Cisco IOS Mobile Wireless Gateway GPRS Support Node Command Reference

gprs gtp echo-timer dynamic enable

To enable the dynamic echo timer on the gateway GPRS support node (GGSN), use the gprs gtp echo-timer dynamic enable command in global configuration mode. To disable the dynamic echo timer, use the no form of this command.

gprs gtp echo-timer dynamic enable

no gprs gtp echo-timer dynamic enable

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Global configuration

Command History

Usage Guidelines

For a GPRS tunneling protocol (GTP) path to be active, the serving GPRS support node (SGSN) needs to be active. To determine that an SGSN is active, the GGSN and SGSN exchange echo messages. Although the GGSN supports different methods of echo message timing, the basic echo flow begins when the GGSN sends an echo request message to the SGSN. The SGSN sends a corresponding echo response message back to the GGSN.

If the GGSN does not receive a response after a certain number of retries (a configurable value), the GGSN assumes that the SGSN is not active. This indicates a GTP path failure, and the GGSN clears all packet data protocol (PDP) context requests associated with that path.

The GGSN supports two different methods of echo timing—the default echo timer and the dynamic echo timer.

Because the GGSN's default echo timer cannot be configured to accommodate network congestion, the GTP path could be cleared prematurely. The dynamic echo timer feature enables the GGSN to better manage the GTP path during periods of network congestion. Use the gprs gtp echo-timer dynamic enable command to enable the GGSN to perform dynamic echo timing.

Default echo timer

The dynamic echo timer is based on the default echo timer in the GGSN. A description of the default echo timer follows as a means of comparison.

The default echo timer configuration uses the following commands:

•gprs gtp n3-requests—Specifies maximum number of times that the GGSN attempts to send a echo-request message. The default is 5 times.

•gprs gtp path-echo-interval—Specifies the number of seconds that the GGSN waits before sending an echo-request message. The default is 60 seconds.

•gprs gtp t3-response—Specifies the number of seconds that the GGSN waits before resending an echo-request message after the path echo interval has expired and the echo response has not been received. The default is 1 second.

If the GGSN receives the echo response within the path echo interval (as specified in the gprs gtp path-echo-interval command; default is 60 seconds), it sends another echo request message after 60 seconds (or whatever time was configured in the gprs gtp path-echo-interval command). This message flow continues as long as the GGSN receives an echo response message within the specified path echo interval.

If the GGSN fails to receive an echo response message within the path echo interval, it resends echo request messages until the N3-requests counter is reached (as specified by the gprs gtp n3-requests command; default is 5). Because the initial request message is included in the N3-requests counter, the total number of retries is N3-1. The T3 timer increases by a factor of 2 for each retry (the factor value is not configurable).

For example, if N3 is set to the default of 5, and T3 is set to the default of 1 second, the GGSN will resend 4 echo request messages (the initial request + 4 retries = 5). The T3 time increments for each additional echo request by a factor of 2 seconds. So, the GGSN resends a message in 2 seconds, 4 seconds, 8 seconds, and 16 seconds. If the GGSN fails to receive an echo response message within the time period of the N3-requests counter, it clears the GTP path and deletes all the PDP contexts.

For the above example, the total elapsed time from when the first request message is sent, to when the GTP path is cleared, is: 60 + 2 + 4 + 8 + 16 = 90 seconds,

where 60 is the initial value of the path echo interval, and the remaining four time periods are the increments of the T3 timer for the subsequent retries.

Dynamic echo timer

The dynamic echo timer method is different from the default echo timer method on the GGSN because it uses a calculated round-trip time (RTT), as well as a configurable factor or multiplier to be applied to the RTT statistic.

The dynamic echo timer configuration uses the following commands:

•gprs gtp echo-timer dynamic enable—Enables the dynamic echo timer on the GGSN.

•gprs gtp echo-timer dynamic minimum—Specifies the minimum time period (in seconds) for the dynamic echo timer. If the RTT is less than this value, the GGSN uses the value set in this command.

•gprs gtp echo-timer dynamic smooth-factor—Configures the multiplier that the dynamic echo timer uses when calculating the time to wait to send retries, when it has not received a response from the SGSN within the path echo interval.

•gprs gtp n3-requests—Specifies the maximum number of times that the GGSN attempts to send an echo-request message. The default is 5 times.

•gprs gtp path-echo-interval—Specifies the number of seconds within which the GGSN expects to receive an echo response. This is the period of time that the GGSN waits before sending another echo-request message. The default is 60 seconds.

The GGSN calculates the RTT statistic for use by the dynamic echo timer feature. The RTT is the amount of time between sending a particular echo request message and receiving the corresponding echo response message. RTT is calculated for the first echo response received; the GGSN records this statistic. Because the RTT value might be a very small number, there is a minimum time for the dynamic echo timer to use. This value is configured using the gprs gtp echo-timer dynamic minimum command.

If the GGSN fails to receive an echo response message within the path echo interval, the GGSN goes into retransmission, or path failure mode. During path failure mode, the GGSN uses a value referred to as the T-dynamic. The T-dynamic is the greater of either the dynamic minimum, or the RTT statistic multiplied by the smooth factor.

The T-dynamic essentially replaces the use of the gprs gtp t3-response command, which is used in the default echo timer method on the GGSN. The T-dynamic timer increases by a factor of 2 for each retry (again, this factor is not configurable), until the N3-requests counter is reached (the N3-requests counter includes the initial request message).

For example, if the RTT is 6 seconds, N3 is set to 5, and the smooth factor is set to 3, the GGSN will resend 4 echo request messages in path failure mode. The T-dynamic value is 18 (RTT x smooth factor), so the GGSN sends a retry echo request message in 36 seconds, 72 seconds, 144 seconds, and 288 seconds. If the GGSN fails to receive an echo response message in this time period, it clears the GTP path and deletes all PDP contexts. The total elapsed time from when the first request message is sent to when the GTP path is cleared is: 60 + 36 + 72 + 144 + 288 = 600 seconds,

where 60 is the initial value of the path echo interval, and the remaining 4 time periods are the increments of the T-dynamic for the subsequent retries.

Examples

The following example turns on the dynamic echo timer, sets the minimum value to 5 seconds, and configures a smooth factor of 3:

gprs gtp echo-timer dynamic enable

gprs gtp echo-timer dynamic minimum 5

gprs gtp echo-timer dynamic smooth-factor 3

Related Commands

gprs gtp echo-timer dynamic minimum

To specify the minimum time period used by the dynamic echo timer, use the gprs gtp echo-timer dynamic minimum command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp echo-timer dynamic minimum number

no gprs gtp echo-timer dynamic minimum number

Syntax Description

Defaults

5 seconds

Command Modes

Global configuration

Command History

Usage Guidelines

Use this command to specify the minimum time period (in seconds) used by the dynamic echo timer, also referred to as the T-dynamic. If the gateway GPRS support node's (GGSN's) current calculation of the round-trip time (RTT) statistic, multiplied by the smooth factor, is less than the configured dynamic minimum value, then the GGSN uses the configured minimum as the T-dynamic.

The GGSN calculates the RTT statistic for use by the dynamic echo timer feature. The RTT is the amount of time between sending a particular echo request message and receiving the corresponding echo response message. RTT is calculated for the first echo response received; the GGSN records this statistic. Because the RTT value might be a very small number, there is a minimum time for the dynamic echo timer to use. This value is configured using the gprs gtp echo-timer dynamic minimum command.

If the GGSN fails to receive an echo response message from the serving GPRS support node (SGSN) within the path echo interval, the GGSN goes into retransmission, or path failure mode. During path failure mode, the GGSN uses a value referred to as the T-dynamic. The T-dynamic is the greater of either the dynamic minimum, or the RTT statistic multiplied by the smooth factor.

The T-dynamic essentially replaces the use of the gprs gtp t3-response command, which is used in the default echo timer method on the GGSN. The T-dynamic timer increases by a factor of 2 for each retry (again, this factor is not configurable), until the N3-requests counter is reached (the N3-requests counter includes the initial request message).

Note For more information about the dynamic echo timer on the GGSN, see the "Usage Guidelines" section for the gprs gtp echo-timer dynamic enable command.

Examples

The following example turns on the dynamic echo timer, sets the minimum value to 6 seconds, and configures a smooth factor of 2:

gprs gtp echo-timer dynamic enable

gprs gtp echo-timer dynamic minimum 6

gprs gtp echo-timer dynamic smooth-factor 2

Related Commands

gprs gtp echo-timer dynamic smooth-factor

To configure the multiplier that the gateway GPRS support node (GGSN) uses to calculate the time to wait to send retries of the dynamic echo timer, use the gprs gtp echo-timer dynamic smooth-factor command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp echo-timer dynamic smooth-factor number

no gprs gtp echo-timer dynamic smooth-factor number

Syntax Description

Defaults

2

Command Modes

Global configuration

Command History

Usage Guidelines

The dynamic echo timer uses the smooth factor to calculate what is known as the T-dynamic. The T-dynamic is calculated by multiplying the RTT (or the value configured in the gprs gtp echo-timer dynamic minimum, whichever is greater) times the smooth-factor.

