Suspected Loopback Condition; Link Condition Verified - Bay Networks Baystream 7 Notice

BayStream 7.3 Documentation Change Notice
A loopback condition is suspected by the DTE if the send sequence number sent
out in the status enquiry message is the same value as the received send sequence
number in the reply (status message) from the DTE.
Note: Link integrity takes place on a bidirectional basis. Sometimes the DCE
or DTE may receive a status enquiry message right after it has sent its own
status enquiry message. This does not necessarily indicate a loopback
condition. It may be the other DCE or DTE sending out its own status enquiry
message. The DTE and the DCE must check the received send sequence
number against their own previously sent send sequence numbers to verify a
loopback condition.

Suspected Loopback Condition

If a loopback condition is suspected, BayStream software does the following:
Discards the status enquiry message
1.
Initiates the loopback verification procedure
2.
Generates a Technician Interface message of severity level info (for example:
3.
cct2, Loopback condition suspected)
The loopback verification procedure increments the send sequence number of the
next status enquiry message by a unique number.

Link Condition Verified

If the DCE that sent the second status enquiry message receives a second status
message from the DTE that contains a send sequence number matching the unique
send sequence number, then the loopback condition is confirmed.
Once the loopback condition is confirmed, BayStream:
Discards the second status message with the matching receive sequence
1.
number.
Generates a Technician Interface log message of severity level warning (for
2.
example: cct 2, Loopback condition exists).
Tears down the affected interface. This means that the PVC entries associated
3.
with this interface are declared inactive and the SVCs torn down. The virtual
circuits associated with this interface will be inactive until the loopback
condition on the interface is corrected.
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BayStream Multiservice Software Version 7.3 115385-D Rev 01