Table Of Contents
Route Processor Redundancy Plus for the
Cisco 12000 Series Internet RouterSynchronization During Initialization
Synchronization of Startup Config
Incremental Synchronization of the Running Configuration
Terminology Changes with Cisco IOS Release 12.0(17)ST
RP Alphanumeric LED Message Changes
Supported Standards, MIBs, and RFCs
Route Processor Redundancy Plus for the
Cisco 12000 Series Internet Router
Feature History
This publication describes the Route Processor Redundancy Plus (RPR+) feature. It includes information on the benefits of the feature, supported platforms, prerequisites, configuration examples, and command reference.
This publication includes the following sections:
•
Supported Standards, MIBs, and RFCs
Feature Overview
When two route processors (RPs) are installed in a Cisco 12000 series Internet Router chassis, one RP acts as the active RP, and the other acts as a backup, or standby, RP. If the active RP fails, or is removed from the system, the standby RP detects the failure and initiates a switchover. During a switchover, the standby RP assumes control of the router, connects with the network interfaces, and activates the local network management interface and system console.
Using the RPR+ feature, the standby RP is fully initialized and configured. This allows RPR+ to dramatically shorten the switchover time if the active RP fails, or if a manual switchover is performed. Because both the startup config and running config are continually synchronized from the active to the standby RP, line cards are not reset during a switchover. The interfaces remain up during this transfer, so neighboring routers do not detect a link flap (that is, the link does not go down and back up).
Note
This section describes the switchover process with RPR+, including synchronization between the active and standby RPs and includes the following topics:
•
Synchronization
To achieve the benefits of RPR+, the chassis and slot configuration information is synchronized from the active RP to the standby RP at startup and whenever changes to the active RP configuration occur. This synchronization occurs in two separate phases:
•
•
Synchronization During Initialization
When a system with RPR+ is initialized, the active RP performs a chassis discovery (discovery of the number and type of line cards and fabric cards in the system) and parses the startup configuration file.
The active RP then synchronizes this data to the standby RP and instructs the standby RP to complete its initialization. This method ensures that both RPs contain the same configuration information.
Note
Synchronization of Startup Config
The startup config is a text file stored in the RP's NVRAM. During system startup, the startup config file is copied from the active RP to the standby RP. Any existing startup config file on the standby RP is overwritten.
The startup config file is also synced whenever you perform the following operations:
•
•
•
•
•
•
•
Note
Incremental Synchronization of the Running Configuration
When both RPs are fully initialized, any further changes to the running config are synced to the standby RP as they occur.
CLI commands
CLI changes to the running config are synced from the active RP to the standby RP. In effect, the CLI command is run on both the active and the standby RP.
SNMP SET Commands
Configuration changes caused by an SNMP SET are also synced on a case-by-case basis. Currently only two SNMP configuration SETs are supported on the Cisco 12000 series Internet Router:
•
•
Changes to Chassis State
•
•
•
Terminology Changes with Cisco IOS Release 12.0(17)ST
In Cisco IOS release 12.0(17)ST and later, the terms for "Primary RP", "Secondary RP", and "failover" have been replaced by "Active RP", "Standby RP", and "switchover", respectively.
RP Alphanumeric LED Message Changes
The following RP LED Messages are changed with Cisco IOS Release 12.0(17)ST.
PRI RP
ACTV RP
This RP is the active RP
SEC RP
STBY RP
This RP is the standby RP
CLI Changes
As a part of the terminology change, the following CLI commands have been changed with Cisco IOS release 12.0(17)ST. The functionality of these new commands is identical to the old commands:
Note
Benefits
RPR+ is part of an ongoing effort to improve high availability in Cisco 12000 series Internet Routers.
Standard RPR
In standard RPR, the system implemented Extended High System Availability (EHSA) redundancy, wherein the standby RP suspended its initialization midway through the startup process. To complete the initialization during a switchover, all line cards were reset and the switch fabric was reinitialized. Since initialization of the standby RP was suspended before configuration was parsed, chassis discovery and startup config parsing were conducted during the switchover.
Improved Switchover Time with RPR+
RPR+ provides a faster switchover by fully initializing and fully configuring the standby RP. The configuration data on the standby RP is fully synchronized with the active RP.
