Now that the Internet and other router-based networks carry a variety of traffic, such as voice, video, and best-effort data, customers have asked service providers to guarantee the delivery of certain class-of-service (CoS) parameters for different traffic classes. CoS assigns different levels of service, such as guaranteed bandwidth or minimal delay, to different traffic classes. This customer need has been a challenge to service providers, because the exact number of CoS parameters and the number of categories available for different traffic flows (the granularity of the CoS offering) have differed not only from network to network, but often from one section of the same network to another. To be of any use to customers, consistent CoS performance must be provided end to end.
Service providers seeking a standard implementation for CoS often use Differentiated Services (DiffServ) to provide a consistent CoS method for varied networks employing IP version 4 (IPv4), IP version 6 (IPv6), and Multiprotocol Label Switching (MPLS) label-switched paths (LSPs). DiffServ is defined in a series of RFCs and Internet drafts, especially RFC 2474, Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers, and RFC 2475, An Architecture for Differentiated Services. These form the basis for the Juniper Networks implementation of DiffServ. This chapter shows how to implement end-to-end DiffServ on J-series, M-series, MX-series, and T-series routing platforms for IPv6.
This chapter assumes the reader is familiar with CoS operation on Juniper Networks routers. For more information on CoS configuration, see the JUNOS Class of Service Configuration Guide.
This feature guide covers these topics: