Re: New Deployment with flat network

miket · ‎03-22-2006

I am in the middle of a new deployment. The existing lan is using a 192.168.x.x/16 approx 500 devices. I am delpoying in a new bldg and suspect that I should use vlans woth the 3750's using a 172.16.x.x /24 network..The issue I am concerned about is How to get the 172.16 to route to the 192.168.0.0 network.. There is no routing available in the current network. If I use a 172 network will it by me anything or should I just add about 60 new devices on the 192 network or should I try and use vlans in the new bldg.

I am looking the pros and cons of each.Any help I could use

pkhatri · ‎03-22-2006

Hi,

The cleaner approach is definitely to use a new network for the new building and put it in a new VLAN. The 3750s are very much layer-3 capable and you can use them to do inter-vlan routing so that uses in the 192.168.x.x network can get to the 172.16.x.x network and vice versa...

Hope that helps - pls rate the post if it does.

Paresh

miket · ‎03-22-2006

The one concern I have is routing between old and new. The dgw is a checkpoint firewall. I was trying to add a route pointing to the 172 network but I had issues.

I suspect that that might be a policy.

I am getting some conflict saying that even of I put the new bldg in vlans it wont make any difference. and that I might as well leave the new bldg in the 192 subnet,,,

Thoughts on performance

pkhatri · ‎03-22-2006

The problems with a big(ger) VLAN is going to be the amount of unncessary broadcast traffic that will be going across the links. Having a L3 network in the middle would certainly help to cut this down.

However, if your equipment will not support it, the flat VLAN will still work, it just won't be an optimal solution...

Hope that helps - pls rate the post if it does.

Paresh

miket · ‎03-23-2006

Thanks for your advice... I agree I am going to try and vlan the new bldg and leave the old one alone..

This is the first time I have come across anyone using 192.168.X.X/16 and having some many devices.I am just not sure how many more devices before perfomance suffers badly..

Thanks again