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Supervisor redundancy reduces unplanned downtime. It enables a quicker switchover between active and standby Supervisors in the event of a fatal error on the active Supervisor. When you configure Supervisor redundancy, the standby Supervisor is synchronized with the active Supervisor. In the event of a fatal error on the active Supervisor, the system immediately switches to the standby Supervisor.
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 Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/. An account on http://www.cisco.com/ is not required.
Note | The hardware components introduced in a given Cisco IOS-XE Release are supported in all subsequent releases unless otherwise specified. |
The Supervisor redundancy feature enables the Cisco cBR router to use two Supervisors in a redundant configuration, so that if the active Supervisor fails or becomes inactive, the system automatically performs a switchover , where the standby Supervisor takes over and assumes full responsibility for systems operations.
The Supervisor redundancy feature does not require a full reboot of the system to perform a switchover. When the system boots up, the standby Supervisor performs full initialization, which includes self initialization, running configuration synchronization from the active Supervisor, and SSO feature data synchronization from the active Supervisor, then it enters into hot standby state and monitors the active Supervisor. If the standby Supervisor detects a failure in the active Supervisor, it can quickly assume the active responsibility for systems operations.
Each Supervisor contains all the resources required to operate the router, such as bootflash memory, hard disks, Ethernet ports, and console port. In the default operation, the standby Supervisor also synchronizes the major systems files, such as the running configuration file, so that during a switchover, the standby Supervisor can duplicate the active Supervisor’s configuration.
You can use Cisco IOS CLI commands to access the standby Supervisor resources, such as the bootflash and hard disk. For example, you can use the dir command to list the contents of a device, or use the copy command to transfer files between the active and standby Supervisor.
A switchover occurs when the standby Supervisor takes over responsibilities from the active Supervisor. The switchover can occur automatically if the standby Supervisor has determined that the active Supervisor has failed, or an operator can initiate a manual switchover whenever desired.
A switchover triggers the following events:
If this is a manual switchover, the active Supervisor verifies that the standby Supervisor is present and has entered into SSO. If so, it instructs the standby Supervisor to begin switchover procedures, and the active Supervisor either attempts to reload its configured Cisco IOS software image or enters ROM monitor mode, depending on the setting of its configuration register.
The standby Supervisor assumes responsibility as the active Supervisor and brings the Cisco cBR chassis into active state, and continues the service as active Supervisor.
The new active Supervisor begins normal systems operations, including passing traffic.
Note | The Supervisor does not begin functioning as a standby Supervisor until it is booted up with a proper Cisco IOS software. |
The usual phenomenon for a Supervisor switchover to be affected is when the active Supervisor has these issues:
Supervisor hangs
Login to Supervisor console or Telnet to chassis fails
Interface cards unable to connect to active Supervisor, hence crashing
Cable modems drop offline
Chassis reload required
Reset of active Supervisor required to restore service
Note | In case there is hardware issue with the Supervisor, do not reinsert the faulty Supervisor in the chassis. Inserting a faulty Supervisor (although a standby Supervisor) may cause the interface card to switch to the faulty Supervisor causing the interface card to crash and cable modems to go offline. |
Both the active and standby Supervisors have active file systems that can be accessed to store and transfer files. The table below lists the available file systems, the filenames that you can use with CLI commands to access the file systems,and a short description of each.
File System |
File Name for CLI Commands |
Description |
---|---|---|
Stores image, crash file, core files, saved configuration files, and various user files. |
||
Stores the running configuration and other system files. |
||
Typically stores the system default configuration file and startup configuration file. |
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Protocols used to transfer files to and from remote devices. |
You can use the privileged EXEC commands dir, del, and copy to manage the contents of the file systems. You can also use the commands mkdir and rmdir to create and remove directories on bootflash or hard disks.