Note See the "Usage Guidelines" section for the gprs gtp echo-timer dynamic enable command for a detailed explanation of how the dynamic echo timer works.

Examples

The following example turns on the dynamic echo timer, sets the minimum value to 1 second, and configures a smooth factor of 2:

gprs gtp echo-timer dynamic enable

gprs gtp echo-timer dynamic minimum 1

gprs gtp echo-timer dynamic smooth-factor 2

Related Commands

gprs gtp error-indication-throttle

To specify the maximum number of error indication messages that the gateway GPRS support node (GGSN) sends out in one second, use the gprs gtp error-indication-throttle command in global configuration mode. To return to the default value, issue the no form of this command.

gprs gtp error-indication-throttle window-size size

no gprs gtp error-indication-throttle

Syntax Description

Defaults

Error indication throttling is disabled.

Command Modes

Global configuration

Command History

Usage Guidelines

GPRS tunneling protocol (GTP) error indication messages are sent by the GGSN to the serving GPRS support node (SGSN) when the SGSN sends data for packet data protocol (PDP) context the GGSN cannot locate. The error indication message informs the SGSN that the PDP context cannot be located so that the SGSN can clean up the PDP context on its end.

Use the gprs gtp error-indication-throttle command to specify the maximum number of error indication messages that are sent by the GGSN in one second. This provides a way to implement flow control for transmission of GTP error messages. This command sets the initial value of a counter which is decremented each time an error indication message is sent. When the counter reaches zero, the GGSN stops transmitting error indication messages. The GGSN resets this counter to the configured throttle value after one second.

If you do not issue the command, error indication throttling is not enabled. To restore the default value (error indication throttling is disabled) use the no form of this command.

Examples

The following example shows a throttle value of 150:

gprs gtp error-indication-throttle window-size 150

gprs gtp ip udp ignore checksum

To configure the GGSN to ignore user datagram protocol (UDP) checksums (in order to support CEF switching on the GGSN), use the gprs gtp ip udp ignore checksum global configuration command. To disable the ignoring of UDP checksums on the GGSN, use the no form of this command.

gprs gtp ip udp ignore checksum

no gprs gtp ip udp ignore checksum

Syntax Description

This command has no arguments or keywords.

Defaults

In releases prior to Cisco IOS Release 12.3(14)XU, UDP checksums are verified by default.

With Cisco IOS Release 12.3(14)XU and later, UDP checksums are ignored by default.

Command Modes

Global configuration

Command History

Usage Guidelines

UDP checksum verification can prohibit operation of CEF switching processing on the GGSN if the checksum should have a non-zero result. Therefore, if you want to enable CEF switching on the GGSN, ensure that the GGSN is configured to ignore UPD checksums (the default).

If UDP checksum verification remains enabled on the GGSN and a non-zero result occurs, the GTP T-PDUs will be process switched, even if you have configured the GGSN for CEF switching.

The gprs gtp ip udp ignore checksum command does not apply if you are only using process switching on the GGSN.

Note When downgrading to an image prior to Cisco IOS Release 12.3(14)YU when using the default for the gprs gtp ip udp ignore checksum command (UDP checksums are ignored), you will need to manually configure the GGSN to ignore UPD checksums. In releases prior to Cisco IOS Release 12.3(14)YU, UDP checksums are verified by the GGSN by default.

For more information about switching processes, refer to the Cisco IOS Switching Services Configuration Guide.

Examples

The following example disables UDP checksum verification on the GGSN:

gprs gtp ip udp ignore checksum

Related Commands

gprs gtp map signalling tos

To specify an IP type of service (ToS) mapping for GPRS tunneling protocol (GTP) signaling packets, use the gprs gtp map signalling tos command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp map signalling tos tos-value

no gprs gtp map signalling tos tos-value

Syntax Description

Defaults

ToS value 5

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs gtp map signalling tos command to specify the IP ToS mapping for GTP signaling packets transmitted by the gateway GPRS support node (GGSN). The higher the value, the higher the class of service provided to the packets.

Examples

The following example specifies a IP ToS mapping value of 3:

gprs gtp map signalling tos 3

Related Commands

gprs gtp n3-buffer-size

To specify the size of the receive buffer that the gateway GPRS support node (GGSN) uses to receive GPRS tunneling protocol (GTP) signaling messages and packets sent through the tunneling protocol, use the gprs gtp n3-buffer-size command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp n3-buffer-size bytes

no gprs gtp n3-buffer-size

Syntax Description

Defaults

8192 bytes

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs gtp n3-buffer-size command to specify the size of the GTP N3 buffer on the GGSN. The N3 buffer is a receive buffer that the GGSN uses to receive GTP signaling messages and packets sent through the tunneling protocol. The recommended value for the N3 buffer size is 8192 bytes (the default size).

Examples

The following example specifies a buffer size of 2084 bytes:

gprs gtp n3-buffer-size 2048

gprs gtp n3-requests

To specify the maximum number of times that the gateway GPRS support node (GGSN) attempts to send a signaling request to a serving GPRS support node (SGSN), use the gprs gtp n3-requests command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp n3-requests requests

no gprs gtp n3-requests requests

Syntax Description

Defaults

5 requests

Command Modes

Global configuration

Command History

Usage Guidelines

The value of the gprs gtp n3-requests command is used for all signaling requests on the GGSN.

The GGSN supports two different methods of echo timing—the default echo timer and the dynamic echo timer. The gprs gtp n3-requests command is used by the GGSN to perform either type of echo processing.

Examples

The following example shows the GGSN attempting to send a signaling request 3 times:

gprs gtp n3-requests 3

Related Commands

gprs gtp path-echo-interval

To specify the number of seconds that the gateway GPRS support node (GGSN) waits before sending an echo-request message to the serving GPRS support node (SGSN) or charging gateway, use the gprs gtp path-echo-interval command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp path-echo-interval interval

no gprs gtp path-echo-interval interval

Syntax Description

Defaults

60 seconds

Command Modes

Global configuration

Command History

Usage Guidelines

The GGSN supports two different methods of echo timing—the default echo timer and the dynamic echo timer. The gprs gtp path-echo-interval command is used on the GGSN to perform either type of echo processing.

Use the gprs gtp path-echo-interval command to specify the interval that the GGSN waits before sending an echo-request message to the SGSN or charging gateway to check for GPRS tunneling protocol (GTP) path failure.

Note A value of 0 seconds disables echo requests on the GGSN.

Examples

The following example shows the GGSN waiting 90 seconds before sending an echo-request message:

gprs gtp path echo-interval 90

Related Commands

gprs gtp path history

To configure the maximum number of path entries for which the gateway GRPS serving node (GGSN) stores statistics after the path is deleted, use the gprs gtp path history command in global configuration mode.

gprs gtp path history number

no gprs gtp path history

Syntax Description

Defaults

100 entries.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs gtp path history command to configure the number of path entries for which the GGSN stores statistics after the path is deleted.

If the maximum number of entries is changed to a lower value, the older entries are deleted.

Examples

The following example configures the GGSN to store statistics for up to 250 entries:

gprs gtp path history 250

Related Commands

gprs gtp path sgsn

To suppress echo requests per SGSN and/or UDP port, use the gprs gtp path sgsn command in global configuration mode. To remove this configuration, use the no form of this command.

gprs gtp path sgsn start-ip-address [end-ip-address] [UDP port] echo 0

no gprs gtp path sgsn start-ip-address [end-ip-address] [UDP port] echo 0

Syntax Description

Command Default

There are no default behaviors or values.

Command Modes

Global configuration

Command History

Usage Guidelines

Echo requests can be disabled per SGSN and/or UDP port. This feature enables operators to selectively disable charging for GSNs that might not have the capability to respond to echo requests from the GGSN entirely, or only those echo requests received on certain UDP ports, while keeping the echo requests intact for the other SGSNs.

When a new path is created, the GGSN checks to see if the path parameters, namely the destination address and port, matches any of the conditions configured when suppressing echo requests. If the parameters match, the GGSN sets the path echo interval to 0 for that path. Otherwise, the global path echo interval configuration is used to send echo requests.

Examples

The following example disables echo requests for one SGSN:

Router(config)# gprs gtp path sgsn 10.10.10.10 echo 0

The following example disables echo request for one SGSN for port 4000 only:

Router(config)# gprs gtp path sgsn 10.10.10.10 4000 echo 0

gprs gtp pdp-context timeout idle

To specify the time, in seconds, that a gateway GPRS support node (GGSN) allows a session to remain idle at any access point before purging the packet data protocol (PDP) context, use the gprs gtp pdp-context timeout idle command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp pdp-context timeout idle seconds [uplink]

no gprs gtp pdp-context timeout idle

Syntax Description

Defaults

259200 seconds (72 hours)

Command Modes

Global configuration

Command History

Usage Guidelines

The GGSN supports the RADIUS Idle-Timeout (Attribute 28) field. The GGSN stores the attribute 28 value if it is present in the access request packets sent by the authentication, authorization, and accounting (AAA) server. When a PDP context is idle for an amount of time that exceeds the session idle timeout duration, the GGSN terminates it.

