Configuring QoS on the GGSN

This chapter describes how to configure quality of service (QoS) functions to differentiate traffic flow through the gateway GPRS support node (GGSN) on the Cisco MWAM in the Cisco 7600 series router platform.

For a complete description of the GGSN commands in this chapter, refer to the Cisco GGSN Command Reference for the Cisco GGSN release you are using. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

This chapter includes the following sections:

•Overview of QoS Support on the GGSN

•Configuring UMTS QoS on the GGSN

•Configuring the GGSN Default QoS as Requested QoS

•Configuring Call Admission Control on the GGSN

•Configuring Per-PDP Policing

•Monitoring and Maintaining QoS on the GGSN

•Configuration Examples

Overview of QoS Support on the GGSN

The Cisco GGSN software supports 3G Universal Mobile Telecommunication System (UMTS) QoS. Each GPRS/UMTS packet data protocol (PDP) context request contains a UMTS QoS profile.

The implementation of QoS support in the GPRS/UMTS public LAN mobile network (PLMN) varies by the service provider and the available resources in the network. The 3GPP standards define the UMTS QoS classes that can be defined by a UMTS MS. However, the resulting QoS is negotiated and variable within the GPRS/UMTS network backbone according to the implementations of the service provider.

UMTS QoS

To manage different level of QoS, UMTS has defined the four QoS traffic classes based on delay, jitter, bandwidth, and reliability factors:

•Conversational

•Streaming

•Interactive

•Background

GGSN Release 4.0 and later delivers end-to-end UMTS QoS by implementing it using the Cisco IOS QoS differentiated services (Diffserv).

This chapter describes the QoS support that the GGSN provides for the UMTS QoS classes.

Configuring UMTS QoS on the GGSN

This section describes how to configure the UMTS QoS on the GGSN. It includes the following topics:

•Overview of UMTS QoS

•Configuring UMTS QoS Task Lists

•Enabling UMTS QoS Mapping on the GGSN

•Mapping UMTS QoS Traffic Classes to a DiffServ PHB Group

•Assigning a DSCP to a DiffServ PHB Group

•Configuring the DSCP in the Subscriber Datagram

•Configuring the Cisco 7600 Platform GGSN UMTS QoS Requirements

•Verifying the UMTS QoS Configuration

Overview of UMTS QoS

3GPP standards define four QoS traffic classes based on delay, jitter, bandwidth, and reliability for UMTS. Table 9-1 describes these UMTS traffic classes and their characteristics, applications, and the mapped Cisco IOS QoS Diffserv class.

Table 9-1 UMTS Traffic Classes

Traffic Class
Conversational
(Real Time)
Streaming
(Real Time)
Interactive
(Best Effort)
Background
(Best Effort)
Characteristics

Preserve time relation (variation) between information entities of the stream.

Conversational pattern, therefore, very low delay and jitter.

Preserve time relation (variation) between information entities of the stream.

Delay and jitter requirements are not as strict as with the conversational class.

Request/response pattern.

Retransmission of payload content in-route.

Destination is not expecting the data with a stringent time.

Retransmission of payload content in-route might occur.

Example Applications

Voice over IP

Streaming audio and video

Web browsing

Downloading email

Diffserv Class /
Map to DSCP

Expedited Forwarding Class

Assured Forwarding 2 Class

Assured Forwarding 3 Class

Best Effort


GGSN Release 4.0 and later support end-to-end UMTS QoS by implementing it using the Cisco IOS Differentiated Services (DiffServ) model. The DiffServ model is a multiple-service model that can satisfy differing QoS requirements. With DiffServ, the network tries to deliver a particular kind of service based on the QoS specified by each packet. This specification can occur in different ways, for example, using the 6-bit differentiated services code point (DSCP) setting in IP packets or source and destination addresses. The network uses the QoS specification to classify, mark, shape, and police traffic, and to perform intelligent queueing.

For complete information on Cisco IOS QoS and the DiffServ service model, refer to the Cisco IOS Quality of Service Solutions Configuration Guide.

Configuring UMTS QoS Task Lists

To implement the UMTS QoS method on a GGSN, you must first enable the function. From there, you can modify the UMTS QoS options to support your network needs.

Configuring GGSN UMTS QoS on the Cisco 7600 Platform Task List

If configuring UMTS QoS on a GGSN on the Cisco 7600 platform, perform the following tasks:

•Enabling UMTS QoS Mapping on the GGSN (Required)

•Mapping UMTS QoS Traffic Classes to a DiffServ PHB Group (Optional)

•Assigning a DSCP to a DiffServ PHB Group (Optional)

•Configuring the DSCP in the Subscriber Datagram (Optional)

•Configuring the Cisco 7600 Platform GGSN UMTS QoS Requirements (Required)

•Configuring Call Admission Control on the GGSN (Optional)

•Verifying the UMTS QoS Configuration

Enabling UMTS QoS Mapping on the GGSN

By default, UMTS QoS is not enabled on the GGSN. To enable UMTS QoS on the GGSN, use the following command in global configuration mode:

Command
Purpose

Router(config)# gprs qos map umts


Enables UMTS QoS mapping on the GGSN.


