Cisco Systems 15454M6DC Manuel D’Utilisation
5-7
Cisco ONS 15454 Installation and Operations Guide
November 2001
Chapter 5 SONET Topologies
Bidirectional Line Switched Rings
5.2.3 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.
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.
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.
number of pass-through STS-1 circuits.
shows the bidirectional bandwidth capacities of
four-fiber BLSRs.
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.
2, and another from Node 2 to Node 3.
Table 5-2
Two-Fiber BLSR Capacity
OC Rate
Working Bandwidth
Protection Bandwidth
Ring Capacity
OC-12
STS1-6
STS 7-12
6 x N
1
- PT
2
1.
N equals the number of ONS 15454 nodes configured as BLSR nodes.
2.
PT equals the number of STS-1 circuits passed through ONS 15454 nodes in the ring (capacity can vary
depending on the traffic pattern).
depending on the traffic pattern).
OC-48
STS 1-24
STS 25-48
24 x N - PT
OC-192
STS 1-96
STS 97-192
96 x N - PT
Table 5-3
Four-Fiber BLSR Capacity
OC Rate
Working Bandwidth
Protection Bandwidth
Ring Capacity
OC-48
STS 1-48 (Fiber 1)
STS 1-48 (Fiber 2)
48 x N - PT
OC-192
STS 1-192 (Fiber 1)
STS 1-192 (Fiber 2)
192 x N - PT