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Quality of Service Configuration Guidelines for Cisco ASR 900 Router Series

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Quality of Service Configuration Guidelines

Contents

Quality of Service Configuration Guidelines

This document outlines Quality of Service features and limitations available on the Cisco ASR 903 Series Router and contains the following sections:

New and Changed Information

Table 1 New and Changed Features

Feature

Description

Changed in Release

Where Documented

  • Support for MLPPP on Serial Interfaces

Ingress and Egress QoS on MLPPP is supported on serial interfaces

Cisco IOS XE Release 3.13

  • Service groups

The Service groups feature allows you to create service groups and apply aggregate features to those service groups.

Cisco IOS XE Release 3.11

  • Dissimilar PHB support for Egress and Ingress MPLS and VPLS interfaces.

Support for PHB support on Egress and Ingress MPLS and VPLS access interfaces.

Cisco IOS XE Release 3.11

  • MQC Limitations
  • Support for police and set commands in same class-map.

Lists the MQC scaling limitations on the router.

Police and set can be configured on same egress policy class-map.

Cisco IOS XE Release 3.10

  • Support for QoS policies on layer 3 Etherchannel interfaces.

Ingress and Egress QoS policies are supported on etherchannel.

Cisco IOS XE Release 3.9

  • Support for QoS matching on Ethernet service instances

Match EFP is supported on service instances.

Cisco IOS XE Release 3.8

Support for QoS features on egress MLPPP interfaces

Support for QoS features on ingress MLPPP interfaces

Egress Qos is supported on MLPPP interfaces.

Cisco IOS XE Release 3.7.1

Cisco IOS XE Release 3.13

Support for Egress Policing

Egress policy is supported.

Cisco IOS XE Release 3.6

Quality of Service

QoS refers to the ability of a network to provide improved service to selected network traffic over various underlying technologies including ATM, Ethernet and 802.1 networks, SONET, and IP-routed networks. In particular, QoS features provide improved and more predictable network service by implementing the following services:

  • Supporting guaranteed bandwidth
  • Improving loss characteristics
  • Avoiding and managing network congestion
  • Shaping network traffic
  • Setting traffic priorities across the network

For more information about Quality of Service, see http:/​/​www.cisco.com/​en/​US/​products/​ps11610/​products_​installation_​and_​configuration_​guides_​list.html

Quality of Service Configuration

This document provides details on the platform-dependent implementation of QoS on the Cisco ASR 903 Series Router. For information about how to understand and configure QoS features, see http:/​/​www.cisco.com/​en/​US/​products/​ps11610/​products_​installation_​and_​configuration_​guides_​list.html

QoS Support Overview

Table below provides an overview of QoS feature support on the Cisco ASR 900 Series Router. For more detail about the support for each feature, see s Global QoS Limitations, page 12-4.

Table 2 QoS Feature Overview

Feature

Main

Service Instance

Trunk EFP

Port-
Channel

Member Link

Dynamic policy modification

3.6

3.6

3.6

 

3.6

EFP QoS Support

3.6

3.6

3.6

   

Classification

       

Ingress

 

3.5

3.5.1

 

3.5

Egress

 

3.5

3.5.1

 

3.5

IPv6

1

3.6

3.6

3.6

 

3.6

Match any

3.6

3.6

3.6

 

3.6

Marking

       

Ingress

3.5

3.5

3.5.1

 

3.5

Egress

3.6

3.6

3.6

 

3.6

Policing

       

Ingress

3.5

3.5

3.5.1

 

3.5

Egress

3.6

3.6

3.6

 

3.6

Priority policing

3.6

3.6

3.6

 

3.6

Shaping

       

Port Shaping

3.6.1

3.6.1

3.6.1

   

Congestion Avoidance

       

WRED

3.6

3.6

3.6

 

3.6

Multiple Priority Queues

3.7

3.7

3.7

 

3.7

Congestion Management

       

Strict Priority

3.5

3.5

3.5.1

 

3.5

Scheduling

       

Ingress

         

Egress

3.5

3.5

3.5.1

 

3.5

QoS ACLs

       

Ingress

3.5.1

3.5.1

3.5.1

 

3.5.1

Egress

         
1 IPv6 based ACLs are not supported for TDM interfaces.
Table 3 QoS Support for TDM Features

Feature

Release

Interface Module

Ingress

Egress

HDLC

3.9

T1/E1

No

Yes

3.13

OC-3

Yes

Yes

MLPPP

3.7

T1/E1

No

Yes

3.8

OC-3

No

Yes

3.13

T1/E1 and OC-3

Yes

Yes

POS

3.8

T1/E1

NA

NA

3.8

OC-3

No

Yes

3.9

OC-12

No

Yes

3.13

OC-3

Yes

Yes

ATM QoS L2 for ATM PW

3.7

T1/E1 and OC-3

Yes

NA

QoS for CEM/ATM/IMA PW

3.9

T1/E1 and OC-3

Yes

NA

Global QoS Limitations

The following limitations apply to multiple QoS features for the Cisco ASR 903 Series Router:

  • When EVCs under a physical interface have a QoS policy attached, the following limitations apply:
    • The port-level policy is limited to the class-default class
    • Only the shape command is supported in the port-level policy
  • The Cisco ASR 903 Series Router supports up to 64 unique QoS classification service instances in a given bridge domain. QoS service instances refer to ports, VLAN classes, EFPs associated with a QoS classification policy.
  • Modification of class-map definitions while applied to an interface or Ethernet Flow Point is not supported.
  • Policy validation—Some QoS policy configurations are not validated until you apply the policy-map to an interface or Ethernet Flow Point. If a QoS configuration is invalid, the router rejects the configuration when you apply it to an interface. In some cases, a QoS configuration may be rejected due to hardware resource exhaustion or limitations. If you receive such an error message, detach the policy and adjust your QoS configuration.
  • The match-all keyword is supported only for QinQ classification.
  • SAToP and CESoPSN pseudowire traffic has a default MPLS Exp priority setting of 5 (high).
  • QoS is supported on POS interfaces on optical interface module.
  • Three-level QoS policies are not supported on the OC-3/OC-12 serial, MLPPP, and PoS interfaces. You can only apply QoS policies on two levels on these interfaces.
  • QoS does not account for CRC values on an interface and assumes that the value is 2 bytes. CRC differences can cause accuracy issues for 2 to 3% of the 128-byte traffic.
  • The Cisco ASR 903 router supports a maximum of 128 internal and reserved labels that represent PHB (cos/dscp/exp/prec) values on a QoS policy. A label exhaustion message is displayed if a policy exceeds the maximum number of labels.

QoS Features Using MQC Limitations

Table below lists the QoS MQC scaling limitations on router per release.

Table 4 Qos on MQC Limitations

Supported on Cisco ASR 903

Cisco IOS XE 3.5S

Cisco IOS XE 3.6S

Cisco IOS XE 3.7S

Cisco IOS XE 3.8S

Cisco IOS XE 3.9S

Cisco IOS XE 3.10S

No. of unique policy-maps

1024

No. of unique class-maps

4096

No. of classes per policy-map

512

256

No. of filters per class-map

16

2 For releases which are not listed, refer to the most recent previous release limit.

Restrictions for Ingress QoS

Restrictions for Ingress QoS in the Cisco IOS Release 3.9 and later:

  • EC main interface
    • Only policing and marking are supported.
    • A class-map can have any type of filter, including the match vlan and match service instance commands.
  • EC EVC/TEFP
    • Only policing and marking are supported.
    • Match service instance is not supported.
  • Member links
    • Only policing and marking are supported.
    • Policy-map on a member link is not supported with EVC configured at the port-channel level.
  • Policy-map application is allowed only on the EC main interface, EC member link, or EC EVC.

Restrictions for Egress QoS

  • The maximum number of classes supported on the policy map is 8, which includes class class-default; 7 user-defined classes and class class-default is supported.
  • The maximum number of port-channel interfaces that can be created and supported for QoS on the router is 16.