Mapping UMTS QoS Traffic Classes to a DiffServ PHB Group

Before you can specify a QoS mapping from the UMTS QoS traffic classes to a DiffServ per-hop behavior (PHB) group, you must enable UMTS QoS mapping using the gprs qos map umts global configuration command.

The default mapping values for UMTS QoS traffic classes are as follows:

•Conversational traffic class to the ef-class DiffServ PHB group

•Streaming traffic class to the af2-class DiffServ PHB group

•Interactive traffic class to the af3-class DiffServ PHB group

•Background traffic class to the best-effort DiffServ PHB group

If you wish to use mapping values other than these defaults, you can use the gprs umts-qos map traffic-class command to map a UMTS traffic class to another DiffServ PHB group.

Note To successfully map UMTS QoS traffic classes to a DiffServ PHB, the class maps must be configured using the class map and match ip dscp Cisco IOS software commands. For more information about configuring class maps, refer to the Cisco IOS Quality of Service Solutions Configuration Guide.

To map a UMTS traffic class to a DiffServ PHB group, use the following command in global configuration mode:

Command
Purpose

Router(config)# gprs umts-qos map traffic-class traffic-class diffserv-phb-group

Enables mapping of UMTS QoS traffic classes to a DiffServ PHB, where the UMTS traffic classes are:

•signalling

•conversational

•streaming

•interactive

•background

and the DiffServ PHB groups are:

•signalling-class

•ef-class

•af1-class

•af2-class

•af3-class

•af4-class

•best-effort


Assigning a DSCP to a DiffServ PHB Group

By default, the default differentiated services code point (DSCP) value associated with a PHB class is used. Table 9-2 lists the default DSCP values for each PHB group.

Table 9-2 Default DSCP Values for PHB Groups 

PHB Group
DSCP Value

EF

101110

AF11

001010

AF12

001100

AF13

001110

AF21

010010

AF22

010100

AF23

010110

AF31

011010

AF32

011100

AF33

011110

AF41

100010

AF42

100100

AF43

100110

Best Effort

000000


However, you can assign a DSCP to PHB groups.

For the Assured Forwarding (AF) PHB group, you can specify up to three DSCPs for each drop precedence. The signalling, EF, and best-effort classes do not have drop precedence, so only the first DSCP value is used. If you enter a value for the dscp2 or dscp3 arguments for these classes, it is ignored.

Note Drop precedence indicates the order in which a packet will be dropped when there is congestion on the network.

Note To successfully map UMTS QoS traffic classes to a DiffServ PHB and assign a DSCP value to a DiffServ PHB group, the class maps must be configured using the class map and match ip dscp commands. For more information about configuring class maps, see Cisco IOS Quality of Service Solutions Configuration Guide and Cisco IOS Quality of Service Solutions Command Reference.

Note By default, signalling class is assigned to CS5 (101000), which is the equivalent of IP precedence 5.

To assign a DSCP value to a DiffServ PHB group, use the following command in global configuration mode:

Command
Purpose

Router(config)# gprs umts-qos map diffserv-phb diffserv-phb-group [dscp1] [dscp2] [dscp3]

Assigns a DSCP to a DiffServ PHB group where the DiffServ PHB groups are:

•signalling

•ef-class

•af1-class

•af2-class

•af3-class

•af4-class

•best-effort

and the DSCPs are:

•dscp1—Required for all classes. Specifies one of 64 DSCP values from 0 to 63. This DSCP value corresponds to drop precedence 1.

•dscp2—(Optional for AF classes) Specifies one of 64 DSCP values from 0 to 63. This DSCP value corresponds to drop precedence 2.

•dscp3—(Optional for AF classes) Specifies one of 64 DSCP values from 0 to 63. This DSCP value corresponds to drop precedence 3.


Configuring the DSCP in the Subscriber Datagram

By default, the DSCP in subscriber datagrams is re-marked with the DSCP assigned to the traffic class when the PDP context was created.

To specify that the subscriber datagram be forwarded through the GTP path without modifying its DSCP, use the following command in global configuration mode:

Command
Purpose

Router(config)# gprs umts-qos dscp unmodified [up | down | all]


Specifies that the subscriber datagram be forwarded through the GTP path without modifying its DSCP.


To return to the default value, issue the no gprs umts-qos dscp unmodified command.

Configuring the Cisco 7600 Platform GGSN UMTS QoS Requirements

When configuring UMTS QoS for a GGSN running on a Cisco MWAM in the Cisco 7600 platform, the different components of the platform perform different QoS functions. Table 9-3 summarizes the QoS function performed by the Cisco 7600 platform component.

Table 9-3 QoS Function by Cisco 7600 Platform Component

Cisco 7600 Component
UMTS QoS Function

Catalyst Line Card

Classification and ingress and egress scheduling

Supervisor Engine

Classification and aggregate policing

Cisco IOS GGSN image on the Cisco MWAM

Classification, DSCP marking, and output queuing


Supervisor Engine

Note The following list is a summary of the required tasks that need to be completed on the supervisor engine for UMTS QoS on a GGSN. For complete information each of these tasks, see the Cisco 7600 Series Cisco IOS Software Configuration Guide.

1. Enable Mutlilayer Switching QoS using the mls qos global configuration command. 

Router# mls qos

2. On the supervisor engine, configure aggregate policing for Gi traffic.

Note Because there can be multiple Gn and Gi interfaces, but all the traffic eventually needs to go to a single GE port on the MWAM (one GE port for two GGSNs), we recommend that you use a Named Aggregate Policer to rate limit the traffic to the MWAM. We also recommend dropping all non-conforming traffic.

