Differentiated Service Model For Cisco Ios Xr Software; Access Node Control Protocol - Cisco ASR 9000 Series Service Configuration Manual
Aggregation services router modular quality
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Also See for ASR 9000 Series:
- Command reference manual (1138 pages) ,
- Routing configuration manual (702 pages) ,
- Reference manual (696 pages)
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Information About Modular Quality of Service on Cisco ASR 9000 Series Routers
Cisco IOS XR software includes traffic policing capabilities available on a per-class basis as well as
class-based shaping.
The traffic policing feature limits the input or output transmission rate of a class of traffic based on
user-defined criteria, and can mark packets by setting values such as IP Precedence, QoS group, or DSCP
value.
Traffic shaping allows control over the traffic that leaves an interface to match its flow to the speed of
the remote target interface and ensure that the traffic conforms to the policies contracted for it. Thus,
traffic adhering to a particular profile can be shaped to meet downstream requirements, thereby
eliminating bottlenecks in topologies with data-rate mismatches.
Cisco IOS XRsoftware supports a class-based traffic shaping method through a CLI mechanism in which
parameters are applied per class.
For detailed conceptual and configuration information about congestion management, see the
"Configuring Modular Quality of Service Congestion Management on Cisco ASR 9000 Series Routers"
module.
Congestion Avoidance
Congestion avoidance techniques monitor network traffic flows in an effort to anticipate and avoid
congestion at common network and internetwork bottlenecks before problems occur. These techniques
are designed to provide preferential treatment for traffic (such as a video stream) that has been classified
as real-time critical under congestion situations while concurrently maximizing network throughput and
capacity utilization and minimizing packet loss and delay. Cisco IOS XR software supports the Random
Early Detection (RED), Weighted RED (WRED), and tail drop QoS congestion avoidance features.
For detailed conceptual and configuration information about congestion avoidance techniques, see the
"Configuring Modular Quality of Service Congestion Management on Cisco ASR 9000 Series Routers"
module in this guide.
Differentiated Service Model for Cisco IOS XR Software
Cisco IOS XR software supports a differentiated service that is a multiple-service model that can satisfy
different QoS requirements. However, unlike in the integrated service model, an application using
differentiated service does not explicitly signal the router before sending data.
For differentiated service, the network tries to deliver a particular kind of service based on the QoS
specified by each packet. This specification can occur in different ways, for example, using the IP
Precedence bit settings in IP packets or source and destination addresses. The network uses the QoS
specification to classify, mark, shape, and police traffic, and to perform intelligent queueing.
The differentiated service model is used for several mission-critical applications and for providing
end-to-end QoS. Typically, this service model is appropriate for aggregate flows because it performs a
relatively coarse level of traffic classification.
Access Node Control Protocol
Access Node Control Protocol (ANCP) creates a control plane between a service-oriented aggregation
device and an access node (AN) (for example, a DSLAM) in order to perform QoS-related,
service-related, and subscriber-related operations. An ANCP Network Access Server (NAS) accepts and
maintains ANCP adjacencies (sessions with an ANCP neighbor), and sending and receiving ANCP
messages.
Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Configuration Guide
QC-4
Modular QoS Overview on Cisco ASR 9000 Series Routers
OL-23108-02
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