Cisco GGSN Release 5.1 Configuration Guide, Cisco IOS Release 12.3(11)YJ - Configuring GGSN GTP Session Redundancy [Cisco IOS Software Releases 12.3 Special and Early Deployments]

Table Of Contents

Configuring GGSN GTP Session Redundancy

GTP Session Redundancy Overview

Prerequisites

Limitations and Restrictions

Configuring GTP Session Redundancy

Configuring the GTP Session Redundancy Inter-Device Infrastructure

Configuring HSRP

Enabling Inter-Device Redundancy

Configuring the Inter-Device Communication Transport

Enabling GTP-SR on the GGSN

Configuring Charging-Related Synchronization Parameters

Monitoring and Maintaining GTP-SR

Configuration Examples

Primary Supervisor Configuration Example

Standby Supervisor Configuration Example

Primary GGSN Configuration Example

Secondary GGSN Configuration Example

Configuring GGSN GTP Session Redundancy

This chapter describes how to configure GTP session redundancy (GTP-SR) between two GGSNs.

For a complete description of the GGSN commands in this chapter, refer to the Cisco GGSN Release 5.2 Command Reference.

To locate documentation of other commands that appear in this chapter, use the command reference master index or search online. See the "Related Documents" section for a list of the other Cisco IOS software documentation that might be helpful while configuring the GGSN.

This chapter includes the following sections:

•GTP Session Redundancy Overview

•Configuring GTP Session Redundancy

•Monitoring and Maintaining GTP-SR

•Configuration Examples

GTP Session Redundancy Overview

Cisco GGSN Release 5.1 and later supports Active/Standby, 1-to-1 inter-device GTP session redundancy (GTP-SR). GTP-SR enables two GGSNs located on separate Cisco Multi-Processor WAN Application Modules (MWAMs) installed in separate Cisco 7600 series chassis to appear as one network entity and ensures that continuous service is provided to mobile subscribers in the event one of the GGSNs fails.

The Cisco GGSN software uses the Cisco IOS Hot Standby Routing Protocol (HSRP), the Cisco IOS Check-point Facility (CF) and Redundancy Framework (CF), and Stream Control Transmission Protocol (SCTP) to provide inter-device redundancy and high availability.

In a GTP-SR implementation, the Active GGSN establishes and terminates 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.

Figure 4-1 illustrates a GTP-SR implementation.

Figure 4-1 GTP-SR Configuration

Note Before GTP-SR can be enabled on the redundant GGSNs, a GTP-SR inter-device infrastructure must be configured. For information on configuring the GTP-SR inter-device infrastructure, see the "Configuring the GTP Session Redundancy Inter-Device Infrastructure" section

Prerequisites

Proper GTP-SR operation requires the following:

•Two Cisco 7600 series routers with a Cisco Supervisor Engine 720 and third-generation policy feature card (PFC3BXL) with integrated Multilayer Switch Feature Card 3 (MSFC3). The MSFC3s must be running the same Cisco IOS software release.

•A Cisco Multi-Processor WAN Application Module (MWAM) in each of the Cisco 7600 series routers. The MWAMs must be running the same Cisco IOS GGSN software release.

•HSRP Version 2.

•The Active and Standby GGSNs have the same configuration except for certain protocol-related configurations that need to be distinct (for example, the IP addresses of the HSRP-enabled interfaces and the remote IP addresses in the SCTP configuration are different). Each of the configurations must be completed in the same order.

•When upgrading to a new Cisco IOS GGSN image, both GGSNs must be loaded together virtually.

•On the SGSN, the values configured for the number GTP N3 requests and T3 retransmissions are larger than the switchover timer. This enables requests sent during a switchover to be serviced by the newly Active GGSN rather than dropped.

•RADIUS has been forced to use the IP address of a specified interface for all outgoing RADIUS packets using the ip radius source-interface global configuration command.

