Cos Functionalities For Ipv4 Over Ppp Interfaces - Juniper ACX1000 Configuration Manual

CoS Functionalities for IPv4 Over PPP Interfaces

Copyright © 2017, Juniper Networks, Inc.
Queues other than best-effort and network-control are assigned 32 Kbps of exact
transmit bandwidth.
Consider another example of a default scheduler map, and an MLPPP bundle with two
T1 links. In such a scenario, the following behavior is observed for MLPPP bundle with
two T1 links:
Traffic that arrives on only the best-effort queue obtains the entire bandwidth capacity
if there is no traffic on any other queue. Traffic that arrives on only the network-control
queue is limited to 1.2288 Mbps, even when no traffic is passing through any other queue.
When traffic arrives on both the queues, it is marked at 1.2288 Mbps for the
network-control queue and at 1.843200 Mbps for best-effort queue.
For a default scheduler-map with an MLPPP bundle that contains 16 T1 links, the traffic
that arrives as only best-effort traffic receives a bandwidth that is equal to (0.95 * 16 *
T1) capacity if there is no traffic on any other queue. Traffic that arrives as only
network-control traffic is limited to 1.2288 Mbps even if no traffic on any other queue is
observed. When traffic arrives on both the queues, it is tagged as 1.2288 Mbps for
network-control and (0.95 * 16 * T1) Mbps for best-effort queues. If you configure a
scheduler-map with a fragmentation map, two or more classes when configured with
same priority receive only the transmit-rate served for them and function as the traffic
defined for exact transmit-rate functionality.
Support for oversubscription between two multi-classes on the same priority is not
provided. The queue corresponding to which there is no-multiclass entry is moved to the
disabled state. Only one-to-one mapping between forwarding-class to multi-class is
supported. One forwarding class can send traffic corresponding to only one multi-class.
The following CoS capabilities are supported on PPP interfaces for IPv4 traffic:
Ingress Classification can be either specified as fixed classifiers or behavior aggregate
(BA) classifiers. Fixed classifiers map all traffic on an interface to the forwarding class.
The forwarding class determines the output queue. To configure a fixed classifier,
include the forwarding-class class-name
interface-name unit logical-unit-number]
BA classification, or CoS value traffic classification, refers to a method of packet
classification that uses a CoS configuration to set the forwarding class of a packet
based on the CoS value in the IP packet header. The CoS value examined for BA
classification purposes can be the Differentiated Services code point (DSCP) value,
or the IP precedence value, or EXP bits. The default classifier is based on the IP
precedence value.
To configure the global EXP classifier, include the following statements at the [edit
class-of-service system-defaults] hierarchy level.
[edit class-of-service]
{
system-defaults
{
classifiers exp classifier-name
Chapter 27: Configuring Class of Service
statement at the [edit class-of-service interface
hierarchy level.
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