Broadband High Availability Stateful Switchover
First Published: December 4, 2006
Last Updated: March 14, 2011
The Cisco IOS XE Broadband High Availability Stateful Switchover feature provides the capability for dual Route Processor systems to support stateful switchover of Point-to-Point Protocol over X (PPPoX, where X designates a family of encapsulating communications protocols such as PPP over Ethernet [PPPoE], PPP over ATM [PPPoA], PPPoEoA, PPPoEoVLAN implementing PPP) sessions, thus allowing applications and features to maintain a stateful state while system control and routing protocol execution is transferred between an active and a standby processor.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information for Broadband High Availability Stateful Switchover.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
•Prerequisites for Broadband High Availability Stateful Switchover
•Restrictions for Broadband High Availability Stateful Switchover
•Information About Broadband High Availability Stateful Switchover
•How to Configure Broadband High Availability Stateful Switchover
•Configuration Examples for Broadband High Availability Stateful Switchover
•Additional References
•Feature Information for Broadband High Availability Stateful Switchover
Prerequisites for Broadband High Availability Stateful Switchover
The stateful switchover (SSO) and nonstop forwarding (NSF) features must be enabled. For more information about SSO, see the "Stateful Switchover" module. For more information about NSF, see the "Configuring Nonstop Forwarding" module.
Restrictions for Broadband High Availability Stateful Switchover
SSO is supported only on High Availability (HA) network devices.
Information About Broadband High Availability Stateful Switchover
•Feature Design of Broadband High Availability Stateful Switchover
•Benefits of Broadband High Availability Stateful Switchover
Feature Design of Broadband High Availability Stateful Switchover
Prior to the implementation of the Broadband High Availability Stateful Switchover feature, unplanned control plane and dataplane failures resulted in service outages and network downtime for PPPoX sessions. Cisco HA features, including SSO, enable network protection by providing fast recovery from such failures. The Broadband High Availability Stateful Switchover feature eliminates a source of outages by providing for stateful switchover to a standby processor while continuing to forward traffic. SSO protects from hardware or software faults on an active Route Processor (RP) by synchronizing protocol and state information for supported features with a standby RP, ensuring no interruption of sessions or connections if a switchover occurs.
The SSO feature takes advantage of RP redundancy by establishing one of the RPs as the active processor, designating the other RP as the standby processor, and then synchronizing critical state information between them. Following an initial (bulk) synchronization between the two processors, SSO dynamically maintains RP state information between them. A switchover from the active to the standby processor occurs when the active RP fails, when it is removed from the networking device, or when it is manually taken down for maintenance. The standby RP then takes control and becomes the active RP, preserving the sessions and connections for the supported features. At this time, packet forwarding continues while route convergence is completed on the newly active RP. A critical component of SSO and Cisco HA technology is the cluster control manager (CCM) that manages session re-creation on the standby processor. The Broadband High Availability Stateful Switchover feature allows you to configure subscriber redundancy policies that tune the synchronization process. For more information, see the "Configuring Subscriber Redundancy Policy for Broadband HA Stateful Switchover" section.
The Broadband High Availability Stateful Switchover feature works with the Cisco NSF and SSO HA features, to maintain PPPoX sessions. NSF forwards network traffic and application state information so that user session information is maintained after a switchover.
For information about High Availability and stateful switchover, see the "High Availability Overview" chapter in the Cisco ASR 1000 Series Aggregation Services Routers Software Configuration Guide.
Supported Broadband Aggregation Protocols
The Broadband High Availability Stateful Switchover feature set supports the broadband aggregation protocols described in the following sections:
•SSO PPPoA
•SSO L2TP
•SSO PPPoE
•SSO RA-MLPS VPN
SSO PPPoA
The Broadband High Availability Stateful Switchover feature delivers stateful switchover capability for PPP over ATM (PPPoA) sessions during Route Processor switchover.
SSO L2TP
The L2TP HA Session SSO/ISSU on a LAC/LNS feature provides a generic stateful switchover/In Service Software Upgrade (SSO/ISSU) mechanism for Layer 2 Tunneling Protocol (L2TP) on a Layer 2 Access Concentrator (LAC) and a Layer 2 Network Server (LNS). This feature preserves all fully established PPP and L2TP sessions during an SSO switchover or an ISSU upgrade or downgrade.
