Basic Functionality And Operation Of A Sparing Panel - Nortel Passport 15000 Hardware Description

292 Chapter 5 Termination panels for FPs

Basic functionality and operation of a sparing panel

241-1501-200 5.2S2
• "Basic functionality and operation of a fanout panel" (page 296)
• "12-port DS3 or E3 fanout panel NTHW52" (page 297)
• "12-port DS3 or E3 sparing panel NTQS31" (page 300)
• "4-port DS3 sparing panel NTHR79" (page 304)
• "3-port DS3, E3, or E1 sparing panel NTFP99AA" (page 306)
• "Multiport aggregate device for a 32-port E1 TDM" (page 308)
• "Dimensions of the termination panels" (page 313)
The basic functionality of a sparing panel for a Passport 15000 or 20000 is to
enable equipment protection of one or more FPs of the same type that are
connected to the far end of an FP connection. The FPs connected to the same
sparing panel must be compatible vintages for equipment protection to occur.
A sparing panel is a patch panel with a mechanical relay. Software tells the
relay when to switch the path of traffic from one FP to another. Some sparing
panels can operate as a patch panel (or fanout panel) without sparing.
Of all the FPs connected to a sparing panel, one must be designated in
software as the Spare FP and all other FPs connected to the same panel must
be designated as Main FPs. The Spare FP is the standby FP for one or more
FPs. When a sparing panel supports only one Main FP, it provides
one-for-one equipment protection. When a sparing panel supports more than
one Main FP, it provides one-for-n equipment protection, where n is the
quantity of Main FPs backed up by the one Spare.
The control processor (CP) software controls which FP or FPs actively use the
sparing panel and which one does not or is on standby. When a Main FP fails,
the active CP identifies which Main FP has failed, and instructs the sparing
panel to switch the relay contacts from the failed FP to the standby FP. The
Spare FP becomes an active FP carrying traffic.
A subsequent switchover cannot occur until the failed FP is replaced and
returned to service. With any Passport FP in a one-for-one or one-for-n
configuration, the replacement FP automatically becomes the standby card
and remains standby even if it was previously the active card. If you decide to
restore active traffic to the replaced FP, you must switch it back manually