The duration specified for the session idle timer applies to all PDP contexts of a session, however, a session idle timer is started for each PDP context. Therefore, the session idle timer is per-PDP, but the timer duration is per-session.

On the GGSN, the session idle timer can be configured globally and at the access point name (APN). The value configured at the APN level using the gtp pdp-context timeout idle access-point configuration command overrides the value configured globally using the gprs gtp pdp-context timeout idle global configuration command. The value configured in the user profile on the RADIUS server overrides the value configured at the APN.

Note The session idle timer started for a PDP context is reset by Transport Protocol Data Unit (TPDU) traffic and GPRS tunneling protocol (GTP) signaling messages for that PDP context. For example, if an Update PDP Context request is received, the session idle timer is reset for that PDP context.

You can disable the session idle timer for a particular user by configuring 0 as the session idle time duration in the user profile on the RADIUS server. If a user is authenticated by RADIUS, the session idle time cannot be disabled.

Note The session idle timeout (RADIUS Attribute 28) support applies to IP PDPs, PPP PDPs terminated at the GGSN, and PPP regenerated PDPs (not PPP L2TP PDPs). The absolute session timeout (Attribute 27) support applies to IP PDPs and PPP PDPs terminated at the GGSN (not PPP Regen or PPP L2TP PDPs). If configured, a session idle timer is started on every PDP context; an absolute session timer is started on the session.

Note Alternately, you can configure the idle timer globally using the gprs idle-pdp-context purge-timer hours global configuration command, however, the two methods cannot be configured at the same time.

Examples

The following example shows configuring the GGSN to wait 18000 seconds before ending an idle PDP context:

gprs gtp pdp-context timeout idle 18000

Related Commands

gprs gtp pdp-context timeout session

To specify the time, in seconds, that the gateway GPRS support node (GGSN) allows a session to exist at any access point before terminating the session, use the gprs gtp pdp-context timeout session command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp pdp-context timeout session seconds

no gprs gtp pdp-context timeout session

Syntax Description

Defaults

Disabled

Command Modes

Global configuration

Command History

Usage Guidelines

When enabled using the gprs radius attribute session-timeout command, the GGSN supports the RADIUS Session-Timeout (Attribute 27). The GGSN stores the attribute timeout value received in access-accept packets sent by the authentication, authorization, and accounting (AAA) server and when the duration of a session exceeds the duration configured as absolute session timer, the GGSN terminates the session and all packet data protocol (PDP) contexts belonging to the session (those with the same International Mobile Subscriber Identity [IMSI] or mobile station [MS] address).

Note The session idle timeout (RADIUS Attribute 28) support applies to IP PDPs, PPP PDPs terminated at the GGSN, and PPP regenerated PDPs (not PPP L2TP PDPs). The absolute session timeout (Attribute 27) support applies to IP PDPs and PPP PDPs terminated at the GGSN (not PPP Regen or PPP L2TP PDPs). If configured, a session idle timer is started on every PDP context; an absolute session timer is started on the session.

Note The active session timeout feature requires that the gprs radius attribute session-timeout command has been enabled.

On the GGSN, the absolute session timer can be configured globally and at the access point name (APN). The value configured at the APN level using the gtp pdp-context timeout session access-point configuration command overrides the value configured globally using the gprs gtp pdp-context timeout session global configuration command. The value configured in the user profile on the RADIUS server overrides the value configured at the APN.

Examples

The following example shows configuring the GGSN to end any session that exceeds 86400 seconds in duration:

gprs gtp pdp-context timeout session 86400

Related Commands

gprs gtp ppp vtemplate

To associate the virtual template interface that defines the PPP characteristics with support for the PPP packet data protocol (PDP) type over GPRS tunneling protocol (GTP) on the gateway GPRS support node (GGSN), use the gprs gtp ppp vtemplate command in global configuration mode. To remove specification of the PPP virtual template interface for GTP on the GGSN, use the no form of this command.

gprs gtp ppp vtemplate number

no gprs gtp ppp vtemplate

Syntax Description

Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Usage Guidelines

Before you configure the gprs gtp ppp vtemplate command, you must configure the virtual template interface with the necessary PPP characteristics. The number that you configure for the virtual template interface that defines the PPP characteristics, must correspond to the number that you specify in the gprs gtp ppp vtemplate command.

Examples

The following example configures two virtual template interfaces on the GGSN, one for GTP encapsulation and one for PPP, and specifies the PPP virtual template interface for GTP on the GGSN.

Note The virtual template interface for PPP is a different virtual template interface than the GPRS/UMTS virtual template interface for GTP encapsulation.

The first section of commands configures the GPRS virtual template interface for GTP:

interface Virtual-Template 1

 ip unnumber loopback 1

 no ip directed-broadcast

 encapsulation gtp

 no ip route-cache

 gprs access-point-list gprs

The following example configures a virtual template interface for PPP and associates the virtual template for support of the PPP PDP type over GTP on the GGSN:

interface Virtual-Template 2

 ip unnumbered FastEthernet 1/0

 no ip directed-broadcast

 no peer default ip address

 ppp authentication chap

 ppp timeout retry 30

gprs gtp ppp vtemplate 2

Related Commands

gprs gtp ppp-regeneration vtemplate

To associate the virtual template interface that is configured for PPP encapsulation with support for regenerated PPP sessions on the GGSN, use the gprs gtp ppp-regeneration vtemplate global configuration command. To remove specification of the PPP virtual template interface for regenerated PPP sessions on the GGSN, use the no form of this command.

gprs gtp ppp-regeneration vtemplate number

no gprs gtp ppp-regeneration vtemplate

Syntax Description

Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Usage Guidelines

Before you configure the gprs gtp ppp-regeneration vtemplate command, you must configure the virtual template interface for PPP encapsulation using the encapsulation ppp command. In addition, you must also configure the ip address negotiated command and the no peer neighbor-route command at the virtual template interface for PPP encapsulation.

The number that you configure for the virtual template interface to support PPP encapsulation, must correspond to the number that you specify in the gprs gtp ppp-regeneration vtemplate command.

Examples

The following example configures two virtual template interfaces on the GGSN, one for GTP encapsulation for communication between the GGSN and the SGSN, and one for PPP regeneration. The virtual template interface for PPP regeneration supports the creation of PPP sessions from the GGSN over Layer 2 Tunneling Protocol (L2TP) tunnels to an L2TP network server (LNS).

Note The virtual template interface for PPP regeneration is a different virtual template interface than the GPRS virtual template interface for PPP PDP type support and for GTP encapsulation.

The first section of commands configures the GPRS virtual template interface for GTP:

interface Virtual-Template 1

 ip unnumber loopback 1

 no ip directed-broadcast

 encapsulation gtp

 no ip route-cache

 gprs access-point-list gprs

The following example configures a virtual template interface for PPP regeneration:

interface Virtual-Template 11

 ip address negotiated

 no peer neighbor-route

 encapsulation ppp

Note The encapsulation ppp configuration will not display in a show running configuration because it is the default encapsulation.

The following example specifies virtual template interface 11 for PPP regeneration on the GGSN:

gprs gtp ppp-regeneration vtemplate 11

Related Commands

gprs gtp response-message pco ipcp nack

To configure IP control protocol (IPCP) options returned in the protocol control option (PCO) information element (IE) by the gateway GPRS support node (GGSN) in the Create packet data protocol (PDP) Context responses, use the gprs gtp response-message pco ipcp global configuration field. To return to the default values, use the no form of the command.

gprs gtp response-message pco ipcp {nack | message-length}

no gprs gtp response-message pco ipcp {nack | message-length}

Syntax Description

Defaults

The GGSN sends an IPCP Conf-Ack (Code 02) in the PCO IE of the Create PDP Context response for the the requested IPCP address options supported by the GGSN. The values being returned might be the same as or differ from those requested, or be zero. For unsupported options, an IPCP Conf-Reject is returned.

The GGSN does not add an extra fieldthat indicates the message length to the PCO IE, when returning IPCP options.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs gtp response-message pco ipcp command to configure IPCP options returned by the GGSN in the PCO IE of a Create PDP Context response.

Use the gprs gtp response-message pco ipcp command, with the nack keyword option specified, to configure the GGSN to return an IPCP Conf-Nack in the PCO IE of a Create PDP Context response when returning IPCP options for which the granted values differ from those requested (non-zero values).

