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Webcast-Catalyst9k
New Member

Bridging DEC over WAN connection

One of our sites (site A) used to be connected to another site (site B) via a DSL connection. Over the DSL connection, we bridged DEC to allow an old system to communicate between locations. It worked without any problem. Recently, the DSL connection was no longer offered by the DSL vendor, so we had to switch to a point-to-point T1 line from site A to a third location (site C) that had an existing T1 frame relay connection to site B. (Follow all that so far?)

Here's how it looks:

Site A<------>Site C<----->Site A

PTP T1 FR T1

We are trying to bridge DEC again, but now over these two hops. However, it does not seem to be working. Here's the basic config (relevant to the bridging) that we are using on each router:

Site A

------

interface Ethernet0/0

bridge-group 1

interface Serial0/0

description ==> PTP T1 to Site C

bridge-group 1

encapsulation ppp

bridge 1 protocol dec

Site B

------

interface Ethernet0/0

bridge-group 1

interface Serial0/0.1 point-to-point

description ==> to Site C

encapsulation frame-relay

frame-relay interface-dlci 123

bridge-group 1

bridge 1 protocol dec

Site C

------

interface Serial0/0.1 point-to-point

description ==> to Site B

encapsulation frame-relay

frame-relay interface-dlci 321

bridge-group 1

interface Serial1

description ==> PTP T1 to Site A

bridge-group 1

bridge 1 protocol dec

If we use the command "show bridge 1" on Site A's router, we can see MAC addresses of devices at Site B and vice versa. The RX count on both ends increments, but the TX count does not. However, at Site B (which has other sites connected to it), the other sites' devices' TX count will increment.

We're at a loss as to why this does not work. Could something about the PTP T1 line have something to do with it? Is PPP incapable of handling this bridging correctly? I would think that if that were true, we wouldn't get the MAC addresses passed back and forth.

Any ideas? Please help if you can! Thanks.

2 REPLIES
New Member

Re: Bridging DEC over WAN connection

I noticed that you do not have the ppp encapsualtion on Router C Serial 1.

New Member

Re: Bridging DEC over WAN connection

That was an omission on my part. It is actually there.

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