Glossary
Terms and Definitions
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G L - 1 7
Lucent Technologies - Proprietary
See notice on first page
365-372-327 R2.0
Issue 1, October 2003
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Terms and Definitions
Numerics
0x1
Set up using unswitched cross connections on UPSR Ring Interfaces.
1+1
The 1+1 protection switching architecture protects against failures of the
optical transmit/receive equipment and their connecting fiber facility. One
bidirectional interface (two fibers plus associated OLIUs on each end) is
designated "service," and the other is designated "protection." In each
direction, identical signals are transmitted on the service and protection lines
("dual-fed"). The receiving equipment monitors the incoming service and
protection lines independently, and selects traffic from one line (the "active"
line) based on performance criteria and technician/OS control. In 1+1 both
service and protection lines could be active at the same time (service in one
direction, protection in the other).
1xN, 1x1
1xN protection switching pertains to circuit pack protection that provides a
redundant signal path through the Metropolis
®
DMXtend (it does not cover
protection switching of an optical facility; se "1+1"). In 1xN switching, a group
of N service circuit packs share a single spare protection circuit pack. 1x1 is a
special case of 1xN, with N=1. In 1x1 only one is active at a time.
A
Active
Active identifies a 1+1 protected OC-N line which is currently selected by the
receiver at either end as the payload carrying signal or a 1x1 or 1xN protected
circuit pack that is currently carrying service. (See Standby).
AGNE - Alarm Gateway Network Element
A defined NE in an alarm group through which members of the alarm group
exchange information.
AIS - Alarm Indication Signal
A code transmitted downstream in a digital network that shows that an
upstream failure has been detected and alarmed.
AMI - Alternate Mark Inversion
A line code that employs a ternary signal to convey binary digits, in which
successive binary ones are represented by signal elements that are normally of
alternating, positive and negative polarity but equal in amplitude, and in which
binary zeros are represented by signal elements that have zero amplitude.