When the gprs gtp response-message pco ipcp nack command is configured, and the PCO IE of the Create PDP Context request contains IPCP options, the PCO IE in the create PDP response includes the following, depending on the whether options are supported by (and values are acceptable to) the GGSN:

•IPCP Conf-Ack—One or (zero) IPCP Conf-Ack for the IPCP options for which the requested values are acceptable by the GGSN.

•IPCP Conf-Nack—One or (zero) IPCP Conf-Nack containing the IPCP options for which the granted values differ from those requested.

•IPCP Conf-Reject—One (or zero) IPCP Conf-Reject containing the requested options which are not supported by the GGSN, or, if supported, for which no values can be granted.

Use the gprs gtp response-message pco ipcp command, with the message-length keyword option specified, to configured the GGSN to add a message length field to the PCO IE in the Create PDP Context response, when returning IPCP options.

Examples

The following configures the GGSN to include an extra field in the header of the PCO IE when returning IPCP options that indicates the message length in Create PDP Context responses.

gprs gtp response-message pco ipcp message-length

Related Commands

gprs gtp response-message wait-accounting

To configure the gateway GPRS support node (GGSN) to wait for a RADIUS accounting response before sending a Create packet data protocol (PDP) Context response to the serving GPRS support node (SGSN) for Create PDP Context requests received across all access points, use the gprs gtp response-message wait-accounting command in global configuration mode. To configure the GGSN to send a Create PDP Context response to the SGSN after sending a RADIUS start accounting message to the RADIUS server (without waiting for a response from the RADIUS accounting server), use the no form of this command.

gprs gtp response-message wait-accounting

no gprs gtp response-message wait-accounting

Syntax Description

This command has no arguments or keywords.

Defaults

The GGSN sends a Create PDP Context response to the SGSN after sending a RADIUS start accounting message to the RADIUS accounting server. The GGSN does not wait for a RADIUS accounting response from the RADIUS accounting server.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs gtp response-message wait-accounting command to configure the GGSN to wait for a RADIUS accounting response from the RADIUS accounting server before sending a Create PDP Context response to the SGSN for Create PDP Context requests received across all access points.

If the GGSN does not receive a response from the RADIUS accounting server when you have configured the gprs gtp response-message wait-accounting command, it rejects the PDP context request.

When broadcast accounting is used (accounting requests are sent to multiple RADIUS servers), if a RADIUS server responds with an accounting response, the GGSN sends a Create PDP Context response and does not wait for the other RADIUS servers to respond.

The GGSN supports configuration of RADIUS response message waiting at both the global and access-point configuration levels. You can minimize your configuration by specifying the configuration that you want to support across most access point names (APNs), at the global configuration level. Then, at the access-point configuration level, you can selectively modify the behavior that you want to support at a particular APN. Therefore, at the APN configuration level, you can override the global configuration of RADIUS response message waiting.

To configure the GGSN to wait for a RADIUS accounting response as the default behavior for all APNs, use the gprs gtp response-message wait-accounting global configuration command. To disable this behavior for a particular APN, use the no response-message wait-accounting access-point configuration command.

To verify whether RADIUS response message waiting is enabled or disabled at an APN, you can use the show gprs access-point command and observe the value reported in the wait_accounting output field.

Examples

The following example globally configures the GGSN to wait for a RADIUS accounting response from the RADIUS accounting server before sending an Activate PDP Context response to the SGSN, for PDP context requests received across all access points except access-point 1. RADIUS response message waiting has been overridden at access-point 1 using the no gtp response-message wait-accounting command.

Note This example shows only a partial configuration of the GGSN, to highlight the commands for implementing RADIUS response message waiting. Additional configuration statements are required to complete a full configuration of the GGSN.

aaa new-model

!

aaa group server radius foo

 server 10.2.3.4

 server 10.6.7.8

!

aaa authentication ppp foo group foo

aaa authorization network default group radius 

aaa accounting exec default start-stop group foo

!

gprs access-point-list gprs

 access-point 1

  access-mode non-transparent

  access-point-name www.pdn1.com

  aaa-group authentication foo

  no gtp response-message wait-accounting

  exit

 access-point 2

  access-mode non-transparent

  access-point-name www.pdn2.com

  aaa-group authentication foo

!

gprs gtp response-message wait-accounting

!

radius-server host 10.2.3.4 auth-port 1645 acct-port 1646 non-standard

radius-server host 10.6.7.8 auth-port 1645 acct-port 1646 non-standard

radius-server key ggsntel

Related Commands

gprs gtp t3-response

To specify the initial time that the gateway GPRS support node (GGSN) waits before resending a signaling request message when a response to a request has not been received, use the gprs gtp t3-response command in global configuration mode. To return to the default value, use the no form of this command.

gprs gtp t3-response response-interval

no gprs gtp t3-response

Syntax Description

Defaults

1 second

Command Modes

Global configuration

Command History

Usage Guidelines

The gprs gtp t3-response command is used by the GGSN to process Delete packet data protocol (PDP) Context requests and to perform the default method of echo timing.

For delete PDP context requests, the gprs gtp t3-response command is used by the GGSN to specify how long the GGSN waits before sending a retry of the delete PDP context request when a response is not received from the serving GPRS support node (SGSN), until the gprs gtp n3-requests limit is reached.

The GGSN supports two echo timer implementations—the default echo timer and the dynamic echo timer. The gprs gtp t3-response command is also used on the GGSN to perform the default type of echo processing, when the dynamic echo timer is not enabled.

If the GGSN receives the echo response within the path echo interval (as specified in the gprs gtp path-echo-interval command; default is 60 seconds), it sends another echo request message after 60 seconds (or whatever time was configured in the gprs gtp path-echo-interval command). This message flow continues as long as the GGSN receives an echo response message within the specified path echo interval.

If the GGSN fails to receive an echo response message from the SGSN within the path echo interval, it resends echo request messages until the N3-requests counter is reached (as specified by the gprs gtp n3-requests command; default is 5). Because the initial request message is included in the N3-requests counter, the total number of retries is N3 - 1. The T3 timer increases by a factor of 2 for each retry (the factor value is not configurable).

For example, if N3 is set to the default of 5, and T3 is set to the default of 1 second, the GGSN will resend 4 echo request messages (the initial request + 4 retries = 5). The T3 time increments for each additional echo request, by a factor of 2 seconds. So, the GGSN resends a message in 2 seconds, 4 seconds, 8 seconds, and 16 seconds. If the GGSN fails to receive an echo response message from the SGSN within the time period of the N3-requests counter, it clears the GPRS tunneling protocol (GTP) path and deletes all the PDP contexts.

For the above example, the total elapsed time from when the first request message is sent, to when the GTP path is cleared, is: 60 + 2 + 4 + 8 + 16 = 90 seconds,

where 60 is the initial value of the path echo interval, and the remaining 4 time periods are the increments of the T3 timer for the subsequent retries.

Examples

The following example shows a T3 interval response interval of 524 seconds:

gprs gtp t3-response 524

Related Commands

gprs gtp update qos-fail delete

To configure the GGSN to delete a PDP context if a GGSN-initiated QoS update fails, and no GGSN-initiated Update PDP Context Request failure action has been configured at the APN, use the gprs gtp update qos-fail delete command in global configuration mode. To return to the default value, use the no form of the command.

gprs gtp update qos-fail delete

no gprs gtp update qos-fail delete

Syntax Description

This command has no arguments or keywords.

Defaults

PDP contexts are not deleted.

Command Modes

Global configuration

Command History

Usage Guidelines

Use this command to configure the GGSN to generate a Delete PDP Context request when a GGSN-initiated Update PDP Context Request for a QoS update fails.

The Acct Stop record generated by the GGSN indicates the update failure.

This configuration applies when the Update PDP Context Response from the SGSN, initiated for a QoS change, times out after n3 tries or the Cause value is a value other than "Request Accepted."

Note The GGSN-initiated Update PDP Context Request failure action defined at the APN overrides this global configuration.

Examples

The following is an example:

Router(config)# gprs gtp update qos-fail delete

Related Commands

gprs idle-pdp-context purge-timer

To specify the time, in hours, that the gateway GPRS support node (GGSN) waits before purging idle mobile sessions, use the gprs idle-pdp-context purge-timer command in global configuration mode. To return to the default value, use the no form of this command.

gprs idle-pdp-context purge-timer hours

no gprs idle-pdp-context purge-timer

Syntax Description

Defaults

72 hours

Command Modes

Global configuration

Command History

Usage Guidelines

To specify the time that the GGSN waits before purging idle mobile sessions, use the gprs idle-pdp-context purge-timer command. To disable this feature, specify a purge-timer value of 0.

You can override the value of the global purge timer using the session idle-time access-point configuration command.

Note With GGSN Release 5.0 and later, you can also configure the session idle timer globally using the gprs gtp pdp-context timeout idle access-point configuration command, however, the two methods cannot be configured at the same time.