The following example illustrates the configuration for a named aggregate policer. The named policer is attached to the Gi interface: 

Access-list 101 permit ip any any dscp ef

Access-list 102 permit ip any any dscp af21

Access-list 103 permit ip any any dscp af31

Access-list 103 permit ip any any dscp af32

Access-list 103 permit ip any any dscp af33

Access-list 104 permit ip any any


Class-map match-all conversational

    Match access-group 101

Class-map match-all streaming

    Match access-group 102

Class-map match-all interactive

    Match access-group 103

Class-map match-all background

    Match access-group 104


Mls qos aggregate-policer AGGREGATE-CONV bit-rate1 normal-burst max-burst 
conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-STREAMING bit-rate1 normal-burst max-burst 
conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-INTERACTIVE bit-rate1 normal-burst max-burst 
conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-BACKGROUND bit-rate1 normal-burst max-burst 
conform-action transmit exceed-action drop


Policy-map Gi-incoming

     Class conversational

         Police aggregate AGGREGATE-CONV

     Class streaming

         Police aggregate AGGREGATE-STREAMING

     Class interactive

         Police aggregate AGGREGATE-INTERACTIVE

     Class background

         Police aggregate AGGREGATE-BACKGROUND


Router(config-if)# service-policy input Gi-incoming

Note To monitor policing statistics, you can use the following show commands:
- show mls qos aggregate-policer name
- show policy-map interface interface
- show policy interface interface

3. Set the trust state of the ingress ports to trust-dscp mode using the msl qos trust dscp interface configuration command: 

Router(config)# interface FastEthernet2/1

Router(config-if)# mls qos trust dscp

4. Configure egress port scheduling by completing the following tasks:

a. Obtain the UMTS traffic class-to-DSCP mappings using the show gprs umts-qos traffic class privilege EXEC command on the GGSN instance running on the Cisco MWAM: 

GGSN1# ggsn show gprs umts-qos traffic-class

b. Obtain the default DSCP-to-CoS mapping by displaying the QoS mapping information using the show mls qos maps privilege EXEC command. 

Router# show mls qos maps

c. Obtain the default CoS-to-queue mapping by displaying the queueing statistics of an interface using the show queuing interface privilege EXEC command. 

Router# show queuing interface interface

d. Using the information obtained in Steps A, B, and C, determine if customized egress DSCP-to-CoS mapping is necessary and if so, define the mapping using the mls qos map dscp-cos global configuration command. 

Router(config)# mls qos map dscp-cos dscp to cos

When customizing DSCP-CoS mapping, ensure that:

- Conversational and streaming traffic are put into egress queue 4

- Interactive and background traffic are equally distributed between the two normal queues.

- Interactive traffic is mapped to different CoS values so that different thresholds can be   configured on the queue to take advantage of WRED.

5. If the line card supports Weighted Random Early Detection WRED, configure congestion avoidance by completing the following tasks:

a. Enable WRED and specify the minimum and maximum threshold for specified queues using the wrr-queue random-detect max-threshold interface configuration command (the defaults are recommended). 

Router(config-if)# wrr-queue random-detect max-threshold queue 
percent-of-queue-size

b. Map CoS values to drop thresholds using the wrr-queue cos map interface configuration command. When the threshold is exceeded, frames with specific CoS values will be dropped. 

wrr-queue cos-map queue-id threshold-id cos-1 ... cos-n

In the following example, CoS values 3 and 4 are assigned to transmit queue 1/threshold 2 and transmit 2/threshold 1. 

Router(config-if)# wrr-queue cos-map 1 1 3

Router(config-if)# wrr-queue cos-map 1 2 4

c. Allocate bandwidth between standard transmit queue 1 (low priority) and standard transmit queue 2 (high priority) using the wrr-queue bandwidth interface configuration command. 

Router(config-if)# wrr-queue bandwidth weight1 weight2 weight3

Cisco GGSN

1. Configure an output queueing strategy for the UMTS traffic classes for each GGSN.

Each MWAM processor complex can run two instances of GGSN, but has only one GE interface to the supervisor engine. The GGSNs share that interface. You can configure a queueing strategy for each of the UMTS traffic classes for each GGSN.

The following configuration example assumes that the UMTS traffic classes and class maps have been defined. 

Interface GigabitEthernet0/0

	Bandwidth <max-bandwidth>

       Service-policy output mwam-output


Policy-map mwam-output

	Class conversational

		Priority percent 5

	Class streaming

		Priority percent15

	Class interactive 

		Bandwidth 20

	Class background

		Bandwidth 20

	Class signaling

		Bandwidth 15

Verifying the UMTS QoS Configuration

To verify your UMTS QoS configuration, use the show running-config command on the supervisor engine and the GGSN instance running on the Cisco MWAM and observe the UMTS QoS parameters in the following example:

Supervisor Engine Configuration: 