Following is a sample output of the show file systems command on the Cisco cBRrouter:
Router# show file systems File Systems: Size(b) Free(b) Type Flags Prefixes - - opaque rw system: - - opaque rw tmpsys: * 7800705024 1574408192 disk rw bootflash: 7800705024 1574408192 disk rw flash: 98394218496 79534682112 disk rw harddisk: 8009056256 8009023488 disk rw usb1: 33554432 33507452 nvram rw stby-nvram: - - opaque rw null: - - opaque ro tar: - - network rw tftp: - - opaque wo syslog: 33554432 33508476 nvram rw nvram: - - network rw rcp: - - network rw pram: - - network rw ftp: - - network rw http: - - network rw scp: - - network rw https: - - opaque ro cns: - - nvram rw stby-rcsf: 7800705024 1635270656 disk rw stby-bootflash: 98394218496 89040576512 disk rw stby-harddisk: - - disk rw stby-usb0: 1000787968 301559808 disk rw stby-usb1: - - opaque rw revrcsf:
When an active Supervisor fails, and the standby Supervisor becomes the active Supervisor, you must use the console port on the new active Supervisor to give CLI commands and display statistics for the router. The standby Supervisor console is disabled by default and cannot be used to run any CLI commands. Following is an sample output of the standby Supervisor console:
Router-stby> Standby console disabled Router-stby>
To access the console, move the PC or terminal's serial cable to the console port on the other Supervisor, which is now acting as the active Supervisor.
The Supervisor is not a single point of hardware failure. If a permanent hardware failure in the active Supervisor occurs, the standby Supervisor recovers the system, increasing the level of network service and reliability.
The standby Supervisor can become the active Supervisor without the manual intervention of a system operator. This reduces the recovery time and the need for an instant response from the network administrators.
The active Supervisor continues to dynamically synchronize the changed configuration and feature data with the standby Supervisor after the system reaches SSO. Therefore, the standby Supervisor always operates as a hot standby and ready to take over.
The Supervisor redundancy feature is automatically enabled when two Supervisor are installed in the Cisco cBR chassis. The active Supervisor automatically synchronizes the running configuration file with the standby Supervisor during the bootup of standby Supervisor.
Note | The Cisco cBR router supports only the SSO mode for Supervisor redundancy. The default redundancy mode is SSO and this mode does not need any new configurations. |
This section contains the following:
To manually force a switchover, so that the standby Supervisor becomes active, use the redundancy force-switchover command in privileged EXEC mode on the active Supervisor. Manually forcing a switchover is useful in the following situations:
You need to remove, replace, or upgrade the currently active Supervisor.
A previous switchover has activated the standby Supervisor and you now want to restore the previously active Supervisor.
Tip | Simply removing the active Supervisor also triggers a switchover, but using the redundancy force-switchover command does not generate a hardware alarm. |
Ensure that the standby Supervisor is in the SSO state using the show redundancy command. For more information, see Verifying Supervisor Redundancy.
Step 1 | Set the
configuration register as 0x02 and the load the appropriate image on both the
Supervisors
Example: Router# configure terminal Router(config)# config-register 0x02 Router(config)# boot system bootflash:cbrsup-universalk9.2015-03-08_01.38_xxxxx.SSA.bin
| ||
Step 2 | Use the
redundancy
force-switchover command to force the switchover.
Example: Router# redundancy force-switchover Proceed with switchover to standby RP? [confirm] Manual Swact = enabled Jan 1 19:23:22.483 R0/0: %PMAN-5-EXITACTION: Process manager is exiting: process exit with reload fru code Initializing Hardware ... System Bootstrap, Version 12.2(20141120:061458) [153], DEVELOPMENT SOFTWARE Copyright (c) 1994-2014 by cisco Systems, Inc. Compiled Thu 11/20/2014 18:04:24.91 by xxxxx The standby Supervisor becomes the active Supervisor. | ||
Step 3 | (Optional) If you have not performed Step 1, the previous active Supervisor is put into the ROM monitor mode after the switchover. To enable the previous active Supervisor to become the new standby Supervisor, manually boot up the new standby Supervisor to enter into SSO mode. |
This section describes how to change the Cisco IOS software configuration register to modify how the system behaviors at power-on or reboot. The software configuration register is a 16-bit register in NVRAM that controls the following boot functions:
Use the following procedure to change the software configuration register settings:
This section describes how to copy a configuration file to a bootflash or hard disk and configure the Cisco cBR router.
