Cisco and Nortel ATM

[cwy]

I tried to connect a Nortel atm router with a ATM line. There were some

problem. Although the interface and the protocol were up, I cannot ping the

ip address of ISP end. I can ping the Nortel atm interface ip address. When

I changed to use another cisco rotuer to connect the ATM line, there was no

probelm. My ISP also using cisco equipments. Does anyone know are there any compability problem of cisco router and nortel router? If yes, any solution?

Andy

[mnordhoff]

I believe I have the solution as we were a mixed Cisco/Nortel ATM shop a few months ago. We had to configure an "adjacent host" on the Nortel equipment to be able to ping the Nortel interfaces. This should solve your problem. Using Site Manager you would Click Protocols/IP/Adjacent Hosts then add an adjacent host entry for the Cisco side of the link with your Nortel interface as the Next hop interface. This should do it!

- MN

[tschmuhl]

You will need to use the Nortel's Adjacent host command. We ran into this in our own network when trying to connect Frame to ATM Ckts from a Nortel rtr to a Cisco rtr. We spent many hours/days on it.

It has to do with the ARP, the cisco sees the Nortel's ARP as an unknown ATM ARP request. The Adjacent host command is easy to set on the Nortel, you can go in thru Site Manager and either reference the Adjacent host using the IP address of the other router (the /30) or by DLCI. Once the Adjacent host is set in the Nortel, you should be able to ping up to 4000byte packets with no problems...

Thomas

[cwy]

Adjacent hosts already configured in the Nortel router before.

[sachin.singhal]

Nortel Routers by default use standard ARP, Cisco use rfc1577 ARP. You can change this on the IP interface or through BCC. Failing this take a PCAP trace and have a look at the inbound encapsulation type, you should be using LLc/SNAP (RFC 1483).