Mls qos


Mls qos map dscp-cos 18 20 22 to 5

Mls qos map dscp-cos 26 to 4

Mls qos map dscp-cos 28,30 to 3



Access-list 101 permit ip any any dscp ef

Access-list 102 permit ip any any dscp af21

Access-list 103 permit ip any any dscp af31

Access-list 103 permit ip any any dscp af32

Access-list 103 permit ip any any dscp af33

Access-list 104 permit ip any any


Class-map match-all conversational

 	Match access-group 101

Class-map match-all streaming

	Match access-group 102

Class-map match-all interactive

	Match access-group 103

Class-map match-all background

	Match access-group 104



Mls qos aggregate-policer AGGREGATE-CONV <bit rate1> <normal-burst> <max-burst>

Conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-STREAMING <bit rate2> <normal-burst> <max-burst> 
conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-INTERACTIVE <bit rate3> <normal-burst> <max-burst> 
conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-BACKGROUND <bit rate4> <normal-burst> <max-burst> 
conform-action transmit exceed-action drop


Policy-map Gi-incoming

	Class conversational

		Police aggregate AGGREGATE-CONV

	Class streaming

		Police aggregate AGGREGATE-STREAMING

	Class interactive

		Police aggregate AGGREGATE-INTERACTIVE

	Class background

		Police aggregate AGGREGATE-BACKGROUND



Interface FastEthernet2/1

	Description "Gi interface"

	Mls qos trust dscp

	Wrr-queue cos-map 1 1 3

        Wrr-queue cos-map 1 2 4

        Wrr-queue bandwidth 50 40 10

	Service-policy input Gi-incoming


Interface FastEthernet2/2

	Description "Gn interface"

	Mls qos trust dscp

GGSN Configuration 

Gprs qos map umts


Class-map match-all conversational

	Match ip dscp 46

Class-map match-any interactive

	Match ip dscp 26

	Match ip dscp 28

	Match ip dscp 30

Class-map match-any streaming

	Match ip dscp 18

	Match ip dscp 20

	Match ip dscp 22

Class-map match-all signaling

	Match ip dscp 40

Class-map match-any background

	Description default class

	Match ip dscp 0


Policy-map mwam-output

	Class conversational

		Priority percent 5

	Class streaming

		Priority percent 15

	Class interactive

		Bandwidth 20

	Class background

		Bandwidth 20

	Class signaling

		Bandwidth 15


interface Gigabitthernet 0/0

        bandwidth 250000

        service-policy output max-output

Configuring the GGSN Default QoS as Requested QoS

If you are not using UMTS QoS mapping on the GGSN, you can configure the GGSN to set its default QoS values in the response message exactly as requested in the Create PDP Context request. By using this command, you can prevent the GGSN from lowering the requested QoS.

To configure the GGSN to set the requested QoS as the default QoS, use the following command, beginning in global configuration mode:

Command
Purpose 
Router(config)# gprs qos default-response requested

(Optional) Specifies that the GGSN sets its default QoS values in the response message exactly as requested in the Create PDP Context request.


Note When the gprs qos default-response requested command is not configured, and GPRS canonical QoS is not enabled, the GGSN sets its default QoS class to best effort.

Configuring Call Admission Control on the GGSN

The Call Admission Control (CAC) feature on the GGSN ensures that required network resources are available for real-time data traffic such as voice and video. CAC is applied at the APN and consists of two functions: maximum QoS authorization and bandwidth management.

The following sections describe how to configure these functions on the GGSN:

•Configuring Maximum QoS Authorization

•Configuring Bandwidth Management

•Configuration Examples

•CAC Configuration Example

Note CAC on the GGSN requires that UMTS QoS has been enabled using the gprs qos map umts global configuration command and that traffic class criterion and traffic policies have been created.

Configuring Maximum QoS Authorization

The CAC maximum QoS authorization function ensures that the QoS requested by a create PDP context does not exceed the maximum QoS configured within an APN. Using a CAC maximum QoS policy, you define certain QoS parameters within a policy and attach the policy to an APN. The CAC maximum QoS policy limits the QoS requested by the PDP during its creation and modification process.

Note A CAC maximum QoS policy can be attached to multiple APNs.

The following parameters can be defined in a CAC maximum QoS policy:

•Maximum number of active PDP contexts—Maximum number of active PDP contexts for an APN. If the total number of active PDPs on an APN exceeds the number configured with this parameter in a policy, the GGSN rejects the PDP context. Optionally, you can configure CAC to accept only PDP contexts with Allocation/Retention priority set to 1 after the threshold is reached.

•Maximum bit rate—Highest maximum bit rate (MBR) that can be allowed for each traffic class in both the uplink and downlink directions for an APN. If an MBR is configured in the policy, CAC ensures that the MBR is greater than the maximum GBR. If an MBR is not configured, CAC accepts any MBR requested by a PDP context.

•Guaranteed bit rate—Highest guaranteed bit rate (GBR) that can be accepted for real-time traffic (conversational and streaming) in both the uplink and downlink directions for an APN. If a GBR is not configured in the policy, the CAC accepts any GBR requested by a PDP context.

•Highest traffic class—Highest traffic class that can be accepted at an APN. If the requested traffic class is higher than the highest traffic class specified in the policy, the PDP context is rejected. If this parameter is not configured, any traffic class is accepted.

