Specifications

Cisco ONS 15454 Product Overview, R3.3

May 2002

Cisco ONS 15454 Product Overview

Network Configuration

Figure 28 Path-protected mesh network

If you check the protected circuit box in CTC, PPMN establishes a second unique

route between Nodes 3 and 9 and automatically creates cross-connections at

nodes 3, 2, 1, 11, and 9, shown by the dashed line. If a signal failure occurs on the

primary path, traffic switches to the second, protected circuit path. In this

example, Node 9 switches from the traffic coming in from Node 7 to the traffic

coming in from Node 11 and service resumes. The switch occurs within 50

milliseconds.

PPMN also allows spans of different SONET line rates to be mixed together in

“virtual rings.” Figure 29 shows Nodes 1, 2, 3, and 4 in a standard OC-48 ring. Nodes

5, 6, 7, and 8 link to the backbone ring through OC-12 ﬁber. The “virtual ring” formed

by Nodes 5, 6, 7, 8 uses both OC-48 and OC-12.

= Primary path

= Secondary path

Working traffic

Protect traffic

Source

Node

Destination

Node

32136

Node 1

Node 11

Node 2

Node 4

Node 5

Node 6

Node 7

Node 8Node 10

Node 9

Node 3