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Network of company where I am working now is designed in star topology with Cisco 3640 in central office and Cisco 2600 in branches and connectivity is made by satellite connection the interfaces with satellite modem are serial interfaces and with some branches between access internet the interface with ISP are Ethernet and communication between my routers end ISP routers is built with DSL line (digital modem) between branches that have access in the Internet I have configured tunnel interfaces and the traffic is routed between those interfaces .

For backup lines I used DDR backup lines where remote routers dial in central router that have one slot with asynchronous line (8 ports with corporate analog modem) aux to aux backup line.

For this reason I used DDR trigger and specifically dialer watch which is monitored the specific network in routing table, where the line is going down the protocol state of interface is down and automatically the specific route is deleted and dialer watch activate the backup interface.

My problem is with Ethernet interface that are connected with DSL modems, where the line is going down the protocol state in Ethernet interface remain UP because is connected directly with Ethernet ports of the digital modem and the specific routing is not deleted and dialer watch not activate the backup line, the same problem is with tunnel interface, for this reason I turn off the power in digital modem in cases when DSL line or internet connection is down that dialer watch to activate the backup interface.

Can You help me with an idea about DDR triggers ( for example DDR trigger to monitor pinging in one specific remote interface and where ping is request time out DDR trigger to activate the the backup interface.

Thanks a lot


  • Other Network Infrastructure Subjects


Dialer watch does not depend on line protocol going down; instead, you watch a route that is being learned by the cisco (not a directly connected route), and once that route disappears (for whatever reason) we will dial out - no interesting traffic required, no idle timer - the link should then stay up until the route returns. It sounds like maybe you are watching a directly connected route?

The only way that DDR can trigger a call is via a lost route (Dialer Watch) or interesting traffic; it can't be triggered by the failure of a ping or any other process.