Troubleshooting atm, An atm interface is always down, Symptom – H3C Technologies H3C SR8800 User Manual

Page 24: Solution, Pvc state is down while atm interface state is up, Pinging opposite end attempts always fail

Troubleshooting ATM

An ATM interface is always down

Symptom

The state of an ATM interface is always down.

Solution

Check the fiber connections of the ATM interface for inverse connections. The ATM interface can go up

only when the transmit fiber and receive fiber are correctly connected.
If two routers are connected back-to-back, check the ATM interfaces for the same clock mode. By default,

the clock mode on a router is slave, namely, adopting the line clock. If two routers are connected

back-to-back, you must configure the clock mode at one side as master to provide clock reference, while
the other side adopts the slave clock mode.

PVC state is down while ATM interface state is up

Symptom

The state of a PVC is down while its ATM interface is up.

Solution

Check if this fault results from enabling OAM F5 Loopback cell transmission and retransmission detection

or OAM continuity check. When two ATM routers are connected, the VPI/VCI value of the PVCs on the

two routers must be the same. Provided that OAM F5 cell transmission and retransmission detection or
OAM continuity check is enabled, and the VPI/VCI value of the remote node (connected directly with the

local node) is not the same as the local node, the local PVC state cannot change into UP.

Excessive packet drops/CRC errors or interface flapping
occurs

Symptom

Two routers are connected back-to-back and can ping each other, but excessive packet drops and CRC
errors or interface flapping up and down occurs occasionally.

Solution

Check the connecting ATM interfaces for fiber type inconsistency. If one side is a multi-mode fiber-optic

interface while the other side is a single-mode fiber-optic interface, replace one interface to make sure

that the same fiber-mode interfaces are used.
The symptom is occasional with the connection between ATM interfaces of different fiber-optic modes,

which can work normally in most cases.

Pinging opposite end attempts always fail

Symptom

The physical layer and the line protocol of an ATM interface are both up, but the opposite end cannot be

pinged.

This manual is related to the following products:

H3C SR6600-X H3C SR6600 H3C MSR 5600 H3C MSR 50 H3C MSR 3600 H3C MSR 30 H3C MSR 2600 H3C MSR 20-2X[40] H3C MSR 20-1X H3C MSR 930 H3C MSR 900 H3C WX6000 Series Access Controllers H3C WX5000 Series Access Controllers H3C WX3000 Series Unified Switches H3C LSWM1WCM10 Access Controller Module H3C LSWM1WCM20 Access Controller Module H3C LSQM1WCMB0 Access Controller Module H3C LSRM1WCM2A1 Access Controller Module H3C LSBM1WCM2A0 Access Controller Module