Restrictions for Egress QoS in the Cisco IOS XE Release 3.9 and later:

  • EC main interface
    • Classification statistics for the policy-map on a port-channel main interface are not supported as no queues are allocated for a port-channel main interface.
    • Policing and marking actions are only allowed in the policy-map on a port-channel main interface.
    • Queuing actions are not supported.
    • Egress TCAM entries are used even in the absence of member links.
  • EC EVC/TEFP
    • Classification statistics for the policy-map on port-channel EVC/TEFP are not supported as no queues are allocated for port-channel EVC/TEFP.
    • Policing and marking actions are only allowed in the policy-map on port-channel EVC/TEFP.
    • Queuing actions are not supported.
    • Egress TCAM entries are used even if there are no member links present.
  • EC Member links
    • For egress match service-instance policy-map on EC member links, the same policy must be present on all other EC member links.
    • Match service-instance policy-map is replicated automatically for all the member links when the first policy is applied on any of the member links.
    • For non-match service-instance policy-map, the same policy-map can be applied for all member-links.
    • Dynamic modification of match service-instance policy-map actions is not allowed.
    • Deleting a global match service instance policy-map is not allowed if it applied to the member links.
    • Policing, marking and queuing action are supported on port-channel member links.
    • The running configuration displays the first member link on the first policy applied in a service-policy configuration.
    • The show policy-map interface brief command only displays the policy-map applied on the running configuration.
    • Applying a same policy again on other member links where a policy-map was already applied will not display any error. A differently named policy if applied again will display an error.
    • For match service instance policy-map on egress member links, the policy-map statistics information is reset, when a member link is added or deleted from a port-channel either by configuration or by LACP port-bundling/unbundling action.
    • There is no difference in behavior for non-match service instance policies on the member links. They continue to work in the legacy mode. There is no conservation of TCAM entries in this mode, even if the same policy is applied on all member links.
    • Policy-map application is allowed only on either EC main interface, or EC member link, or EC EVC.

Routed Port-Channel

Routed Port-channel Interface

The following features are supported for the ingress policy-map on a routed port-channel interface:

  • Marking
  • Policing
  • Conditional marking
  • Marking and policing
  • Classification criteria is prec, dscp or ip acl.

Example for Routed Port-channel Interface


policy-map routed_pc_ingress
class prec1
set prec 2
class prec2
police cir 100m
class prec3
police cir 150m conform-action set-prec-transmit 4 exceed-action drop
class prec4
police cir 200m
set prec 0
!
end

The following features are supported for egress policy-map on routed port-channel interface:

  • Marking
  • Policing
  • Classification criteria is prec or dscp.

Example for egress policy-map on routed port-channel interface


policy-map pc_egress
class dscp0
set dscp 16
class dscp48
police cir 1m
!
end

Member-links on Routed Port-channel Interface

The following features are supported for ingress policy-map on member links on the routed port-channel interface:

  • Marking
  • Policing
  • Conditional marking
  • marking and policing
  • Classification criteria is prec, dscp or ip acl.

The following features are supported for egress policy-map on member links on the routed port-channel interface:

  • Shaping
  • Queue-limit
  • Bandwidth (kbps, percent)
  • Bandwidth remaining (ratio, percent)
  • WRED
  • Port Shaper
  • Low Latency Queue (LLQ or priority queue)

Example for egress policy-map on member links on the routed port-channel interface


policy-map mem_link_egress
class qos-group0
bandwidth percent 90
class qos-group67
police cir 1m
priority
class class-default
shape average 64k
!
end

Port-channel with EFP

The following features are supported for ingress policy-map on port-channel on EFP:

  • Marking
  • Policing
  • Conditional marking
  • marking and policing
  • The classification criteria is VLAN or EFP, Cos in child.

Example for Port-channel with EFP


policy-map cos_child
class cos0
set cos1
!
policy-map efp_pc_ingress
class vlan100
police cir 10m
service-policy cos_child
!
end

The following features are supported for egress policy-map on port-channel on EFP:

  • Marking
  • Policing
  • Conditional marking
  • marking and policing
  • The classification criteria is VLAN or EFP, Cos in child

Example for egress policy-map on port-channel on EFP


policy-map cos_child
class cos0
set cos1
!
policy-map efp_pc_ingress
class vlan100
police cir 10ms
service-policy cos_child
!
end

EFP of Port-channel with EFP Configuration

  • The following features are supported for ingress and egress policy-map on EFP of port-channel on EFP:
    • Marking
    • Policing
    • Conditional marking
    • marking and policing
    • The classification criteria is VLAN or EFP, Cos in child.

Note


Match EFP is cannot be configured.


Member Links of Port-channel with EFP Configuration

  • The following features are supported for ingress and egress policy-map on member links of port-channel on EFP:
    • Marking
    • Policing
    • Conditional marking
    • marking and policing
    • The classification criteria is VLAN or EFP, Match VLAN and Cos in child.

Restrictions for Hierarchical Policies

The Cisco ASR 903 Router supports hierarchical QoS policies with up to three levels, allowing for a high degree of granularity in traffic management.

There are limitations on the supported classification criteria at each level in the policy-map hierarchy. The following limitations apply when configuring hierarchical policy-map classification:

  • The topmost policy-map in a three-level hierarchy only supports classification using class-default.

Sample Hierarchical Policy Designs

The following are examples of supported policy-map configurations:

  • Three-Level Policy—You can only apply a three-level policy to a physical port on the router. A three-level policy consists of:
    • Topmost policy: class-default
    • Middle policy: match vlan
    • Lowest policy: match qos-group/match prec/match cos/match dscp The following sample policy uses a flat class-default policy on the port and VLAN policies on EFP interfaces to unique QoS behavior to each EFP.

Sample Policy


Policy-map port-shaper
Class class-default
Shape average percent 70
Service-policy Vlan_set

Policy-map Vlan_set
Class vlan100
Bandwidth percent 20
Shape average 200m
Service-policy child1
Class vlan200_300
Bandwidth percent 75
Service-policy child2

Policy-map child1
Class prec2
Shape average percent 40

Policy-map child2
Class prec4
Police cir percent 50
  • Two-Level Policy
    • Topmost policy: match vlan
    • Lowest policy: match qos-group/match prec/match cos/match dscp
  • Two-Level Policy
    • Topmost policy: class-default
    • Lowest policy: match vlan
  • Two-Level Policy
    • Topmost policy: class-default
    • Lowest policy: match mpls experimental topmost
  • Flat policy: match ip dscp
  • Flat policy: match vlan inner
  • Flat policy: class-default

Ingress and Egress Hierarchical Policing

In releases before Cisco IOS XE Release 3.9, policing was supported only at one level in the ingress and egress policy. It was only at the PHB or class level.

Effective with Cisco IOS XE Release 3.9, policing is supported at two levels of the policy-map.

  • Ingress policing
    • Port and EFP level
    • EFP and Class level
    • Port and Class level
  • Egress policing
    • EFP and Class level
    • Port and Class level

      Note


      Egress hierarchical policing is supported on two levels but one of the levels must be Class level.


If an Ingress hierarchal policy is configured on the interface, the show Ethernet service instance interface command does not display the service instance statistics.

The class-level in an Egress hierarchal policy is configured internally as shaper.

Dissimilar PHB Support for MPLS and VPLS Interfaces

Effective with Cisco IOS XE Release 3.11S, dissimilar per-hop behavior (PHB) match on exp is supported for Ingress and Egress on MPLS and VPLS interfaces.

In earlier releases prior to Cisco IOS XE Release 3.11S, when qos-group or discard-class based on exp classification was configured, Egress based classification was not allowed on any other classification except Ingress set qos-group or discard-class. This was due to the PHB security model.

With Cisco IOS Release 3.11, only EVC based tunnel type configuration with either Layer2 VPN or Layer3 VPN is supported.

As pipe mode and uniform mode are supported, when qos-group or discard class (pipe-mode) is matched again on the Egress interface, all qos-groups in tunnel types (such as Layer2 VPN, Layer3 VPN, and MPLS VPN ) are supported only if the tunnel type exists on the EFP. The qos-group entries in the TCAM are matched on the tunnel type. Thus, dissimilar PHB match at the egress is supported for both Ingress and Egress simultaneously on the router.

For example, the qos-group configured at Layer2 terminating Egress interface is matched against the Layer2 VPN tunnel type. This enables the dscp (uniform-mode) on the Layer3 VPN terminating Egress interface to match with the Layer3 VPN Egress interface.

Restrictions for Dissimilar PHB Support for MPLS and VPLS Interfaces

  • Supported for qos-group or discard-class and dscp dissimilar matches for Egress PE (VPN terminating) and not for regular EVCs.
  • If match discard-class policy is applied at the interface level (the policy is applied to the Layer3 interface), the match dscp policies on the other Layer3 VPN interfaces cannot be applied. We recommend that the policy is applied at the EVC level on individual Layer2 or Layer3 interfaces instead of at port-level. Alternatively, configuring a match EFP policy to match qos-group or discard-class classification on the EFP for Layer 2 VPN, and match dscp on the EFP for Layer3 VPN is recommended.
  • If both Layer2 VPN and Layer3 VPN configurations exists on an interface, and the port-based policy has match qos-group or discard-class, then two match dscp classifications are not supported on the match dscp.

MPLS VPN QoS Mapping

Table below summarizes the default MPLS mappings for the Cisco ASR 903 Series Router.

