Layer2 and Layer3 switch

[ljCharlie]

Can anyone explain the difference between a layer 2 and layer 3 switch and when to use what?

Many thanks in advance!

ljCharlie

[ktkendall]

Layer 3 is a bit more sophistacated, you can do more with it as far as routing, creating vlans and many other things.There is much more involved in software on a layer 3. It can address and route at the layer3 level which is the IP address level if I remember correctly, whereas layer 2 is the mac address level, and with a layer 2 switch you pretty much just plug it in and plug the PC's in and it works.. That is probably why the cisco switch you saw was so much more expensive than the other ones you seen. It was probably a layer 3.. From your other post for what you described that you need for your organization you will be fine with a linksys, or 3com basic 48 port switch..

[ljCharlie]

Thank you very much for your response. I'll have to check if the Cisco 2950 is a layer 3 or 2. Forgive me for asking you to explain more, but what's the different between routing at the IP address level and MAC level? I want to make sure if purchase the correct switch for our purpose. Here's our situation. We are a department of a University campus network. In our building we have switch that supplies the Internet for our building as well as a couple other buildings. Now here's what want to do. We want to break from the main switch to a firewall, then from the firewall it goes to a two 24 or one 48 ports switch. All of our 40 machines will be connected to that switch. So do we just buy a layer 2 switch in this situation or layer 3?

Again, thank you.

ljCharlie

[ktkendall]

Layer 3 is a bit more sophistacated, you can do more with it as far as routing, creating vlans and many other things.There is much more involved in software on a layer 3. It can address and route at the layer3 level which is the IP address level if I remember correctly, whereas layer 2 is the mac address level, and with a layer 2 switch you pretty much just plug it in and plug the PC's in and it works.. That is probably why the cisco switch you saw was so much more expensive than the other ones you seen. It was probably a layer 3.. From your other post for what you described that you need for your organization you will be fine with a linksys, or 3com basic 48 port switch..

[ljCharlie]

One more thing. What is the difference between an unmanaged and manage switch?

ljCharlie

[ktkendall]

Sorry for the double post, anyways it sounds like you would be fine with a layer 2 switch. You see being able to route and set things from the IP address layer allows you to create vlans (virtual Lans) which is like a way of having everyone connected togother to access some of the same resources but also being able to segment some into groups that cannot be accessed by others outside that vlan. Like I said a basic layer 2 switch is pretty much plug and play and all your settings and everything will be from the server/workstations.. Layer 3 gives you some additional flexability to adjust things from within the switch itsef..

A router actually works at the layer 3 level, so a layer3 switch is close to a router it's just that the additional thing with a router is to connect your network to another dissimilar network which the switch can not do..

[ktkendall]

A managed switch has a little bit of sophistacation to it, some settings and such but I do believe it still works at layer 2. The unmanaged switch has no settings or anything just plug it in and plug the PC's in and all settings are in the PC's. A managed switch may even be another name for a layer 3 switch..I don't work too much with this stuff so I'm far from an expert but do have my net+ cert and with the newer telcom stuff it is all going IP network connectivity, so even us old phone guys are getting into this stuff nowadays...

[mbossman2]

long and involved discussion to fully understand but here is the readers digest version:

1) the 2950 is a layer 2 switch

2) a layer 3 switch comes into play when you decide to have 2 seperate networks (2 ip subnets) and want the ability to move traffic between the 2 subnets.

From what you describe your network, Layer 3 switching would be nice, but not a requirement.

[ljCharlie]

Good! Because a layer 3 switch is out of our budget. Would a 48 ports switch better or two 24 ports switch better? And if I decide to go with a layer 2 switch, would a Netgear or 3Com switch be part of my consideration or should I just go with a Cisco switch? Anyways, many thanks for both of your suggestions and explanations.

ljCharlie

[mbossman2]

Single box is a better solution rather than 2 boxes. The reason for that is that the connection between the 2 boxes is a 1GB link so that can act as a bottleneck. with a single box solution there is no such bottleneck (with a properly designed switch).

[ljCharlie]

What do you think are the top 5 brand of layer 2 switches? I really like the 48 ports Cisco switch but it really is too expensive. So I'm trying to narrow down to another brand that will still be good but not too expensive.

ljCharlie

[ljCharlie]

I'm thinking of the NETGEAR FS750AT 48-Port 10/100 Switch, Dell PowerConnectTM 3348, or the 3Com SuperStack 3 Switch 4250T 48-Port Switch. What are your opinions?

[mbossman2]

The Netgear is a low choice: not manageable..good short term solution if $$ is an issue, but if your overall IT department may not like it cause they won't be able to see or management

Dell - they make good pc's but their switches, on a good day, stink. They OEM their products from Accton, if you weren't considering Accton (or rejected them) why consider a Dell?

3Com - other than their lack of cohesive management, not a bad choice.

The top 5 switch manufacturers are:

Cisco - best in the enterprise
3Com - 2nd place - but their overall strategy concerns me
HP - good feature set for a good price for the enterprise or middling SMB company
Linksys - good products in the lower end of the SMB
Extreme - up and comer

These are rated in no particular order and are my opinion only

[ljCharlie]

Thanks!

ljCharlie