Connect Catalyst 2924 to Linksys Router

It all depends what VLAN the router is in (in regards to access ports). If you place ALL ports into VLAN 100, including the router, this will work. If the router is not in VLAN 100, then it will not work as the clients will be in a VLAN that has no router as a default route. Unless your linksys supports trunking, and you place IPs in both VLANs on the router and trunk the VLANs back to the switch, this will never work. If the switch supports routing itself, you can place an IP address in VLAN 100 and ensure that routing is enabled, but I'm fairly certain the 2924 will not support this. Now technically you could probably place two connections from the linksys, one into an access port in vlan 1, and one into an access port in vlan 100, and it should work. The only caveat here is that they hosts on VLAN 1 may have trouble talking to hosts on VLAN 100. Technically it should traverse the router and work, but direct broadcasts will not work.

thanks for the info.. this is what I thought.

I only have the 1 router. I was under the impression that the vlans could all be routed out through vlan 1 ports to the linksys, but your statement makes it clear this won't work.

as for the recommendation of plugging into 2 ports and not talking; I'm not worried. I won't have anything plugged into vlan 1 anway. just vlan 1 and vlan 2. I'm trying to separate a small home business and home personal network; nothing major.

if I wanted to; which I tried, how can I assign the switchports an ip? I can't seem to do that.

thanks for your help though!

GNY

It would have to be a layer 3 switch, which I don't think the 2900 does. A 3550 or 60 would provide this functionality, allowing you to put IPs on ports as well as route between VLANs which would solve your issue. But with your hardware, you are limited without additional router interfaces/connections.

No, not on a layer-2 switch. You could do VLAN trunk'ing, but I doubt the linksys supports vlan trunks.

One thing to note in Cisco switches. VLAN 1 is special. This is the default 'native' vlan, in which all traffic comes out untagged on VLAN 1.

I don't think this affects you much at all in your setup, but it may.

Get a layer-3 switch. A layer-2 switch isn't going to allow you.

Or, add a router capable of doing VLAN trunking.

Ok thanks for the recommendation ..

Yep.. I understnd about the vlan 1 native behavior .. The question is would be Trendkill's suggestion work?

Thanks for the help.. ill come back if this does not work.. :)

Given my configuration can I use different ip address ranges for each vlan?

Example: vlan 100 = 192.168.1.0/24 vlan 200 = 10.1.25.0/24

Technically you probably have to in the routing world, as you can't assign the same range to two different interfaces on the same router. And even if you could, it would not be advised unless you know exactly what you are doing and what is what. I won't say there is 'no' reason to do it, but there would be very few, if any, reasons to have two different vlans with the same address ranges.

Hey Trendkill ..

Thanks for answering my question.

I tried plugging each of the vlan ports 100&200 into a port on the linksys switch and i got a native vlan mismatch error first and oddly both vlans were able to talk to eachother. I'm guessing due to the linksys ports not being vlan enabled it puts them all into one vlan/ network.

So I think overall i need a router capable of doing the vlans. due to my example of what i did and wanting to use differnet ip ranges. the router is set to use say 192.168.1.0/24 and isnt aware of any clients using the 10.1.25.0/24 address and the switch is configured with a

192.168.1.0/24 ip address.

I think through trial and error i have figured it out. I do have 2 other linksys routers that i could use to work my way around, by plugging them in after the witch, assigning the appropriate lan addresses and plugging into the linksys router going into the cable modem, but then again; these networks would then be all on the same network theoretically due to the top level router not capable of doing vlans or seperating ports. so you could change the ip of one of the workstations on one vlan to the ip of the other and might be able to access that network.. maybe im wrong here..

hmm .. ebay has some great cheap devices .. what would you recommend to achieve what im looking to do?

What im looking to do is more then what I have posted here. I would like to use like a 2514 to connect to my cable modem and have those 2 vlan networks on different network ranges.

Simple enough :) I know how to work with the devices (routers and switches) fully, but designing and the architecture is where i fall short.

Suggestions on devices?

Thanks again..

GNY

Yeah and perhaps I answered your question incorrectly last go-round. While you definitely would need two different addresses on the two VLANs, the linksys would not support that as it only supports a single network in its configuration. Therefore you can't make it have two different router IPs in two different networks. Truthfully, you could set your first linksys or whatever into the switch in vlan 100 at

192.168.1.0/24. You could then hook in a second linksys directly into that first one, and just make sure its LAN addresses are different than 192.168.1.0/24. What I mean here, is its WAN IP would be coming from the first linksys (192.168.1.X), and then it can serve LAN addresses in a different network like 192.168.2.0/24. The only problem with doing this is that nodes from the first network would not be able to talk to nodes on the second network, as linksys' use NATing and therefore once host A sent packets to router A, router A would not know to send these to router B for host B. Therefore you could get around this by creating a static route on the first router to 192.168.2.0 via the WAN IP of the first router.

I know its confusing, but it should make sense/work.

To answer your second question, yes the easy answer is to buy any router with multiple ethernet interfaces, or that will will support vlan trunking to the 2900 or whatever you are running. This way the routers first interface would plug into the linksys, and its second would trunk vlan 100 and 200 to the 2900, each with its own network and dhcp. The router would then be the gateway for hosts in either vlan (and you could put either vlan on any port on the switch), and they would be able to intra and inter communicate as desired.

Hope this helps.

Trendkill,

Thanks for your help so far ..

Cant address your whole post right now..

but cant i use the 2514 in place of the linksys to make life easier for what i would like to do. Considering the 2514 will run the latest ios and what not.. i will address the rest of your post when im not at work :)

Thanks a whole lot

GNY