Table 5 Default MPLS QoS Mapping

Feature

Imposition

Disposition

L3VPN, MPLS

IP Prec bit copied to MPLS Exp bit.

IP Prec bit is unchanged.

If a VLAN tag is pushed at egress, CoS bit is set to 0.

L2VPN 
(EoMPLS, VPLS)

MPLS Exp bit is set to 0

IP Prec bit is unchanged.

If a VLAN tag is pushed at egress, CoS bit is set to 0.

MPLS-TP

   

CESoPN

MPLS Exp bit is set to 5

IP Prec bit is unchanged.

SAToP

MPLS Exp bit is set to 5

IP Prec bit is unchanged.

6VPE, 6PE

Prec bit value is copied to the MPLS Exp bit

IP Prec bit is unchanged.

If a VLAN tag is pushed at egress, CoS bit is set to 0.


Note


You can modify the default mapping behaviors using explicit marking policies.


QoS Policer and Shaper Calculation

Table below summarizes the packet accounting information used to make policer and shaper calculations on the Cisco ASR 903 Series Router.

Table 6 QoS Accounting Calculation

Feature

Direction

Traffic Type

Values Counted

Policing

Ingress

IPv4/L3VPN

L2 overhead, VLAN tag, CRC

Shaping

Egress

IPv4/L3VPN

L2 Ethernet overhead, VLAN tag, CRC, preamble, IPG

Policing

Egress

IPv4/L3VPN

Layer 2 Ethernet overhead, VLAN

Policing

Ingress

L2VPN

Layer 2 Ethernet overhead, VLAN tag, CRC

Shaping

Egress

L2VPN

Layer 2 Ethernet overhead, VLAN tag, CRC, preamble, IPG

Policing

Egress

L2VPN

Layer 3 payload (without CRC)

The following considerations also apply when understanding QoS policer and shaper calculations:

  • Egress shaping is applied at layer 1.
  • Ingress packet length accounting is performed at egress.
  • Egress shaping and policing do not account for newly pushed VLAN tags and MPLS labels.
  • If two policers are configured at egress, the statistics on the child PHB or PQ level are not displayed.

Service Groups

The Service Group feature (aggregate policing) introduced in Cisco IOS XE Release 3.11 allows you create service groups, add service instances to those service groups, and apply service policies to the newly created groups. The service policies contain the aggregate features such as traffic policing that can applied to the groups.

A service group can be configured with certain match conditions and police traffic can flow via multiple targets at PHB level, EFP level or multiple ports.

The following features are supported in Cisco IOS XE Release 3.11:
  • Policing is only supported for service groups. Both Ingress and Egress policies are supported.
  • Service groups are supported on EFPs and Trunk EFPs.
  • Service groups are supported at both Ingress and Egress.
  • A service group policy can be configured as hierarchical policy of user-defined classes.
  • EFPs support both regular and service group policies.
  • At Ingress, only two level policer is allowed on the service group policy.
  • At Egress, only one level policer is allowed on the service group policy.

Restrictions for Service Groups

  • Service groups is not supported on port and port-channels.
  • Queuing and Marking on service group policy is not supported in Cisco IOS XE Release 3.11.
  • Classification based on match input vlan, match input interface, and match service instance is not supported.
  • Service group policies is not supported on EFPs configured on port channel.
  • The same EFP cannot be configured as members of multiple service groups.
  • If an EFP is a member of service group with a policy-map present in service group, the same policy-map cannot be applied on that EFP. The same policy-map applied on an EFP cannot be used in a service group.
  • Limited support for statistics counters is provided.
  • The no policy-map command cannot be executed for policies attached to service groups or to the policies attached to service instance which are configured as member of service groups.
  • Policer percentage policy-maps are not supported on service groups.
  • If dynamic modification is performed on the service-group policy or policy attached to EFP that is part of service-group, you have to exit of the policy-map sub-mode for the changes to take effect
  • Service-group can have EFP members present across ports. If these ports are present across the ASIC in the router, then aggregate policing cannot work. For aggregate policing to work correctly, ports has to be present on same ASIC.

Merging Service Groups and EFP Policies

  • If an EFP is a member of a service group without any policy configuration, and a service group policy is configured, then the service group policy is internally attached to the EFP.
  • If an EFP which is member of service-group has a policy configured, then the service-group policy and EFP policy are merged to form a new internal policy that is attached to the EFP.
  • The show policy-map interface interface_num service instance id command displays the statistics for the policy configured on the service instance. This command output deviates when service groups are configured.
    • If the service instance is a member of a service group without a policy configured, it displays statistics for the service group policy.

Example

policy-map ex
class phb
police cir 50000000
class class-default
!
service-group 1
service-policy input ex
end
interface GigabitEthernet0/0/1
no ip address
negotiation auto
service instance 1 ethernet
encapsulation dot1q 100
group 1
bridge-domain 100
!
End

Router(config)# show policy-map interface gigabitEthernet 0/0/1 service instance

GigabitEthernet0/0/1: EFP 1
Service-policy input: ex
Class-map: phb (match-all)
2210042 packets, 3315063000 bytes
5 minute offered rate 82024000 bps, drop rate 77782000 bps
Match: cos 1
police:
cir 50000000 bps, bc 1562500 bytes
conformed 112980 packets, 169470000 bytes; actions:
transmit
exceeded 2097062 packets, 3145593000 bytes; actions:
drop
conformed 4191000 bps, exceeded 77782000 bps
Class-map: class-default (match-any)
0 packets, 0 bytes
5 minute offered rate 0000 bps, drop rate 0000 bps
Match: any
  • If the service instance is configured with a policy, it displays statistics for the merged policy.

Example

policy-map efpp
class efpc
set dscp 2
!
end
interface GigabitEthernet0/0/1
no ip address
negotiation auto
service instance 1 ethernet
encapsulation dot1q 100
group 1
service-policy input efpp
bridge-domain 100
!
End

Router(config)# show policy-map interface gigabitEthernet 0/0/1 service instance

GigabitEthernet0/0/1: EFP 1
Service-policy input: ex+efpp
Class-map: phb (match-all)
0 packets, 0 bytes
5 minute offered rate 0000 bps, drop rate 0000 bps
Match: cos 1
police:
cir 50000000 bps, bc 1562500 bytes
conformed 0 packets, 0 bytes; actions:
transmit
exceeded 0 packets, 0 bytes; actions:
drop
conformed 0000 bps, exceeded 0000 bps
Class-map: efpc (match-all)
0 packets, 0 bytes
5 minute offered rate 0000 bps, drop rate 0000 bps
Match: dscp 1
QoS Set
dscp 2
Marker statistics: Disabled
Class-map: class-default (match-any)
0 packets, 0 bytes
5 minute offered rate 0000 bps, drop rate 0000 bps
Match: any

Restrictions for Merging Service Groups and EFP Policies

  • If the physical port of a member EFP has a policy, the policy cannot be attached to a service group.
  • If the physical port of a member EFP has an egress policy, attaching the egress policy on the service group or adding a member after attaching a policy is not supported on the service group.
  • If EFP has rewrite push configured, the EFP cannot be a member to a service group with any policy configured.
  • Internally created (merged) policies cannot be used for configuring of interfaces. Modifications to these policies is not supported.
  • Policer actions with similar class names on both policies is not allowed.
  • Conditional and non-conditional marking simultaneously in same class not allowed.
  • Marking at more than one level is not supported.
  • Only single level policer is supported at Egress.
  • 3 level Ingress policer is not supported.
  • Attach queuing-based child policy to a non-queuing based class is not supported.
  • Match EXP and, match L4 port type is not supported in a single policy-map.
  • The maximum number of PHB level classes cannot exceed 8 in an Egress policy.
  • The following commands are not supported:
    • show policymap interface interface_name service group service_group_id
    • show policy-map target service-group
    • show service-group traffic-stats

Creating a Service Group

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    service-group service-group-identifier

    4.    description descriptive-text

    5.    service-policy (input | output) policy-map-name

    6.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 service-group service-group-identifier


    Example:
    Device(config)# service-group 20
     
    Creates a service group and enters service-group configuration mode.
    • service-group-identifier—Service group number.
     
    Step 4 description descriptive-text


    Example:
    Device(config-service-group)# description subscriber account number 105AB1
     
    (Optional) Creates a description of the service group.
    • descriptive-text— Additional information about the service group. Descriptions can be a maximum of 240 characters.
     
    Step 5 service-policy (input | output) policy-map-name


    Example:
    Device(config-service-group)# service-policy input policy1
    
     
    (Optional) Attaches a policy map to the service group, in either the ingress (input) or egress (output) direction.
    • policy-map-name—previously created policy map.
     