Limitations and Restrictions

Before configuring GTP-SR, please note the following limitations and restrictions:

•GTP-SR is supported on the Cisco 7600 platform only.

•PDP Contexts —Redundancy is not supported for the following types of PDP contexts. In the case of a switchover, these PDP contexts require re-establishment on the Standby GGSN once it becomes active.

–PPP type PDP

–PPP regeneration / L2TP access

–Network Initiated

•Timers—Except for the session timer, GGSN timers are not synchronized to the Standby GGSN. When a switchover occurs, the timers on the newly Active GGSN are restarted with an increment to prevent many of them from expiring simultaneously.

When a PDP context is recreated on the Standby GGSN, the session timer is restarted with the elapsed time subtracted from the initial session timer value. Once the session expires on the Standby GGSN, the PDP context is deleted.

•Counters and Statistics—Counters and statistics are not synchronized between the Active and Standby GGSN. If a switchover occurs, the newly Active GGSN restarts all counters and statistics.

•Sequence numbers related to GTP signaling and data are not synchronized between the Active and Standby GGSNs.

•Charging—All pertinent information to establish charging on the Standby GGSN for a PDP context is synchronized, however, the user data related charging information for a PDP context is not. Therefore all CDRs in the previously Active GGSN that were not sent to the charging gateway are lost when a switchover occurs.

•Once a GTP-SR relationship is formed between two GGSNs, modifying the configuration of a GGSN might cause the GGSN to reload before the changes can be saved. To ensure that this does not occur, before modifying the configuration of a GGSN:

–Shut down the SCTP association

–Wait until the peer GGSN become active

–Make and save the desired changes

–Reestablish the GTP-SR relationship by configuring no shutdown under the SCTP association.

Configuring GTP Session Redundancy

To configure GTP-SR, complete the tasks in the following sections:

•Configuring the GTP Session Redundancy Inter-Device Infrastructure

•Enabling GTP-SR on the GGSN

•Configuring Charging-Related Synchronization Parameters

Configuring the GTP Session Redundancy Inter-Device Infrastructure

The GGSN GTP-SR feature uses the Cisco IOS Check-point Facility (CF) to send stateful data over Stream Control Transmission Protocol (SCTP) to a redundant GGSN. Additionally, in conjunction with Cisco IOS HSRP, the GGSN uses the Cisco IOS Redundancy Facility (RF) to monitor and report transitions on Active and Standby GGSNs.

To configure the GTP-SR inter-device infrastructure before enabling GTP-SR on the redundant GGSNs, complete the tasks in the following sections

•Configuring HSRP

•Enabling Inter-Device Redundancy

•Configuring the Inter-Device Communication Transport

Configuring HSRP

The Hot Standby Router Protocol (HSRP) provides high network availability because it routes IP traffic from hosts on networks without relying on the availability of any single router. HSRP is used in a group of routers for selecting an Active router and a Standby router. HSRP monitors both the inside and outside interfaces so that if any interface goes down, the whole device is deemed to be down and the Standby device becomes active and takes over the responsibilities of an Active device.

Restrictions and Recommendations

When configuring HSRP, note that the following recommendation and restrictions apply:

•At minimum, HSRP must be enabled and an HSRP "primary" group defined on one interface per GGSN instance. A "follow" group can be configured on all other GGSN interfaces using the standby interface configuration command with the follow keyword option specified. The follow group feature enables all interfaces on which it is configured to share the HSRP parameters of the primary group. Interfaces that share the same group track states together and have the same priority.

•The same HSRP group cannot be used on another Active/Standby GGSN pair mapped to the same physical VLAN.

•Do not configure a preemption delay on the Standby GGSN using the standby preempt interface configuration command.

•When the standby use-bia command is not used to allow bridge and gateways to learn the virtual MAC address, for optimization purposes, configure the standby mac-refresh command to a value greater than the default (hello messages are sent every 10 seconds) under the main interface (gig0/0). Once configured, all HSRP groups (primary and follow) will send Hello messages only if the node is in Active mode.

