Using the Resource Reservation Protocol
The Resource Reservation Protocol (RSVP) is the first attempt at an industry
standard implementation of the Internet Integrated Services (Intserv) model of
QoS. Researchers at the Information Sciences Institute (ISI) at the University of
Southern California (USC) and the Xerox Palo Alto Research Center first conceived
of RSVP.
NOTE
In 1993, the Internet Engineering Task Force (IETF) started working
toward standardization through an RSVP working group. Version 1 of
this protocol is currently defined by RFC 2205. Interested readers may
find the IETF Applicability Statement (RFC 2208) helpful in pointing out
both the uses and current issues with an RSVP deployment. This chapter
will illustrate both of these briefly.
The Intserv model is characterized by applications or end stations reserving
resources across a network to guarantee a particular level of service. RSVP is a
protocol that implements this signaling.
RSVP is independent of, yet complimentary to, Intserv.Whereas Intserv specifies
the set of classes of service and the parameters to deliver QoS, RSVP
requests this service level from network nodes and, in some cases, carries the
Intserv parameters.
RSVP does not provide QoS directly to applications, but instead, coordinates
an overall service level by making reservation requests with as many nodes as possible
across the network. It is up to other QoS mechanisms to actually prevent
and control congestion, provide efficient use of links, and classify and police
traffic. A successful implementation of RSVP requires that it work in conjunction
with these other mechanisms.
Advanced QoS for AVVID Environments • Chapter 8 223
224 Chapter 8 • Advanced QoS for AVVID Environments
RSVP’s popularity lies in its capacity to give guaranteed QoS to real-time
applications, such as voice, that have either constant bandwidth requirements or
low latency requirements.This is why its primary use today on networks is to
deliver multimedia streams such as voice and video, making it a viable option for
your overall AVVID QoS strategy. Unfortunately, there are some scalability concerns
with RSVP, which we will address as the chapter progresses.