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New Member

setup VLANs or not?

Hi everyone, I’m looking for some feedback from you guys on a scenario I have here. We've got about 100-120 devices on our network. We have 3 Intel 510T switches, a Cisco Catalyst 2950 Switch, and 2 Intel 220T hubs.

Currently we have there are no VLans setup, and I just started reviewing their configuration and was wondering if it would be beneficial to setup the network up differently.

Right now one Intel Switch is the backbone switch which the servers are connected to, along w/ the Pix Firewall connected to a T1, along with 5 ports connecting to the other switches/hubs using crossover cables all in the same wiring closet. Real basic network. All users access the same Resources and Printers, so I haven't thought of a reason to setup Vlans, but was wondering if anyone would suggest a different configuration. I just started working w/ the network, and when I saw the capabilities of the switches I wondered if there was a more optimal configuration for these devices.

One question I have, if I setup some VLans, I realize I would need a router to connect the two Vlans, now if the router connects to a switched port that is members of 2 VLans, if the Router is only operating at a 10Mb connection, would this create a bottleneck in the 100Mb network, or is the Vlan Routing done in the switch, or is all the data passed in/out of the router to connect the 2 Vlans.

New Member

Re: setup VLANs or not?


If you do not have any real network performance issues at the moment then I would keep the same configuration.

Once you segment you flat network with vlans, you will need a router to route between networks, this can be done in a couple of ways:

1) Use a multi-port router and place one port in each network.

2) Use a single port router and trunk multiple vlans through a single port. This would have to use a trunking method such as 802.1Q or cisco's ISL.

10 Mb ports on cisco routers do not support vlan trunking (only 100Mb plus) so if its a cisco router, you cannot do it.

In regards to congestion, it could become a bottleneck, depending upon your design.

I'd hold back until you are going to upgrade all equipment, and then buy a layer 3 3550 and 2950's or a small cat 4000, also layer 3.

New Member

Re: setup VLANs or not?

Thanks for the feedback. I myself couldn't really think of a reason to split the network up, but thought I would ask people that knew more about them..


New Member

Re: setup VLANs or not?


You may want to think of that in a different way. You may want to consider upgrading your network in the near future since it will likely start to have issues. Having all your users and devices on one segment will cause the following.

1) Servers and client devices with be subjected to unwanted broadcast. Causing cpu cycles on your servers to be wasted.

2) Having one segment can leave you open for problems if a device fails and starts a broadcast storm.

3) You are restricted on the type of security you can offer by not having segments.

4) If your switches are daisy chained, traffic & broadcast will create unwanted bottlenecks.

You don't have alot of users at this point but in my mind you are approaching a point where you may what to replace some equipment and segment, so you don't run into severe problems. If you introduce a new application or a number of users you could start to degrade your network.

Have fun!

Randy McIver