•Use the same group number for each GGSN follow group as is defined for the primary group. Using the same group number for the primary and follow groups facilitates HRSP group setup and maintenance in an environment that contains a large number of GGSN interfaces and HRSP groups.

Note A GGSN will reload if additional HSRP configurations are added after the initial HSRP setup has been configured.

For complete information on configuring Cisco IOS HSRP, see "Configuring the Hot Standby Router Protocol" section of the Cisco IOS IP Configuration Guide, Release 12.3.

Enabling HSRP and Configuring an HSRP Primary Group

To enable HSRP on an interface and configure the primary group, use the following commands in interface configuration mode:

Command

Purpose

Step 1

Router(config-if)# standby version 2

Changes the HSRP version to HSRP Version 2.

Step 2

Router(config-if)# standby [group-number] ip [ip-address [secondary]]

Enables the HSRP on the interface.

Step 3

Router(config-if)# standby [group-number] priority priority

Set the Hot Standby priority used in choosing the active router. The priority value range is from 1 to 255, where 1 denotes the lowest priority and 255 denotes the highest priority. Specify that, if the local router has priority over the current active router, the local router should attempt to take its place as the active router.

Step 4

Router(config-if)# standby [group-number] name name

Specifies the name of the standby group.

Step 5

Router(config-if)# standby use-bia [scope interface]

(Optional) Configures HSRP to use the burned-in address of an interface as its virtual MAC address instead of the preassigned MAC address.

Configuring Follow Groups

Once HSRP has been enabled and the primary group configured on a GGSN interface, additional GGSN interfaces can be configured to share the HSRP parameters of the primary group by defining a follow group on the interface using the standby interface configuration command with the follow keyword option specified. Interfaces that share a group track states together and have the same priority.

Note HSRP group parameters such as priority, name, tracking, and timers are configured under the primary group only. Do not configure these parameters under follow groups because they inherit them from the primary group.

To configure an interface to follow a primary group, use the following command in interface configuration mode:

Command

Purpose

Step 1

Router(config-if)# standby group-number follow group-name

Specifies the number of the follow group and the name of the primary group to follow and share status.

Note We recommend that the group number specified is the same as the primary group number.

Step 1

Router(config-if)# standby group-number ip virtual-ip-address

Specifies the group number and virtual IP address of the follow group.

Note We recommend that the group number specified is the same as the primary group number.

Enabling Inter-Device Redundancy

To enable inter-device redundancy, use the following commands beginning in global configuration mode.

Command

Purpose

Step 1

Router(config)# redundancy inter-device

Configures redundancy and enters inter-device configuration mode.

To remove all inter-device configuration, use the no form of the command.

Step 2

Router(config-red-interdevice)# scheme standby standby-group-name

Defines the redundancy scheme that is to be used. Currently, "standby" is the only supported scheme.

•standby-group-name—Must match the standby name specified in the standby name interface configuration command (see the "Configuring HSRP" section). Also, the standby name should be the same on both GGSNs.

Step 3

Router(config-red-interdevice)# exit

Returns to global configuration mode.

Configuring the Inter-Device Communication Transport

Inter-device redundancy requires a transport for communication between the redundant GGSNs. This transport is configured using Interprocess Communication (IPC) commands.

To configure the inter-device communication transport between the two GGSNs, use the following commands beginning in global configuration mode:
Command

Purpose

Step 1

Router(config)# ipc zone default

Configures the Inter-device Communication Protocol (IPC) and enters IPC zone configuration mode.

Use this command to initiate the communication link between the Active device and the Standby device.

Step 2

Router(config-ipczone)# association 1

Configures an association between two devices and enters IPC association configuration mode.

In IPC association configuration mode, you configure the details of the association, such as the transport protocol, local port and local IP addresses, and the remote port and remote IP addresses.

Valid association IDs range from 1 to 255. There is no default value.
Step 3
Router(config-ipczone)# no shutdown
Restarts a disabled association and its associated transport protocol.