SSO PPPoE
The Broadband High Availability Stateful Switchover feature delivers stateful switchover capability for PPP over Ethernet (PPPoE) subscriber access sessions, including PPPoE, PPPoEoVLAN, and PPPoEoQinQ.
SSO RA-MLPS VPN
The Broadband High Availability Stateful Switchover feature delivers stateful switchover capability for PPPoX terminated into remote access (RA)-Multiprotocol Label Switching (MPLS) VPN or PPPoX into MPLS VPN sessions during processor switchover.
Figure 1 shows a typical broadband aggregation HA deployment with SSO functionality.
Figure 1 Broadband Aggregation High Availability Deployment
Benefits of Broadband High Availability Stateful Switchover
•Reduces operating costs associated with outages.
•Delivers higher service levels to subscribers.
•Improves network availability.
•Promotes continuous connectivity, lower packet loss, and consistent path flow through nodes providing specific network services.
•Mitigates service disruptions, reduces downtime costs, and increases operational efficiency.
How to Configure Broadband High Availability Stateful Switchover
•Configuring Subscriber Redundancy Policy for Broadband HA Stateful Switchover
•Verifying and Troubleshooting Subscriber Redundancy Policy for Broadband HA Stateful Switchover
Configuring Subscriber Redundancy Policy for Broadband HA Stateful Switchover
Perform this task to configure subscriber redundancy policy for HA SSO capability for broadband subscriber sessions.
SUMMARY STEPS
1. enable
2. configure terminal
3. subscriber redundancy {bulk limit {cpu percent delay seconds [allow sessions] | time seconds} | dynamic limit cpu percent delay seconds [allow sessions] | delay seconds | rate sessions seconds}
4. exit
DETAILED STEPS
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Step 1 |
enable
Router> enable |
Enables privileged EXEC mode. •Enter your password if prompted. |
Step 2 |
configure terminal
Router# configure terminal |
Enters global configuration mode. |
Step 3 |
subscriber redundancy {bulk limit {cpu percent delay seconds [allow sessions] | time seconds} | dynamic limit cpu percent delay seconds [allow sessions] | delay seconds | rate sessions seconds}
Router(config)# subscriber redundancy bulk limit cpu 75 delay 20 allow 30 |
(Optional) Configures subscriber redundancy policy. •bulk—Configures bulk synchronization redundancy policy. •limit—Specifies the limit for the synchronization. •cpu percent—Specifies a CPU busy threshold value as a percentage. Range is from 0 to 100; default is 90. •delay seconds—Specifies the minimum amount of time, in seconds, that a session must be ready before bulk or dynamic synchronization occurs. Range is from 1 to 33550. •allow sessions—(Optional) Specifies the minimum number of sessions to synchronize once the CPU busy threshold is exceeded and the specified delay is met. Range is from 1 to 2147483637; default is 25. •dynamic—Configures a dynamic synchronization redundancy policy. •rate sessions seconds—Specifies the number of sessions per time period for bulk and dynamic synchronization. –sessions—Range is from 1 to 32000; default is 250. –seconds—Range in seconds is from 1 to 33550; default is 1. |
Step 4 |
exit
Router(config)# exit |
Exits global configuration mode and returns to privileged EXEC mode. |
Verifying and Troubleshooting Subscriber Redundancy Policy for Broadband HA Stateful Switchover
To view the configuration, use the show running-config command. Sample output is available at "Configuration Examples for Broadband High Availability Stateful Switchover" section.
SUMMARY STEPS
1. show ccm clients
2. show ccm sessions
3. show ppp subscriber statistics
4. show pppatm statistics
5. show pppoe statistics
6. show vpdn redundancy
7. show vpdn history failure
8. show pppatm redundancy
9. show pppoe redundancy
10. debug pppatm redundancy
11. debug pppoe redundancy
DETAILED STEPS
Step 1 show ccm clients
This command is useful for troubleshooting the CCM synchronization component. This command
displays information about the CCM, which is the HA component that manages the capability to
synchronize session launch on the standby processor of a redundant processor HA system.