    Step 6 end


    Example:
    Device(config-service-group)# end
     

    (Optional) Returns to privileged EXEC mode.

     

    Adding Service Instance Members to the Service Group

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    interface gigabitethernet slot/subslot/port

      4.    service instance number ethernet [name]

      5.    group service-group-identifier

      6.    exit

      7.    end


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2 configure terminal


      Example:
      Device# configure terminal
       

      Enters global configuration mode.

       
      Step 3 interface gigabitethernet slot/subslot/port


      Example:
      Device(config)# interface gigabitEthernet 0/1/5
       
      Specifies the Gigabit Ethernet or Ten Gigabit Ethernet interface to configure and enters interface configuration mode, where:
      • slot/subslot/port—The location of the interface.
        • slot—The chassis slot number where the interface module is installed.
          Note    The interface module slot number is always 0.
        • subslot—The subslot where the interface module is installed. Interface module subslots are numbered from 0 to 5, from bottom to top.
        • port—The number of the individual interface port on an interface module.
       
      Step 4 service instance number ethernet [name]


      Example:
      Device(config-if)# service instance 200 ethernet
       
      Configure an EFP (service instance) and enter service instance configuration) mode.
      • The number is the EFP identifier, an integer from 1 to 4000.
      • (Optional) ethernet name is the name of a previously configured EVC. You do not need to use an EVC name in a service instance.
       
      Step 5 group service-group-identifier


      Example:
      Device(config-if-srv)# group 20
      
       
      Creates a service group.
      • service-group-identifier—Service group number.
       
      Step 6 exit


      Example:
      Device(config-if-srv)# exit
       

      (Optional) Returns to interface configuration mode.

       
      Step 7 end


      Example:
      Device(config-if-srv)# end
       

      (Optional) Returns to privileged EXEC mode.

       

      Deleting a Service Group

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    no service-group service-group-identifier

        4.    end


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example:
        Device> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.
         
        Step 2 configure terminal


        Example:
        Device# configure terminal
         

        Enters global configuration mode.

         
        Step 3 no service-group service-group-identifier


        Example:
        Device(config)# service-group 20
         
        Deletes a service group and deletes all members from the service group.
        • service-group-identifier—Service group number.
        Note    When you delete a service group, all members of the service group are automatically removed from the service group.
         
        Step 4 end


        Example:
        Device(config)# end
         

        (Optional) Returns to privileged EXEC mode.

         

        Configuration Examples

        • This example shows policing action on the service group:
          policy-map qos-group-in
          class cos1
          police cir 64000
          policy-map qos-group-out
          class cos2
          police cir 64000
          policy-map qos-member-out1
          class cos3
          police cir 64000
          policy-map qos-member-out2
          class cos4
          police cir 64000
        • This example shows both Ingress and Egress policies supported on the service group:
          service-group 1
          service-policy in qos-group-in
          service-policy out qos-group-out
          int gigabitEthernet1/0/0
          service instance 101 ethernet
          group 1
          service-policy out qos-member-out1
          service instance 102 ethernet
          group1
          service-policy out qos-member-out2
          int gigabitEthernet1/0/1
          service instance 200 ethernet
          group 1
          service-policy out qos-member-out1
          service instance 300 ethernet
          service-policy out qos-member-out2

        Verifying the Service Group

        • Use the show running-config service group command to verify the service groups configuration: Router# show running-config service-group 1
          Building configuration...
          Current configuration:
          service-group 1
          service-policy input co1
          end
        • Use the show platform software uea-qos service-group stats command to verify the statistics of service groups: Router# show platform software uea-qos service-group 1 stats
          Service Group 1
          Service-policy input: co1
          class-map: co1:
          policy name co1, parent class , parent policy
          conformed 54645 packets, 3497280 bytes
          exceeded 3705853 packets, 237174592 bytes
          violated 0 packets, 0 bytes
          conformed 93000 bps, exceeded 6300000 bps

        MPLS Diffserv Tunneling Modes Implementation

        The MPLS specification defines three Diffserv operation modes:

        • Uniform—There is only one DiffServ marking that is relevant for a packet when traversing the MPLS network.
        • Pipe—The network uses two markings for traffic: the original marking value, which is used once the packets leave the MPLS network, and a separate marking value that is used while the traffic crosses intermediate nodes on the LSP span. The second marking value is dropped when traffic exits the MPLS network.
        • Short-Pipe—the egress LSR uses the original packet marking instead of using the marking used by the intermediate LSRs.

        The following sections describe how to implement these modes on the Cisco ASR 903 Series Router using QoS policies.

        Implementing Uniform Mode

        Use the following guidelines to implement uniform mode on the Cisco ASR 903 Series Router:

        Imposition

        To copy the diffserv value to the MPLS Exp bit, create a QoS configuration as follows:

        • Option 1
          • Classify based on Prec bit or DSCP bit at ingress.
          • Set the qos-group.
          • Classify on qos-group.
          • Set the MPLS exp value.
        • Option 2
          • Classify based on Prec bit or DSCP bit at ingress.
          • Set the mpls Exp bit at imposition.

        Tag-to-tag Transfer

        To ensure that outer tag values are copied to inner tags, explicitly mark the outer Exp value on the inner Exp bit.

        Disposition

        To copy the MPLS Exp bit to the diffserv/IP prec bit, create a QoS configuration as follows:

        • Classify based on MPLS Exp bit on the ingress interface.
        • Set the qos-group value.
        • Classify based on qos-group on the egress interface.
        • Mark the IP prec or DSCP bit.

        Implementing Pipe Mode

        Use the following guidelines to implement pipe mode on the Cisco ASR 903 Series Router:

        Imposition

        To set the MPLS Exp bit by policy, create a QoS configuration as follows:

        • Option 1
          • Set the qos-group on the egress interface.
          • Classify based on qos-group on the egress interface.
          • Set the MPLS Exp value.
        • Option 2
          • Apply the set mpls exp imposition command at ingress. Disposition

        To preserve the original IP Prec or diffserv value so that egress queuing is based on MPLS exp value, create a QoS configuration as follows:

        • Classify on MPLS Exp value on the ingress interface.
        • Set the qos-group on the egress interface.
        • Classify based on qos-group value on the egress interface.

        Implementing Short-Pipe Mode

        Use the following guidelines to implement short-pipe mode on the Cisco ASR 903 Series Router:

        Disposition

        To preserve the original IP Prec or diffserv value so that egress queuing is based on MPLS Prec or diffserv value, create a QoS configuration as follows:

        • Classify based on IP prec or DSCP value on the egress interface.
        • Mark the IP prec or DSCP bit.

        Classification

        Classifying network traffic allows you to organize packets into traffic classes or categories on the basis of whether the traffic matches specific criteria. Classifying network traffic (used in conjunction with marking network traffic) is the foundation for enabling many quality of service (QoS) features on your network.

        Table below summarizes the QoS Classification limitations for the Cisco ASR 900 Series Router. In the table, I represents Ingress and E represents Egress.

        Table 7 QoS Classification Limitations

        Match

        Main

        Layer 3

        Interface

        EFP

        Interface

        Trunk

        EFP

        L3

        Ether-

        channel

        L2

        Port

        Channel

        L3

        Port

        Channel

        Member

        L2

        Port

        Channel

        Member

        OC-3

        OC-12

        T1/E1

        MLPPP

        Features

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        Multiple

        match

        statements

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        3.13

        3.7.1

        access

        -group

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        3.13

        3.7.1

        all

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        any

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        class

        -map

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        cos

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        cos inner

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        destination

        -address

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        discard-class

        X

        3.5

        X

        3.5

        X

        3.5

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        dscp (IPv4)

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        3.13

        3.7.1

        dscp (IPv6)

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        flow pdp

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        frde

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        frdlci

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        ip dscp

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        ip

        precedence (IPv4)

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        ip

        precedence (IPv6)

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        ip rtp

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        mpls experimental

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        mpls experimental topmost

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        not

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        packet length

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        precedence (IPv4)

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        3.13

        3.7.1

        precedence

        (IPv6)

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        protocol

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        qos-group

        X

        3.5

        X

        3.5

        X

        3.5

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        service

        instance

        ethernet

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        source-

        address

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        vlan

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        vlan

        inner

        3.5

        3.5

        3.5

        3.5

        3.5

        3.5

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        X

        3.7.1

        Ingress Classification Limitations

        The following limitations apply to QoS classification on the Cisco ASR 900 Series Router:

        • If you configure egress classification for a class of traffic affected by an input policy-map, you must use the same classification criteria on the ingress and egress policy-maps.