Note Shutdown of the association is required for any changes to the transport protocol parameters.
Step 4

Router(config-ipczone-assoc)# protocol sctp

Configures Stream Control Transmission Protocol (SCTP) as the transport protocol for this association and enables SCTP protocol configuration mode.
Step 5
Router(config-ipc-protocol-sctp)# local-port local_port_num
Defines the local SCTP port number to use to communicate with the redundant peer and enables IPC Transport-SCTP local configuration mode.

Valid port numbers range from 1 to 65535. There is no default value.

Note The local port number should be the same as the remote port number on the peer router.
Step 6
Router(config-ipc-local-sctp)# local ip ip_addr
Defines the local IP address that is used to communicate with the redundant peer. The local IP address must match the remote IP address on the peer router.
Step 7

Router(config-ipc-local-sctp)# keepalive [period [retries]]

Enables keepalive packets and specifies the number of times that the Cisco IOS software tries to send keepalive packets with a response before bringing down the interface or tunnel protocol for a specific interface.

Valid value for period is an integer value in seconds great than 0. The default is 10. Valid value for retries is an integer value greater than one and less than 355. The default is the previously used value or 5 if there was no value previously specified.

Step 8

Router(config-ipc-local-sctp)# retransmit-timeout interval

Configures the message retransmission time.

Valid range is 300 to 60000 milliseconds. The default is minimum 300/maximum 600.

Step 9

Router(config-ipc-local-sctp)# path-retransmit number

Configures the maximum number of keep-alive retries before the corresponding destination address is marked inactive.

Valid range is 2 to 10. The default is 4.

Step 10

Router(config-ipc-local-sctp)# assoc-retransmit number

Defines the maximum number of retransmissions over all destination addresses before an association is declared failed.

Valid range is 2 to 20. The default is 4.
Step 11
Router(config-ipc-local-sctp)# exit
Exits IPC transport - SCTP local configuration mode.
Step 12

Router(config-ipc-protocol-sctp)# remote-port port_nun

Defines the remote SCTP port that is used to communicate with the redundant peer and enables IPC Transport-SCTP remote configuration mode.

Valid port numbers range from 1 to 65535. There is no default.

Note The remote port number should be the same as the local port number on the peer device.
Step 13
Router(config-ipc-remote-sctp)# remote-ip ip_addr
Defines the remote IP address of the redundant peer that is used to communicate with the local device. All remote IP addresses must refer to the same device.
To remove an association configuration, use the no form of the command.

Enabling GTP-SR on the GGSN

To enable GTP-SR on a GGSN, use the following command in global configuration mode on both GGSNs of a redundant pair:

Command

Purpose

Router(config)# gprs redundancy

Enables GTP-SR on a GGSN.

Configuring Charging-Related Synchronization Parameters

Charging-related data necessary to establish charging for a PDP context is synchronized to the Standby GGSN. This data includes:

–Charging Identity (CID) associated with a PDP context

–Local sequence number

–Record sequence number

–GTP' sequence number

Charging Identity (CID) and Local Record Sequence Number

When an established PDP context is synchronized, the CID assigned to the PDP context's CDR is also synchronized to the Standby GGSN. When the Standby GGSN receives the synchronized data for the PDP context, if the CID value provided is greater than the current value of the global CID counter, it writes the value to the global CID counter. If a switchover occurs, the newly Active GGSN starts from the latest CID value that was written, plus a window/offset for all new PDP contexts created on the newly Active GGSN.

When the Active GGSN's CID timer expires and it writes the global CID counter value to memory, the CID value and local record sequence (if configured) are synchronized to the Standby GGSN, which writes the information to its memory. If the local sequence number is also configured, when the write timer associated with the local sequence number expires, both the CID and the local sequence number are synchronized to the Standby GGSN. When the unit becomes active, it will use the local record sequence number, plus the latest CID value written to memory, plus a window/offset for subsequent PDP contexts created on the newly Active GGSN.