Neighboring Routers Do Not See a Link Flap
Because the interfaces remain up across a switchover, neighboring routers do not see a link flap (the link does not go down and back up).
Restrictions
Supported Line Cards
See the Release Notes for Cisco IOS Release 12.0 S for the list of supported line cards.
Note
General Restrictions
•
Cisco IOS images, the system reverts to standard RPR mode even if RPR+ is configured.•
•
•
Note
Note
Dynamic States
Dynamic states information is maintained on the active RP. However, it is not synchronized to the standby RP, so dynamic states information is lost on a switchover. Some examples of this include:
•
Note
•
•
•
Config Mode Restrictions
•
Config mode locked out till standby initializes•
Simultaneous configs not allowed:locked from console *(or vty#)•
Simultaneous configs not allowed, forcing out of config mode:locked from console *(or vty#).Switchover Process
•
•
•
Related Documents
•
•
•
Supported Platforms
•
See the Release Notes for Cisco IOS Release 12.0 S for the list of supported line cards.
Note
Supported Standards, MIBs, and RFCs
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco Connection Online (CCO) at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
No new or modified RFCs are supported by this feature.
Prerequisites
RPR+ is supported with the following hardware and software configuration:
•
•
•
•
•
•
Configuration Tasks
See the following sections to configure RPR+ in the Cisco 12000 series Internet Router:
Configuring RPR+
The default redundancy mode in the Cisco 12000 series Internet Router is standard RPR. To enable RPR+, both RPs must be running the same version of Cisco IOS software.
Note
Note
Verifying RPR+ Configuration
To verify RPR+ configuration, follow these steps:
Step 1
Router#show running-config
!redundancymode rpr-plus!....Step 2
Router#show redundancy
Active GRP in slot 7:Preferred GRP: 7Operating Redundancy Mode: RPR PlusAuto synch: startup-config running-configswitchover timer 8 seconds
Fast Software Upgrade
The Fast Software Upgrade (FSU) procedure allows you to upgrade the Cisco IOS image on the RPs and line cards without reinitializing the system. To perform an FSU, the Cisco IOS software is upgraded on the standby RP, and a manual switchover is performed. The new IOS image can then be upgraded on the second RP.
Step 1
Refer to the Cisco IOS Configuration Guide.
Copies the new Cisco IOS image to the bootflash/flash on both RPs.
Step 2
The commands in this step are an example of those used to boot from a new image. Refer to the Cisco IOS Configuration Guide for more details:
Router#config terminal
Router(config)# config-register 0x2
Router(config)# boot system flash slot0:gsr-p-mz.120-17.ST
Configures the RPs to boot the new image to be reloaded.
Step 3
Router# write memory
Saves the configuration.
Step 4
Router# hw-module standby reload
Resets the standby RP and brings it back online (running the new version of the Cisco IOS software).
Step 5
Router# redundancy force-switchover
Conducts a manual switchover to the standby RP. The standby RP becomes the new active RP running the new IOS image. The line cards are reset and the line card software is downloaded from the new active RP.
The old active RP reboots with the new image and becomes the standby RP.
Note
Note
Troubleshooting Tips
If RPR+ is not enabled after mode rpr-plus is run, verify that both the active and standby RPs are running the same Cisco IOS software release, 12.0(17)ST or higher. If the active RP detects a different version of the image on the standby RP, the system automatically reverts to standard RPR behavior.
Configuration Examples
This section provides an example of RPR+ configuration:
router# config terminalEnter configuration commands, one per line. End with CNTL/Z.router(config)#redundancyrouter(config-r)#mode rpr-plusrouter(config-r)#exitrouter(config)#exitrouter#02:05:36: %SYS-5-CONFIG_I: Configured from console by vty0router#show running-configBuilding configuration........!boot system flash slot0:gsr-p-mz.120-17.ST!....!redundancymode rpr-plus!....endrouter#show redundancyActive GRP in slot 15:Standby GRP in slot 7:Preferred GRP: 15Operating Redundancy Mode: RPR PlusAuto synch: startup-config running-configswitchover timer 8 seconds [default]Command Reference
This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publications.
mode {rpr|rpr-plus}
This command allows you to chose between RPR or RPR+ mode.