Step 1 | Copy the
configuration file to the bootflash or hard disks in both
Supervisors.
Example: Router# copy running-config bootflash:cbr8-config Router# copy running-config stby-bootflash:cbr8-config Router# copy running-config harddisk:cbr8-config Router# copy running-config stby-harddisk:cbr8-config |
Step 2 | If the
configuration file is currently on a TFTP server, copy the file from the TFTP
server to the bootflash or hard disk in each
Supervisor.
Example: Router# copy tftp://192.168.100.10/router-config bootflash:cbr8-config Router# copy tftp://192.168.100.10/router-config stby-bootflash:cbr8-config Router# copy tftp://192.168.100.10/router-config harddisk:cbr8-config Router# copy tftp://192.168.100.10/router-config stby-harddisk:cbr8-config |
This section contains the following:
Step 1 | Display the startup
configuration and verify that the lines configuring redundancy appear:
Example: Router# show startup-config ... redundancy mode sso ... | ||
Step 2 | Display the current
Supervisor
redundancy state using the
show redundancy command. The active
Supervisor
typically is shown in slot 4 (SUP0):
Router# show redundancy Redundant System Information : ------------------------------ Available system uptime = 28 minutes Switchovers system experienced = 0 Standby failures = 0 Last switchover reason = none Hardware Mode = Duplex Configured Redundancy Mode = sso Operating Redundancy Mode = sso Maintenance Mode = Disabled Communications = Up Current Processor Information : ------------------------------- Active Location = slot 4 Current Software state = ACTIVE Uptime in current state = 28 minutes Image Version = Cisco IOS Software, IOS-XE Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Experimental Version 15.5(20150302:044048) [v155_2_s_xe315_throttle-xxxxx-XE315_0301 121] This software is an Engineering Special Copyright (c) 1986-2015 by Cisco Systems, Inc. Compiled Wed 04-Mar-15 00:21 by xxxxx BOOT = bootflash:cbrsup-universalk9.2015-03-04_00.38_xxxxx.SSA.bin,12; CONFIG_FILE = bootflash:startup_config1419513118 Configuration register = 0x2 Peer Processor Information : ---------------------------- Standby Location = slot 5 Current Software state = STANDBY HOT Uptime in current state = 24 minutes Image Version = Cisco IOS Software, IOS-XE Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Experimental Version 15.5(20150302:044048) [v155_2_s_xe315_throttle-xxxxx-XE315_0301 121] This software is an Engineering Special Copyright (c) 1986-2015 by Cisco Systems, Inc. Compiled Wed 04-Mar-15 00:21 by xxxxx BOOT = bootflash:cbrsup-universalk9.2015-03-04_00.38_xxxxx.SSA.bin,12; CONFIG_FILE = bootflash:startup_config1419513118 Configuration register = 0x2 If a switchover has occurred, the show redundancy command will produce a display similar to the following, showing that the active Supervisor has changed slots that is, moving from slot 4 (SUP0) to slot 5 (SUP1). Router# show redundancy Redundant System Information : ------------------------------ Available system uptime = 39 minutes Switchovers system experienced = 1 Standby failures = 0 Last switchover reason = user forced Hardware Mode = Duplex Configured Redundancy Mode = sso Operating Redundancy Mode = sso Maintenance Mode = Disabled Communications = Up Current Processor Information : ------------------------------- Active Location = slot 5 Current Software state = ACTIVE Uptime in current state = 10 minutes Image Version = Cisco IOS Software, IOS-XE Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Experimental Version 15.5(20150302:044048) [v155_2_s_xe315_throttle-xxxxx-XE315_0301 121] This software is an Engineering Special Copyright (c) 1986-2015 by Cisco Systems, Inc. Compiled Wed 04-Mar-15 00:21 by