Examples

The following example specifies for the GGSN to wait 60 hours before purging idle sessions:

gprs idle-pdp-context purge-timer 60

Related Commands

gprs iscsi

To configure the GGSN to use an iSCSI target interface profile for record storage, use the gprs iscsi command in global configuration mode. To remove this configuration, use the no form of this command.

gprs iscsi target_profile_name

no gprs iscsi target_profile_name

Syntax Description

Command Default

iSCSI storage is disabled.

Command Modes

Global configuration

Command History

Usage Guidelines

Multiple iSCSI profiles can be configured on the GGSN, however, only one target can be defined per profile, and the GGSN can be configured to use only one profile at a time using the gprs iscsi global configuration command.

Examples

The following example configures the GGSN to use an iSCSI target interface profile named "targetA" to store and retrieve G-CDRs:

gprs iscsi targetA

Related Commands

gprs maximum-pdp-context-allowed

To specify the maximum number of packet data protocol (PDP) contexts (mobile sessions) that can be activated on the gateway GPRS support node (GGSN), use the gprs maximum-pdp-context-allowed command in global configuration mode. To return to the default value, use the no form of this command.

gprs maximum-pdp-context-allowed pdp-contexts

no gprs maximum-pdp-context-allowed

Syntax Description

Defaults

10000 PDP contexts

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs maximum-pdp-context-allowed command to specify the maximum number of PDP contexts allowed on the GGSN. When the maximum allowable number of PDP contexts is reached, the GGSN refuses new PDP contexts (mobile sessions) until sessions are available.

The practical upper limit for the maximum number of PDP contexts supported on a GGSN is dependent on the memory and platform in use and the GGSN configuration (for example, whether or not a method of PPP has been configured to forward packets beyond the terminal equipment and mobile termination, whether Dynamic Feedback Protocol [DFP] is being used or the memory protection feature is enabled, and the rate of PDP context creation to be supported).

Note DFP weighs PPP PDPs against IP PDPs with one PPP PDP equal to 8 IP PDPs.

Cisco 7200 Series Router

The following list shows the maximum number of PDP contexts supported on the GGSN according to the memory and Cisco 7206 router in use when a method of PPP has not been configured:

•Cisco 7206 VXR NPE-300 with 256 Mb of RAM—80,000 IP PDP contexts.

•Cisco 7206 VXR NPE-400 router with 512 Mb of RAM—135,000 IP PDP contexts.

Catalyst 6500 Series Switch / Cisco 7600 Series Router

The Cisco Multi-processor WAN Application Module (MWAM) can support up to 60,000 IP PDP contexts per GGSN instance with a maximum number of 300,000 IP PDP contexts per MWAM on which five GGSNs are configured.

Note When the maximum allowable number of PDP contexts is reached, the GGSN refuses new PDP contexts (mobile sessions) until sessions are available.

Note If you use dynamic feedback protocol (DFP) with GPRS tunneling protocol (GTP) load balancing, you must also specify a maximum number of PDP contexts for each GGSN, using the gprs maximum-pdp-context-allowed command. Do not accept the default value of 10000 PDP contexts. Significantly lower values can impact performance in a GTP load-balancing environment.

DFP weighs PPP PDPs against IP PDPs, with one PPP PDP equal to 8 IP PDPs. Therefore, when using DFP, be aware that the configured maximum number of PDP contexts affects the GGSN weight. The lower the maximum number of PDP contexts, the lower the weight when all other parameters remain the same.

Note For more information about configuring GTP load balancing, see the IOS Server Load Balancing, documentation located at Cisco.com.

Examples

In the following example 15000 PDP contexts are allowed on the GGSN:

gprs maximum-pdp-context-allowed 15000

Related Commands

gprs mcc mnc

To configure the mobile country code (MCC) and mobile network code (MNC) that the gateway GPRS support node (GGSN) uses to determine if a Create packet data protocol (PDP) Context request is from a roamer, use the gprs mcc mnc command in global configuration mode. To return to the default values, use the no form of this command.

gprs mcc mcc-num mnc mnc-num [trusted]

no gprs mcc mcc-num mnc mnc-num [trusted]

Syntax Description

Defaults

000—For both the MCC and MNC. A valid code must be a non-zero value.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs mcc mnc command as part of the configuration required on the GGSN to support creation of call detail records (CDRs) for roaming mobile subscribers, or to block roamers from being able to Create PDP Context requests.

The MCC and MNC together identify a GPRS/UMTS public land mobile network (PLMN). The values you configure using the gprs mcc mnc command without the trusted keyword option specified are those of the home PLMN ID - the PLMN to which the GGSN belongs. Only one home PLMN can be defined for a GGSN at a time. The GGSN uses the values that you configure in this command to compare with the international mobile subscriber identity (IMSI) in a Create PDP Context request.

The GGSN automatically specifies values of 000 for the MCC and MNC. However, you must configure non-zero values for both the MCC and MNC before you can enable the GGSN to create charging CDRs for roamers.

To properly issue the gprs mcc mnc command, you must specify both the mcc keyword with its argument and the mnc keyword with its argument. You cannot issue the command without specifying both keywords.

It is important that you configure the gprs mcc mnc and gprs charging roamers commands in their proper order. After you configure the MCC and MNC values, use the gprs charging roamers command to enable charging for roamers on the GGSN. You can change the MCC and MNC values by reissuing the gprs mcc mnc command.

Using the gprs mcc mnc command, you can also configure up to 5 "trusted" PLMNs by specifying the trusted keyword. A Create PDP Context request from a mobile subscriber in a trusted PLMN is treated the same as a Create PDP Context request from a mobile subscriber in the home PLMN.

To verify your configuration of these codes on the GGSN, use the show gprs charging parameters command.

Note To see a list of some established MCC and MNC codes, see the "Table of MCC and MNC Codes" appendix in the Cisco GGSN Configuration Guide. To find more information about MCC and MNC codes, see the ITU E.212 recommendation, Identification Plan for Land Mobile Stations.

Examples

The following example replaces the default values of 000 on the GGSN, and specifies an MCC code of 310 for the USA and an MNC code of 15 for the Bell South service provider:

gprs mcc 310 mnc 15

Related Commands

gprs memory threshold

To prevent the gateway GPRS support node (GGSN) from draining processor memory during abnormal conditions (such as charging gateways [CGs] being down), use the gprs memory threshold command in global configuration mode to configure a memory threshold, that when reached, activates the memory protection feature on the GGSN.

gprs memory threshold threshold

no gprs memory threshold

Syntax Description

Defaults

The default is 10% of the total memory available at the time GGSN services are enabled.

Command Modes

Global configuration

Command History

Usage Guidelines

The GGSN memory protection feature prevents processor memory from being drained during periods of abnormal conditions (such as when all charging gateways are down and the GGSN is buffering call detail records (CDRs) into memory.

By default, the memory threshold is 10% of the total memory available at the time GGSN services are enabled using the gprs ggsn service global configuration command. You can use the gprs memory threshold global configuration command to configure the threshold according to the router and memory size.

When the amount of memory remaining on the system reaches the defined threshold, the memory protection feature activates and the GGSN performs the following actions to keep the processor memory from falling below the threshold:

•Rejects new Create packet data protocol (PDP) Context requests with the cause value "No Resource."

•Drops any existing PDPs for which an update is received with the cause value "Management Intervention."

•Drops any PDPs for which a volume trigger has occurred.

Examples

The following example sets the memory threshold to 50 KB:

gprs memory threshold 512

gprs ms-address exclude-range

To specify the IP address range(s) used by the GPRS/UMTS network, and thereby excluded from the mobile station (MS) IP address range, use the gprs ms-address exclude-range command in global configuration mode. To remove the specified range(s), use the no form of this command.

gprs ms-address exclude-range start-ip end-ip

no gprs ms-address exclude-range start-ip end-ip

Syntax Description

Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Usage Guidelines

An MS cannot have the same IP address as another GPRS network entity. Use the gprs ms-address exclude-range command to reserve certain IP address ranges for use by the GPRS/UMTS network, and to disallow these address ranges from use by an MS.

The gprs ms-address exclude range command verification is performed only for IP PDPs and does not apply to MS addresses assigned to virtual private networks (VPNs) or for PPP Regen or PPP PDP types.

During processing of a Create packet data protocol (PDP) Context request, the gateway GPRS support node (GGSN) verifies whether the IP address of an MS falls within the specified excluded range. If there is an overlap of the MS IP address with an excluded range, then the Create PDP Context request is rejected. This measure prevents duplicate IP addressing in the network.

You can configure up to 100 IP address ranges. A range can be one or more addresses. However, you can configure only one IP address range per command entry. To exclude a single IP address, you can repeat the IP address in the start-ip and end-ip arguments. IP addresses are 32-bit values.

