Equipping rules, Oc-48 protection switching – Nortel Networks OPTera Metro 3500 User Manual
Page 298
3-70 Hardware feature descriptions
OPTera Metro 3500 Multiservice Platform NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
Alarm LED definitions
The following table lists the OC-48 STS interface circuit pack LEDs.
Equipping rules
The OC-48 STS optical interface circuit pack can be installed in slots 3
through 12. See
for operational temperature ranges.
Note 1: Requires the shelf to be equipped with STX-192 circuit packs in
slots 13 and 14.
Note 2: Supports STS managed connections only.
OC-48 protection switching
OC-48 traffic can be protected by 1+1 linear, or UPSR protection.
1+1 linear protection
OC-48 linear protection switching is 1+1 non-revertive, unidirectional or
bidirectional. If a fiber cut occurs in either the receive or transmit fibers of the
active fiber path, or the transmitter or receiver OC-48 optical interface circuit
pack fails at either end of the active fiber span, traffic is switched from the
active OC-48 transmitter or receiver to the standby OC-48 transmitter or
receiver. Switching can also take place under user control.
In bidirectional protection switching, if traffic in one of the two directions is
interrupted, traffic in both directions is switched to the protection line. In
unidirectional protection switching, if traffic in one of the two directions is
interrupted, only the interrupted traffic switches to the protection line; traffic
in the uninterrupted direction remains on the working fiber. Both OC-48
interface circuit packs are active if f unidirectional switching occurs and one
fiber fails.
The signal degrade threshold is user-provisionable for the working OC-48
facility of a 1+1 linear protected OC-48 pair. The default value is 10
-6
. The
threshold is provisionable within the range 10
-5
to 10
-9
. If the bit error rate
(BER) drops below the threshold, an autonomous protection switch occurs.
UPSR path protection
OC-48 path switching uses nonrevertive protection. There are no permanent
STS-1 STS-3c, STS-12, STS-12c, STS24c or STS-48c protection or working
paths. The network element receives two incoming STS-1, STS-3c, STS-12,
LED
Color
Description
Status (top)
Red
Circuit pack failure
Yellow Loss
of
signal
Status (bottom)
Green
In service and carrying traffic