Scenario 1: Fiber Cut In Nodes Using Opt-Bst Or Opt-Bst-E Cards; Figure 16-8 Nodes Using Opt-Bst/Opt-Bst-E Cards - Cisco ONS 15454 DWDM Installation And Operation Manual

Chapter 16 DWDM Network Reference
•

16.4.1 Scenario 1: Fiber Cut in Nodes Using OPT-BST or OPT-BST-E Cards

Figure 16-8

Figure 16-8 Nodes Using OPT-BST/OPT-BST-E Cards

Node A
Side B
10
9
P P
OPT-PRE
13
OPT-BST/OPT-BST-E
P = power monitoring photodiode
= logical AND function
Two photodiodes at Node B monitor the received signal strength for the optical payload and optical
service channel (OSC) signals. When the fiber is cut, a loss of signal (LOS) is detected at both of the
photodiodes. The AND function then indicates an overall LOS condition, which causes the
OPT-BST/OPT-BST-E transmitter, OPT-PRE transmitter, and OSCM lasers to shut down. This in turn
leads to a LOS for both the optical payload and OSC at Node A, which causes Node A to turn off the
OSCM, OPT-PRE transmitter, and OPT-BST/OPT-BST-E transmitter lasers. The sequence of events
after a fiber cut is as follows (refer to the numbered circles in
1.
2.
3.
4.
5.
6.
7.
December 2004
Nodes using OSC-CSM cards (passive nodes)
shows nodes using OPT-BST or OPT-BST-E cards with a fiber cut between them.
1
11
X
8
OSCM
8
12
Fiber is cut
Power monitoring photodiode detects a LOS on the OSC and OSCM detects LOS
Power monitoring photodiode detects a LOS for the optical payload
LOS is declared
The OPT-BST/OPT-BST-E amplifier laser is shut down in less than three seconds
The OSCM laser is shut down
The OPT-PRE laser is shut down
16.4.1 Scenario 1: Fiber Cut in Nodes Using OPT-BST or OPT-BST-E Cards
Node B
Side A
2
P
2
OSCM
6
5
OPT-BST/OPT-BST-E
Figure
Cisco ONS 15454 DWDM Installation and Operations Guide, R4.7
OPT-PRE
7
P
3
4
16-8):
16-19