Chapter8.PNNI Explained

Chapter 8. PNNI Explained

ATM is a fabulous implementation of a transport protocol. It provides differentiated Quality of Service (QoS), offers dynamic circuit provisioning, and initiates traffic rerouting around network failures. Many of these automatic features would not be possible without the inter-ATM switch routing and signaling protocol called Private Network-to-Network Interface (PNNI). PNNI is defined by the ATM Forum. The complete specification, af-pnni-0050.000, is available for download at the Forum's Web site. Many popular broadband consumer services such as high-speed data access via cable and DSL and next-generation wireless networks all rely on PNNI's services in the ATM core of the network to route massive amounts of end-user traffic. This reliance is because of the distributed control, scalable, resilient, easy to maintain, and standards-based nature of PNNI.

The discussion of PNNI must include a section on ATM end-system addressing for completeness because a PNNI-controlled ATM switch cannot deliver information to end systems without addresses.