Record Sequence Number

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. 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.

To configure the window size used to determine when the CDR record sequence number needs to be synchronized to the Standby GGSN, use the following command in global configuration mode:

Command

Purpose

Router# gprs redundancy charging sync-window cdr rec-seqnum size

Configures the window size used to determine when the CDR record sequence number needs to be synchronized. Valid range is 1 to 20. The default is 10.

GTP' Sequence Number

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 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.

To configure the window size used to determine when the GTP' sequence number needs to be synchronized to the Standby GGSN, use the following command in global configuration mode:

Command

Purpose

Router# gprs redundancy charging sync-window gtpp seqnum size

Configures the window size used to determine when the GTP' sequence number needs to be synchronized. Valid range is 5 to 65535. The default is 10000.

Note Since a GGSN can transmit 128 GTP packets without any acknowledgement, we recommend that you configure the window size to be greater than 128.

Monitoring and Maintaining GTP-SR

The following privilege EXEC show commands can be used to monitor the different aspects of the GTP-SR configuration on the GGSN.

Command

Purpose

Router# show gprs redundancy

Displays statistics related to GTP-SR.

Router# show redundancy [clients | counters | events | history | states | switchovers]

Displays current or historical status and related information on planned or logged handovers.

Router# show standby

Displays HSRP information.

Configuration Examples

This section provides examples of the of the following examples:

•Primary Supervisor Configuration Example

•Standby Supervisor Configuration Example

•Primary GGSN Configuration Example

•Secondary GGSN Configuration Example

Note The following configurations examples are just samples of configurations. Actual configurations vary based on network design.

