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.
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see
Bug Search Tool and 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 table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to
www.cisco.com/go/cfn. An account on Cisco.com is not required.
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
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.
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.
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.
The figure below 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
limit--Specifies the limit for the synchronization.
cpupercent--Specifies a CPU busy threshold value as a percentage. Range is from 0 to 100; default is 90.
delayseconds--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.
allowsessions--(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.
ratesessionsseconds--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
Example:
Router(config)# exit
Exits global configuration mode and returns to privileged EXEC mode.
Verifying and Troubleshooting Subscriber Redundancy Policy for Broadband HA Stateful Switchover
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
Example:
Router# show ccm clients
CCM bundles sent since peer up:
Sent Queued for flow control
Sync Session 16000 0
Update Session 0 0
Active Bulk Sync End 1 0
Session Down 0 0
ISSU client msgs 346 0
Dynamic Session Sync 0 0
Unknown msgs 0 0
Client events sent since peer up:
PPP 144000
PPPoE 96002
VPDN FSP 0
AAA 64000
PPP SIP 0
LTERM 16000
AC 0
L2TP CC 0
SSS FM 16000
VPDN LNS 0
Standby Route Processor
Example:
Router# show ccm clients
CCM bundles rcvd since last boot:
Sync Session 16000
Update Session 0
Active Bulk Sync End 1
Session Down 0
ISSU client msgs 173
Dynamic Session Sync 0
Unknown msgs 0
Client events extracted since last boot:
PPP 144000
PPPoE 96002
VPDN FSP 0
AAA 64000
PPP SIP 0
LTERM 16000
AC 0
L2TP CC 0
SSS FM 16000
VPDN LNS 0
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
Example:
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
------------ -------- --------- ----------- --------- --------
Rate 00:00:01 - 64 - -
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
Example:
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
------------ -------- --------- ----------- --------- --------
Rate 00:00:01 - 0 - -
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 showpppsubscriberstatistics command to display a cumulative count of PPP subscriber events and statistics, and to display an incremental count since the clearpppsubscriberstatistics command was last issued.
The following is sample output from the showpppsubscriberstatistics command:
Example:
Router# show ppp subscriber statistics
PPP Subscriber Events TOTAL SINCE CLEARED
Encap 5 5
DeEncap 0 0
CstateUp 7 7
CstateDown 4 4
FastStart 0 0
LocalTerm 7 7
LocalTermVP 0 0
MoreKeys 7 7
Forwarding 0 0
Forwarded 0 0
SSSDisc 0 0
SSMDisc 0 0
PPPDisc 0 0
PPPBindResp 7 7
PPPReneg 3 3
RestartTimeout 5 5
PPP Subscriber Statistics TOTAL SINCE CLEARED
IDB CSTATE UP 4 4
IDB CSTATE DOWN 8 8
APS UP 0 0
APS UP IGNORE 0 0
APS DOWN 0 0
READY FOR SYNC 8 8
Step 4
showpppatmstatistics
This command is useful for obtaining statistics for PPPoA sessions. Use the showpppatmstatistics command to display a total count of PPPoA events since the clearpppatmstatisticscommand was last issued.
The following example displays PPPoA statistics:
Example:
Router# show pppatm statistics
4000 : Context Allocated events
3999 : SSS Request events
7998 : SSS Msg events
3999 : PPP Msg events
3998 : Up Pending events
3998 : Up Dequeued events
3998 : Processing Up events
3999 : Vaccess 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
showpppoestatistics
This command is useful for reviewing PPPoX session statistics. Use the showpppoestatistics command to display a cumulative count of PPPoE events and statistics, and to display an incremental count since the clearpppoestatistics command was last issued.
The following is sample output from the showpppoestatistics command:
Use this command to verify the failure of any L2TP tunnels.
Example:
Router# show vpdn redundancy
L2TP HA support: Silent Failover
L2TP HA Status:
Checkpoint Messaging on: FALSE
Standby RP is up: TRUE
Recv'd Message Count: 0
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
showvpdnhistoryfailure
Use this command to verify the failure of any VPDN groups.
Example:
Router# show vpdn history failure
% VPDN user failure table is empty
Step 8
showpppatmredundancy
Use the showpppatmredundancy command to display the PPPoA HA sessions summary. The following is sample output from the showpppatmredundancy command from a Cisco 10000 series router standby processor:
Example:
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
showpppoeredundancy
This command is useful for reviewing PPPoX session statistics. Use the showpppoeredundancy 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 clearpppoeredundancy command was last issued.
The following is sample output from the showpppoeredundancy command from a Cisco 10000 series router standby processor:
Example:
Router-stby# show pppoe redundancy
12 Event Queues
size max kicks starts false suspends ticks(ms)
9 PPPoE CCM EV 0 1 2 3 1 0 20
Event Names
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
debugpppatmredundancy
Use the debugpppatmredundancy 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 thedebugpppatmredundancy command from a Cisco 10000 series router active processor:
Example:
Router# debug pppatm redundancy
PPP over ATM redundancy debugging is on
Step 11
debugpppoeredundancy
Use the debugpppoeredundancy 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.
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
hostname Router
!
boot-start-marker
boot system bootflash:packages.conf !
enable password cisco
!
aaa new-model
!
!
aaa authentication ppp default local
!
!
!
aaa session-id common
ppp hold-queue 80000
ip subnet-zero
no ip gratuitous-arps
no ip domain lookup
ip vrf vrf1
rd 1:1
route-target export 1:1
route-target import 1:1
!
