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Community Member

vlans in different routers

Hello, i have a big doubt

i have this scenary

site 1     ....................................................................Site2

pcvlan10---------switch-----router---------  ( WAN/CLOUD )------------------router----------swich------------pcvlan10

pcvlan11                                                                                                                            pcvlan11

172.20.30.1                                                                                                                    172.20.30.1

172.20.40.1                                                                                                                    172.20.40.1  

could be posssible  conect Vlans in this way????

8 REPLIES

Re: vlans in different routers

If the switch is L3 switch then you can enable ip routing and add static route or a routing protocol to advertise the different Vlans

Sent from Cisco Technical Support iPhone App

Super Bronze

vlans in different routers

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Posting

Normally no unless you set up some kind of L2 pseudowire.

Bronze

vlans in different routers

If your routers support the "connect" command, you can (like Joseph said) "bridge" those interfaces together and have an L2 vlan go across a wan connection.  We do it, but we have ASR's running over an RPR to bridge two Internet connections with HSRP.

Ven

Ven Taylor
Community Member

Re: vlans in different routers

Hi Ven Taylor, I am trying to configure two ASR1002 for bridging. We have point-to-point network between two sites. Can you please, send me your config. I have been searching Cisco Site but no luck.

Thank. Stephen

Bronze

Re: vlans in different routers

Stephen:

Sure!  Here's an example of the interface configuration that allows three tagged vlans across a single physical link.

LAN <----> L3 switch <---->  ASR  <----> {WAN / RPR / WHATEVER} <----> ASR <----> L3 switch <----> LAN

interface GigabitEthernet0/1/0      <-- This is the trunk that connects to your local L3 switch.
no ip address
negotiation auto
cdp enable                                      <-- not necessary, but useful.
service instance 200 ethernet            <-- Ties it to the other side
  encapsulation dot1q 200                  <-- Tags the traffic
  bridge-domain 200                           <-- Bridges the whole thing together.
!
service instance 201 ethernet   <-- First "sub-vlan" for lack of a better term.
  encapsulation dot1q 201
  bridge-domain 201
!
service instance 210 ethernet  <-- Second "sub-interface".
  encapsulation dot1q 210
  bridge-domain 210
!

interface GigabitEthernet0/0/3  <-- This is your "WAN" interface - goes to the other ASR.
no ip address
negotiation auto
cdp enable
service instance 200 ethernet
  encapsulation dot1q 200
  bridge-domain 200
!
service instance 201 ethernet
  encapsulation dot1q 201
  bridge-domain 201
!
service instance 210 ethernet
  encapsulation dot1q 210
  bridge-domain 210
!
end

The other router will have the exact same configuration.  Once this is done, you'll have vlans 200, 201, and 210 trunking across a wan link.

Obviously, you can use any vlan schema, but remember, no IP addresses on these interfaces.  Just on the L3 switches at the distant ends of this connection.

hope this helps!

Ven

Ven Taylor
Cisco Employee

vlans in different routers

Adding to Ven's post, you can either enable the IRB to achieve this or If you have an ASR1K router, you can use OTV with the latest realese due to be out soon.

Cheers,

-amit singh

Community Member

Re: vlans in different routers

One drawback that I found with OTV is that all of you clients must now run IGMPv3 for SSM. This is great unless you have dozens of senders/receivers for the same group.

Cisco Employee

Re: vlans in different routers

Inter VLAN communication is possible provided we have an L3 switch before the OTV ED device, or we can make the OTV ED device itself act as both the L3 device for the different vlans and for OTV router as well.

If this post is still un-answered  let me know, we can provide the solution for the concern posted above.

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