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The supervisor engine redundant operation feature allows you to install a second supervisor engine module in the Catalyst 5505 or Catalyst 5500 switches to create a high-speed, fault-tolerant environment that supports mission-critical applications. The second supervisor engine takes over if the active supervisor engine fails. No software commands are needed to enable this functionality.
When you use two supervisor engine modules in the Catalyst 5505 or 5500 switch, the first supervisor engine module to come up is considered the active module; the second supervisor engine module remains in standby mode. All network management functions, such as Simple Network Management Protocol (SNMP), command-line interface (CLI) console, Telnet, Spanning-Tree Protocol, Cisco Discovery Protocol (CDP), and virtual LAN (VLAN) Trunk Protocol (VTP), take place on the active supervisor engine module. The Ethernet ports on the standby supervisor engine module are inactive in the same way that enabled ports on disabled modules are inactive. The console port on the standby supervisor engine module is also inactive.
You must install the redundant supervisor engine modules in the first two slots of the chassis. The supervisor engine modules are hot-swappable, and the system continues to operate with the same configuration after switching over to the redundant supervisor engine. For information on installing redundant supervisor engine modules, refer to the Catalyst 5000 Series Installation Guide.
This section shows example displays of the redundant supervisor engine module.
This example shows the display for the second supervisor engine module when you enter the show module command:
Console> show module
Mod Module-Name Ports Module-Type Model Serial-Num Status
--- -------------------- ----- ------------------- -------- ---------- ------
1 Supervisor 2 100BaseTX Supervisor WS-X5509 001040409 ok
2 Supervisor 2 100BaseTX Supervisor WS-X5509 001040410 standby
5 Management 12 100BaseFX Ethernet WS-X5111 000023012 ok
8 Marketing 24 10BaseT Ethernet WS-X5010 012304930 ok
12 ATM BackBone 1 MM OC-3 ATM WS-X5155 000459238 ok
Mod MAC-Address(es) Hw Fw Sw
--- ---------------------------------------- ------ ------ -------------
1 00-40-0b-90-00-24 thru 00-40-0b-90-04-23 1.3 1.4 3.1(1)
2 00-40-0b-90-00-24 thru 00-40-0b-90-04-23 1.3 1.4 3.1(1)
5 00-40-0b-92-9e-04 thru 00-40-0b-92-9e-0f 1.1 1.1 3.1(1)
8 00-40-0b-92-9e-fc thru 00-40-0b-92-9f-13 1.0 1.1 3.1(1)
13 00-40-0b-05-01-48 1.7 2.1 3.2(3)
Console>
This example shows the display for the second supervisor engine module when you enter the show port command. The ports on the standby supervisor engine indicate a status of standby.
Console> show port Port Name Status Vlan Level Duplex Speed Type ---- -------------------- -------- ---------- ------ ------ ----- ------------ 1/1 Management Port connect 1000 high full 100 100 BASE-TX 1/2 InterSwitchLink connect trunk high full 100 100 BASE-TX 2/1 Management Port standby 1000 high full 100 100 BASE-TX 2/2 InterSwitchLink standby 1000 high full 100 100 BASE-TX ...
This example shows the display for standby supervisor engine module when you enter the show test mod_num command. You can see the diagnostic test results for both the standby and active supervisor engine modules.
Console> (enable) show test 2
Network Management Processor (NMP) Status: (. = Pass, F = Fail, U = Unknown)
ROM: . RAM: . DUART: . Flash-EEPROM: . Ser-EEPROM: . NVRAM: .
FAN: . Temperature: .
PS (3.3V) . PS (12V): . PS (24V): .
8051 Diag Status for Module 2(. = Pass, F = Fail, N = N/A)
CPU : . Ext Ram 0: . Ext Ram 1: . Ext Ram 2: N
DPRAM : . LTL Ram 0: . LTL Ram 1: N LTL Ram 2: N
BootChecksum: . CBL Ram 0: . CBL Ram 1: N CBL Ram 2: N
Saints : . Pkt Bufs : . Repeaters: N Sprom : .
SAINT Status :
Ports 1 2 3
--------------
. . .
Packet Buffer Status :
Ports 1 2 3
--------------
. . .
System Diagnostic Status : (. = Pass, F = Fail, N = N/A)
Module 2: MCP
EARL Status :
NewLearnTest: .
IndexLearnTest: .
DontForwardTest: .
MonitorTest .
DontLearn: .
FlushPacket: .
ConditionalLearn: .
EarlLearnDiscard: .
PMD Loopback Status :
Ports 1 2 3
--------------
. . .
Console> (enable)
You can switch over to the standby supervisor engine module by entering the reset mod_num command, where mod_num is the number of the active supervisor engine. After entering the reset mod_num command, you see this display:
Console> (enable)reset 1This command will force a switch-over to the standby supervisor module and disconnect your telnet session. Do you want to continue (y/n) [n]?yConnection closed by foreign host. host%
You can also switch to the standby supervisor engine module by setting the CISCO-STACK-MIB moduleAction variable to reset(2) on the active supervisor engine module.When the switchover occurs, the system sends a standard SNMP warm-start trap to the configured trap receivers.
The active supervisor engine module sends information to the standby supervisor engine module to keep the nonvolatile random-access memory (NVRAM) configuration on the standby supervisor engine current. If the software images on the active and standby supervisor engine modules are different, the active supervisor engine module downloads its image to the standby supervisor engine module.
At power-up, both supervisor engine modules run through initial module-level diagnostics. Assuming both modules pass this level of diagnostics, the two modules communicate over the backplane, allowing them to cooperate during switching-bus diagnostics. The module in slot 1 then becomes active, and the module in slot 2 enters standby mode. At this point, if the software versions of the two modules are different, the active supervisor engine automatically downloads its software image to the standby supervisor engine. If the NVRAM configuration on the two modules is different, the active supervisor engine automatically downloads its configuration to the standby supervisor engine.
