Failures That Cause A Low-Speed Switchover; Enabling And Disabling Low-Speed Switchovers - Carrier Access Wide Bank 28 DS3 User Manual

Product Description
Low-Speed (LS) Redundancy

Failures that Cause a Low-Speed Switchover

The Wide Bank checks for the following events every 200 milliseconds, and if one or more of them
occur, initiates a low-speed switchover.
Transmitter Failure. A transmitter failure is declared when:
1. There is a lack of activity on the transmit clock.
2. There is a lack of activity on the transmit tip and ring outputs (either or both). This
System Clock Failure. When there are no transitions on the master clock of a low-speed card,
a failure is declared for all four DS1 (three E1) circuits on the card.
Write/Read/Verify Failure. If the Controller cannot correctly read and write certain test
registers on a DS1 card, it declares a failure for that card.
Receiver Failure. This failure can be caused by either a low-speed receiver failure or an
external failure of the low-speed line. This failure is declared when there is either no receive
activity (Loss of Signal, or LOS) for 2.5 seconds or a Major Line Code Violation (Major
LCV). After the switchover, if no signal improvement is seen, the traffic is automatically
returned back to the original circuits to retain the availability of the spare.

Enabling and Disabling Low-Speed Switchovers

The low-speed automatic switchovers can be either enabled or disabled for all circuits by using the
ds1 protect or ls protect commands. The factory default setting of low-speed protection is ON. For
more information see LSMODE on
Example:
To disable automatic switchovers for all low-speed circuits:
(A:Active)> ds1 protect off
or
(A:Active)> ls protect off
To enable automatic switchovers for all low-speed circuits:
(A:Active)> ds1 protect on
or
(A:Active)> ls protect on
2-26
event is ignored if AMI line coding is selected.
page 8-58.
July 2004 Wide Bank 28 DS3 - Release 2.4