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New Member

two serial interfaces, same bridge group, does it load balance?

If I have a 7206 router in Site A and a 7206 router in Site B and I have two seperate Point to Point DS3s connecting the two sites, and I want to configure a bridge between the two.

If the ethernet and serial interfaces of both routers are in the same bridge group, would the two links load balance between the two sites?

Site A................................................Site B

Ethernet--->Router======Router--->Ethernet

5 REPLIES
Hall of Fame Super Gold

Re: two serial interfaces, same bridge group, does it load balan

No, a STP loop is detected and one port is blocked. But, you can configure circuit groups:

http://www.cisco.com/en/US/docs/ios/bridging/configuration/guide/br_transprnt_brdg_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1004152

to achieve load balancing.

New Member

Re: two serial interfaces, same bridge group, does it load balan

Paolo,

There is a single ethernet connection on both ends in that bridge group.

What about using the below under the ethernet as a precaution:

bridge-group x spanning-disabled

Updat:

After looking at this, it looks like that is the way to go with this.

Thanks Paolo

I have a question aout bgp load balancing as well.

Hall of Fame Super Gold

Re: two serial interfaces, same bridge group, does it load balan

In search for efficient balancing, you could even try bridging over MLPPP.

But usually the best solution is to eliminate bridging altogether.

New Member

Re: two serial interfaces, same bridge group, does it load balan

Thanks Paolo,

But in this application I have to use bridging, I can't use MPPP.

We have a unique set up that we have the routers doing frame relay switching and 4 seperate PVCs to isolate the traffic.

One of the PVCs is routed to the other side, the others are bridged.

I was wondering about the bgp load balancing, using the number of paths =2 in the bgp config.

I can see both serial interfaces as routes to the other side, but is it true load balancing?

Will the traffic actually split between the two interfaces as it leaves the router?

Hall of Fame Super Gold

Re: two serial interfaces, same bridge group, does it load balan

Why do you have to bridge? Why you can't subnet ? You should communicate clearly to the customer, that LANs in differently physical locations, MUST have different network address.

Regarding BGP, the protocol used doesn't matter. With CEF load balancing, you have a statistical load balancing, in most cases is very effective. With MLPPP, you have perfect balancing.

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