Bandwidth Constraint Models - Cisco ASR 9000 Series Configuration Manual

Differentiated Services Traffic Engineering
IETF mode supports multiple bandwidth constraint models, including RDM and MAM, both with two
bandwidth pools. In an IETF DS-TE network, identical bandwidth constraint models must be configured on
all nodes.
TE class map is used with IETF DS-TE mode and must be configured the same way on all nodes in the
network.

Bandwidth Constraint Models

IETF DS-TE mode provides support for the RDM and MAM bandwidth constraints models. Both models
support up to two bandwidth pools.
Cisco IOS XR software provides global configuration for the switching between bandwidth constraint models.
Both models can be configured on a single interface to preconfigure the bandwidth constraints before swapping
to an alternate bandwidth constraint model.
NSF is not guaranteed when you change the bandwidth constraint model or configuration information.
Note
By default, RDM is the default bandwidth constraint model used in both pre-standard and IETF mode.
Maximum Allocation Bandwidth Constraint Model
The MAM constraint model has the following characteristics:
• Easy to use and intuitive.
• Isolation across class types.
• Simultaneously achieves isolation, bandwidth efficiency, and protection against QoS degradation.
Related Topics
Configuring an IETF DS-TE Tunnel Using MAM, on page 178
Russian Doll Bandwidth Constraint Model
The RDM constraint model has these characteristics:
• Allows greater sharing of bandwidth among different class types.
• Ensures bandwidth efficiency simultaneously and protection against QoS degradation of all class types.
• Specifies that it is used in conjunction with preemption to simultaneously achieve isolation across
class-types such that each class-type is guaranteed its share of bandwidth, bandwidth efficiency, and
protection against QoS degradation of all class types.
Note We recommend that RDM not be used in DS-TE environments in which the use of preemption is precluded.
Although RDM ensures bandwidth efficiency and protection against QoS degradation of class types, it
does guarantee isolation across class types.
Cisco ASR 9000 Series Aggregation Services Router MPLS Configuration Guide, Release 4.3.x
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Implementing MPLS Traffic Engineering
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