Active Route Processor
CCM bundles sent since peer up:
Sent Queued for flow control
Client events sent since peer up:
Standby Route Processor
CCM bundles rcvd since last boot:
Client events extracted since last boot:
Step 2 show ccm sessions
This command is useful for troubleshooting the CCM synchronization component. This command shows information about sessions managed by CCM.
Active Route Processor
Router# show ccm sessions
Global CCM state: CCM HA Active - Dynamic Sync
Global ISSU state: Compatible, Clients Cap 0x9EFFE
Current Bulk Sent Bulk Rcvd
----------- ----------- -----------
Number of sessions in state Down: 0 0 0
Number of sessions in state Not Ready: 0 0 9279
Number of sessions in state Ready: 0 0 6721
Number of sessions in state Dyn Sync: 16000 16000 0
Timeout: Timer Type Delay Remaining Starts CPU Limit CPU Last
------------ -------- --------- ----------- --------- --------
Dynamic CPU 00:00:10 - 0 90 0
Bulk Time Li 00:08:00 - 1 - -
RF Notif Ext 00:00:01 - 475 - -
Standby Route Processor
Router# show ccm sessions
Global CCM state: CCM HA Standby - Collecting
Global ISSU state: Compatible, Clients Cap 0x9EFFE
Current Bulk Sent Bulk Rcvd
----------- ----------- -----------
Number of sessions in state Down: 0 0 0
Number of sessions in state Not Ready: 0 0 8384
Number of sessions in state Ready: 16000 0 7616
Number of sessions in state Dyn Sync: 0 0 0
Timeout: Timer Type Delay Remaining Starts CPU Limit CPU Last
------------ -------- --------- ----------- --------- --------
Dynamic CPU 00:00:10 - 0 90 0
Bulk Time Li 00:08:00 - 1 - -
RF Notif Ext 00:00:01 - 0 - -
Step 3 show ppp subscriber statistics
This command is useful for reviewing PPPoX session statistics. Use the show ppp subscriber statistics command to display a cumulative count of PPP subscriber events and statistics, and to display an incremental count since the clear ppp subscriber statistics command was last issued.
The following is sample output from the show ppp subscriber statistics command:
Router# show ppp subscriber statistics
PPP Subscriber Events TOTAL SINCE CLEARED
PPP Subscriber Statistics TOTAL SINCE CLEARED
Step 4 show pppatm statistics
This command is useful for obtaining statistics for PPPoA sessions. Use the show pppatm statistics command to display a total count of PPPoA events since the clear pppatm statistics command was last issued.
The following example displays PPPoA statistics:
Router# show pppatm statistics
4000 : Context Allocated events
3999 : SSS Request events
3998 : Up Dequeued events
3998 : Processing Up events
3999 : AAA unique id allocated events
3999 : No AAA method list set events
3999 : AAA gets nas port details events
3999 : AAA gets retrived attrs events
68202 : AAA gets dynamic attrs events
3999 : Access IE allocated events
Step 5 show pppoe statistics
This command is useful for reviewing PPPoX session statistics. Use the show pppoe statistics command to display a cumulative count of PPPoE events and statistics, and to display an incremental count since the clear pppoe statistics command was last issued.
The following is sample output from the show pppoe statistics command:
Router# show pppoe statistics
PPPoE Events TOTAL SINCE CLEARED
------------------------------ ------------- -------------
PPPoE Statistics TOTAL SINCE CLEARED
------------------------------ ------------- -------------
PPPoE Handles Allocated 0 0
Step 6 show vpdn redundancy
Use this command to verify the failure of any L2TP tunnels.
Router# show vpdn redundancy
L2TP HA support: Silent Failover
Checkpoint Messaging on: FALSE
L2TP Tunnels: 2/2/2/0 (total/HA-enabled/HA-est/resync)
L2TP Sessions: 10/10/10 (total/HA-enabled/HA-est)
L2TP Resynced Tunnels: 0/0 (success/fail)
Step 7 show vpdn history failure
Use this command to verify the failure of any VPDN groups.
