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Dial on Demand Routing

We have a Cisco 3800 Serial port connected to TA for ISDN connectivity. The other end is a Cisco 3600 Router with PRI line.

We are using PPP on both the router and authentication is PPP Chap.

Here is the problem :-

1) There is no problem dialing to remote site, the remote site ( cisco 3600 with PRI ) accepts the call and authentication works fine.

2) We can able to check sh isdn status, sh dialer, sh isdn his at Cisco 3600 router, all command results confirm "Layer 3 call is active.

3) At the Cisco 3800 router the Dialer Interface assigined with ip address 10.10.1.2/24 where as remote end assigned with 10.10.1.1/24. From the Cisco 3800 we can able to ping 10.10.1.2 which is its own dialer interface. It's given 70/73/72 ms latency. However we can't able ping to the other end of the Cisco 3600 Dialer interface.

4) We have tried to ping Cisco 3600 own dialer interface, which is failed.

5) When we bring down ISDN connectivity we could not able to ping Cisco 3800 own dialer interface.

Here is the problem in a nutshell :-

ISDN Layer1,Layer2 & Layer3 working fine but the IP packet not traversing across the ISDN.

Please advise.

1 REPLY
Anonymous
N/A

Re: Dial on Demand Routing

When the line is up and you ping the 3800

from the 3800, what is really happening is

that the ICMP echo requests are still going

across the line to the 3600, which sends them

back. This is expected. In general, it doesn't

make much sense to ping yourself, so pinging

the remote end is a sufficient test. If you can't

ping the 3600 from the 3800, or vice versa,

when the ISDN link is up, you may want to check a

few things:

sh dialer map - ensure that each end has a dialer

map for each other with the correct name.

- debug ip icmp - see if either end is receiving the

ICMP packets

- sh interface - ensure that there are no drops or errors.

You should try to ping beyond the routers, too, to

see what is and is not successful. Telnet (or other

data besided ICMP) would be useful, too.

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