Nortel Networks OPTera Metro 3500 - Manual (Page 227)

Operation, administration, and maintenance (OAM) features 2-189
Planning and Ordering Guide—Part 1 of 2 NTRN10AN Rel 12.1 Standard Iss 1 Apr 2004
UPSR planning guidelines summary
This section summarizes guidelines for STS-managed OPTera Metro 3500 and
OPTera Metro 3000 UPSR configurations.
General guidelines
• Always consider current and future traffic requirements when designing a
network.
• Always consider “A-Z” traffic in terms of logical rings. Note that UPSR
logical rings start and end at the path bridge and select points.
Physical subtending rings
• If your subtending ring application does not use OPE circuit packs or
shared VT-managed STS:
— Keep your logical UPSR ring small. Use a UPSR path selector on
STS-managed OPTera Metro 3500 for traffic entering STS-managed
OPTera Metro 3500 (not for traffic that originates and terminates on the
same subtending ring).
• If your subtending ring application uses shared VT-managed STS:
— Evaluate your bandwidth requirements. If possible, eliminate the
shared VT-managed STS and instead dedicate STS at each site. See
Figure 2-63 on page 2-176 for an example.
— If you cannot dedicate STS at each site, do not use a UPSR path
selector on the shared VT-managed STS. Extend your shared STS as
larger logical rings towards a node capable of terminating the UPSR
path (use STS-managed OPTera Metro 3500 as a passthrough node
only). See
Figure 2-65 on page 2-178 for an example.
— If you cannot dedicate STS at each site or extend the logical ring, your
application might not be suited for a subtending ring. Consider using a
collocated head-end ring connection.
Virtual rings across the STS-managed OPTera Metro 3500 backbone
network
In a logical UPSR that spans a physical UPSR/BLSR/UPSR configuration
(also referred to as a virtual ring), the UPSR protection path is also routed on
BLSR working time slots. See
Figure 2-65 on page 2-178 for an example.
VT grooming at an STS-managed OPTera Metro 3500 site
An OPTera Metro 3000 NE collocated at an STS-managed OPTera Metro 3500
site can be used to groom VTs in order to optimize bandwidth utilization
across the STS-managed OPTera Metro 3500 backbone network.
The collocated OPTera Metro 3000 NE can use dedicated STS at each site or
shared VT-managed STS. See
Figure 2-70 on page 2-185 for an example of
dedicated STS at each site. See Figure 2-71 on page 2-187 and Figure 2-72 on
page 2-188 for examples of shared VT-managed STS.