Primary Supervisor Configuration Example

The following configuration example shows part of a sample configuration on the Primary Supervisor with some of the commands that you use to configure GTP-SR highlighted in bold text:
sup-primary#show running-config 
Building configuration...
Current configuration : 7144 bytes
!
! Last configuration change at 12:28:26 UTC Tue Oct 21 2003
! NVRAM config last updated at 13:32:08 UTC Thu Oct 16 2003
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname sup-primary
!
...
!
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
ip subnet-zero
!
!
no ip domain-lookup
!
!
ip slb probe PING-PROBE ping
 interval 3
 faildetect 5
!
ip slb serverfarm GGSN-SR-FARM
 probe PING-PROBE
 !
 real 10.20.30.11
  weight 4
  reassign 4
  faildetect numconns 1 numclients 1
  no inservice
 !
 real 10.20.30.12
  weight 4
  reassign 4
  faildetect numconns 1 numclients 1
  inservice
 !
 real 10.20.30.13
  weight 4
  reassign 4
  faildetect numconns 1 numclients 1
  no inservice
 !
 real 10.20.30.14
  weight 1
  faildetect numconns 1 numclients 1
  no inservice
 !
 real 10.20.30.15
  weight 1
  faildetect numconns 1 numclients 1
  no inservice
!
ip slb vserver VIRTUAL-GGSN-V0
 virtual 10.20.30.91 udp 3386 service gtp
 serverfarm GGSN-SR-FARM
 idle gtp request 180
 inservice
!
ip slb vserver VIRTUAL-GGSN-V1
 virtual 10.20.30.91 udp 2123 service gtp
 serverfarm GGSN-SR-FARM
 idle gtp request 180
 inservice
!
mpls ldp logging neighbor-changes
mls flow ip destination
mls flow ipx destination
!
spanning-tree extend system-id
!
redundancy
 mode rpr-plus
 main-cpu
  auto-sync running-config
  auto-sync standard
!
interface GigabitEthernet2/1
 description "VLAN for Inter-dev SCTP"
 no ip address
 switchport
 switchport access vlan 498
 switchport mode access
 no cdp enable
!
...
!
interface FastEthernet3/25
 description "VLAN for Gn"
 no ip address
 duplex full
 switchport
 switchport access vlan 410
 switchport mode access
 no cdp enable
!
interface FastEthernet3/26
 description "VLAN for Gi"
 no ip address
 duplex full
 switchport
 switchport access vlan 420
 switchport mode access
!
...
!
interface Vlan1
 no ip address
 shutdown
!
interface Vlan410
 description "Virtual LAN for Gn interface for all GGSNs on an MWAM"
 ip address 10.20.21.1 255.255.255.0
 no ip redirects
!
interface Vlan420
 description "One Gi Vlan all GGSN images of mwmam"
 ip address 10.20.51.1 255.255.255.0
 no ip redirects
!
interface Vlan498
 description "VLAN for Inter-dev_SCTP"
 ip address 10.70.71.1 255.255.255.0
!
router ospf 1
 router-id 10.20.1.2
 log-adjacency-changes
 summary-address 10.20.30.0 255.255.255.0
 redistribute static subnets route-map GGSN-routes
 network 10.20.1.0 0.0.0.255 area 1
!
ip classless
ip route 0.0.0.0 0.0.0.0 128.107.234.100
ip route 1.8.0.0 255.255.0.0 1.8.0.1
ip route 1.12.0.0 255.255.0.0 1.12.0.1
ip route 10.2.5.0 255.255.255.0 10.2.15.1
ip route 10.20.30.11 255.255.255.255 10.20.21.81
ip route 10.20.30.12 255.255.255.255 10.20.21.82
ip route 10.20.30.13 255.255.255.255 10.20.21.83
ip route 10.20.30.14 255.255.255.255 10.20.21.84
ip route 10.20.30.15 255.255.255.255 10.20.21.85
ip route 110.1.0.0 255.255.0.0 10.20.51.91
ip route 120.1.0.0 255.255.0.0 10.20.51.92
ip route 128.107.241.185 255.255.255.255 128.107.234.161
ip route 130.1.0.0 255.255.0.0 10.20.51.93
ip route 140.1.0.0 255.255.0.0 10.20.51.94
ip route 150.1.0.0 255.255.0.0 10.20.51.95
ip route 172.19.23.55 255.255.255.255 172.19.24.1
ip route 223.0.0.0 255.0.0.0 1.8.0.1
ip route 223.0.0.0 255.0.0.0 1.12.0.1
no ip http server
no ip http secure-server
ip pim bidir-enable
!
!
access-list 1 permit 10.20.30.0 0.0.0.255
access-list 101 permit ip 128.107.234.160 0.0.0.31 any
access-list 102 permit ip any 128.107.234.160 0.0.0.31
arp 127.0.0.22 0000.2200.0000 ARPA
!
route-map GGSN-routes permit 10
 match ip address 1
!
!         
line con 0
 exec-timeout 0 0
 logging synchronous
line vty 0 4
 exec-timeout 0 0
 password abc
 logging synchronous
 transport input lat pad mop telnet rlogin udptn nasi
line vty 5 15
 exec-timeout 0 0
 password abc
 logging synchronous
!
ntp master
end
mwd-c7609a-sup#
Standby Supervisor Configuration Example