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
no mpls traffic-eng
mpls ldp graceful-restart
mpls ldp router-id Loopback100
no virtual-template snmp
no issu config-sync policy bulk prc
no issu config-sync policy bulk bem
!
redundancy mode sso
username cisco password 0 cisco
!
bba-group pppoe grp1
virtual-template 1
!
bba-group pppoe grp2
virtual-template 2
!
bba-group pppoe grp3
virtual-template 3
!
bba-group pppoe grp4
virtual-template 4
!
bba-group pppoe grp5
virtual-template 5
!
bba-group pppoe grp7
virtual-template 7
!
bba-group pppoe grp8
virtual-template 8
!
bba-group pppoe grp6
virtual-template 6
!
!
interface Loopback0
ip vrf forwarding vrf1
ip address 10.1.1.1 255.255.255.255
!
interface Loopback100
ip address 192.168.0.1 255.255.255.255
!
interface FastEthernet0/0/0
ip address 192.168.2.26 255.255.255.0
speed 100
full-duplex
!
interface GigabitEthernet1/0/0
no ip address
load-interval 30
!
interface GigabitEthernet1/0/0.1
encapsulation dot1Q 2
pppoe enable group grp1
!
!
interface GigabitEthernet1/0/0.2
encapsulation dot1Q 2
pppoe enable group grp2
!
!
interface GigabitEthernet1/0/1
no ip address
!
interface GigabitEthernet1/0/1.1
encapsulation dot1Q 2
pppoe enable group grp3
!
!
interface GigabitEthernet1/0/1.2
encapsulation dot1Q 2
pppoe enable group grp4
!
!
interface GigabitEthernet1/0/2
no ip address
!
interface GigabitEthernet1/0/2.1
encapsulation dot1Q 2
pppoe enable group grp5
!
!
interface GigabitEthernet1/0/2.2
encapsulation dot1Q 2
pppoe enable group grp6
!
!
interface GigabitEthernet1/0/3
no ip address
!
interface GigabitEthernet1/0/3.1
encapsulation dot1Q 2
pppoe enable group grp7
!
!
interface GigabitEthernet1/0/3.2
encapsulation dot1Q 2
pppoe enable group grp8
!
interface GigabitEthernet7/0/3
no ip address
!
interface GigabitEthernet8/0/0
mac-address 0011.0022.0033
ip vrf forwarding vrf1
ip address 10.1.1.2 255.255.255.0
negotiation auto
!
interface GigabitEthernet8/1/0
ip address 10.1.1.1 255.255.255.0
negotiation auto
mpls ip
!
interface Virtual-Template1
ip vrf forwarding vrf1
ip unnumbered Loopback0
no logging event link-status
peer default ip address pool pool1
no snmp trap link-status
keepalive 30
ppp authentication pap
!
interface Virtual-Template2
ip vrf forwarding vrf1
ip unnumbered Loopback0
no logging event link-status
peer default ip address pool pool2
no snmp trap link-status
keepalive 30
ppp authentication pap
!
interface Virtual-Template3
ip vrf forwarding vrf1
ip unnumbered Loopback0
no logging event link-status
peer default ip address pool pool3
no snmp trap link-status
keepalive 30
ppp authentication pap
!
interface Virtual-Template4
ip vrf forwarding vrf1
ip unnumbered Loopback0
no logging event link-status
peer default ip address pool pool4
no snmp trap link-status
keepalive 30
ppp authentication pap
!
interface Virtual-Template5
ip vrf forwarding vrf1
ip unnumbered Loopback0
no logging event link-status
peer default ip address pool pool5
no snmp trap link-status
keepalive 30
ppp authentication pap
!
interface Virtual-Template6
ip vrf forwarding vrf1
ip unnumbered Loopback0
no logging event link-status
peer default ip address pool pool6
no snmp trap link-status
keepalive 30
ppp authentication pap
!
interface Virtual-Template7
ip vrf forwarding vrf1
ip unnumbered Loopback0
no logging event link-status
peer default ip address pool pool7
no snmp trap link-status
keepalive 30
ppp authentication pap
!
interface Virtual-Template8
ip vrf forwarding vrf1
ip unnumbered Loopback0
no logging event link-status
peer default ip address pool pool8
no snmp trap link-status
keepalive 30
ppp authentication pap
!
router ospf 1
log-adjacency-changes
nsf
network 10.1.1.0 0.0.0.255 area 0
network 224.0.0.0 0.0.0.255 area 0
!
router bgp 1
no synchronization
bgp log-neighbor-changes
bgp graceful-restart restart-time 120
bgp graceful-restart stalepath-time 360
bgp graceful-restart
neighbor 224.0.0.3 remote-as 1
neighbor 224.0.0.3 update-source Loopback100
no auto-summary
!
address-family vpnv4
neighbor 224.0.0.3 activate
neighbor 224.0.0.3 send-community extended
exit-address-family
!
address-family ipv4 vrf vrf1
redistribute connected
redistribute static
no auto-summary
no synchronization
exit-address-family
!
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
ip classless !
!
no ip http server
!
!
arp 10.20.1.1 0020.0001.0001 ARPA
arp vrf vrf1 10.20.1.1 0020.0001.0001 ARPA !
!
!
line con 0
line aux 0
line vty 0 4
password cisco
!
exception crashinfo file bootflash:crash.log !
end
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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Link
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Feature Information for Broadband High Availability Stateful Switchover
The following table provides release information about the feature or features described in this module. This table 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.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to
www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1 Feature Information for the Broadband High Availability Stateful Switchover Feature
Feature Name
Releases
Feature Information
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:
subscriberredundancy,
debugpppatmredundancy,
debugpppoeredundancy,
showpppoeredundancy,
showpppatmstatistics.
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:
clearpppsubscriberstatistics,
clearpppoestatistics,
debugpppoeredundancy,showccmclients,showccmsessions,showpppsubscriberstatistics,showpppoestatistic,subscriberredundancy.