Nortel Passport 15000 Hardware Description page 293

using the appropriate software commands. The switchback behavior for a
1-for-n configuration depends on the software attribute for revertive
equipment protection.
It is expected that you will test a replaced FP while it is on standby, then verify
the operation of the sparing panel.
Some traffic loss occurs between the start of the switchover and the instant
traffic runs through the mate. The amount of loss depends on
• the amount of traffic passing through the FP at the time of the switchover
• whether the FP supports hot, warm, or cold equipment protection
(sparing)
• what services the FP supports, for example a DS3 with IMA can take /
longer than other cards
• how much configuration (provisioning) is on the FP, for example, with
one-for-n sparing, the card that fails cannot be predicted so the
configuration cannot be loaded onto the spare card until the failed FP is
identified, and traffic or services cannot run on the card until it is loaded
• how fast the mechanical relay is for the specific type of sparing panel (all
the values are in milliseconds)
To determine how much time a switchover can take, monitor the duration for
your particular configuration of services and the amount of traffic passing
through.
When disconnecting cables from the standby FP that uses a sparing panel,
traffic is unaffected provided the active mate remains in service. If you
accidently disconnect an active cable, traffic is lost through that connection
until the cable is re-connected.
For information on configuring the software to facilitate DS3 or E3 sparing,
see 241-5701-600 Passport 7400, 15000, 20000 Configuration Guide. For the
procedures to install, replace or redeploy a sparing panel, see 241-1501-240
Passport 15000, 20000 Hardware Installation, Maintenance and Upgrade.
For the description and running of card tests, see 241-5701-520 Passport
7400, 15000, 20000 Troubleshooting and Testing.
Chapter 5 Termination panels for FPs 293
Passport 15000, 20000 Hardware Description 5.2S2