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Cisco ONS 15530 Configuration Guide and Command Reference
78-14227-01, Cisco IOS Release 12.1(10)EV2
Chapter9 Monitoring Your Network Topology
About the OSC
Figure9-1 OSC Signal Path in a Ring Configuration
The OSC performs the following functions:
•Discovery—CDP (Cisco Discovery Protocol) sends packets on the OSC to discover neighboring
nodes. CDP runs by default every 60 seconds. The information gathered by CDP ca n be di spla yed
using the CLI (command-line interface) and used by the NMS (network management system) to
discover the logical topology of the network.
•Monitoring—OSCP (OSC Protocol) runs over the OSC to provide monitoring of the status of
adjacent nodes. OSCP is a keepalive mechanism similar to the PNNI Hello protocol used in ATM
(Asynchronous Transfer Mode). Using OSCP, nodes exchange packets that allow them to determine
the operational status of their neighbors. OSCP must establish that there i s two-way communication
before declaring to the upper layer protocols that a nod e is “up .”
•Management—IP packets are carried over the OSC to support SNMP and Telnet sessions. Using
Telnet over the OSC allows you to access the CLI of all systems on your Cisco ONS 15530 network
with a single Ethernet connection. Also, just one Ethernet connectio n is requ ire d fr om th e N MS t o
monitor all Cisco ONS 15530 systems on the network using SNMP.
Hardware Guidelines for Using OSC
To provide protection against failure of the laser or a fiber break in protected con figurat ions
(point-to-point or ring), the following rules apply:
•One slot contains a carrier motherboard with two OSC cards.
•Both OADM modules must support OSC along with the band of wavelengths.
For more information on hardware configuration rules, refer to the
Cisco ONS 15530 Planning and Design Guide.
CPU
Slot 0 Slot 1
Mux/demux
Slot 0/1
Slot 0/0
CPU
Mux/demux Mux/demux
Node 1
Node 3
CPU
Slot 0/0
Slot 0/1
Mux/demux Mux/demux
Node 2
Mux/demux
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