        Egress Classification Limitations

        • Egress policy-map with police action is supported on port-channel interface(LAG).
        • When applying a QoS policy to a link aggregation group (LAG) bundle, you must assign the policy to a physical link within the bundle; you cannot apply the policy to the LAG bundle or the port channel interface associated with the bundle.
        • MPLS Pipe Mode Limitations—When you configure pipe mode for Time to Live (TTL), the router enables pipe mode for QoS as well. When pipe mode is enabled, you cannot enable egress classification based on the header on an egress interface. For example, you cannot classify based on egress DSCP value for MPLS IP packets when the router is in pipe mode.

        Traffic Classifying on MLPPP Interfaces

        Release 3.7(1) introduces support for egress QoS on MLPPP interfaces. The Cisco ASR 900 Series Router supports the following match commands in a QoS class-map applied to an egress MLPPP interface.

        • match discard-class
        • match dscp
        • match precedence
        • match qos-group
        Release 3.13 introduces support for ingress QoS on MLPPP interfaces. The Cisco ASR 900 Series Router supports the following match commands in a QoS class-map applied to a ingress MLPPP interface.
        • match access-group
        • match dscp
        • match precedence

        The Cisco router supports service-policy input policy-name command on the ingress and egress QoS interface.

        Classifying Traffic using an Access Control List

        You can classify inbound packet based on an IP standard or IP extended access control list (ACL). By default, TCAM optimization or expansion method is used. Both Security ACL and QoS ACL can be configured on the same interface. Follow these steps to classify traffic based on an ACL:

        1. Create an access list using the access-list or ip access-list commands
        2. Reference the ACL within a QoS class map using the match access-group configuration command
        3. Attach the class map to a policy map
        Limitations and Usage Guidelines

        The following limitations and usage guidelines apply when classifying traffic using an ACL:

        • QoS ACLs are supported only for IPv4 and IPv6 traffic
        • QoS ACLs are supported only for ingress traffic
        • You can use QoS ACLs to classify traffic based on the following criteria:
          • Source and destination host
          • Source and destination subnet
          • TCP source and destination
          • UDP source and destination
        • Named and numbered ACLs are supported.
        • You can apply QoS ACLs only to the third level class (bottom-most).
        • The following range of numbered access lists are supported:
          • 1-99—IP standard access list
          • 100-199—IP extended access list
          • 1300-1999—IP standard access list (expanded range)
          • 2000-2699—IP extended access list (expanded range)
        • You must create an ACL before referencing it within a QoS policy.
        • Deny statements within an ACL are ignored for the purposes of classification.
        • Classifying traffic based on TCP flags using an ACL is not supported.
        • Classifying traffic using multiple mutually exclusive ACLs within a match-all class-map is not supported.
        • Classifying traffic on a logical/physical level using an ACL is not supported.
        • Applying QoS ACLs to MAC addresses is not supported.
        • Port matching with the neq keyword is only supported for a single port.
        • A given command can consume multiple matching operations if you specify a source and destination port, as shown in the following examples:
          • permit tcp any lt 1000 any—Uses one port matching operation
          • permit tcp any lt 1000 any gt 2000—Uses two port matching operations
          • permit tcp any range 1000 2000 any 400 500—Uses two port matching operations
        • Only the following combination of matches are currently supported for Ingress policies:
          • Combination A: DSCP, Outer COS, UDP/TCP Source and Destination port number, IP SA/DA
          • Combination B: IP SA/DA, Outer COS, Inner COS, DSCP, MPLS EXP
          • Combination C: MAC DA, Outer COS, Inner COS, DSCP, MPLS Exp

            Note


            Policy with match on L4 ACL and MPLS EXP together is currently not supported.


        For more information about configuring QoS, see http:/​/​www.cisco.com/​en/​US/​products/​ps11610/​products_​installation_​and_​configuration_​guides_​list.html. For more information about configuring access control lists, see the Security Configuration Guide: Access Control Lists, Cisco IOS XE Release 3S (ASR 900 Series).

        Additional Classification Limitations

        • The topmost policy-map in a three-level hierarchy only supports classification using class-default.

        Configuring Multiple Match Statements

        In IOS XE Release 3.5, the Cisco ASR 903 Series Router supported a single match or match-any command in a given QoS class-map, as shown in the following example:

        Exampe for IOS XE 3.5 Class Map

        
        class-map match-any my-restrict-class_00
           match ip prec
        
        class-map match-any my-restrict-class_01
           match qos-group 2
        
        class-map match-any my-restrict-class_03
        

        match cos 3

        IOS XE Release 3.6 introduces support for multiple match or match-any commands in a given QoS class-map, as shown in the following example:

        Example for IOS XE 3.6 Class Map

        
        class-map match-any my-class
           match ip prec 1
           match qos-group 2
           match cos 3
        

        The router treats the statements as a logical OR operation and classifies traffic that matches any match statement in the class map.

        Traffic Classification Using Match EFP Service Instance Feature

        Service Provider configurations have various service instances on the PE. QoS policy-maps are applied on these service instances or group of service instances. Cisco IOS XE Release 3.9S introduces the Match EFP Service Instance feature. The benefits of this feature are:

        • Identify the various types of service-instances like EFP, Trunk EFPs
        • Apply policies on these service instances at the port
        • Manage bandwidth and priority across the service instances on the port and across classes within the service instance
        • Apply policies on a group of transport service instances such as applying similar policies to a group of EFPs.
        Restrictions for Configuring Match Service Instances
        • Ethernet service instances configured under the interface can be classified in a class of a policy-map. The class can match on a group or set of match service instance statements.
          
          class-map match-any policeServiceInstance
              match service instance ethernet  100
              match service instance ethernet 200
          
        • Ingress and Egress Match service instance are supported.
        • match service instance and match PHB per flows classification are defined at respective levels in the policy hierarchy under the port.
        • The number of EFPs supported per group is 256. Only 256 match statements are supported per class.
        • Match EFP policy-map can be configured only on the port and not under the service instance.
        Example for Configuring Match Service Instances
        
        interface GigabitEthernet0/3/4
         no ip address
         negotiation auto
         service-policy output BTS_Total
         service instance 10 ethernet
          encapsulation dot1q 100
          rewrite ingress tag pop 1 symmetric
          bridge-domain 100
         !
         service instance trunk 20 ethernet
          encapsulation dot1q 20-29
          rewrite ingress tag pop 1 symmetric
          bridge-domain from-encapsulation
         !
         service instance 30 ethernet
          encapsulation dot1q 30
          xconnect 192.44.32.21 101 encapsulation mpls
        
        
        class-map match-any service-instance-group-with-BMG
        match service instance ethernet 10
        match service instance ethernet 20
        
        class-map service-instance-30
        match service instance ethernet 30
        
        class-map service-instance-20
        match service instance ethernet 20
        
        class-map VOICE
        match qos-group 0
        
        class-map SIGNALING
        match qos-group 1
        
        class-map match-any DATA
        match qos-group 2
        match qos-group 4
        
        policy-map child-X
        class VOICE
        priority level 1
        police cir 20m
        class SIGNALING
        priority level 2
        police cir 30m
        class DATA
        shape average 90m
        random-detect cos-based
        
        
        policy-map BTS_OUT_Bi
        class service-instance-group-with-BMG
        shape average 100m
        service-policy child-X
        class service-instance-30
        shape average 200m
        service-policy child-X
        
        policy-map BTS_Total
        class class-default
        shape average 250m
        service-policy BTS_OUT_Bi
        

        QoS Marking

        QoS marking allows you to set a desired value on network traffic to make it easy for core devices to classify the packet.

        Table below summarizes the QoS Marking limitations for the Cisco ASR 903 Series Router. In the table, I represents Ingress and E represents Egress.

