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L2 Broadcast through Routers

I have a SUN server that uses a remote SIT server to get OS images from. The SUN server resides on a LAN, the SIT server resides on another LAN. There are two routers between the two LAN. The SUN server sends out a L2 broadcast to get it's IP address, however I'm not sure how allow the L2 broadcast through the two routers. Can anyone help? Again this is a L2 broadcast vice a L3 broadcast. I know for the layer 3 I could used the IP HELPER command.

-thxs

jekood001

5 REPLIES
Bronze

Re: L2 Broadcast through Routers

Hi,

Integrated Routing and Bridging (IRB) meet your requirement.

http://www.cisco.com/en/US/tech/tk389/tk815/technologies_tech_note09186a0080094663.shtml

HTH...

thanks

Arun

Pls rate if it helps

Hall of Fame Super Silver

Re: L2 Broadcast through Routers

Arun

With 2 routers between I do not believe that IRB would be an effective solution. That would mean that both LANs and everything between would be in a single broadcast domain and in a single subnet. I think it is likely that it would impact devices other than the Sun and the server.

jekood001

Have you tried using ip helper-address? Do know what kind of packet is in the broadcast? (is it some variation on bootp ?)  I am not positive but I think that it might work.

HTH

Rick

Re: L2 Broadcast through Routers

Here's a useful link for this purpose :-

http://www.cisco.com/en/US/customer/docs/ios/11_3/np1/configuration/guide/1cipadr.html#wp2215

It explains how you can make directed broadcast in to physical broadcast and also explains uses of ip helper address , ip directed-broadcast etc.

hope it helps

Manish

Bronze

Re: L2 Broadcast through Routers

Hi Rick,

Agreed and thanks for pointing it out. I didn't think about the performance of the devices. Even in our network we faced device performance issues due to IRB with routers in STP and it didnt stirke me when i posted.

How about extending LAN between routers using L2TPv3? Will this meet the requirement other than ip-helper command.

thanks

Arun

Hall of Fame Super Silver

Re: L2 Broadcast through Routers

Arun

L2TPv3 is an interesting suggestion. If jekood001 can get it to work with ip helper-address that would be simpler and better. But if helper-address does not work for him then L2TPv3 would be a feature that he should look at.

HTH

Rick

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