Troubleshooting guide

All possible debugging has been turned off.

Verify your VPI/VCI values, and then make the necessary changes to your configuration.

If you do not see output during the 60 seconds of debugging, contact your ISP.

Can you ping the default gateway from your PC?

In a bridged environment, pinging the default gateway is a good test of connectivity. In general, if you can

ping to your default gateway, you know that Layer 1 and Layer 2 services are functioning properly. Open an

MS−DOS window and try to ping the default gateway.

C:\>ping 192.168.1.1

Pinging 192.168.1.1 with 32 bytes of data:

Reply from 192.168.1.1: bytes=32 time<10ms TTL=247

Ping statistics for 192.168.1.1:

Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli−seconds:

Minimum = 0ms, Maximum = 0ms, Average = 0ms

If your success rate is 80−100 percent, try to ping a valid Internet address (198.133.219.25 is

www.cisco.com). If you can ping the default gateway from the PC but you cannot ping another Internet

address, make sure you have only one static default route in the configuration (for example, IP route 0.0.0.0

0.0.0.0 192.168.1.1).

For the example above, if you already have a correct static default route and cannot ping Internet addresses,

contact your ISP to resolve the routing issue.

If the ping test fails, you see output similar to the output shown below. In this case, continue with the

troubleshooting steps that follow.

C:\>ping 192.168.1.1

Pinging 192.168.1.1 with 32 bytes of data:

Request timed out.

Ping statistics for 192.168.1.1:

Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

Approximate round trip times in milli−seconds:

Minimum = 0ms, Maximum = 0ms, Average = 0ms

Is the bridge port in a forwarding state?

For your Cisco DSL Router to forward packets to your ISP, your bridged interface must be in a forwarding

state. If your bridged interface is in a blocking state, there is a loop in your network that you have to remove

before you are able to pass traffic. The most common cause of a loop in a DSL network is having two bridged

DSL circuits to the same ISP.

Router#show spanning−tree

Cisco DSL Router Configuration and Troubleshooting Guide