        Table 8 Marking QoS Limitations

        Features

        Main

        Layer 3

        Interface

        EFP

        Interface

        Trunk

        EFP

        L3

        Ether-

        channel

        L2

        Port

        Channel

        L3

        Port

        Channel

        Member

        L2

        Port

        Channel

        Member

        OC-3

        OC-12

        T1/E1

        MLPPP

        set

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        atm-

        clp

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        cos

        3.5

        3.6

        3.5

        3.6

        3.5.1

        3.6

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        cos

        inner

        3.5

        3.6

        3.5

        3.6

        3.5.1

        3.6

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        discard-

        class

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        3.13

        3.7.1

        dscp

        3.6

        3.6

        3.6

        3.6

        3.6

        3.6

        3.9

        3.9

        3.9

        3.9

        3.6

        3.6

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        3.13

        3.7.1

        dscp-

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        X

        ip

        dscp

        3.5

        3.6

        3.5

        3.6

        3.5.1

        3.6

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        3.13

        3.7.1

        ip

        prece-

        dence

        3.5

        3.6

        3.5

        3.6

        3.5.1

        3.6

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        3.13

        3.7.1

        mpls

        experi-

        mental

                                                   

        mpls

        experi-

        mental

        impo-

        sition

        3.5

        X

        3.5

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        mpls

        experi-

        mental

        impo-

        sition

        qos-

        group

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        mpls

        experi-

        mental

        topmost

        3.5

        3.6

        3.5

        3.6

        3.5.1

        3.6

        3.9

        3.9

        3.9

        3.9

        3.5

        3.5

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        3.13

        3.9

        prece-

        dence

        3.6

        3.6

        3.6

        3.6

        3.6

        3.6

        3.9

        3.9

        3.9

        3.9

        3.6

        3.6

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        3.13

        3.7.1

        prec-

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        X

        qos-

        group

        3.6

        X

        3.6

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        3.13

        Overview of Marking

        The Cisco ASR 903 Series Router supports the following parameters with the set command:

        • set cos
        • set discard-class
        • set dscp
        • set precedence
        • set ip dscp
        • set ip precedence
        • set mpls experimental imposition (ingress marking)
        • set mpls experimental topmost
        • set qos-group

        CoS Marking Limitations

        The following limitations apply when configuring CoS marking:

        • set cos—This set action has no effect unless there is a egress push action to add an additional header at egress. The COS value set by this action will be used in the newly added header as a result of the push rewrite. If there are no push rewrite on the packet, the new COS value will have no effect.
        • The set cos inner command is not supported.

        Ingress Marking Limitations

        The following limitations apply to QoS marking on the Cisco ASR 903 Series Router:

        • The Cisco ASR 900 Series Router does not support hierarchical marking.
        • You can configure marking and policing for any number of classes on any one of the three levels of the policy-map hierarchy. If you configure marking on one level, you can configure policing without marking (transmit, drop) on another level.

        Egress Marking Limitations

        IOS XE Release 3.6 introduces support for egress marking. The following limitations apply when configuring marking on egress interfaces:

        • The set cos inner command is not supported.
        • The set mpls experimental imposition command is not supported.
        • The set mpls experimental topmost command is supported for marking MPLS Exp bits; other commands for marking MPLS Exp bits are not supported.

        Traffic Marking on MLPPP Interfaces

        Release 3.7(1) introduces support for egress QoS on MLPPP interfaces. The Cisco ASR 903 Series Router supports the following parameters with the set command on egress MLPPP interfaces:

        • set ip dscp
        • set ip precedence
        Release 3.13 introduces support for ingress QoS on MLPPP interfaces. The Cisco ASR 903 Series Router supports the following parameters with the set command on the ingress MLPPP interfaces:
        • set dscp
        • set precedence
        • set ip dscp
        • set ip precedence
        • set mpls exp imposition
        • set mpls exp topmost
        • set qos-group
        • set discard-class

        IPv6 Traffic Marking

        The Cisco ASR 903 supports the following commands for marking both IPv4 and IPv6 packets:

        • set dscp
        • set precedence

        For more information about IPv6 QoS, see:

        Additional Marking Limitations

        The following additional marking usage guidelines apply in Release 3.9:

        • Release 3.9 introduces support for ingress MPLS Exp marking on pseudowire CEM and ATM interfaces, including SAToP, CESoPSN, ATM IMA, and ATMoMPLS. For more information about configuring bit marking, see MPLS Diffserv Tunneling Modes Implementation, page 12-12.
        • Marking is supported on Etherchannel interfaces and individual member links; however, you cannot configure marking on both interface levels at once.

        Traffic Policing

        Traffic policing allows you to control the maximum rate of traffic sent or received on an interface, and to partition a network into multiple priority levels or class of service (CoS). This section describes the policing limitations and configuration guidelines for the Cisco ASR 903 Series Router.

        The Cisco ASR 903 Series Router supports the following policing types:

        • Single-rate policer with two color marker (1R2C) (color-blind mode)
        • Two-rate policer with three color marker (2R3C) (color-blind mode)

        Table below summarizes the QoS policing limitations for the Cisco ASR 903 Series Router. In the table, I represents Ingress and E represents Egress.

        Policing QoS Limitations

        Features

        Main

        Layer 3

        Interface

        EFP

        Interface

        Trunk

        EFP

        L3

        Ether-

        channel

        L2

        Port

        Channel

        L3

        Port

        Channel

        Member

        L2

        Port

        Channel

        Member

        OC-3

        OC-12

        T1/E1

        MLPPP

         

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        Rate

        Limiting

                                                   

        One

        rate

        3.5

        3.6

        3.5

        3.6

        3.6

        3.6

        3.9

        3.9

        3.9

        3.9

        3.5

        3.6

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        One

        rate

        and

        two

        marking

        3.5

        3.6

        3.5

        3.6

        3.6

        3.6

        3.9

        3.9

        3.9

        3.9

        3.5

        3.6

        3.9

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        Two

        rates

        and

        two

        Marking

        3.5

        X

        3.5

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        X

        Two

        rates

        and

        three

        actions

        3.5

        X

        3.5

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        X

        Color

        Aware

        policing

                                                   

        Commands

                                                   

        bandwidth

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        bandwidth remaining ratio

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        bandwidth percent

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        police (percent)

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        police

        (policy

        map)

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        police (policy

        map

        class)

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        police (two rates)

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        priority

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        Supported

        actions

                                                   

        drop

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        X

        set-

        qos-

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        3.13

        X

        set-

        cos-

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        3.13

        X

        set-

        dscp-

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        3.13

        X

        set-

        prec-

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        3.13

        X

        set-

        discard-

        class-

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        3.13

        X

        set-

        mpls-

        experi-

        mental-

        topmost-

        transmit

        3.5

        3.6

        3.5

        3.6

        3.5.1

        3.6

        3.9

        3.9

        3.9

        3.9

        3.5

        3.6

        3.9

        3.9

        X

        3.9

        X

        X

        3.9

        X

        3.9

        3.13

        3.9

        set-

        mpls-

        experi-

        mental-

        impo-

        sition-

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        3.13

        X

        transmit

        3.5

        X

        3.5

        X

        3.5.1

        X

        3.9

        X

        3.9

        X

        3.5

        X

        3.9

        X

        X

        X

        X

        X

        X

        X

        X

        X

        Supported Commands

        The Cisco ASR 903 Series Router supports the following policing commands on ingress interfaces:

        • police (percent)—police cir percent percentage [burst-in-msec] [bc conform-burst-in-msec ms] [be peak-burst-in-msec ms] [pir percent percentage] [conform-action action [exceed-action action [violate-action action]]]
        • police (policy map)—police cir bps [[bc] normal-burst-bytes [maximum-burst-bytes | [be] [burst-bytes]]] [pir bps [be burst-bytes]] [conform-action action [exceed-action action [violate-action action]]]
        • police (two rates)—police cir cir [bc conform-burst] [pir pir] [be peak-burst] [conform-action action [exceed-action action [violate-action action]]]

        The Cisco ASR 903 Series Router supports the following policing commands on egress interfaces:

        • bandwidth (policy-map class)—bandwidth {bandwidth-kbps | remaining percent percentage | percent percentage} [account {qinq | dot1q} aal5 subscriber-encapsulation]
        • bandwidth remaining ratiobandwidth remaining ratio ratio [account {qinq | dot1q} [aal5] {subscriber-encapsulation | user-defined offset}]
        • police (policy map)—police cir bps [[bc] normal-burst-bytes [maximum-burst-bytes | [be] [burst-bytes]]] [pir bps [be burst-bytes]] [conform-action action [exceed-action action [violate-action action]]]
        • priority—priority {bandwidth-kbps | percent percentage} [burst]

        Several restrictions apply when using egress policing; see the Egress Policing Limitations, page 12-27 section for more information.

        Supported Actions

        The Cisco ASR 903 Series Router supports the following policing actions on ingress interfaces:

        • transmit
        • drop
        • set-qos-transmit
        • set-cos-transmit
        • set-dscp-transmit
        • set-prec-transmit
        • set-discard-class-transmit
        • set-mpls-experimental-topmost-transmit
        • set-mpls-experimental-imposition-transmit

        Percentage Policing Configuration

        The router calculates percentage policing rates based on the maximum port PIR rate. The PIR rate is determined as follows:

        • Default—Port line rate
        • Speed command applied—Operational rate
        • Port shaping applied to port—Shaped rate

        Ingress Policing Limitations

        The following limitations apply to QoS policing on the Cisco ASR 903 Series Router:

        • If you configure a policer rate or burst-size that the router cannot achieve within 1% accuracy, the configuration is rejected. The command output presents recommendations for the closest possible lower and higher configuration value.
        • You can configure marking and policing for any number of classes on any one of the three levels of the policy-map hierarchy. If you configure marking on one level, you can configure policing without marking (transmit, drop) on another level.
        • If you configure marking using the set command, you can only configure policing on that level using the transmit and drop command.
        • If you configure a policer using a set command, you cannot use the set command at other levels of the hierarchical policy-map.

