New Features and Feature Enhancements 15
Given the scalability problems associated with RSVP, the emerging IETF standard for scalable
Brief descriptions of additional QoS features are listed below. For further information on IPQoS, consult RFC 2474 (Definition of Differentiated Service Field in IP Headers) and RFC 2309 (Recommendations on Queue Management & Congestion Avoidance in the Internet).
■Policy-based QoS Management
Flexible QoS control is configured via the IPQoS Service as port specific policies. QoS policies can be applied to the inbound traffic at the ingress port and/or the outbound traffic at the egress port. QoS policies are associated with flows.
Policies are stored in the
A network manager can define the following types of QoS policy:
■Bandwidth control - If rate limiting is specified in a QoS policy, the associated traffic flow will be metered and policed. Rate limiting can be applied to traffic transmitted or received on an interface. User may also define actions, such as forward/discard/remark
■TOS control - TOS can be set to a specified TOS value. This allows incoming packets to be classified into a small number of
■Service class control - A specific service class can be assigned to a flow independent of the DSCP value in the TOS byte. By default, the
■Traffic redirect - traffic can be redirected at the ingress port.
■IEEE 802.1P Prioritization
When the ingress port is connected to a
When the egress port is connected to a
IP traffic can also be classified via a QoS policy to be tagged with a specific 802.1P priority.