Examples

Example 1

The following example specifies the IP address ranges used by the GPRS/UMTS network (which are thereby excluded from the MS IP address range):

gprs ms-address exclude-range 10.0.0.1 10.20.40.50

gprs ms-address exclude-range 172.16.150.200 172.30.200.255

gprs ms-address exclude-range 192.168.100.100 192.168.200.255

Example 2

The following example excludes an MS from using the IP address 10.10.10.1:

gprs ms-address exclude-range 10.10.10.1 10.10.10.1

Related Commands

gprs plmn ip address

To specify the IP address range of a public land mobile network (PLMN), use the gprs plmn ip address command in global configuration mode.

gprs plmn ip address start_ip end_ip [sgsn]

no gprs plmn ip address start_ip end_ip [sgsn]

Syntax Description

Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs plmn ip address global configuration command to specify the IP address range of the PLMN.

The gprs plmn ip address command defines addresses that belong to a PLMN. To indicate that the addresses are SGSN addresses within the PLMN, issue the gprs plmn ip address command with the sgsn keyword option specified. This option is used by the charging for roamers feature (gprs charging roamers command).

When using the gprs plmn ip address command with the GGSN charging for roamers feature, depending on how the PLMN IP address ranges have been defined using the gprs plmn ip address start_ip end_ip [sgsn] command, the charging for roamers feature operates as follows:

•If no PLMN IP address ranges are configured using the gprs plmn ip address start_ip end_ip [sgsn] command, the GGSN generates CDRs for all initiated PDP contexts regardless of whether the GGSN and SGSN are located within the same PLMN.

•If a list of PLMN IP address ranges has been configured using the gprs plmn ip address start_ip end_ip [sgsn] command, and one or more of those ranges has been defined using the sgsn keyword, the GGSN uses those ranges defined with the sgsn keyword to determine whether an SGSN is located within the same PLMN.

With this configuration, the following scenarios outline how the charging for roamers feature will function:

–Mobile station 1 (MS1) is subscribed to PLMN1 and attaches to an SGSN in PLMN2. From PLMN2, MS1 initiates a packet data protocol (PDP) context with the GGSN in PLMN1. In this case, MS1 is a roamer, and the GGSN generates a call detail record (CDR) because it determines that the SGSN is located in a different PLMN.

–MS1 is subscribed to PLMN1 and attaches to an SGSN in PLMN2. From PLMN2, MS1 initiates a PDP context with the GGSN in PLMN2. In this case, MS1 is not a roamer because the SGSN and GGSN are in the same PLMN. The GGSN does not create a CDR.

Configuration Guidelines

To enable charging for roamers on the GGSN, you should first define a set of IP address ranges for a PLMN using the gprs plmn ip address command.

It is important that you configure the gprs plmn ip address and gprs charging roamers commands in their proper order. After you configure the IP address range for a PLMN, use the gprs charging roamers command to enable charging for roamers on the GGSN. You can change the IP address range by reissuing the gprs plmn ip address command.

To verify your configuration, use the show gprs charging parameters command to see if the charging for roamers feature is enabled. To verify your PLMN IP address ranges, use the show gprs plmn ip address command.

Examples

The following example specifies the IP address range of a PLMN:

gprs plmn ip address 10.0.0.1 10.20.40.50

Related Commands

gprs pcscf

To configure a group of P-CSCF addresses and enter P-CSCF group configuration mode, use the gprs pcscf command in global configuration mode. To disable the P-CSCF server group, issue the no form of this command.

gprs pcscf group-name

no gprs pcscf group-name

Syntax Description

Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs pcscf command to define a P-CSCF server group for P-CSCF Discovery and enter P-CSCF group configuration mode.

The GGSN can be configured to return a list of preconfigured Proxy Call Session Control Function (P-CSCF) server addresses for an APN when it receives a Create PDP Context request that contains a "P-CSCF Address Request" field in the PCO.

The MS sets the P-CSCF Address Request field of the PCO in the Activate PDP Context request. This request is forwarded to the GGSN in the Create PDP Context request from the SGSN. Upon receiving, the GGSN returns all the P-CSCF addresses configured for the APN in the "P-CSCF Address" field of the PCO.

If a Create PDP Context Request does not contain the P-CSCF address request field in the PCO, or if no P-CSCF addresses are preconfigured, the Create PDP Context Response will not return any P-CSCF addresses. An error message will not be generated and the Create PDP Context Request will be processed.

To configure the P-CSCF Discovery support, you must preconfigure P-CSCF server groups on the GGSN using the gprs pcscf command and configure P-CSCF server groups for an APN using the pcscf access-point configuration command.

Note The order of the addresses returned in the "P-CSCF Address Field" of the PCO is the same as the order in which they are defined in the P-CSCF server group and the groups are associated with the APN.

Examples

The following example configures a P-CSCF group identified as "groupA":

gprs pcscf groupA

Related Commands

gprs qos bandwidth-pool

To create or modify a Call Admission Control (CAC) bandwidth pool that can be attached to one or more APNs, use the gprs qos bandwidth-pool command in global configuration mode. To delete the bandwidth pool, use the no form of this command.

gprs qos bandwidth-pool pool-name

no gprs qos bandwidth-pool pool-name

Syntax Description

Defaults

No bandwidth pools are configured.

Command Modes

Global configuration

Command History

Usage Guidelines

The CAC feature ensures that required network resources are available for real-time data traffic (such as voice, video, etc.). The CAC feature consists of two functions: maximum quality of service (QoS) authorization using CAC maximum QoS policies and bandwidth management.

The CAC bandwidth management function ensures that there is sufficient bandwidth for real-time packet data protocol (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

Note The CAC feature requires that Universal Mobile Telecommunications System (UMTS) QoS is enabled on the GGSN. For more information on configuring UMTS QoS on the GGSN, see the GGSN Release 6.0 Configuration Guide.

Once a bandwidth pool is allocated for a traffic class, it cannot be borrowed by the other sub pools allocated for the different traffic classes. The request is only admitted within the bandwidth pool to which the traffic class belongs.

Use the gprs qos bandwidth-pool command to create or modify a CAC bandwidth pool and apply the bandwidth pool to one or more APNs using the bandwidth-pool access point configuration command.

Examples

The following example creates a bandwidth pool named "pool a":

gprs qos bandwidth pool a

Related Commands

gprs qos cac-policy

To create or modify a Call Admission Control (CAC) maximum quality of service (QoS) policy that can be attached to one or more access point names (APNs), and enter CAC maximum QoS policy configuration mode, use the gprs qos cac-policy command in global configuration mode. To return to the default value, use the no form of this command.

gprs qos cac-policy policy-name

no gprs qos cac-policy policy-name

Syntax Description

Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Usage Guidelines

The CAC feature on the gateway GPRS support node (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 CAC maximum QoS authorization function ensures that the QoS requested by a Create packet data protocol (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.

Use the gprs qos cac-policy command to create or modify a CAC maximum QoS policy and apply the policy to an APN using the cac-policy access point configuration command.

Note The CAC feature requires that Universal Mobile Telecommunications System (UMTS) QoS has been configured. For information on configuring UMTS QoS, see the GGSN Release 6.0 Configuration Guide.

Once you have entered policy configuration mode using the gprs qos cac-policy command, you can configure the following QoS parameters in a policy and apply the policy to an APN:

•Maximum number of active PDP contexts (maximum pdp-context command)

•Maximum bit rate (mbr traffic-class command)

•Guaranteed bit rate (gbr traffic-class command)

•Maximum traffic class (maximum traffic-class command)

•Traffic handling priority (maximum traffic-class command with priority option)

•Delay class (maximum delay-class command)

•Peak throughput class (maximum peak-throughput command)

Examples

The following example creates a CAC maximum QoS policy named "policy a":

gprs qos cac-policy a

Related Commands

gprs qos default-response requested

To specify that the gateway GPRS support node (GGSN) sets its default quality of service (QoS) values in the response message exactly as requested in the Create packet data protocol (PDP) Context request message, use the gprs qos default-response requested command in global configuration mode. To return to the default QoS, use the no form of this command.

gprs qos default-response requested

no gprs qos default-response requested

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled. The GGSN sets its QoS default to the best-effort class.

Command Modes

Global configuration

Command History

Usage Guidelines

The gprs qos default-response requested command is useful only when canonical QoS is not configured on the GGSN. Canonical QoS is enabled using the gprs qos map canonical-qos command.

When canonical QoS is not enabled, and the gprs qos default-response requested command has not been configured on the GGSN, the GGSN always sets its QoS values to best-effort in the response message.

Examples

The following example enables the GGSN to set its QoS values in the response message according to the QoS values requested in the Create PDP Context request message:

gprs qos default-response requested

Related Commands

gprs qos map canonical-qos

To enable mapping of general packet radio service (GPRS) quality of service (QoS) categories to a canonical QoS method that includes best-effort, normal, and premium QoS classes, use the gprs qos map canonical-qos command in global configuration mode. To disable canonical mapping, use the no form of this command.

gprs qos map canonical-qos

no gprs qos map canonical-qos

Syntax Description

This command has no arguments or keywords.

Defaults

Canonical QoS mapping is disabled.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the qprs qos map canonical-qos command to map GPRS QoS into the following canonical categories: best effort, normal, and premium.