If the background diagnostics on the active supervisor engine detect a major problem or an exception occurs, the active supervisor engine resets. The standby supervisor engine detects that the active supervisor engine is no longer running and becomes active. The standby supervisor engine also can detect if the active supervisor engine is not functioning and can force a reset, if necessary. Once the reset supervisor engine comes up, it behaves as if a hot swap occurred, eventually entering the standby mode.
In the case of a just-inserted supervisor engine module, the newly inserted module communicates with the active supervisor engine after completing its initial module-level diagnostics. Because the active supervisor engine is already switching traffic on the backplane, no switching-bus diagnostics are run for the just-inserted supervisor engine. Running diagnostics would disrupt normal traffic. The just-inserted supervisor engine goes immediately into standby mode. At this point, the active supervisor engine downloads software and configuration information to the standby supervisor engine, if necessary.
The switchover time does not include spanning-tree convergence time.
The Catalyst 5000 series supervisor engine boot image is stored differently in Supervisor Engine III than in Supervisor Engine II modules. Supervisor Engine II modules use 8-MB onboard Flash memory to store a single boot image, and only one boot image can be stored at a time. However, the Supervisor Engine III module has two Personal Computer Memory Card International Association (PCMCIA) slots in addition to the onboard boot Flash memory; these slots can hold PCMCIA memory cards that can store additional boot images.
The Supervisor Engine III module uses two Flash images: the boot image and the runtime image. The boot image is the image that the ROM monitor will use to boot the system the next time the system is reset. The boot image filename is specified in the BOOT environment variable, which is stored in NVRAM. The runtime image is the boot image that the ROM monitor uses to boot the Supervisor Engine III module. After the system boots, the runtime image resides in dynamic RAM (DRAM).
Since the Supervisor Engine III module can have multiple boot devices, it needs to know the name of the boot file image and its location in the Flash device in order to boot and synchronize properly.
The Supervisor Engine II module contains DRAM that stores the boot image. You can download this boot image using a Trivial File Transfer Protocol (TFTP) command or Transmission Control Protocol/Internet Protocol (TCP/IP) messages sent between the active and standby supervisor engine modules. The Supervisor Engine III module does not have memory dedicated to storing the boot image; rather, a file system is implemented in the Flash memory devices and the boot image is read directly into the file system. The valid Flash devices are as follows:
The Flash file system devices allow you to perform operations on the files stored in the Flash memory (such as copy, delete, undelete, and so on), and to store the boot image of the active supervisor engine in the standby supervisor engine boot Flash.
For information on Flash memory commands, see the "Managing the Supervisor Engine III" section in this document and the Catalyst 5000 Series Command Reference publication.
When a Catalyst 5505 or Catalyst 5500 switch with redundant Supervisor Engine III modules is powered up or reset, the runtime image and the boot image are the same on both supervisor engines. Synchronization ensures that the runtime and boot images on the standby supervisor engine are the same as the images on the active supervisor engine.
The Supervisor Engine III module can have different runtime and boot images. For example, if the current boot image and the runtime image are the same, and you change the BOOT environment variable or overwrite or destroy the current boot image on the Flash device that was used to boot the system, the runtime and boot images will differ. Whenever the boot image is reconfigured, the active supervisor engine synchronizes its current boot image with that of the standby supervisor engine.
In the synchronization process, the active supervisor engine checks the standby supervisor engine runtime image to make sure it matches its own runtime image. The active supervisor engine checks three conditions:
The following section describes the conditions that can initiate Flash synchronization. Refer to the "Synchronization Examples" section later in this chapter for examples of how the system synchronizes the Flash images on Supervisor Engine III engines with various configuration.
Certain conditions initiate the synchronization of the runtime and boot images on the active and standby Supervisor Engine III modules. Some of these conditions are as follows:
Certain conditions or events will cause the synchronization of images between redundant Supervisor Engine III modules to fail or to produce unexpected results. Some of these conditions or events are as follows:
The following examples show what happens when the synchronization function encounters certain conditions. These examples are not intended to cover every possible condition.
This section contains four examples in which the active supervisor engine runtime image is synchronized with the standby supervisor engine.
The configuration for example 1 is as follows:
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1
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| Bootflash: | f1
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1
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| Bootflash: | f1
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The configuration for example 2 is as follows:
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1
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| Bootflash: | f1
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Runtime image: | bootflash:f2
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| Boot string: | bootflash:f2,1
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| Bootflash: | f2
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The configuration for example 3 is as follows:
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1
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| Bootflash: | f1
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Runtime image: | bootflash:f2
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| Boot string: | bootflash:f2,1
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| Bootflash: | f1,f2
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The configuration for example 4 is as follows:
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1
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| Bootflash: | f1
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Runtime image: | bootflash:f2
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| Boot string: | bootflash:f2,1;
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| Bootflash: | f2, f3, f4 (less than 1 MB left on device)
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This section contains four examples in which the bootstrings on the active and standby Supervisor Engine III modules are synchronized.
The configuration for this example is as follows:
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1;
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| Bootflash: | f1
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1;
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| Bootflash: | f1
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The configuration for this example is as follows:
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1;
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| Bootflash: | f1,f2
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1;
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| Bootflash: | f1
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The configuration for this example is as follows:
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1;
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| Bootflash: | f1,f2
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1;
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| Bootflash: | f1,f2
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The configuration for this example is as follows:
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1;
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| Bootflash: | f1,f2
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Runtime image: | bootflash:f1
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| Boot string: | bootflash:f1,1;
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| Bootflash: | f0,f1,f3 (less than 1 MB left on device)
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