xxxxx BOOT = bootflash:cbrsup-universalk9.2015-03-04_00.38_xxxxx.SSA.bin,12; CONFIG_FILE = bootflash:startup_config1419513118 Configuration register = 0x2 Peer Processor Information : ---------------------------- Standby Location = slot 4 Current Software state = STANDBY HOT Uptime in current state = 4 minutes Image Version = Cisco IOS Software, IOS-XE Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Experimental Version 15.5(20150302:044048) [v155_2_s_xe315_throttle-xxxxx-XE315_0301 121] This software is an Engineering Special Copyright (c) 1986-2015 by Cisco Systems, Inc. Compiled Wed 04-Mar-15 00:21 by xxxxx BOOT = bootflash:cbrsup-universalk9.2015-03-04_00.38_xxxxx.SSA.bin,12; CONFIG_FILE = bootflash:startup_config1419513118 Configuration register = 0x2 If the standby Supervisor is not installed or is not operational, the show redundancy command will produce a display similar to the following: Router# show redundancy Redundant System Information : ------------------------------ Available system uptime = 31 minutes Switchovers system experienced = 1 Standby failures = 0 Last switchover reason = user forced Hardware Mode = Simplex Configured Redundancy Mode = sso Operating Redundancy Mode = Non-redundant Maintenance Mode = Disabled Communications = Down Reason: Failure Current Processor Information : ------------------------------- Active Location = slot 5 Current Software state = ACTIVE Uptime in current state = 2 minutes Image Version = Cisco IOS Software, IOS-XE Software (X86_64_LINUX_IOSD-UNIVERSALK9-M), Experimental Version 15.5(20150302:044048) [v155_2_s_xe315_throttle-xxxxx-XE315_0301 121] This software is an Engineering Special Copyright (c) 1986-2015 by Cisco Systems, Inc. Compiled Wed 04-Mar-15 00:21 by xxxxx BOOT = bootflash:cbrsup-universalk9.2015-03-04_00.38_xxxxx.SSA.bin,12; CONFIG_FILE = bootflash:startup_config1419513118 Configuration register = 0x2 Peer (slot: 4) information is not available because it is in 'DISABLED' state
|
Step 1 | Verify the LEDs on the Supervisor Card. When a Supervisor becomes active, the RP ACT and FP ACT LEDs on the Supervisor Card illuminate green to indicate that they have initialized and acting as the active Supervisor. The RP ACT and FP ACT on standby Supervisor Card are off. For more information, see Monitoring the Supervisor in the Cisco cBR Chassis. |
Step 2 | To verify that
a switchover has occurred, use the
show redundancy switchover
history command. Assuming that the original
Supervisor had been in
slot 4 (SUP0), and that the standby
Supervisor is in slot 5
(SUP1), the following is the sample output:
Example: Router# show redundancy switchover history Index Previous Current Switchover Switchover active active reason time ----- -------- ------- ---------- ---------- 1 48 49 user forced 19:23:11 CST Sun Jan 1 2012 where, 48 indicates SUP0 and 49 indicates SUP1. |
The following example shows the relevant portion of the Cisco IOS configuration file for the default configuration for the Supervisor redundancy feature, which should be used for most applications:
Router# show running-config | sec redundancy redundancy mode sso Router#
Related Topic | Document Title |
---|---|
CMTS commands | Cisco IOS CMTS Cable Command Reference |
Stateful Switchover | Stateful Switchover |
Description | Link |
---|---|
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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 | The table below 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. |
Feature Name |
Releases |
Feature Information |
---|---|---|
Supervisor Redundancy |
Cisco IOS-XE Release 16.4.1 |
This feature was integrated into Cisco IOS-XE Release 16.4.1 on the Cisco cBR Series Converged Broadband Routers. |