Troubleshooting Dsl Interfaces - 3Com MSR 50 Series Configuration Manual

82 C 1: ATM
HAPTER AND
Troubleshooting DSL
Interfaces
DSL I C
NTERFACE ONFIGURATION
The ping command can test network connectivity. Extended ping command can
be used to specify some options in the IP header in addition to that function. For
more information about the ping command, see
Debugging" on page
If the interface cannot be pinged, check whether:
The interface is down, which causes missing of its route in the routing table.
■
The AAL5 encapsulation of PVC is incorrect (for 155 Mbps ATM interface only).
■
Improper line operation is one of the faults that you may encounter in DSL
applications. Such a fault is likely to occur on whichever devices or nodes in the
hierarchical broadband network architecture. It is probably caused by the CPE
device, copper wire, splitter, DSL port on DSLAM, or even the broadband access
server. For this reason, you should segment the network to locate the problem.
Generally, DSLAM provides you with abundant fault isolating methods and a
complete guide, which are however, beyond the scope of this manual.
On the CPE, you may do the following when problem occurs:
1 Read the LEDs for the DSL interface card
When the DSL line is training, the LINK LED blinks. After the activation succeeds,
the LINK LED which should otherwise be OFF lights and stays ON. The Activity LED
blinks when data being transmitted on the line.
2 Display the DSL state information with the display dsl status command
The State of driver/chipsets field provides the information about interfaces and
transceiver states.
Common interface states include Activating, Active, Startupping, Deactive, and
Test Mode.
Common transceiver states include Idle, Data Mode, HandShaking, and Training.
3 Perform the debugging physical command to view details about activation, such
as sending of the activate command, activation timeout, training process, and
activation success.
4 If line activation attempts always fail, check that the line is securely connected and
functioning normally.
5 If bit error rate is high or interference happens too often, reset the interface with
the shutdown/undo shutdown command or reboot the device and reconnect
the line. If the problem is still there, make an overall line condition and
environment check.
2119.
"System Maintaining and