QoS Policies
7950 XRS Quality of Service Guide
Page 45
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Per-service egress subrate capabilities especially for multipoint services.
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More granular, fairer scheduling per-service into the access network.
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Per-service statistics for forwarded and discarded service packets.
The subrate capabilities and per-service scheduling control are required to make multiple services
per physical port possible. Without egress shaping, it is impossible to support more than one
service per port. There is no way to prevent service traffic from bursting to the available port
bandwidth and starving other services.
For accounting purposes, per-service statistics can be logged. When statistics from service ingress
queues are compared with service egress queues, the ability to conform to per-service QoS
requirements within the service core can be measured. The service core statistics are a major asset
to core provisioning tools.
Service egress QoS policies define egress queues and map forwarding class flows to queues. In the
simplest service egress QoS policy, all forwarding classes are treated like a single flow and
mapped to a single queue. To define a basic egress QoS policy, the following are required:
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A unique service egress QoS policy ID.
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A QoS policy scope of template or exclusive.
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At least one defined default queue.
Optional service egress QoS policy elements include:
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Additional queues up to a total of 8 separate queues (unicast).
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IEEE 802.1p priority value remarking based on forwarding class.
Each queue in a policy is associated with one of the forwarding classes. Each queue can have its
individual queue parameters allowing individual rate shaping of the forwarding class(es) mapped
to the queue.
More complex service queuing models are supported in the router where each forwarding class is
associated with a dedicated queue.
The forwarding class determination per service egress packet is determined at ingress. If the
packet ingressed the service on the same router, the service ingress classification rules determine
the forwarding class of the packet. If the packet is received, the forwarding class is marked in the
tunnel transport encapsulation.
Service egress QoS policy ID 1 is reserved as the default service egress policy. The default policy
cannot be deleted or changed. The default access egress policy is applied to all SAPs service
egress policy explicitly assigned. The characteristics of the default policy are listed in the
following table.
Summary of Contents for 7950
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Page 16: ...Preface Page 16 7950 XRS Quality of Service Guide ...
Page 82: ...Editing QoS Policies Page 82 7950 XRS Quality of Service Guide ...
Page 90: ...Applying Network Queue Policies Page 90 7950 XRS Quality of Service Guide ...
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Page 98: ...Command Hierarchies Page 98 7950 XRS Quality of Service Guide ...
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Page 156: ...Basic Configurations Page 156 7950 XRS Quality of Service Guide exit exit ...
Page 164: ...Queue Depth Monitoring Page 164 7950 XRS Quality of Service Guide ...
Page 304: ...Service Queue QoS Policy Commands Page 304 7950 XRS Quality of Service Guide ...
Page 368: ...Command Hierarchies Page 368 7950 XRS Quality of Service Guide ...
Page 430: ...Configuration Commands Page 430 7950 XRS Quality of Service Guide ...
Page 532: ...Editing QoS Policies Page 532 7950 XRS Quality of Service Guide ...
Page 552: ...Editing Advanced Policies Page 552 7950 XRS Quality of Service Guide ...
Page 600: ...Command Hierarchies Page 600 7950 XRS Quality of Service Guide ...
Page 602: ...QoS Commands Page 602 7950 XRS Quality of Service Guide ...
Page 610: ...Standards and Protocols Page 610 7950 XRS Quality of Service Guide ...
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