about 30 or so odd users of Oracle database services over the WAN, too.

*No VoIP.

*No Wireless traffic to a centralized WLC.

There is wireless at the remote site, but it is in autonomous mode and could use the PoE convenience to power them up.

So, I was thinking of perhaps deploying some 3750 stackables with L3 functionality in case I want to configure a routed access layer. They offer the kind of flexibility that is good when the floor plan is not written in stone yet.

I was also thinking of 3800 series routers at the edge, facing the DC. Maybe 3825s. Sound sufficient?

I think those are pretty good selections. What do you think? OK? Outlandish? Stupid?

Bandwidth is what I am having a hard time deciding on. I was thinking of maybe deploying the 4-port HWIC modules in the 3800s and bundling 3 T1s, with growth to move to a 4th. Does that sound like too little bandwidth given the specs I have given?

Please, I would like opinions. No 30,000 foot views or philosophizing. LOL. :-)

Please pretend that YOUR design is going to be IT.

Thank you so much ahead of time.

  • LAN Switching and Routing

Re: Designing a Remote LAN

Your design sounds good, but I'm wondering if your WAN pipe is big enough. We have all servers at Corp so we need bigger pipes. Where will your servers be? We have a couple of 500-700 user offices and I can provide some 95% utilization for you to guide off of.

We have 3560's at the edge, connecting to 4500's at the distro, with 3800's on the WAN. I prefer the 3750's and stacking. The 4500's are overkill, but management is scared to go any lower in hardware.


Re: Designing a Remote LAN

Thanks, Collin. Nice info.

Let me tell you, just to make it clear, I was thinking of a routed access layer with the 3750s (inter-vlan routing done there) and then those would be uplinked to a pair of 3800s. So, 2 layers, not 3, like yours.

Im wondering if those 3750s are robust enough to handle all the inter vkan routing, which given the fact that all the servers sit at the DC, may actually not be all that much.

I can add another routed layer between the 3800s and the 3750s, but I am really wondering what that buys me, since I am running a routed access layer.

What do you think, man?

Re: Designing a Remote LAN

If you have 500-700 users that means at least two stacks. How do you plan on connecting the stacks to the routers (will you have redundant routers/WAN?)? I like the idea of connecting the stacks to another set of layer 3 switches for growth, security, any other crazy stuff that always comes up. Yes it's extra money, but it saves having to go back later and put it in.


Re: Designing a Remote LAN

"If you have 500-700 users that means at least two stacks."

Yup. No good?

"How do you plan on connecting the stacks to the routers (will you have redundant routers/WAN?)?"

Dual-homing each 3750 stack to each WAN router.

Re: Designing a Remote LAN

So you'll put something like a 4 port ethernet switch in the router for that? That will work just fine. Are you still cool with your WAN pipes?

Re: Designing a Remote LAN

I've attached the performance guide for your reference in routing between the stacks.


Re: Designing a Remote LAN

You know, the WAN pipe is what I have the boggest doubts about.

I may just price out a 10M Metro-E and be done with it.

With 500 users, thats 100 users per 2Megs. Thats 50 per 1 Meg. Thats 75 per 1.5 Megs (T1). So, given that a T1 is 24 DS0s, and ideally it would be great to give everyone 64Kbps of dedicated bandwidth (that isnt possible, too expensive and overkill), then 75 users per T1 is about a 3:1 oversubscription rate.

That may be OK.

Plus, I dont have to worry about the extra facilities.

So I may go with the 10 M Metro-E. What do you think?

Also, as far as having another routed layer between the WAN routers and the 3750s, I honestly dont think that buys me too much given that they do nothing at this site. No servers will sit there, except maybe for a print server or 2. No firewall. Nothing that I would really place at that distro layer.

Im not 100% with the rouetd access jazz, Im just brainstorming now. I may get corny and do the classic switched access, routed distro...yawn...yawn...yawn....


Thanks, boss.


Re: Designing a Remote LAN



Re: Designing a Remote LAN

I would think 10MB should be enough but only you know your applications. We use redundant DS-3's, but our utilization is pretty low. The old C-D-A works! If it aint broke, don't fix it.

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