Blsr Bandwidth - Cisco ONS 15327 User Documentation

Bidirectional Line Switched Rings
Figure 5-3
Node 3

5.2.2 BLSR Bandwidth

BLSR nodes can terminate traffic that is fed from either side of the ring. Therefore, BLSRs are suited
for distributed node-to-node traffic applications such as interoffice networks and access networks.
BLSRs allow bandwidth to be reused around the ring and can carry more traffic than a network with
traffic flowing through one central hub. BLSRs can also carry more traffic than a UPSR operating at the
same OC-N rate.
capacity is the OC-N rate divided by two, multiplied by the number of nodes in the ring minus the
number of pass-through STS-1 circuits.
Table 5-2
OC Rate
OC-12
OC-48
1. N equals the number of ONS 15327 nodes configured as BLSR nodes.
2. PT equals the number of STS-1 circuits passed through ONS 15327 nodes in the ring (capacity can vary
Figure 5-4
simultaneously on different spans on the ring: one set from Node 3 to Node 1, one from Node 1 to Node
2, and another from Node 2 to Node 3.
Cisco ONS 15327 User Documentation, R3.3
5-4
Four-node, two-fiber BLSR traffic pattern following line break
Node 0
Node 2
Table 5-2 shows the bidirectional bandwidth capacities of two-fiber BLSRs. The
Two-Fiber BLSR Capacity
Working Bandwidth
STS1-6
STS 1-24
depending on the traffic pattern).
shows an example of BLSR bandwidth reuse. The same STS carries three different traffic sets
OC-48 Ring
Protection Bandwidth
STS 7-12
STS 25-48
Chapter 5 SONET Topologies
Node 1
Traffic flow
Fiber 1
Fiber 2
Ring Capacity
1 2
6 x N - PT
24 x N - PT
June 2002