To enable RPR+, use the mode rpr-plus config redundancy sub mode command. To disable RPR+ and enable standard RPR, use the mode rpr command.
mode {rpr|rpr-plus}
Syntax Description
Defaults
The default value is rpr.
Command Modes
Config redundancy submode.
Command History
12.0(17)ST
This command was introduced.
12.0(22)S
This command was integrated into Cisco IOS Release 12.0(22)S.
Usage Guidelines
This command configures the redundancy mode as either RPR or RPR+. When a new configuration mode is configured, the standby RP is reloaded. Configuring the same mode again does not have any effect.
Examples
The following example configures the redundancy mode for RPR+:
mode rpr-plusshow redundancy
To display the redundancy status (either RPR or RPR+), use the show redundancy EXEC command. This command was modified to include information on RPR+.
show redundancy
Syntax Description
Defaults
No default behavior or values.
Command Modes
EXEC
Command History
11.2 GS
This command was introduced.
12.0(17)ST
This command was modified to display information on RPR+.
12.0(22)S
This command was integrated into Cisco IOS Release 12.0(22)S.
Usage Guidelines
This command is available on the active RP only.
Examples
The following example shows how to list redundancy information for a Cisco 12000 series Internet Router.
Router# show redundancyActive GRP in slot 7:Preferred GRP: 7Operating Redundancy Mode: RPR PlusAuto synch: startup-config running-configswitchover timer 8 secondsGlossary
active RP—The RP that controls the system, runs the routing protocols, and presents the system management interface.
APS—Automatic Protection Switching. SONET switching mechanism that routes traffic from working lines to protect them in case of a line card failure or fiber cut.
BGP—Border Gateway Protocol. Interdomain routing protocol. BGP exchanges reachability information with other BGP systems.
CEF—Cisco Express Forwarding
CLI—command-line interface
CSC/SFC—Clock Scheduler Card and Switch Fabric Card
Cutover—See switchover.
dCEF—Distributed CEF
DLCI—Data Link Connection Identifier. Value that specifies a PVC or SVC in a Frame Relay network.
EHSA—Enhanced High System Availability. Redundancy method wherein the standby RP suspends its initialization midway through the startup process. See also RPR.
FIB—Forwarding Information Base. The FIB is conceptually similar to a routing table or information base. It maintains a mirror image of the forwarding information contained in the IP routing table. When routing or topology changes occur in the network, the IP routing table is updated and those changes are reflected in the FIB. The FIB maintains next-hop address information based on the information in the IP routing table and is maintained by the router.
FSU—Fast Software Upgrade. A mechanism to upgrade the Cisco IOS software images on the RPs and line cards without reinitializating the entire system.
HA—High Availability
Hot swap—The feature was formerly known as OIR.
HSU—Hitless Software Upgrade. Provides continued service for planned upgrade situations.
LC—Line card
NSF—Non-Stop Forwarding. The ability of a router to continue to forward traffic toward a router that may be recovering from a transient failure. Also, the ability of a router recovering from a transient failure in the control plane to continue correctly forwarding traffic sent to it by a peer.
OIR—Online Insertion and Removal. Feature that permits the addition, replacement, or removal of cards without interrupting the system power, entering console commands, or causing other software or interfaces to shut down. Also called "hot swapping" or "power-on servicing".
POS—Packet-over-SONET interface. Enables core routers to send native IP packets directly over SONET/SDH frames.
Primary RP—Term previously used for active RP
PVC—Permanent Virtual Circuit
RP—Route Processor
RPR—Route Processor Redundancy. In RPR, linecards are reset on switchover and line card software is reloaded.
RPR+—Route Processor Redundancy Plus. An enhancement to RPR/EHSA in which the standby RP is fully initialized. An RPR+ switchover does not involve line card reset nor line card software reload.
Secondary RP—Term previously used for standby RP
SNMP—Simple Network Management Protocol
standby RP—The RP that waits for the active or primary RP to fail.
SVC—Switched Virtual Circuit
Switchover—An event in which system control and routing protocol execution is transferred from a failed processor to a standby RP.
Guest