        Egress Policing Limitations

        IOS XE Release 3.6 introduces support for egress policing. The Cisco ASR 900 Series Router supports the bandwidth and bandwidth-remaining commands on egress interfaces under the following conditions:

        • Mixed bandwidth types are not supported in the same policy. For example, you cannot configure a policy containing both the bandwidth remaining percent command and bandwidth remaining ratio command.
        • The bandwidth and bandwidth-remaining commands are not supported in a class containing the priority command. The bandwidth and bandwidth-remaining commands must be configured on classes of the same level.
        • If you want to create a configuration that uses the bandwidth or bandwidth-remaining commands and the priority command, you must include a police statement in the QoS class. The following is a sample supported configuration:
          
          Router# show policy-map
            Policy Map PHB
              Class cos1
               police cir 200000 bc 8000
                 conform-action transmit
                 exceed-action drop
                priority
              Class cos2
                bandwidth 100
                bandwidth remaining percent 40
              Class cos3
                bandwidth 200
                bandwidth remaining percent 50
          
        • The priority and police commands must be applied on a single class. The following is a sample supported configuration:
          
          Router# show policy-map
            Policy Map PHB
              Class cos1
               police cir 200000 bc 8000
                 conform-action transmit
                 exceed-action drop
                priority
              Class cos2
                bandwidth 100
              Class cos3
                bandwidth 200
          
        • Egress MLPPP interfaces support a single-rate policer with two color marker (1R2C) (color-blind mode) at the LLQ level.
        • Egress port-level policing is supported with ingress EFP policy on the router. The following is a sample supported configuration:
          
          Policy-map ingress_policy
            Class cos3
              Set cos 5
          Policy-map egress policy
            Class cos5
              Shape average 30m
          
          ###Ingress
          interface GigabitEthernet0/4/0
          no ip address
          negotiation auto
          service instance 100 ethernet
            encapsulation dot1q 100
            service-policy input ingress_policy  >>>> Ingress policy in EFP
            bridge-domain 100
          
          ###Egress
          interface GigabitEthernet0/4/0
          no ip address
          negotiation auto
          service-policy output egress_policy   >>>>>Egress policy on Port
          service instance 100 ethernet
            encapsulation dot1q 100
            bridge-domain 100
          
        • Release 3.7(1) introduces support for QoS features on egress policing on MLPPP interfaces using the police command. Egress MLPPP interfaces support a single-rate policer with two color marker (1R2C) (color-blind mode) at the LLQ level.
        • Police and Set in same policy class-map Effective 3.10 and later, police and set commands can be configured together in the egress policy class-map. In prior releases, a error message was displayed when both police and set commands were configured. Sample example displaying the error message:
          
          Router(config)#policy-map egress
          Router(config-pmap)#class p1
          Router(config-pmap-c)#police cir 200m
          Router(config-pmap-c-police)#set prec 2
          Qos:Configuration failed - Set and police not allowed in same class p1 of policy egress
          QoS: Configuration failed. Invalid set
          
        • Egress Policing on Non Priority Queue Starting Cisco IOS XE Release 3.6 and later, policing is supported at the egress on non priority queues.

        Sample configuration:

        
        Router#sh policy-map testp
          Policy Map testp
            Class cos1
              priority
             police cir 20000000 bc 625000
               conform-action transmit
               exceed-action drop
            Class cos2
             police cir 20000000 bc 625000
               conform-action transmit
               exceed-action drop
            Class cos4
             police cir 50000000 bc 1562500
               conform-action transmit
               exceed-action drop
        

        Traffic Policing on MLPPP Interfaces

        Release 3.13 introduces support for egress QoS on MLPPP interfaces. 1R2C color-blind policer is supported for egress QoS on MLPPP interfaces.

        Release 3.13 introduces support for ingress QoS on MLPPP interfaces. The Cisco ASR 900 Series Router supports the following parameters with the set command on the ingress MLPPP interfaces:
        • set dscp transmit
        • set prec transmit
        • set mpls exp imposition transmit
        • set mpls exp topmost transmit
        • set qos transmit
        • set discard-class transmit

        1R2C color-blind policer and 2R3C color-blind policer is supported for ingress QoS on MLPPP interfaces.

        Traffic Shaping

        Traffic shaping allows you to control the speed of traffic that is leaving an interface in order to match the flow of traffic to the speed of the receiving interface. Percentage-based policing allows you to configure traffic shaping based on a percentage of the available bandwidth of an interface.Configuring traffic shaping in this manner enables you to use the same policy map for multiple interfaces with differing amounts of bandwidth.

        This section describes the shaping limitations and configuration guidelines for the Cisco ASR 903 Series Router.

        Table below summarizes the QoS shaping limitations for the Cisco ASR 903 Series Router.; an X indicates support.

        Table 9 Shaping Limitations by Interface
         

        GigE

        10 GigE

        EFP

        Trunk

        EFP

        Port

        Channel

        Member

        Link

        OC-3

        OC-12

        T1/E1

        Serial

        MLPPP

        ACL

         

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        Features

                                                       

        Class-

        Based

                                                       

        Distri-

        buted

                                                       

        Frame

                                                       

        Generic

                                                       

        Shape

                                                       

        adaptive

         

        X

             

        X

         

        X

           

        X

                                 

        average

         

        X

             

        X

         

        X

           

        X

                           

        X

           

        fecn-

        adapt

         

        X

             

        X

         

        X

           

        X

                                 

        max-

        buffers

         

        X

             

        X

         

        X

           

        X

                                 

        peak

         

        X

             

        X

         

        X

           

        X

                                 

        Additional Shaping Limitations

        The following additional shaping usage guidelines apply in Release 3.9:

        • Policies using shaping are supported only on individual member links of an etherchannel. Applying a shaping policy directly on an etherchannel interface is not supported.
        • Class-based shaping is supported at all levels.

        Configuring Egress Shaping on EFP Interfaces

        Configuring an EFP port shaper allows you to shape all EFPs on a port using a port policy with a class-default shaper configuration, as in the following partial sample configuration:

        
        policy-map port-policy
          class class-default
            shape average percent 50
        policy-map efp-policy
          class class-default
            shape average percent 25
            service-policy child-policy
        policy-map child-policy
          class phb-class
            <class-map actions>
        

        The following configuration guidelines apply when configuring an EFP port shaping policy:

        • When the configuration specifies a shaper rate using a percentage, the router calculates the value based on the operational speed of a port. The operational speed of a port can be the line rate of the port or the speed specified by the speed command.
        • The rates for bandwidth percent and police percent commands configured under a port-shaper are based on the absolute rate of the port-shaper policy.
        • You can combine a port shaper policy (a flat shaper policy with no user-defined classes) with an egress EFP QoS shaping policy.
        • Configure the port shaper policy before configuring other egress QoS policies on EFP interfaces; when removing EFP QoS configurations, remove other egress EFP QoS policies before removing the port shaper policy.

        Congestion Management

        Congestion management features allow you to control congestion by determining the order in which packets are sent out an interface based on priorities assigned to those packets. Congestion management entails the creation of queues, assignment of packets to those queues based on the classification of the packet, and scheduling of the packets in a queue for transmission.

        This section describes the classification limitations and configuration guidelines for the Cisco ASR 903 Series Router.

        Table below summarizes the QoS congestion management and queuing limitations for the Cisco ASR 903 Series Router. In the table, I represents Ingress and E represents Egress.

        Table 10 Congestion Management QoS Limitations

        Features

        Main

        Layer 3

        Interface

        EFP

        Interface

        Trunk

        EFP

        L3

        Ether-

        channel

        L2

        Port

        Channel

        L3

        Port

        Channel

        Member

        L2

        Port

        Channel

        Member

        OC-3

        OC-12

        T1/E1

        MLPPP

         

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        CBWFQ

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.8

        X

        3.9

        X

        3.9

        X

        3.7.1

        D-CBWFQ

                                                   

        IP RTP

        priority

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        Frame

        Relay

        IP RTP

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        Frame

        Relay

        PVC

        Interface

        Priority

        Queuing

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        LLQ

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.8

        X

        3.9

        X

        3.9

        X

        3.7.1

        D-LLQ

                                                   

        LLQ-FR

                                                   

        Custom

        queuing

                                                   

        Priority

        Queuing

                                                   

        Commands

                                                   

        bandwidth (kbps)

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        bandwidth percent

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        bandwidth remaining percent

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        bandwidth remaining ratio

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        compression header ip

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        drop

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        fair-queue

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        priority

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        priority (kbps)

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        priority (without queue-limit)

                                                   

        priority percent

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        queue-limit

        (cells)

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        queue-limit

        (packets)

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        Ingress Queuing Limitations

        The Cisco ASR 903 Series Router does not support queuing on ingress interfaces.