The following configuration example shows part of a sample configuration on the Standby Supervisor with some of the commands that you use to configure GTP-SR highlighted in bold text:
sup-secondary#show running-config 
Building configuration...
Current configuration : 6430 bytes
!
version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname sup-secondary
!
...
!
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
mwam module x port y allowed-vlan 1-1000
ip subnet-zero
!         
!
no ip domain-lookup
!
...
!
ip slb vserver VIRTUAL-GGSN-V0
 virtual 10.20.30.91 udp 3386 service gtp
 serverfarm GGSN-SR-FARM
 idle gtp request 180
 inservice
!
ip slb vserver VIRTUAL-GGSN-V1
 virtual 10.20.30.91 udp 2123 service gtp
 serverfarm GGSN-SR-FARM
 idle gtp request 180
 inservice
!
...
!
interface FastEthernet2/25
 description "VLAN for Gn"
 no ip address
 switchport
 switchport access vlan 410
 switchport mode access
 no cdp enable
!
interface FastEthernet2/26
 description "VLAN for Gi"
 no ip address
 switchport
 switchport access vlan 420
 switchport mode access
 no cdp enable
!
...
!
interface Vlan410
 description "Virtual LAN for Gn interface for all GGSNs on an MWAM"
 ip address 10.20.21.2 255.255.255.0
 no ip redirects
!
interface Vlan420
 description "One Gi Vlan all GGSN images of mwmam"
 ip address 10.20.51.2 255.255.255.0
 no ip redirects
!
interface Vlan498
 description "VLAN for Inter-dev_SCTP"
 ip address 10.70.71.2 255.255.255.0
!
router ospf 1
 router-id 10.20.1.2
 log-adjacency-changes
 summary-address 10.20.30.0 255.255.255.0
 redistribute static subnets route-map GGSN-routes
 network 10.20.1.0 0.0.0.255 area 1
!
ip classless
ip route 1.8.0.0 255.255.0.0 1.8.0.1
ip route 1.12.0.0 255.255.0.0 1.12.0.1
ip route 10.20.30.11 255.255.255.255 10.20.21.81
ip route 10.20.30.12 255.255.255.255 10.20.21.82
ip route 10.20.30.13 255.255.255.255 10.20.21.83
ip route 10.20.30.14 255.255.255.255 10.20.21.84
ip route 10.20.30.15 255.255.255.255 10.20.21.85
ip route 110.1.0.0 255.255.0.0 10.20.51.91
ip route 120.1.0.0 255.255.0.0 10.20.51.92
ip route 130.1.0.0 255.255.0.0 10.20.51.93
ip route 140.1.0.0 255.255.0.0 10.20.51.94
ip route 150.1.0.0 255.255.0.0 10.20.51.95
ip route 172.19.22.60 255.255.255.255 172.19.24.1
ip route 172.19.23.55 255.255.255.255 172.19.24.1
ip route 223.0.0.0 255.0.0.0 1.8.0.1
ip route 223.0.0.0 255.0.0.0 1.12.0.1
no ip http server
no ip http secure-server
ip pim bidir-enable
!
!         
access-list 1 permit 10.20.30.0 0.0.0.255
!
route-map GGSN-routes permit 10
 match ip address 1
!
!
line con 0
 exec-timeout 0 0
 logging synchronous
line vty 0 4
 exec-timeout 0 0
 password abc
 logging synchronous
 login
 transport input lat pad mop telnet rlogin udptn nasi
line vty 5 15
 exec-timeout 0 0
 password abc
 logging synchronous
 login
!
ntp clock-period 17179775
ntp server 8.8.8.200
end
mwd-c7609b-sup#
Primary GGSN Configuration Example