The GGSN does not downgrade the traffic classes during PDP context creation, however, the GGSN does downgrade the traffic class during the PDP context modification if the highest traffic class configured in an APN is changed after the PDP context creation and the GGSN receives a request for a new traffic class (in a PDP context update request) that is greater than the new highest traffic class. If this occurs, the GGSN downgrades the request to the new highest traffic class.

•Maximum traffic handling priority—Specifies the maximum traffic handling priority for interactive traffic class that can be accepted at an APN. If this parameter is not specified, all traffic handling priorities are accepted.

•Maximum delay class—Defines the maximum delay class for R97/R98 QoS that can be accepted at an APN.

•Maximum peak throughput class—Defines the maximum peak throughput class for R97/R98 QoS that can be accepted at an APN.

Configuring a CAC Maximum QoS Policy

To configure a CAC maximum QoS policy, use the following commands, beginning in global configuration mode:

 
Command
Purpose

Step 1 

Router(config)# gprs qos cac-policy policy-name

Creates or modifies a CAC maximum QoS policy.

Step 2 

Router(config-umts-cac-policy)# maximum pdp-context number [threshold number2]

Specifies the maximum number PDP contexts that can be created for a particular APN. Optionally, a second threshold can be configured that after reached, only PDP contexts with allocation/retention priority 1 are accepted.

Step 3 

Router(config-umts-cac-policy)# maximum traffic-class traffic-class-name [priority value]

Specifies the highest traffic class that can be accepted at an APN. Valid values are conversational, streaming, interactive, or background.

Optionally, the highest traffic handling priority for the interactive traffic class can be specified.

Step 4 

Router(config-umts-cac-policy)# maximum peak-throughput value [reject]

Defines the maximum peak throughput for R97/R98 QoS that can be accepted at an APN. Valid values are between 1 and 9.

By default, PDP contexts for which the peak throughput is higher than the configured value are downgraded to the configured value. Optionally, you can specify the reject keyword to have these PDP contexts rejected instead.

Step 5 

Router(config-umts-cac-policy)# maximum delay-class value [reject]

Specifies the maximum delay class for R97/R98 QoS that can be accepted at an APN.

By default, PDP contexts for which the maximum delay-class is higher than the configured value are downgraded to the configured value. Optionally, you can specify the reject keyword to have these PDP contexts rejected instead.

Step 6 

Router(config-umts-cac-policy)# mbr traffic-class traffic-class-name bitrate {uplink | downlink} [reject]

Specifies the maximum bit rate (MBR) that can be allowed for each traffic class in both directions (downlink and uplink). Valid value is between 1 and 16000.

Note Although the valid command range for both the uplink and downlink direction is 1 to 16000, the maximum rate that can be acheived in the uplink direction is 8640. Additionally, a value greater than 8640 in the downlink direction is supported for GTPv1 PDPs only.

Optionally, using the reject keyword option, you can specify for create PDP context requests to be rejected when the MBR exceeds the configured value.

Step 7 

Router(config-umts-cac-policy)# gbr traffic-class traffic-class-name bitrate {uplink | downlink} [reject]

Specifies the highest guaranteed bit rate (GBR) that can be allowed in uplink and downlink directions for real-time classes (conversational and streaming) at an APN. Valid value is between 1 and 16000.

Note Although the valid command range for both the uplink and downlink direction is 1 to 16000, the maximum rate that can be acheived in the uplink direction is 8640. Additionally, a value greater than 8640 in the downlink direction is supported for GTPv1 PDPs only.

Optionally, using the reject keyword option, you can specify for create PDP context requests to be rejected when the GBR exceeds the configured value.

Enabling the CAC Maximum QoS Policy Function and Attaching a Policy to an APN

To enable the CAC maximum QoS policy function and attach a policy to an APN, use the following command in access-point configuration mode:

Command
Purpose 
Router(config-access-point)# cac-policy

Enables the maximum QoS policy function of the CAC feature and applies a policy to an APN.


Configuring Bandwidth Management

The CAC bandwidth management function ensures that there is sufficient bandwidth for real-time PDP contexts during the PDP context activation and modification process.

The CAC feature uses user-defined bandwidth pools to negotiate and reserve bandwidth. In these pools, you define the total bandwidth allocated to that pool and then allocate a percentage of that bandwidth to each traffic class.

In the following example, bandwidth pool (pool A) has been created with 100000 kbps allocated to it. Additionally, a percentage of that 100000 kbps of bandwidth has been allocated to each traffic class, creating four "traffic class-based" bandwidth pools. 

gprs bandwidth-pool A

  bandwidth 100000

  traffic-class conversational percent 40

  traffic-class streaming percent 30

  traffic-class interactive percent 20

  traffic-class background percent 10

Configuring a CAC Bandwidth Pool

Note The CAC bandwidth pool is used by CAC to negotiate and reserve bandwidth. However, to guarantee reserved bandwidth, a Cisco IOS QoS service policy that defines queuing and scheduling must be created and attached to the physical interface.

To configure a CAC bandwidth pool, use the following commands, beginning in global configuration mode:

 
Command
Purpose

Step 1 

Router(config)# gprs qos bandwidth-pool pool-name

Creates or modifies a CAC bandwidth pool.

Step 2 

Router(config-gprs-bw-pool)# bandwidth value

Specifies the total bandwidth, in kilobits per second, for a bandwidth pool. Valid value is a number from 1 to 4294967295.

