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Glossary
GL-14
Issue 1
December 1997
Non-Revertive
A protection switching mode in which, after a protection switch occurs, the equipment
remains in its current configuration after any failure conditions that caused a protection
switch to occur clear or after any external switch commands are reset. (See Revertive.)
NRZ
Nonreturn to Zero
NSA
Not Service Affecting
NSAP
Network Services Access Point — An address that identifies a network element. Used for
maintenance subnetwork communication using the OSI protocol.
NTF
No Trouble Found
O
OAM&P
Operations, Administration, Maintenance, and Provisioning
OC, OC-n
Optical Carrier — The optical signal that results from an optical conversion of an STS
signal; that is, OC-1 from STS-1 and OC-n from STS-n.
OC-1
Optical Carrier Level 1 Signal (51.84 Mb/s)
OC-3
Optical Carrier Level 3 Signal (155 Mb/s)
OC-3c (STS-3c)
Optical Carrier Level 3 Concatenated Signal — Low-speed broadband signal equivalent
to three STS-1s linked together with a single path overhead.
OC-12
Optical Carrier Level 12 Signal (622 Mb/s)
OHCTL
The overhead controller circuit pack provides user access to the SONET overhead
channels.
OLIU
Optical Line Interface Unit
OOF
Out of Frame
OOL
Out of Lock