The following configuration example shows part of a sample GGSN configuration on the Primary GGSN with some of the commands that you use to configure GTP-SR highlighted in bold text:
Act_GGSN#show running-config 
Building configuration...
Current configuration : 2942 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
service gprs ggsn
no service dhcp
!
hostname Act_GGSN
!
...
!
redundancy inter-device
 scheme standby Gn
!
ipc zone default
 association 1
  no shutdown
  protocol sctp
   local-port 5000
    local-ip 10.70.71.5
    keepalive 3000
    retransmit-timeout 300 10000
    path-retransmit 10
    assoc-retransmit 20
   remote-port 5000
    remote-ip 10.70.71.9
!
no aaa new-model
ip subnet-zero
!
!
no ip cef
no ip domain lookup
!
!
interface Loopback1
 description VT address of processor3:GGSN"
 ip address 10.20.30.12 255.255.255.255
!
interface Loopback2
 description "Loopback of GTP-SLB for dispatch mode"
 ip address 10.20.30.91 255.255.255.255
!
interface GigabitEthernet0/0
 no ip address
 standby use-bia
!
interface GigabitEthernet0/0.3
 description "VLAN for Gn interface of UMTS"
 encapsulation dot1Q 410
 ip address 10.20.21.52 255.255.255.0
 no ip mroute-cache
 no keepalive
 no cdp enable
 standby version 2 
 standby 7 ip 10.20.21.82
 standby 7 priority 190
 standby 7 name Gn
!
interface GigabitEthernet0/0.31
 description "VLAN for Gi interface of UMTS"
 encapsulation dot1Q 420
 ip vrf forwarding internet
 ip address 10.30.21.52 255.255.255.0
 standby 7 follow Gn
 standby 7 ip 10.30.21.82
!
interface GigabitEthernet0/0.71
 description "VLAN for inter-dev_SCTP"
 encapsulation dot1Q 498
 ip address 10.70.71.5 255.255.255.0
!
interface Virtual-Template1
 ip unnumbered Loopback1
 no ip redirects
 encapsulation gtp
 gprs access-point-list gprs
!
ip local pool APN1 110.1.0.1 110.1.10.255
ip classless
no ip http server
!
!
gprs access-point-list gprs
  access-point 1
   access-point-name apn1
   ip-address-pool local APN1
   !
  !
!
gprs gtp path-echo-interval 0
gprs gtp ip udp ignore checksum
!
gprs charging disable
gprs redundancy
!
!
...
!
!
end
Act_GGSN-3#
Secondary GGSN Configuration Example

The following configuration example shows part of a sample GGSN configuration on the Standby GGSN with some of the commands that you use to configure GTP-SR highlighted in bold text:
Stby_GGSN#show running config
Building configuration...
Current configuration : 2823 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Stby_GGSN
!
service gprs ggsn
!
...
!
redundancy inter-device
 scheme standby Gn
!
ipc zone default
 association 1
  no shutdown
  protocol sctp
   local-port 5000
    local-ip 10.70.71.9
    keepalive 3000
    retransmit-timeout 300 10000
    path-retransmit 10
    assoc-retransmit 20
   remote-port 5000
    remote-ip 10.70.71.5
!
no aaa new-model
ip subnet-zero
!
!
no ip cef
!!
interface Loopback1
 description VT address of processor3:GGSN"
 ip address 10.20.30.12 255.255.255.255
!
interface Loopback2
 description "Loopback of GTP-SLB for dispatch mode"
 ip address 10.20.30.91 255.255.255.255
!         
interface GigabitEthernet0/0
 no ip address
 standby use-bia
!
interface GigabitEthernet0/0.3
 description "VLAN for Gn interface of UMTS"
 encapsulation dot1Q 410
 ip address 10.20.21.62 255.255.255.0
 no ip mroute-cache
 no keepalive
 no cdp enable
 standby version 2 
 standby 7 ip 10.20.21.82
 standby 7 priority 160
 standby 7 name Gn
!
interface GigabitEthernet0/0.31
 description "VLAN for Gi interface of UMTS"
 encapsulation dot1Q 420
 ip vrf forwarding internet
 ip address 10.30.21.62 255.255.255.0
 standby 7 follow Gn
 standby 7 ip 10.30.21.82
!
interface GigabitEthernet0/0.71
 description "VLAN for inter-dev_SCTP"
 encapsulation dot1Q 498
 ip address 10.70.71.9 255.255.255.0
!
interface Virtual-Template1
 ip unnumbered Loopback1
 no ip redirects
 encapsulation gtp
 gprs access-point-list gprs
!
ip local pool APN1 110.1.0.1 110.1.10.255
ip classless
no ip http server
!
!
gprs access-point-list gprs
  access-point 1
   access-point-name apn1
   ip-address-pool local APN1
   !
  !       
!
gprs gtp ip udp ignore checksum
gprs gtp create-request v1 update-existing-pdp
!
gprs charging disable
gprs redundancy
!
!
...
!
!         
end
Stby_GGSN-3#