Step 3 

Router(config-gprs-bw-pool)# traffic-class traffic-class [percent] value


Allocates bandwidth from a bandwidth pool to a specific traffic class in either a percentage (1 to 100% when used with the optional percent keyword), or absolute value in kilobits per second (0 to 4292967295). Note that the same unit (percentage or absolute value) must be used for all traffic classes.

Enabling the CAC Bandwidth Management Function and Applying a Bandwidth Pool to an APN

To enable the CAC bandwidth management function and apply a bandwidth pool to an APN, use the following command in access-point configuration mode:

Command
Purpose 
Router(config-access-point)# bandwidth pool {input | 
output} pool-name

Enables the CAC bandwidth management function and applies a bandwidth pool to the input (Gn) interface in the downlink direction (input keyword) or output (Gi) interface in the uplink direction (output keyword) of an APN.


Note A CAC bandwidth pool can be applied to multiple APNs.

Configuring Per-PDP Policing

Per-PDP policing (session-based policing) is a GGSN Traffic Conditioner (3G TS 23.107) function that can be used to limit the maximum rate of traffic received on the Gi interface for a particular PDP context.

The policing function enforces the CAC-negotiated data rates for a PDP context. The GGSN can be configured to either drop non-conforming traffic or mark non-conforming traffic for preferential dropping if congestion occurs.

The policing parameters used depends on the PDP context. Specifically,

•For GTPv1 PDPs with R99 QoS profiles, the MBR and GBR parameters from the CAC-negotiated QoS profile are used. For non real time traffic, only the MBR parameter is used.

•For GTPv1 PDPs with R98 QoS profiles and GTPv0 PDPs, the peak throughput parameter from the CAC-negotiated QoS policy is used.

Restrictions

Before configuring per-PDP policing, note the following:

•Per-PDP policing is supported for IPv4 PDP contexts only.

•UMTS QoS mapping must be enabled on the GGSN.

•Cisco Express Forwarding (CEF) must be enabled on Gi interface.

•Per-PDP policing is supported for downlink traffic at the Gi interface only.

•The initial packets of a PDP context are not policed.

•Hiearchical policing is not supported.

•If flow-based policing is configured in a policy map that is attached to an APN, the show policy-map apn command displays the total number of packets received before policing and does not display the policing counters.

•A service policy that has been applied to an APN cannot be modified. To modify a service policy, remove the service policy from the APN, modify it, and then re-apply it.

•Multiple class maps, each with match flow pdp configured and a different differentiated services code point (DSCP), are supported in a policy map only if the DSCP is trusted (the gprs umts-qos dscp unmodified global configuration command has not been configured on the GGSN).

Per-PDP Policing Configuration Task List

To configure per-PDP policing on the GGSN, perform the following tasks:

•Creating a Class Map with PDP Flows as the Match Criterion

•Creating a Policy Map and Configuring Traffic Policing

•Attaching the Policy to an APN

•Resetting APN Policing Statistics

Creating a Class Map with PDP Flows as the Match Criterion

To create a class match and specify PDP flows as the match criterion, use the following commands, beginning in global configuration mode:

 
Command
Purpose

Step 1 

Router(config)# class-map class-map-name

Creates a class map to be used for matching packets.

Step 2 

Router(config-cmap)# match flow pdp

Specifies PDP flows as the match criterion in a class map.

Step 3 

Router(config-cmap)# exit


Exits class map configuration mode.

Note Do no specify the match-any option when defining a class for PDP flow classification. The default is match-all.

Note Additional match criteria can also be configured in the class map. DSCP and precedence-based classifications are supported.

Creating a Policy Map and Configuring Traffic Policing

To create a policy map and assign the class map, use the following commands, beginning in global configuration mode:

 
Command
Purpose

Step 1 

Router(config)# policy map policy-map-name

Creates or modifies a policy map that can be attached to one or more APN to specify a service policy.

Step 2 

Router(config-pmap)# class class-map-name

Specifies the name of the class whose policy you want to create or change.

Step 3 

Router(config-pmap)# police rate pdp [burst bytes] [peak-rate pdp [peak-burst bytes]] conform-action action exceed-action action [violate-action action]



Configures traffic policing and the action to take on non-conforming packets.

The rate and peak-rate parameters are obtained from individual flows.

Note When configuring the police command, burst sizes may be specified but are not recommended. Incorrect configuration of burst values results in incorrect behavior.

Possible values for the action variable are:

•drop—Drops the packet.

•set-dscp-transmit—Sets the IP differentiated services code point (DSCP) value and transmits the packet with the new IP DSCP value setting.

•set-prec-transmit—Sets the IP precedence and transmits the packet with the new IP precedence value setting.

•transmit—Transmits the packet. The packet is not altered.

Step 4 

Router(config-pmap)# exit

Exits policy map configuration mode.

Attaching the Policy to an APN

To attach the policy map to an APN, use the following commands, beginning in access-point configuration mode:

 
Command
Purpose

Step 1 

Router(config-)# access-point index

Specifies an access point number and enters access-point configuration mode.

Step 2 

Router(config-access-point)# service-policy input policy-map-name


Attaches a service policy to an APN, to be used as the service policy in the downlink direction for PDP flows of that APN.

Step 3 

Router(config-access-point)# exit

Exits access-point configuration mode.

