No misses should occur. An extended ping that uses a data pattern of
0x0000 is helpful in resolving line problems because a T1 or E1
connection derives clock speed from the data and requires a transition
every 8 bits. A data pattern with many 0s helps to determine whether the
transitions are appropriately forced on the trunk. A pattern with many 1s
is used to appropriately simulate a high 0 load in case a pair of data
inverters is in the path. The alternating pattern (0x5555) represents a
???typical??? data pattern. If your pings fail or if you get cyclic redundancy
check (CRC) errors, a bit error rate tester (BERT) with an appropriate
analyzer from the telephone company (telco) is needed.
Step 4 When you are ?¬?nished testing, ensure that you return the encapsulation
of the interface to Frame Relay.
An incorrect statically de?¬?ned DLCI on a subinterface can also cause the status of the
subinterface to appear as ???down/down,??? and the PVC status might appear as ???deleted.??? To
350 Chapter 8: Extending the Network into the WAN
verify that the correct DLCI number has been con?¬?gured, use the show frame-relay pvc
command, as demonstrated in Example 8-8.
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