How to bridge vlans across T3 using 3725 ver 12.3(5c)

[jswaim]

I need to trunk two vlans from a cat6500(catIOS) to a 3725 fastE0/1:10/100 and bridge them across the WAN to another 3725 connected fast0/1:10/100 to a cat6500(nativeIOS). No routing is necessary, since L2 connectivity is the only requirement.

What is the best method?

Create trunk between the cat and the router using subinterfaces and create a bridge group for each vlan, or will a single bridge group suffice? What are the things to look out for with this type of implementation?

Can you provide me with examples????

Thanks in advance,

Jeff Swaim

[kghutton]

I too am looking at a similar situation. I am trying to trunk 8 VLAN's across an OC-3 (point-to-point). The 2 ways I have come across that make any sense are either Transparent Bridging or 802.1q tunneling. From what I have read so far the Transparent Bridging seems the more logical choice. I would also like someone who has done this before to chime in if you please. Jeff, do a search for Tranparent Bridging and you should come up with the PDF. Read the section Configure Transparent Bridging over WANs. If you have problems finding it email me and I can email it to you.

Thanks

Kevin Hutton

[kghutton]

The solution that I have come up with is to utilize frame-relay encapsulation on the serial side and use sub interfaces, one for each vlan on the trunk, on the fastethernet ports. Then assign bridge groups to each pair (one serial sub to one fa sub) to put them on the same layer 2 domain. I guess you could technically use more than one interface but if you have a limited number of interfaces this is a way to get more connections or vlans out of your config. Here is the config for the router on one end:

interface FastEthernet0

no ip address

!

interface FastEthernet0.160

encapsulation dot1q 160

no ip address

bridge-group 160

!

interface FastEthernet0.161

encapsulation dot1q 161

no ip address

bridge-group 161

!

interface FastEthernet0.162

encapsulation dot1q 162

no ip address

bridge-group 162

!

interface FastEthernet0.163

encapsulation dot1q 163

no ip address

bridge-group 163

!

interface Serial0

no ip address

encapsulation frame-relay

no keepalive

!

interface Serial0.160 point-to-point

no ip address

frame-relay interface-dlci 160

bridge-group 160

!

interface Serial0.161 point-to-point

no ip address

frame-relay interface-dlci 161

bridge-group 161

!

interface Serial0.162 point-to-point

no ip address

frame-relay interface-dlci 162

bridge-group 162

!

interface Serial0.163 point-to-point

no ip address

frame-relay interface-dlci 163

bridge-group 163

!

bridge 160 protocol ieee

bridge 161 protocol ieee

bridge 162 protocol ieee

bridge 163 protocol ieee

I believe this could solve your problem. I got this suggestion from TAC and I am in the middle of trying to test this. Let me know what you find. I hope this helps.

Thanks

Kevin

[amitbatra]

hi

i believe that u need to configure bridge-irb . in the global config. and if u want to do intervlan routing on this router only u need to configure inteface brige and give ip to these interfaces. like we generally do with interface vlan's.

hope this help u out.

[MAKhan]

Hello guys!

I am also working at the same problem; please provide your feedback whether it has been successful for you?

Can I use both bridge-group 101 and 102 on the same serial link or do I need two separate links?

Best regards

[kghutton]

Well... We decided that it would be better to engage our local ground cable company (Verizon) and see what services they had that we could use. They had 2 possible solutions for us that work very well. We have a 100Mb hand-off at either end and it's all layer 2. We have an appropriate SLA and so on. Since we are doing this temporarily this solution works out very well.

To answer your question, you will need to build sub interfaces on the serial link for the different bridge groups. This goes for the VLAN's on the ethernet side also. The partial config above is what I received from TAC, so it should work as desired. My organization let me know that I had a budget to get this done and rather than run off into the unknown I decided to get something a little more robust. Hope this helps.

Thanks

Kevin