Resetting APN Policing Statistics

To reset policing counters displayed by the show policy-map apn command, use the following command in global configuration mode

Command
Purpose 
Router(config)# clear gprs access-point 
statistics access-point-index

Clears statistics counters for a specific access point.


Monitoring and Maintaining QoS on the GGSN

This section describes the commands used to display QoS configuration parameters and status on the GGSN. It contains the following information:

•show Command Summary

•Monitoring UMTS QoS

show Command Summary

This section provides a summary list of the show commands that you can use to monitor GPRS and UMTS QoS on the GGSN. Not all commands provide information for all types of QoS methods on the GGSN.

The following privileged EXEC commands are used to monitor and maintain QoS on the GGSN:

Command
Purpose 
Router# show gprs bandwidth-pool status pool-name

Displays a list of configured CAC bandwidth pools, along with their status. 

Router# show gprs gtp pdp-context imsi hex-data

Displays PDP contexts by international mobile subscriber identity (IMSI). 

Router# show gprs gtp pdp-context tid hex-data

Displays PDP contexts by tunnel ID. 

Router# show gprs gtp pdp-context qos-umts-class 
{conversational | streaming | interactive | 
background}

Displays PDP context by UMTS QoS traffic class. Applies to UMTS QoS only. 

Router# show gprs qos status

Displays QoS statistics for the GGSN. 

Router# show gprs umts-qos map traffic-class

Displays UMTS QoS mapping information. 

Router# show gprs umts-qos police pdp tid tid

Displays policing statistics for a PDP context. 

Router# show gprs umts-qos profile pdp tid tid

Displays requested and negotiated QoS information for a PDP context.


Monitoring UMTS QoS

This section describes the commands used to display UMTS QoS configuration parameters and status on the GGSN.

It includes the following topics:

•Displaying UMTS QoS Status on the GGSN

•Displaying UMTS QoS Information for a PDP Context

Displaying UMTS QoS Status on the GGSN

You can use the show gprs qos status command to display the number of current active PDP contexts by UMTS traffic class.

The following example shows 100 active PDP contexts on the GGSN that are using the UMTS QoS conversational traffic class, 140 active PDP contexts that have a streaming UMTS QoS traffic class, 1345 active PDP contexts that have an interactive UMTS traffic class, and 2000 active PDP contexts that have a background UMTS QoS traffic class.

The following example shows output from the show gprs qos status command for UMTS QoS: 

Router# show gprs qos status

GPRS QoS Status:

  type:UMTS

  conversational_pdp      100   streaming_pdp     150

  interactive_pdp         1345  background_pdp    2000

Displaying UMTS QoS Information for a PDP Context

To display UMTS QoS information for a particular PDP context, you can use the show gprs gtp pdp-context command with the tid or imsi keyword. The following example shows sample output for the show gprs gtp pdp-context tid command for a PDP context in the XX UMTS QoS traffic class. The output fields displaying QoS information are shown in bold: 

Router# show gprs gtp pdp-context tid 111111111111111

TID              MS Addr         Source  SGSN Addr       APN

1111111111111111 10.0.0.1        Static  10.39.39.1      www.corporate.com


current time :Nov 12 2002 08:10:23

    user_name (IMSI):213000000000000    MS address:2.0.0.1

    MS International PSTN/ISDN Number (MSISDN):987

    sgsn_addr_signal:15.15.0.2          sgsn_addr_data:  15.15.0.3

    control teid local: 0x6309ABF4

    control teid remote:0x00000021

    data teid local:    0x6308AA38

    data teid remote:   0x00000022

    primary pdp:Y           nsapi:1

    signal_sequence: 1                  seq_tpdu_up:     0

    seq_tpdu_down:   0

    upstream_signal_flow:  0            upstream_data_flow:  0

    downstream_signal_flow:0            downstream_data_flow:0

    RAupdate_flow:         0

    pdp_create_time:  Nov 12 2002 08:10:09

    last_access_time: Nov 12 2002 08:10:09

    mnrgflag:         0                tos mask map:68

    gtp pdp idle time:72

    umts qos_req:0911016901010111050101

    umts qos_neg:0911016901010111050101

    QoS class:interactive

    QoS for charging:       qos_req:000000      qos_neg:000000

    rcv_pkt_count:    0             rcv_byte_count:  0

    send_pkt_count:   0             send_byte_count: 0

    cef_up_pkt:       0             cef_up_byte:     0

    cef_down_pkt:     0             cef_down_byte:   0

    cef_drop:         0

    charging_id:        223415403

    pdp reference count:2

    primary dns:        0.0.0.0

    secondary dns:      0.0.0.0

    primary nbns:       0.0.0.0

    secondary nbns:     0.0.0.0

    ntwk_init_pdp:      0

Configuration Examples

This section includes the following examples:

•UMTS QoS Configuration Examples

•CAC Configuration Example

•Per-PDP Policing Configuration Example

UMTS QoS Configuration Examples

Supervisor Engine Configuration: 

