Can you spread a vlan over a t1 link via cisco routers?

[kulagun]

Just wondering if anyone can point me in the right direction. I have 2 sites, both with cisco 2621 routers and cisco 2950 switches, I have a seperate vlan at one of our sites that I would like to spread over to the other site. Can this be done?

 

[svermill]

I'm just thinking out loud here, because I've never heard of the sort of thing you're talking about being done, but would you be able to bridge across that T1? Integrated Routing and Bridging maybe? That might be somthing to look into?

As for truley *routing* between a VLAN, I doubt it. Maybe some sort of tunnel technology might allow for it, but routers generally route between layer 3 networks/subnets.

Just some rambling thoughts...

 

[marks66]

Yes it can be done, using bridging. Although even with a T1 link you could have speed problems.

I wouldn't do it.

 

[bythespy]

Why do you want to span the VLAN across the T-1? Maybe there is a better way to accomplish your goal.

Mspivey
CCNP

 

[kmg365]

As someone previously stated....you can do that with bridging. Both routers must have software that supports vlans. Regulr IP software won't work....so you need ip plus to make this happen.

I recommend you spend the extra 1000 to 1500 dollars for each router and set up bridging...just to learn it....then "rip it out" and go back to layer 3. Of course your boss won't like it...but he doesn't have to know.

Jim

 

[baddos]

lol "rip it out and go back to layer3"

 

[dnels]

If you're trying to support a broadcast application you could use ip helpering. Can't think of many other reasons, maybe security, to span a vlan between sites.

 

[4work]

You can do this by simulating Frame Relay encapsulation on the serial sub interfaces and using 802.1q on the Ethernet sub interface. The key is to have the remote side set for frame switching and to make sure that your using the correct bridge groups. Here are some of the important configurations you need.
Host side:
interface FastEthernet0/0.1
encapsulation dot1Q 1 native
no ip route-cache
no ip mroute-cache
bridge-group 1
interface Serial0/0
no ip address
encapsulation frame-relay
no ip route-cache
no ip mroute-cache
no fair-queue
interface Serial0/0.1 point-to-point
no ip route-cache
no ip mroute-cache
frame-relay interface-dlci 20
bridge-group 1

Remote side:

frame-relay switching

interface FastEthernet0/0.1
encapsulation dot1Q 1 native
no ip route-cache
no ip mroute-cache
bridge-group 1
interface Serial0/0
no ip address
encapsulation frame-relay
no ip route-cache
no ip mroute-cache
no fair-queue
frame-relay intf-type dce
!
interface Serial0/0.1 point-to-point
no ip route-cache
no ip mroute-cache
frame-relay interface-dlci 20
bridge-group 1

bridge 1 protocol ieee

 

[l3stuff]

please just remember why we moved from bridged broadcast domains to routed segmented broadcast domains

 

[kmg365]

Let's see, you have a 100mb lan on one side and the other is 100mb and you want to put about a 1mb connection between the two. You can do that if you want....but 1.5mb layer three works sooooo much better connecting 2 100mb lans...than does 1.5mb layer two.

Cheers,

Jim

 

[mada973]

Hello everyone! I'm very interested for this subject, and I have question. What to do if I have following : switch-router3640-atm router 4500- atm switch-atm switch-router 4500-router 3640-switch, and I wont to connect two switch on the end sides to one vlan, in purpose to transfer ppp broadcast packets. Sorry ,my english is not very well I have more expirience with SNMP protocol, monitoring tools, and some simple configurations on Cisco routers, but my boss take me assigment to make project for connecting two switches on way I mentioned. If isn't some very complicated, please send me your suggestions. Best regards from Selma!