Summary

In this chapter, you learned some considerations in the design of MSPP networks, and you explored the operation and application of various MSPP network topologies.

With regard to network resiliency and protection, multiple mechanisms and design features are available with MSPPs to ensure high availability for critical services. These include the use of redundant power feeds, common control cards, tributary interfaces, synchronization sources, and MSPP chasses. In addition, system reliability can be substantially improved through diverse cable routing and ring network topologies.

MSPP network topologies include linear networks, UPSRs, BLSRs (both 2-Fiber and 4-Fiber), mesh networks, subtended rings and nodes, and diverse ring interconnections. Whereas linear networks are not commonly used in current MSPP networks, UPSR and BLSR networks are standard configurations in service-provider and enterprise networks. UPSRs are advantageous because of their design simplicity and fast protection switch times, but they are inefficient in terms of bandwidth use for meshed traffic patterns between MSPP network sites. UPSRs are typically used in access networks, where all traffic hubs to a central site (such as a telco central office). BLSRs, which have slower protection-switching times because of the required internode switching protocol, can accommodate a much higher amount of traffic in a meshed traffic pattern, such as a service provider core network.