Bridging two sites connected via ethernet

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Sep 13th, 2010
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I need to span a vlan 100 across 2 sites connected via ethernet. I am thing about using BVI.

Both sites are sharing different VLANs. How I can use BVI for this solution and not brake other connection for other VLANs ?

New vlan is 200

Old VLANs :  vlan 100 --

                    vlan  50

                    vlan  10

                                               int fa0/0                                                                 int fa 0/0

                                 SITE 1 <---------------------------------------------------------------------------------- -------------   > SITE 2   (  vlan 100, vlan 50,  10, 5 )

                                   | fa0/1                                  E T H E R N ET




How I should configure BVI in this design ?

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Laurent Aubert Mon, 09/13/2010 - 21:58
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I don't think BVI is the solution as an interface can belong to only one bridge-domain. If you want to keep your L3 subnet between both sites and propagate VLAN at the same time, you should upgrade your routers at both sites to a model which support switching and routing features. The idea is to make your WAN link a trunk.s

You could also terminate your ethernet link on a L2 switch so your WAN becomes a trunk and you connect your router to it so their L3 subnet will be on a dedicated VLAN.



smailbouabdallah Tue, 09/14/2010 - 09:12
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Thanks for the reply.

I have a Cisco 3825 router on onesite A  and a 6500 switch on site B .

The sites are connected via ethernet . I need to span a vlan with few users on site B and one user on site A.

I have an ethernet interface connecting the sites and on router site A , I have 3 other interfaces :

ethernet connecting from A to B

one connecting to backup site

another connecting to voice vlan

Other interface connecting to local switch

Any help regarding how to use this BVI ? Thanks,


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