TABLE OF CONTENTS This chapter discusses two specific IP QoS mechanisms: IntServ and DiffServ. Some of the generic IP QoS functional requirements discussed in Chapter 4 will be discussed further as they apply to IntServ and DiffServ, if appropriate.
In IntServ, an individual IP flow is identified by the following quintuple of parameters:
Protocol identifier
Destination IP address
Destination port address
Source IP address
Source port address
To make a resource reservation for a flow, the source application must provide a flow specification. A flow specification consists of a traffic characterization and service requirements for the flow. The traffic characterization includes the peak rate, the average rate, the burst size and the leaky bucket parameters; and the service requirements include the minimum bandwidth required and the performance requirements, e.g., delay, delay jitter, and packet loss rate. IntServ uses the Resource Reservation Protocol (RSVP) for reserving resources for a flow.
RSVP is specified in RFC 2205.17 RSVP is an IP QoS reservation setup protocol. It supports both IPv4 and IPv6 and is applicable for both multicast and unicast mode of IP. In RSVP, resource is reserved in each direction separately.
The source and destination hosts exchange RSVP messages to establish the packet classification and forwarding state at each node. The source initiates the reservation request but the determination of available resources and the actual reservation of the resources begin from the receive end. The "state" of resource...