Examples

The following example shows canonical QoS mapping enabled:

qos map canonical-qos

Related Commands

gprs qos map delay

To enable mapping of general packet radio service (GPRS) quality of service (QoS) categories to delay QoS classes, use the gprs qos map delay command in global configuration mode. To disable delay mapping, use the no form of this command.

gprs qos map delay

no gprs qos map delay

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs qos map delay command to enable QoS delay mapping on the gateway GPRS support node (GGSN). To map the QoS delay classes (class 1, class 2, class 3, and best effort) to IP type of service (ToS) categories, use the gprs delay-qos map tos command.

Examples

The following example enables delay QoS mapping:

gprs qos map delay

Related Commands

gprs qos map umts

To enable universal mobile telecommunication system (UMTS) quality of service (QoS) on the gateway GPRS support node (GGSN), use the gprs qos map umts command in global configuration mode. To disable this mapping and return to the default QoS mapping, use the no form of this command.

gprs qos map umts

no gprs qos map umts

Syntax Description

This command has no arguments or keywords.

Defaults

UMTS QoS mapping is disabled.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs qos map umts command to enable UMTS QoS mapping.

Examples

The following example enables UMTS traffic QoS mapping:

gprs qos map umts

Related Commands

gprs radius attribute chap-challenge

To specify that the CHAP challenge always be included in the Challenge Attribute field (and not in the Authenticator field) in an Access-Request to the Remote Access Dial-In User Service (RADIUS) server, use gprs radius attribute chap-challenge global configuration command in global configuration mode. To disable, use the no form of this command.

gprs radius attribute chap-challenge

no gprs radius attribute chap-challenge

Syntax Description

This command has no arguments or keywords.

Defaults

If the CHAP challenge length is 16 bytes, it is sent in the Authenticator field of an Access-Request. If it is greater than 16 bytes, it is sent in the Challenge Attribute field.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs radius attribute chap-challenge command when configuring RADIUS security on the GGSN.

When the gprs radius attribute chap-challenge command is configured, the CHAP challenge is always sent in the Challenge Attribute field of an Access-Request to the RADIUS server and not in the Authenticator field. When the command is not configured, the CHAP challenge is sent in the Authenticator field unless the challenge exceeds 16 bytes, in which case, it is sent in the Challenge Attribute field of the Access-Request.

Examples

The following example configures the CHAP challenge to always be sent in an Access Request to the RADIUS server:

gprs radius attribute chap-challenge

Related Commands

gprs radius attribute quota-server ocs-address

To configure the GGSN to send the Online Charging Server (OCS) IP address (received in an Access-Accept response from a RADIUS server) in the csg:quota server attribute in Accounting-Start messages, use gprs radius attribute quota-server ocs-address global configuration command in global configuration mode. To disable this configuration, use the no form of this command.

gprs radius attribute quota-server ocs-address

no gprs radius attribute quota-server ocs-address

Syntax Description

This command has no arguments or keywords.

Defaults

The GGSN sends its own IP address in the csg:quota server field.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs radius attribute quota-server ocs-address command to configure the GGSN to send the IP address and port of an external OCS (that has been received in the conditional "csg:quota_server" attribute in an Access-Accept response for a prepaid subscriber from the RADIUS server), in Accounting-Start messages to the CSG.

When the gprs radius attribute quota-server ocs-address command has been configured, the CSG can interface directly with an external OCS to which it has a GTP' interface. This external OCS will function as the quota server for the prepaid users, providing an alternate online billing solution than the one provided by the GGSN, interacting with Diameter/DCCA, functioning as the quota server for prepaid users.

When the gprs radius attribute quota-server ocs-address command is configure, the GGSN functions as the quota server for just postpaid users. The GGSN does not generate enhance G-CDRs for prepaid users, however, it does continue to generate G-CDRs for them.

For more information about the GGSN support for OCS address selection, see the Configuring Enhance Service-Aware Billing" chapter of the GGSN Configuration Guide.

Examples

The following configures the GGSN to send the IP address of an external OCS in the csg:quota server attribute in Accounting-Start messages for prepaid users:

gprs radius attribute quota-server ocs-address

Related Commands

gprs radius attribute session-timeout

To specify that the Session-Timeout (Attribute 27) field be included in a Remote Access Dial-In User Service (RADIUS) request, use the gprs radius attribute session-timeout command in global configuration mode. To disable, use the no form of this command.

gprs radius attribute session-timeout

no gprs radius attribute session-timeout

Syntax Description

This command has no arguments or keywords.

Defaults

Attribute 27 is not included.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs radius attribute session-timeout command to configure the Session-Timeout (Attribute 27) field be included in a Remote Access Dial-In User Service (RADIUS) request.

The GGSN stores the attribute value received in Access-Accept packets sent by the AAA server and terminates the PDP context upon expiration of the time. You can configure the number of seconds the GGSN allows a session to be active before terminating the session at the global level (gprs gtp pdp-context timeout session command) and at the access-point level (gtp pdp-context timeout session command.

Examples

The following example configures Attribute 27 to always be sent in an Access Request to the RADIUS server:

gprs radius attribute session-timeout

Related Commands

gprs radius msisdn first-byte

To specify that the first byte of the mobile station ISDN (MSISDN) information element (IE) is included in a RADIUS request, use the gprs radius msisdn first-byte command in global configuration mode. To remove the first byte from the MSISDN IE in a RADIUS request, use the no form of this command.

gprs radius msisdn first-byte

no gprs radius msisdn first-byte

Syntax Description

This command has no arguments or keywords.

Defaults

The first byte is not included.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs radius msisdn first-byte command when configuring RADIUS security on the gateway GPRS support node (GGSN).

The first octet of an MSISDN IE using E.164 addressing is 91 in hexadecimal, that is, 10010001. In this 91 code, the 1 is the extension bit, 001 is the international number, and 0001 indicates E.164 numbering.

Examples

The following example specifies that the first byte of the MSISDN IE is included in a RADIUS request:

gprs radius msisdn first-byte

gprs redundancy

To enable GPRS tunneling protocol session redundancy (GTP-SR) on a gateway GPRS support node (GGSN), use the gprs redundancy command in global configuration mode. To disable GTP-SR, use the no form of this command.

gprs redundancy

no gprs redundancy

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs redundancy command to enable GTP-SR on a GGSN.

Cisco GGSN Release 5.1 and later supports Active/Standby, 1-to-1 inter-device GTP-SR. GTP-SR enables two GGSNs to appear as one network entity and ensures that continuous service is provided to mobile subscribers in the event one of the GGSNs fails.

In a GTP-SR implementation, the Active GGSN establishes and terminates packet data protocol (PDP) sessions and sends required stateful data to the Standby GGSN. To stay current on the states of active PDP sessions, the Standby GGSN receives the stateful data sent by the Active GGSN. As soon as the Standby GGSN detects that the Active GGSN has failed, it becomes active and assumes the responsibilities of the Active GGSN.

Before GTP-SR can be enabled on two redundant GGSNs, a GTP-SR inter-device infrastructure must be configured. For information on configuring a inter-device infrastructure, see the "Configuring GTP Session Redundancy" chapter of the Cisco GGSN Release 6.0 Configuration Guide.

Examples

The following example enables GTP-SR on a GGSN:

gprs redundancy

Related Commands

gprs redundancy charging sync-window cdr rec-seqnum

To configure the window size used to determine when the call detail record (CDR) record sequence number needs to be synchronized to the Standby gateway GPRS support node (GGSN), use the gprs redundancy charging sync-window cdr rec-seqnum command in global configuration mode. To return to the default value, use the no form of this command.

gprs redundancy charging sync-window cdr rec-seqnum size

no gprs redundancy charging sync-window cdr rec-seqnum size

Syntax Description

Defaults

10

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs redundancy charging sync-window cdr rec-seqnum command to configure the window size used to determine when the record sequence number needs to be synchronized.

The record sequence number is used by the charging gateway to detect duplicate CDRs associated with a PDP context. To minimize the amount of data being synchronized to the Standby GGSN, the record sequence number is not synchronized each time a CDR is closed. Instead, a window threshold for the record sequence number is synchronized each time a CDR closes. The current value of the record sequence number and the record number last synchronized for a PDP context is checked, and if the difference is the value configured for the window size using the gprs redundancy charging sync-window cdr rec-seqnum global configuration command, the current record sequence number is synchronized to the Standby GGSN.

When a Standby GGSN becomes the Active GGSN, it starts from the last value synchronized, plus the window size.

Examples

The following example configures a window size of 15:

gprs redundancy charging sync-window cdr rec-seqnum 15

Related Commands

gprs redundancy charging sync-window gtpp seqnum

To configure the window size used to determine when the GTP' sequence number needs to be synchronized to the Standby gateway GPRS support node (GGSN), use the gprs redundancy charging sync-window gtpp seqnum command in global configuration mode. To return to the default value, use the no form of this command.

gprs redundancy charging sync-window gtpp seqnum size

no gprs redundancy charging sync-window gtpp seqnum size

Syntax Description

Defaults

10000

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs redundancy charging sync-window gtpp seqnum command to configure the window size used to determine when the GTP' sequence number needs to be synchronized.