Router# show vpdn history failure
% VPDN user failure table is empty
Step 8 show pppatm redundancy
Use the show pppatm redundancy command to display the PPPoA HA sessions summary. The following is sample output from the show pppatm redundancy command from a Cisco 10000 series router standby processor:
Router-stby# show pppatm redundancy
0 : Session recreate requests from CCM
0 : Session up events invoked
0 : Sessions reaching PTA
0 : Sessions closed by CCM
0 : Session down events invoked
0 : Queued sessions waiting for base hwidb creation
0 : Sessions queued for VC up notification so far
0 : Sessions queued for VC encap change notification so far
0 : VC activation notifications received from ATM
0 : VC encap change notifications received from ATM
0 : Total queued sessions waiting for VC notification(Encap change+VC Activation)
Step 9 show pppoe redundancy
This command is useful for reviewing PPPoX session statistics. Use the show pppoe redundancy command to display statistics and events for PPPoE sessions. This command gives a cumulative count of PPPoE events and statistics, and an incremental count since the clear pppoe redundancy command was last issued.
The following is sample output from the show pppoe redundancy command from a Cisco 10000 series router standby processor:
Router-stby# show pppoe redundancy
size max kicks starts false suspends ticks(ms)
9 PPPoE CCM EV 0 1 2 3 1 0 20
Events Queued MaxQueued Suspends usec/evt max/evt
1* 9 Recreate UP 2 0 1 0 1500 3000
2* 9 Recreate DOWN 0 0 0 0 0 0
3* 9 VC Wait UP 0 0 0 0 0 0
4* 9 VC Wait Encap 0 0 0 0 0 0
Sessions waiting for Base Vaccess: 0
Sessions waiting for ATM VC UP: 0
Sessions waiting for Auto VC Encap 0
Step 10 debug pppatm redundancy
Use the debug pppatm redundancy command to display CCM events and messages for PPPoA sessions on HA systems. This command is generally used only by Cisco engineers for internal debugging of CCM processes. The following is sample output from the debug pppatm redundancy command from a Cisco 10000 series router active processor:
Router# debug pppatm redundancy
PPP over ATM redundancy debugging is on
Step 11 debug pppoe redundancy
Use the debug pppoe redundancy command to display CCM events and messages for PPPoE sessions on HA systems. This command is generally used only by Cisco engineers for internal debugging of CCM processes.
Router# debug pppoe redundancy
Nov 22 17:21:11.327: PPPoE HA[0xBE000008] 9: Session ready to sync data
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = PADR, length = 58
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = SESSION ID, length = 2
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = SWITCH HDL, length = 4
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = SEGMENT HDL, length = 4
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = PHY SWIDB DESC, length = 20
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = VACCESS DESC, length = 28
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: Sync collection for ready events
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = PADR, length = 58
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = SESSION ID, length = 2
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = SWITCH HDL, length = 4
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = SEGMENT HDL, length = 4
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = PHY SWIDB DESC, length = 20
Nov 22 17:21:11.351: PPPoE HA[0xBE000008] 9: code = VACCESS DESC, length = 28
Configuration Examples for Broadband High Availability Stateful Switchover
This section provides the following configuration example:
•Example: Configuring Broadband High Availability Stateful Switchover
Example: Configuring Broadband High Availability Stateful Switchover
The following example shows how to configure the Broadband High Availability Stateful Switchover feature:
Router# configure terminal
Router(config)# subscriber redundancy bulk limit cpu 75 delay 20 allow 30
The following is a sample configuration of PPPoX terminated into an RA-MPLS network with SSO. Commands that appear in the configuration task tables for this feature but that do not appear in the running configuration output are configured for their default settings.
Router# show running-config
boot system bootflash:packages.conf !
