Specifications

35
Cisco ONS 15327 Product Overview, R3.3
June 2002
Cisco ONS 15327 Product Overview
Network Configurations
Network Configurations
The ONS 15327 supports unidirectional path switched rings (UPSRs),
bidirectional line switched rings (BLSRs), subtending rings, linear add-drop
multiplexer (ADM) supporting 1+1 protection, and mixed configurations. You can
also create path-protected mesh networks (PPMNs)
Bidirectional Line Switched Ring
The ONS 15327 supports two-fiber BLSRs with up to 32 ONS 15327 nodes. BLSRs
work well for distributed traffic applications, such as interoffice networks.
Two-fiber BLSRs allocate half the available fiber bandwidth for protection. In a
two-fiber OC-48 BLSR, for example, STSs 1–24 are allocated to working traffic,
and STSs 25–48 are allocated for protection. If a break occurs on one fiber,
working traffic switches to the protection bandwidth (STSs 25–48) on the other
fiber. Working traffic travels in one direction on STSs 1–24 on one fiber, and on
STSs 1–24 in the opposite direction on the second fiber. You can create OC-12
and OC-48 two-fiber BLSRs. Figure 27 shows an example of a two-fiber BLSR.