Mlppp Qos/Mlfr Qos - Cisco ASR 9000 Series Service Configuration Manual

Modular QoS Deployment Scenarios on Cisco ASR 9000 Series Routers
CE2
interface gig0/4/0/0.26
encapsulation dot1q 100
ipv4 add 10.0.0.2 255.0.0.0

MLPPP QoS/MLFR QoS

Multilink provides a mechanism for aggregating multiple serial links into a bundle. Bundles support
more bandwidth, load balancing between links, and improved service availability by protecting against
single points of failure. The service allows users to increase bandwidth by aggregating multiple low
speed links, which can be more cost-effective than upgrading to a single higher speed link. This provides
a cost-effective solution for users requiring leased line service with bandwidth greater than T1 rates but
below T3 rates.
Multilink interfaces can be configured with PPP encapsulation (MLPPP) or with Frame Relay
encapsulation (MLFR). When a multilink interface is configured with Frame Relay encapsulation,
subinterfaces can be configured below it.
The total bandwidth available for the multilink interface can change dynamically when links are added
or removed to or from a multilink interface. The total bandwidth available can also change if the member
links change state operationally to up or down, or by modifying the suspended condition of the policy.
QoS policies applied on such interfaces need to be updated based on the bandwidth changes. In this case,
one of the following actions is taken:
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•
•
OL-23108-02
Suspend the policy—Policy is suspended if the bandwidth requirements of the attached policy are
more than the available bandwidth (which is reduced due to a member link going operationally
down). Once the policy is suspended, any incoming or outgoing packets on that interface are not
subject to QoS.
A policy is suspended on ingress under these conditions:
– In Enhanced Hierarchical Ingress Policing, when the sum of child police rates is greater than
the parent police conform rate
Police peak rate is less than the police conform rate
–
A policy is suspended on egress under these conditions:
– Minimum bandwidth rate + priority class police rate is greater than the interface rate
– Shape rate is less than the minimum bandwidth rate
– Priority class police conform rate is greater than the interface rate
Priority class police peak rate is greater than the interface rate
–
Police peak rate is less than the police conform rate
–
Resume the policy—Policy is resumed if the bandwidth requirements of the attached policy are less
than or equal to the available bandwidth, which increased due to a member link going operationally
up. A suspended policy can also be resumed by modifying the suspended condition of the policy
map without any change in the member link status.
Update the policy—Active policy rates are updated to reflect the new available bandwidth. The
available bandwidth could have increased or decreased, but the applied policy's bandwidth
requirements can still be satisfied.
Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Configuration Guide
MLPPP QoS/MLFR QoS
QC-171