aaa authentication ppp default local
no ip dhcp use vrf connected
no subscriber policy recording rules
The following lines show the subscriber redundancy policy configuration:
subscriber redundancy dynamic limit cpu 90 delay 10
subscriber redundancy bulk limit cpu 90 delay 10
subscriber redundancy rate 4000 1
subscriber redundancy delay 10
mpls ldp graceful-restart
mpls ldp router-id Loopback100
no issu config-sync policy bulk prc
no issu config-sync policy bulk bem
username cisco password 0 cisco
ip address 10.1.1.1 255.255.255.255
ip address 192.168.0.1 255.255.255.255
interface FastEthernet0/0/0
ip address 192.168.2.26 255.255.255.0
interface GigabitEthernet1/0/0
interface GigabitEthernet1/0/0.1
interface GigabitEthernet1/0/0.2
interface GigabitEthernet1/0/1
interface GigabitEthernet1/0/1.1
interface GigabitEthernet1/0/1.2
interface GigabitEthernet1/0/2
interface GigabitEthernet1/0/2.1
interface GigabitEthernet1/0/2.2
interface GigabitEthernet1/0/3
interface GigabitEthernet1/0/3.1
interface GigabitEthernet1/0/3.2
interface GigabitEthernet7/0/3
interface GigabitEthernet8/0/0
mac-address 0011.0022.0033
ip address 10.1.1.2 255.255.255.0
interface GigabitEthernet8/1/0
ip address 10.1.1.1 255.255.255.0
interface Virtual-Template1
no logging event link-status
peer default ip address pool pool1
interface Virtual-Template2
no logging event link-status
peer default ip address pool pool2
interface Virtual-Template3
no logging event link-status
peer default ip address pool pool3
interface Virtual-Template4
no logging event link-status
peer default ip address pool pool4
interface Virtual-Template5
no logging event link-status
peer default ip address pool pool5
interface Virtual-Template6
no logging event link-status
peer default ip address pool pool6
interface Virtual-Template7
no logging event link-status
peer default ip address pool pool7
interface Virtual-Template8
no logging event link-status
peer default ip address pool pool8
network 10.1.1.0 0.0.0.255 area 0
network 224.0.0.0 0.0.0.255 area 0
bgp graceful-restart restart-time 120
bgp graceful-restart stalepath-time 360
neighbor 224.0.0.3 remote-as 1
neighbor 224.0.0.3 update-source Loopback100
neighbor 224.0.0.3 activate
neighbor 224.0.0.3 send-community extended
address-family ipv4 vrf vrf1
ip local pool pool2 10.1.1.1 10.1.16.160
ip local pool pool3 10.13.1.1 10.13.16.160
ip local pool pool4 10.14.1.1 10.14.16.160
ip local pool pool5 10.15.1.1 10.15.16.160
ip local pool pool6 10.16.1.1 10.16.16.160
ip local pool pool7 10.17.1.1 10.17.16.160
ip local pool pool8 10.18.1.1 10.18.16.160
arp 10.20.1.1 0020.0001.0001 ARPA
arp vrf vrf1 10.20.1.1 0020.0001.0001 ARPA !
exception crashinfo file bootflash:crash.log !
Additional References
Related Documents
Standards
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No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
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MIBs
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None |
To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs |
RFCs
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No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature. |
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Technical Assistance
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The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
http://www.cisco.com/cisco/web/support/index.html |
Feature Information for Broadband High Availability Stateful Switchover
Table 1 lists the features in this module and provides links to specific configuration information.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note Table 1 lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Table 1 Feature Information for the Broadband High Availability Stateful Switchover Feature
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SSO—PPPoA |
Cisco IOS XE Release 3.3S |
In Cisco IOS XE Release 3.3S, this feature was implemented on ASR 1000 Series Routers. The Broadband High Availability Stateful Switchover feature delivers stateful switchover capability for PPP over ATM (PPPoA) sessions during RP switchover. The following commands were introduced or modified: subscriber redundancy, debug pppatm redundancy, debug pppoe redundancy, show pppoe redundancy, show pppatm statistics. |
SSO—PPPoE |
Cisco IOS XE Release 2.1 Cisco IOS XE Release 2.5 |
In Cisco IOS XE Release 2.1, this feature was implemented on ASR 1000 Series Routers. This feature uses the SSO—PPPoE feature to provide the capability for dual Route Processor systems to support stateful switchover of PPPoX sessions and allow applications and features to maintain state while system control and routing protocol execution is transferred between an active and a standby processor. The following commands were introduced or modified: clear ppp subscriber statistics, clear pppoe statistics, debug pppoe redundancy, show ccm clients, show ccm sessions, show ppp subscriber statistics, show pppoe statistic, subscriber redundancy. |
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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.
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