The GTP' sequence number is used by the charging gateway to prevent the duplication of packets. The GGSN sends encoded CDRs associated with a PDP context in a GTP packet to the charging gateway. If the GTP packet is acknowledged by the charging gateway, it removes the packet from memory. If it is not acknowledged, it is retransmitted. The charging gateway cannot acknowledged GTP packets if the sequence number repeats.

To minimize the amount of data being synchronized to the Standby GGSN, the GTP' sequence number is not synchronized each time a CDR is closed. Instead, a window threshold for the GTP' sequence number is synchronized each time a CDR message is sent. The current value of the GTP' sequence number and the gtpp sequence number last synchronized for a PDP context is checked and if the difference is the value configured for the window size (using the gprs redundancy charging sync-window gtpp seqnum global configuration command), the current GTP prime sequence number is synchronized to the Standby GGSN.

When a Standby GGSN becomes the Active GGSN, it starts from the last value synchronized plus the window size.

Examples

The following example configures the window size for the GTP' sequence number synchronization to be 120:

gprs redundancy charging sync-window gtpp seqnum 120

Related Commands

gprs service-aware

To enable service-aware billing on the gateway GPRS support node (GGSN), use the gprs service-aware command in global configuration mode. To disable the support, use the no form of this command

gprs service-aware

no gprs service-aware

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs service-aware global configuration command to enable service-aware billing on the on the GGSN.

Note Service-aware billing must be enabled before configuring other enhanced service-aware billing features on the GGSN. These features include the GGSN-to-CSG interface, the GGSN-to-Diameter/DCCA interface, and support of enhanced service-level G-CDRs.

Examples

The following configuration example enables service-aware billing on a GGSN:

 gprs service-aware

Related Commands

gprs service-mode

To configure the global service-mode state of a gateway GPRS support node (GGSN), use the gprs service-mode command in global configuration mode.

gprs service-mode {operational | maintenance}

no gprs service-mode {operational | maintenance}

Syntax Description

Defaults

Operational.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs service-mode command to place the global service-mode state of a GGSN in maintenance mode.

The GGSN service-mode function enables you to make configuration changes and test calls without affecting all active sessions on a GGSN. You can configure the service-mode state globally, for an access-point, and for the GGSN charging function. There are two service-mode states: operational and maintenance. The default is operational mode.

When a GGSN is placed in global maintenance mode, it rejects all new Create PDP Context requests. Therefore, no new PDP contexts are activated for an entire GGSN while it is in global maintenance mode.

Note When a GGSN is in global maintenance mode, all APNs are in maintenance mode as well.

Examples

The following example places a GGSN in maintenance mode:

gprs service-mode maintenance

Related Commands

gprs service-mode test imsi

To configure a test user for which you can Create PDP Contexts to test an APN configuration, use the gprs service-mode test imsi command in global configuration mode. To remove the test user configuration, use the no form of this command.

gprs service-mode test imsi imsi-value

no gprs service-mode test imsi imsi-value

Syntax Description

Defaults

No test user is configured on the GGSN.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs service-mode test imsi command to configure a test user for which Create PDP Contexts will be created to test configurations.

Only one test user can be configured per GGSN.

Note PDP context creation from a test user is only supported while a GGSN is in operational mode.

Examples

The following example creates a test user with the IMSI 211F111130000000:

gprs service-mode test imsi 211F111130000000

Related Commands

gprs slb mode

To define the Cisco IOS SLB operation mode for gateway GPRS support node (GGSN)-IOS SLB messaging, use the gprs slb mode command in global configuration mode.

gprs slb mode {dispatched | directed}

Syntax Description

Defaults

Dispatched

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs slb mode command to defined the Cisco IOS SLB mode of operation when configuring GGSN-IOS SLB messaging.

GGSN-IOS SLB Messaging CAC Failure Notification Support

When configuring support for GGSN-IOS SLB messaging CAC failure notifications, if Cisco IOS SLB is operating in dispatched mode, the virtual server that forwarded the Create PDP Context request to the GGSN is known to the GGSN, and the GGSN can send the CAC failure notification directly to that server. Therefore, only the gprs slb notify command is required to enable GGSN-SLB messaging on the GGSN.

However, if the Cisco IOS SLB is functioning in directed server NAT mode, the virtual server is not known to the GGSN. Therefore, a list of virtual servers that the GGSN should notify when a CAC failure occurs must be defined on the GGSN using the gprs slb vserver global configuration command and the Cisco IOS SLB mode of operation must be defined using the gprs slb mode global configuration command.

Note When configuring support for GGSN-IOS SLB messaging CAC failure notifications when the Cisco IOS SLB is functioning in directed server NAT mode, the gprs slb mode and gprs slb vserver global configuration commands are required.

GGSN-IOS SLB Messaging Delete Notification Support

When configuring support for GGSN-IOS SLB messaging delete notifications (GTP IMSI sticky database support), the Cisco IOS SLB operation mode must be defined using the gprs slb mode command and a list of virtual servers that the GGSN should send delete notifications must be defined on the GGSN using the gprs slb vserver global configuration command.

For complete information on configuring GGSN-IOS SLB messaging, refer to the "Configuring Messaging from the GGSN to the Cisco IOS SLB" section of the "Configuring Load Balancing on the GGSN" chapter for the GGSN Configuration Guide.

Examples

The following example defines Cisco IOS SLB to be in directed server NAT mode:

gprs slb mode directed

Related Commands

gprs slb notify

To enable the gateway GPRS support node (GGSN) to notify the Cisco IOS Server Load Balancing (SLB) when a specific condition occurs, use the gprs slb notify global configuration command. To disable GGSN-IOS SLB messaging, issue the no form of this command.

gprs slb notify {cac-failure | session-deletion}

no gprs slb notify {cac-failure | session-deletion}

Syntax Description

Defaults

Disabled

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs slb notify command to enable GGSN-IOS SLB messaging.

The GGSN-IOS SLB messaging function enables you to configure the GGSN to notify the Cisco IOS SLB when a certain condition exists that affects a session forwarded by the Cisco IOS SLB. The notification also instructs the Cisco IOS SLB on how to react to the condition.

There are two types of GGSN-IOS SLB notifications that can be configured using the gprs slb notify command—CAC failure notifications and delete notifications (for GTP IMSI sticky database support).

CAC Failure Notifications

When support for CAC failure notifications is configured on the GGSN and the Cisco IOS SLB, when a Create PDP Context request is rejected by the GGSN because of a CAC failure, the GGSN notifies the Cisco IOS SLB that the failure has occurred, and instructs the Cisco IOS SLB to reassign the session to another GGSN in the server farm.

Note If the Cisco IOS SLB is functioning in directed server NAT mode, a list of virtual servers must be defined on the GGSN using the gprs slb vserver global configuration command, and the Cisco IOS SLB mode of operation must be defined using the gprs slb mode global configuration command.

Delete Notifications (GTP IMSI Sticky Database Support)

When support for delete notifications is configured on the GGSN and the Cisco IOS SLB, a sticky database entry is created on the Cisco IOS SLB when the first Create PDP Context request from a subscriber is received. When the last PDP context of that IMSI is deleted on the GGSN, the GGSN sends a delete notification to the Cisco IOS SLB that instructs the Cisco IOS SLB to remove the sticky entry from the database.

Note This configuration requires that the virtual virtual server configuration command be configured with the service gtp keywords specified.

For complete information on configuring GGSN-IOS SLB messaging, refer to the "Configuring Messaging from the GGSN to the Cisco IOS SLB" section of the "Configuring Load Balancing on the GGSN" chapter for the GGSN Configuration Guide.

Examples

Example 1

The following example configures the GGSN to notify the Cisco IOS SLB when a Create PDP Context request has been rejected because of a UMTS QoS CAC failure and the Cisco IOS SLB is functioning in dispatched mode.

On the GGSN:

gprs slb notify cac-failure

On the Cisco IOS SLB:

gtp notification cac 4

Example 2

The following example configures the GGSN to notify the Cisco IOS SLB when a Create PDP Context request has been rejected because of a UMTS QoS CAC failure and the Cisco IOS SLB is functioning in directed server NAT mode.

On the GGSN:

gprs slb mode directed

gprs slb notify cac-failure

gprs slb vserver 10.10.10.10

On the Cisco IOS SLB:

gtp notification cac 4

Example 3

The following example configures the GGSN to notify the Cisco IOS SLB (functioning in directed server NAT mode) when the last PDP context associated with a IMSI is deleted:

On the GGSN:

gprs slb mode directed

gprs slb notify session-deletion

gprs slb vserver 10.10.10.10

On the Cisco IOS SLB: