Cisco GGSN Release 9.2 Command Reference, Cisco IOS Release 12.4(22)YE3

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) must 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 by 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 by 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 configured to attempt to send a signaling request 3 times:

gprs gtp n3-requests 3

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 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 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 by the gtp pdp-context timeout idle access point configuration command overrides the value configured globally by 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 Alternatively, 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 by 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 is 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 by the gtp pdp-context timeout session access point configuration command overrides the value configured globally by 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

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 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 field that 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.

Note Wait accounting is required for an eGGSN implementation, but is optional for a Standalone GGSN Quota Enforcement.

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 is overridden at access point 1 by 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 abc

 server 10.2.3.4

 server 10.6.7.8

!

aaa authentication ppp abc group abc

aaa authorization network default group radius 

aaa accounting exec default start-stop group abc

!

gprs access-point-list gprs

 access-point 1

  access-mode non-transparent

  access-point-name www.pdn1.com

  aaa-group authentication abc

  no gtp response-message wait-accounting

  exit

 access-point 2

  access-mode non-transparent

  access-point-name www.pdn2.com

  aaa-group authentication abc

!

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 is 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 by 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 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 only one profile can be defined at the global level by the gprs iscsi command (charging group 0) or at the APN level, only on iSCSI profile can be defined per charging groups 1 to 29 by the iscsi charging group configuration command.

Examples

The following example configures a global level iSCSI target 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 is 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 eight IPv4 PDPs. One IPv6 PDP equals eight IPv4 PDPs.

Table 1 lists the maximum number of PDP contexts the Cisco SAMI with the 1 GB memory option can support. Table 2 lists the maximum number the Cisco SAMI with the 2 GB memory option can support.:

Note Table 1 and Table 2 list the maximum number of PDPs supported when the no virtual-template subinterface global configuration command is not configured on the GGSN.

With Cisco GGSN Release 8.0 and later, PDPs regenerated to a PPP session run on software interface description blocks (IDBs), which increases the number of sessions the GGSN can support. The GTP virtual template is a subinterface. If the no virtual-template subinterface command is configured in global configuration mode, PDPs regenerated to a PPP session run on hardware IDBs instead. When sessions are running on hardware IDBs, the GGSN supports fewer sessions.

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, by 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 eight 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 by configuring a memory threshold that when reached, activates the memory protection feature on the GGSN, use the gprs memory threshold command in global configuration mode. To return to disable the memroy protection feature, use the no version of the command.

gprs memory threshold threshold

no gprs memory threshold

Syntax Description

Defaults

By default, the memory protection feature is disabled. When enabled, the default threshold is 10 percent 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 percent of the total memory available at the time GGSN services are enabled by the gprs ggsn service command.

You can use the gprs memory threshold 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 a "No Resource" cause value.

•Drops any existing PDPs for which an Update PDP Context request is received with a "Management Intervention cause value.

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

Note While the memory protection feature is active, byte counts are tracked and reported when the GGSN recovers. However, because some change conditions are not handled when the GGSN is in memory protection mode, some counts (for example, QoS and tariff conditions) do not reflect the accurate charging condition.

Examples

The following example sets the memory threshold to 512 MB:

gprs memory threshold 512

Related Commands

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 pcscf

To configure a group of Proxy Call Session Control Function (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 to enter P-CSCF group configuration mode.

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

The mobile station (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 by 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; server groups are associated with the APN.

Examples

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

gprs pcscf groupA

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).

Depending on how the PLMN IP address ranges are configured, the charging for roamers feature operates as follows:

•If no PLMN IP address ranges have been configured by the gprs plmn ip address start_ip end_ip [sgsn] command, the GGSN generates G-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 is configured by the gprs plmn ip address start_ip end_ip [sgsn] command, and one or more of those ranges have been defined with the sgsn key word specified, the GGSN uses the ranges defined with the sgsn keyword to determine whether an SGSN is located within the same PLMN.

With this configuration, the following scenarios describe how the charging for roamers feature functions:

–MS1 is subscribed to PLMN1 and attaches to an SGSN in PLMN2. From PLMN2, MS1 initiates a PDP context with the GGSN in PLMN1. In this scenario, MS1 is a roamer, and the GGSN generates a G-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 scenario, MS1 is not a roamer, and the GGSN does not generate a G-CDR because it determines that it is in the same PLMN as the SGSN.

Configuration Guidelines

If using the gprs plmn ip address to configure charging for roamers, note the following:

•To use the RAI IE in Create PDP Context requests to detect roamers, a valid home PLMN must be configured on the GGSN by the gprs mcc mn command in global configuration mode.

When a valid home PLMN is configured, or valid trusted PLMNs, a G-CDR is not generated if the RAI matches the configured home (or trusted) PLMN. A G-CDR is created for all PDPs with RAIs that do not match the home or trusted PLMN.

•If the RAI field is not present in a Create PDP Context request, and an address range has not been configured by the gprs plmn ip address command with the sgsn keyword option specified, the PDP is classified as "unknown" and treated as a roamer.

•Before enabling the charging for roamers feature using the gprs charging roamers command, you must 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. First you configure the IP address range for a PLMN by using the gprs plmn ip address command and then you enable the charging for roamers feature on the GGSN using the gprs charging roamers command. You can change an 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 prepaid quota threshold

To configure the maximum limit on the volume/time quota threshold in terms of percentage of the volume/time quota received, use the gprs prepaid quota threshold command in global configuration mode. To return to the default values, use the no form of the command.

gprs prepaid quota threshold percentage

no gprs prepaid quota threshold

Syntax Description

Defaults

Prepaid quota threshold is enabled and the maximum limit is 80 percent.

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs prepaid quota threshold command to configure the maximum limit on the volume/time quota threshold in terms of percentage of the volume/time quota received.

When the prepaid quota threshold is configured, the threshold value used on the GGSN will be the lesser of the following:

•Threshold value received in a CCA

•Configured percentage of the quota grant.

For example, if a DCCA server sends quota grant in a CCA with a volume quota of 1000 bytes and a volume quota threshold of 900 bytes, the percentage is more than the default gprs prepaid quota threshold command limit (1000*80/100). The GGSN will not honor the threshold received, but will set the threshold to 800 internally, and whenever usage falls below 800 bytes rather than 900 bytes, the GGSN will send a CCR update to the DCCA server to reauthorize quota.

If the DCCA server sends quota grant in the CCA with a volume quota of 1000 bytes and a volume quota threshold of 500 bytes, the GGSN will accept 500 bytes as the threshold because it is less than the configured maximum limit.

This command applies to both volume quota and time quota.

Examples

The following example sets the maximum threshold to 50 percent:

ggsn(config)# gprs prepaid quota threshold 50

Related CommandsE

gprs prepaid stand-alone

To configure the GGSN to perform prepaid quota enforcement in standalone mode, use the gprs prepaid stand-alone command in global configuration mode. To return to the default, use the no form of this command.

gprs prepaid stand-alone

no gprs prepaid stand-alone

Syntax Description

This command has no keywords or arguments.

Defaults

Disabled. Prepaid quota enforcement is provided by the eGGSN (GGSN and Cisco CSG2).

Command Modes

Global configuration

Command History

Usage Guidelines

Use the gprs prepaid stand-alone command to configure the GGSN to perform prepaid quota enforcement without using a Cisco Content Services Gateway - 2nd Generation (CSG2).

Typically, prepaid quota enforcement is provided the eGGSN (GGSN and CSG2 working together).

When prepaid quota enforcement is provided by the eGGSN, the CSG2 monitors the data plane packet sent on the Gi interface. When a PDP context is first created, the GGSN interacts with the OCS server to determine the quota available to the user, and if so, pushes the quota to the CSG2. Once the PDP context is established, the CSG2 monitors the data packets sent on the Gi interface and requests more quota if required. The CSG can perform volume and time quota on multiple categories for the same user.

When the prepaid quota enforcement is performed by a GGSN in standalone mode, the GGSN monitors data packets on volume basis, time basis, or both for each prepaid subscriber. If configured for both volume and time quota, the GGSN inspects both usages, and request additional quota as soon as either usage meets the threshold or expires.

When configuring standalone GGSN prepaid quota enforcement, note the following:

•The measurement of time starts as soon as the session is established.

•The GGSN monitors on a per-user basis, not on a per-service basis.

•In a redundant configuration, the active GGSN synchronizes quota allocated information to the standby GGSN when event triggers occur, such as at each quota grant time. (Periodic synchronization of quota usage information is not preformed). To ensure a user is not overcharged, the standby and active GGSNs maintain synchronization of the CC-Request-Number along with each quota grant.

•Quota is monitored on a per-user basis. Therefore, when the standalone GGSN requests quota, only one service is expected in the MSCC AVP. If the CCA contains multiple services, or no service in the MSCC AVP, the CCA is considered an invalid answer, and the GGSN action is determined by the CCFH.

•Only single service is supported. If multiple services are configured, whether the GGSN rejects the PDP or converts it to postpaid is determined by the CCFH.

•In the case of a dual quota, the Quota Holding Timer (QHT) starts after the Quota Consumption Timer (QCT). Even though the QCT does not apply to volume quota, this behavior is due to time quota. In the case of time quota, the QHT starts after the quota consumption ceases, which occurs after the QCT.

•If there is not a DCCA profile configured under the charging profile, the PDP is rejected.

•Once a PDP is converted to postpaid, enhanced GGSN CDRs are no longer generated - only G-CDRs.

•In a redundant configuration, all timers (QHT, QCT, time threshold, etc.) except for the Quota Validity Timer (QVT) are restarted once the standby GGSN becomes active. The QVT timestamp is synchronized, and when a standby GGSN becomes active, the newly active GGSN waits for the remaining time to elapse instead of restarting the timer.

Examples

The following example configures the GGSN to preform prepaid quota enforcement in standalone mode:

Router(config)# gprs prepaid stand-alone

Related CommandsE

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) is created with 100000 kbps allocated to it. Additionally, a percentage of that 100000 kbps of bandwidth is 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 is 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 class (maximum peak- 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

When 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

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 to always include the CHAP challenge 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 to the Cisco CSG2, 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 is 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 you configure the gprs radius attribute quota-server ocs-address command, the CSG can interface directly with an external OCS to which it has a GTP' interface. In a service-aware GGSN implement using OCS address selection support, the external OCS functions as the quota server for the prepaid subscribers and provides an alternative online billing solution than the one provided by the GGSN using Diameter/DCCA. In a service-aware GGSN implementation using Diameter/DCCA, the GGSN functions as

the quota server for prepaid subscribers.

When the gprs radius attribute quota-server ocs-address command is configure, the GGSN functions as the quota server for just postpaid subscribers. The GGSN does not generate enhance G-CDRs for prepaid subscribers, 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 subscribers:

gprs radius attribute quota-server ocs-address

Related Commands

gprs radius attribute session-timeout

To specify to include the Session-Timeout (Attribute 27) field 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