Mls qos


Mls qos map dscp-cos 18 20 22 to 5

Mls qos map dscp-cos 26 to 4

Mls qos map dscp-cos 28,30 to 3



Access-list 101 permit ip any any dscp ef

Access-list 102 permit ip any any dscp af21

Access-list 103 permit ip any any dscp af31

Access-list 103 permit ip any any dscp af32

Access-list 103 permit ip any any dscp af33

Access-list 104 permit ip any any


Class-map match-all conversational

 	Match access-group 101

Class-map match-all streaming

	Match access-group 102

Class-map match-all interactive

	Match access-group 103

Class-map match-all background

	Match access-group 104



Mls qos aggregate-policer AGGREGATE-CONV <bit rate1> <normal-burst> <max-burst>

Conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-STREAMING <bit rate2> <normal-burst> <max-burst> 
conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-INTERACTIVE <bit rate3> <normal-burst> <max-burst> 
conform-action transmit exceed-action drop

Mls qos aggregate-policer AGGREGATE-BACKGROUND <bit rate4> <normal-burst> <max-burst> 
conform-action transmit exceed-action drop


Policy-map Gi-incoming

	Class conversational

		Police aggregate AGGREGATE-CONV

	Class streaming

		Police aggregate AGGREGATE-STREAMING

	Class interactive

		Police aggregate AGGREGATE-INTERACTIVE

	Class background

		Police aggregate AGGREGATE-BACKGROUND



Interface FastEthernet2/1

	Description "Gi interface"

	Mls qos trust dscp

	Wrr-queue cos-map 1 1 3

        Wrr-queue cos-map 1 2 4

        Wrr-queue bandwidth 50 40 10

	Service-policy input Gi-incoming


Interface FastEthernet2/2

	Description "Gn interface"

	Mls qos trust dscp

GGSN Configuration 

Gprs qos map umts


Class-map match-all conversational

	Match ip dscp 46

Class-map match-any interactive

	Match ip dscp 26

	Match ip dscp 28

	Match ip dscp 30

Class-map match-any streaming

	Match ip dscp 18

	Match ip dscp 20

	Match ip dscp 22

Class-map match-all signaling

	Match ip dscp 40

Class-map match-any background

	Description default class

	Match ip dscp 0


Policy-map mwam-output

	Class conversational

		Priority percent 5

	Class streaming

		Priority percent 15

	Class interactive

		Bandwidth 20

	Class background

		Bandwidth 20

	Class signaling

		Bandwidth 15


interface Gigabitthernet 0/0

        bandwidth 250000

        service-policy output max-output

CAC Configuration Example

The following is a configuration example of CAC and QoS implemented on a GGSN running on the Cicso MWAM in a Cisco 7600 series router. 

!Enable UMTS QoS Mapping


gprs qos map umts


!Create CAC Maximum QoS authorization policy

gprs qos cac-policy abc_qos_policy1

  maximum pdp-context 1200 threshold 1000

  maximum traffic-class conversational

  mbr traffic-class conversational 100 uplink

  mbr traffic-class conversational 100 downlink

  mbr traffic-class streaming 100 uplink

  mbr traffic-class streaming 100 downlink

  mbr traffic-class interactive 120 uplink

  mbr traffic-class interactive 120 downlink

  mbr traffic-class background 120 uplink

  mbr traffic-class background 120 downlink

  gbr traffic-class conversational 64 uplink

  gbr traffic-class conversational 80 uplink

  gbr traffic-class streaming 80 downlink

  gbr traffic-class streaming 80 downlink


gprs qos cac-policy max_qos_policy2

  maximum pdp-context 1500

  maximum traffic-class interactive priority 1

  mbr traffic-class interactive 200

  mbr traffic-class background 150


! Create class-map to classify UMTS traffic class


class-map match-any conversational

  match ip dscp ef


class-map match-any streaming

  match ip dscp af21

  match ip dscp af22

  match ip dscp af23


class-map match-any interactive

  match ip dscp af31

  match ip dscp af32

  match ip dscp af33


class-map match-any background

  match ip dscp default


!Create traffic policy


policy-map ggsn1_traffic_policy

  class conversational

  priority percent 25


class streaming

  bandwidth percent 20


class interactive

  bandwidth percent 20

  random-detect dscp-based


 class background

  bandwidth percent 10

  random-detect dscp-based


! Create bandwidth pool


gprs qos bandwidth-pool ggsn1_bw_pool

  bandwidth 500000


  traffic-class streaming percent 20

  traffic-class interactive percent 20

  traffic-class background percent 10


! Set interface bandwidth


int gigabitEthernet 0/0

  bandwidth  500000

  service-policy output ggsn1_traffic_policy


!Attach bandwidth pool to the APN


gprs access-point-list gprs

 access-point 1

  access-point-name abc.com

  cac-policy abc_qos_policy1

  bandwidth-pool output ggsn1_bw_pool

  bandwidth-pool input ggsn1_bw_pool


 access-point 2

  access-point-name xyz.com

  cac-policy xyz_qos_policy1

  bandwidth-pool output ggsn1_bw_pool

  bandwidth-pool input ggsn1_bw_pool

Per-PDP Policing Configuration Example

The following is a configuration example of per-pdp policing. 

! Create a class for PDP flows

class-map class-pdp

  Match flow pdp


! Create a policy map and assign a class to the map

policy-map policy-gprs

  class class-pdp


! Configure traffic policing

  police rate pdp conform-action action exceed-action action violate-action action


! Attach a service policy to an APN

gprs access-point-list gprs

 access-point 1

  service-policy in policy-gprs