If the ATM interfaces are down, or if they continue to come up and then go down (they do not stay up and up), begin to troubleshoot at Layer 1. If the statuses of ATM0 and ATM0.1 are up and the protocol is up, begin to troubleshoot at Layer 2. Interface IP-Address OK? Method Status ProtocolĪTM0 unassigned YES manual up up ATM0.1 unassigned YES unset up up The output of this command differs slightly depending on your configuration. The easiest way to determine which layer you should begin to troubleshoot is to issue the command show ip interface brief. Layer 2.2 – Point-to-Point Protocol over ATM (PPPoA), Point-to-Point Protocol over Ethernet (PPPoE), RFC1483 Bridging, or RFC1483 Routing Layer 1 – DSL physical connectivity to the Digital Subscriber Line Access Multiplexer (DSLAM) of your ISP There are three layers in which the failure can occur. The first troubleshooting step is to determine which layer of your Asynchronous Digital Subscriber Line (ADSL) service is failing. The goal of this document is to isolate the cause of the failure and repair it. There are many reasons why your Digital Subscriber Line (DSL) connection might not function properly.
