5-2
IntServ Service Model
The integrated service (IntServ) model is a multiple-service model that can accommodate diverse QoS
requirements. It provides the most granularly differentiated QoS by identifying and guaranteeing
definite QoS for each data flow.
In the IntServ model, an application must request service from the network before it sends data. IntServ
signals the service request with the Resource Reservation Protocol (RSVP). All nodes that receive the
request reserve resources as requested and maintain state information for the application flow.
The IntServ model demands high storage and processing capabilities, because it requires that all nodes
along the transmission path maintain resource state information for each flow. The model is suitable for
small-sized or edge networks, but not large-sized networks, for example, the core layer of the Internet,
where billions of flows are present.
For more information about RSVP, see
MPLS TE
in the
MPLS Configuration Guide
.
DiffServ Service Model
The differentiated service (DiffServ) model is a multiple-service model that can satisfy diverse QoS
requirements. Unlike IntServ, DiffServ does not require an application to signal the network to reserve
resources before sending data. DiffServ is easy to implement and extend.
All QoS techniques in this document are based on the Diff-Serv model.
QoS Techniques Overview
The QoS techniques fall into traffic classification, traffic policing, traffic shaping, line rate, congestion
management, and congestion avoidance. The following part briefly introduces these QoS techniques.