        Egress Queuing Limitations

        The Cisco ASR 903 Series Router supports tail drop queuing on egress interfaces using the queue-limit command. The following limitations apply to egress queuing:

        • If you configure a queue size that the router cannot achieve within 1% accuracy, the configuration is rejected. The command output presents recommendations for the closest possible lower and higher configuration value.
        • Egress policy-map with queuing action is not supported on port-channel interface(LAG). The policy must be applied to the policy-maps on the member links.
        • Release 3.8 extends the maximum bytes value of the queue-limit number-of-packets [bytes | ms | packets] command. The previous maximum value was 491520 bytes; the new value is 2 MB.
        • Release 3.8 enhances the show policy-map interface command to display the default queue-limit.
        • Release 3.8 introduces support for the queue-limit percent command.

        Support for Queuing Features on MLPPP Interfaces

        Release 3.7(1) introduces support for QoS features on egress MLPPP interfaces. The following queuing features are supported on egress MLPPP interfaces:

        • Tail drop queuing uses the queue-limit command.
        • Hierarchical QoS is not supported on MLPPP. MLPPP egress queuing is supported only on the 3rd level classes (bottom-most).
        • 3-level policies are not supported on MLPPP interfaces.

        Support for Low Latency Queuing on Multiple EFPs

        IOS XE 3.6 Release for the Cisco ASR 903 router introduces support for QoS policies that allow for low-latency queuing (LLQ) across multiple EFPs. For more information about this feature, see http:/​/​www.cisco.com/​en/​US/​docs/​ios-xml/​ios/​qos_plcshp/​configuration/​xe-3s/​qos-plcshp-ehqos-pshape.html.

        Additional Queuing Limitations

        The following additional queuing usage guidelines apply in Release 3.9:

        Congestion Avoidance

        Congestion avoidance techniques monitor network traffic loads in an effort to anticipate and avoid congestion at common network bottlenecks. Congestion avoidance is achieved through packet dropping. Among the more commonly used congestion avoidance mechanisms is Random Early Detection (RED), which is optimum for high-speed transit networks. Cisco IOS QoS includes an implementation of RED that, when configured, controls when the router drops packets. If you do not configure Weighted Random Early Detection (WRED), the router uses the cruder default packet drop mechanism called tail drop.

        Table below summarizes the QoS congestion avoidance limitations for the Cisco ASR 903 Series Router. In the table, I represents Ingress and E represents Egress.

        Table 11 Congestion Avoidance QoS Limitations

        Features

        Main

        Layer 3

        Interface

        EFP

        Interface

        Trunk

        EFP

        L3

        Ether-

        channel

        L2

        Port

        Channel

        L3

        Port

        Channel

        Member

        L2

        Port

        Channel

        Member

        OC-3

        OC-12

        T1/E1

        MLPPP

         

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        I

        E

        Tail

        Drop

        (default)

                                                   

        RED

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        random-

        detect

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        WRED

        not supported on ingress ifcs

                                               

        random-

        detect

        discard-

        class

                                                   

        random-

        detect

        discard-

        class-

        based

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        random-

        detect

        expon-

        ential-

        weight-

        ing-

        constant

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        fair-

        queue

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        X

        prece-

        dence

                                                   

        random-

        detect

        cos-

        based

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        random-

        detect

        dscp-

        based

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        random-

        detect

        prec-

        edence-

        based

        X

        3.6

        X

        3.6

        X

        3.6

        X

        X

        X

        X

        X

        3.6

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.9

        X

        3.7.1

        shape

                                                 

        D-WRED

                                                   

        Flow-

        based

        WRED

                                                   

        Diffserv

        WRED

                                                   

        Congestion Avoidance Configuration

        The following sections describe the supported congestion avoidance features on the Cisco ASR 903 Series Router:

        Supported Commands

        The Cisco ASR 903 Series Router supports the following commands for WRED:

        • random-detect cos-based—Outer CoS
        • random-detect dscp-based— IPv4 DSCP
        • random-detect precedence-based— IPv4 Precedence bit

        Supported Interfaces

        WRED is supported at the PHB level but not on logical or physical interfaces. You can apply WRED policies on the following interface types:

        • Main Layer 3 interface
        • Port-channel Layer 3 member-links
        • Service instances
        • Trunk EFPs

        Ingress Congestion Avoidance Limitations

        WRED is not supported on ingress interfaces.

        Egress Congestion Avoidance Limitations

        The following limitations apply when configuring congestion avoidance on the Cisco ASR 903 Series Router:

        • Queuing feature to support WRED in a class such as shape or bandwidth are supported.
        • You must apply WRED within a policy map.
        • WRED is only supported on egress interfaces.
        • WRED is not supported in priority queues.
        • WRED is supported in the class-default class if there are no other user-defined classes in the policy-map.
        • You can configure a maximum of 2 WRED curves per class.
        • Fair-queue is not supported. You can configure WRED with either the shape or the fair-queue (CBWFQ) commands.
        • The default value for exponential-weighting-constant is 9.
        • The default value for mark-probability is 10.
        • You can specify the minimum-threshold and maximum-threshold in terms of bytes or microseconds. Setting threshold values in terms of packets is not supported.

        Egress Congestion Avoidance on MLPPP Interfaces

        Release 3.7(1) introduces support for the following egress congestion features on MLPPP interfaces:

        • RED queuing using the random-detect command
        • WRED queuing using the random-detect command. You can apply WRED to:
          • DSCP
          • Precedence
          • Qos-group
          • Discard-class

        MLPPP egress queuing is supported only on the 3rd level classes (bottom-most).

        • Class-based Weighted Fair Queuing (CBWFQ) using the bandwidth and bandwidth percent commands. CBWFQ is supported on 2nd and 3rd level classes.
        • Class-based Shaping using the shape average and shape average percent commands. Class-based shaping is supported at all levels.
        • Class-based excess bandwidth scheduling using the bandwidth remaining percent and bandwidth remaining ratio commands. Class-based excess bandwidth scheduling is supported on 2nd and 3rd level QoS classes.

        Additional Congestion Avoidance Limitations

        • You can specify the minimum-threshold and maximum-threshold in terms of bytes or microseconds. Setting threshold values in terms of packets is not supported.
        • Policies using Class-based Weighted Fair Queuing (CBWFQ) and WRED are supported only on individual member links of an etherchannel. Applying a CBWFQ policy directly on an etherchannel interface is not supported.
        • Aggregate-WRED is not supported. However, multiple random-detect statements with the same curve are supported in the same class.

        Verifying the Configuration

        You can use the show policy-map interface command to display the number of WRED drops and tail drops.

        For more information about configuring congestion avoidance, see the following documents:

        Scheduling

        This section describes the scheduling limitations and configuration guidelines for the Cisco ASR 903 Series Router.

        Ingress Scheduling Limitations

        The Cisco ASR 903 Series Router does not support scheduling on ingress interfaces.

        Egress Scheduling Limitations

        • If you configure a CIR, PIR, or EIR rate that the router cannot achieve within 1% accuracy, the configuration is rejected. The command output presents recommendations for the closest possible lower and higher configuration value.
        • You can only configure one priority value on each parent class applied to a QoS class or logical interface.
        • You can only configure priority on one class in a QoS policy.
        • You can not configure priority value and a policer in the same class.

        The following limitations apply when configuring a 3-level scheduling policy on an egress interface configured as an EFP:

        • Only two of the three levels can contain scheduling actions such as bandwidth, shape, or priority.
        • Class-based excess bandwidth scheduling is supported on 2nd and 3rd level QoS classes.
        • One of the levels containing scheduling actions must be the class (bottom) level.

        Egress Scheduling on MLPPP Interfaces

        Release 3.7(1) introduces support for QoS features on egress MLPPP interfaces including scheduling. The following scheduling features are supported:

        • Strict priority using the priority command; strict priority is supported on 2nd and 3rd level classes.
        • Multi-level priority using the priority level command. You can configure two priority levels; the feature is supported on 3rd level classes.

        The following limitations apply when configuring a 3-level scheduling policy on an egress interface configured as an EFP:

        • Only two of the three levels can contain scheduling actions such as bandwidth, shape, or priority.
        • QoS policies using the priority command are supported only on individual member links.
        • MLPPP is not supported on port-channel (etherchannel).