Cisco ONS 15454 SDH Especificaciones descargar pdf (Pagina 39)

Cisco ONS 15454 SDH Product Overview, R3.4

September 2002

Cisco ONS 15454 SDH Product Overview

Network Configuration

The ONS 15454 SDH supports subnetwork connection protection (SNCP) rings,

multiplex section-shared protection rings (MS-SPRings), subtending rings, linear

add/drop multiplexers (ADMs) that support 1+1 protection, and mixed

configurations. You can also create extended SNCP mesh networks (extended

SNCP).

Circuit protection can be configured in CTC. You can also use CTC to specify the

nodes and spans to use for the protect path.

Subnetwork Connection Protection Ring

The default protection scheme for an ONS 15454 SDH is the SNCP ring. An

SNCP ring is a closed-loop, two-fiber transport architecture that survives cable

cuts and equipment failure because it provides duplicate fiber paths for each

service. Nodes in the ring are connected using a single pair of optical fibers.

Working traffic flows in one direction on the ring and the second fiber provides a

protection path flowing in the opposite direction. If a problem occurs in the

working traffic path, the receiving node switches to the path coming from the

opposite direction. SNCP signal thresholds—the levels that determine when the

SNCP path is switched—are set at the circuit level.

Services can originate and terminate on the same SNCP or can be passed to an

adjacent access or interoffice ring for transport to the service-terminating

location. You can also create an SNCP bridge/selector circuit entry point in a

multivendor SNCP. Because each traffic pathis transported around the entire ring,

SNCPs are best suited for networks where traffic concentrates in one or two

locations and is not widely distributed.

Figure 19 shows a basic SNCP ring configuration. If Node A sends a signal to

Node C, the working signal travels on the working traffic path through Node B.

The same signal is also sent on the protect traffic path through Node D. If a fiber

break occurs, Node C switches its active receiver to the protect signal coming

through Node D.

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Cisco ONS 15454 SDH Especificaciones Pagina 39