SSO Dual-Route Processors and Cisco Nonstop Forwarding. SSO is supported in Cisco IOS Release 12. Step 3:. The software upgrade procedure supported by supervisor engine redundancy allows you to reload the Cisco IOS software image on the redundant supervisor engine, and once complete, reload the active supervisor engine. Cisco NSF with SSO allows for the forwarding of data packets to continue along known routes while the routing protocol information is being restored following a switchover. 2(20)EWA and later releases. 2(20)EWA and later releases. First you can completely configure the first WLC as you wish. Device# show redundancy Redundant System Information : ----- Available system uptime = 6 days, 5 hours, 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. config redundancy mode sso. The Cisco RF Gateway 10 Supervisor Engine 7-E uplink ports are not recommended for data or management traffic in Supervisor Redundancy Mode. 0. The mode sso command can be entered only from within redundancy configuration mode. Follow these guidelines when configuring your system to SSO mode: You must use identical Cisco IOS images on the supervisor modules to support SSO mode. Follow these guidelines when configuring your system to SSO mode: You must use identical Cisco IOS images on the switches in the stack to support SSO mode. Last switchover reason = none. 5. Router#show redundancy Redundant System Information : ----- Available system uptime = 6 days, 4 hours, 17 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 =. 2(20)EWA and later releases. Verifies that SSO is enabled. The problem is a version mismatch. In this article, we take a look at how to configure High Availability Stateful Switchover (HA SSO) on the Cisco 9800 WLCs running IOS-XE using Redundancy Management Interfaces (RMI) in addition to the Redundancy Ports (RP). Example: Device(config-red)# end: Exits redundancy configuration mode and returns to. their Capwap tunnel, APs and clients get disconnected. Communications = Up. Switchover Time. If the HA unit is not an HA sku, then you need a minimum of 50 ap license. 90. Step 2. The processing of mirroring this information between route processors is known as checkpointing. 133，称为WLC2。. The Cisco Nexus 9504, 9508,. Device(config-red)# mode sso: Configures stateful switchover. Step 4: mode sso. Usage Guidelines. We have two Cisco WLC 8540 in HA pair. +1 is the power supply module reserved for redundancy. Router# copy running. Redundancy Mode (Configured) = sso Redundancy State = sso Maintenance Mode = Disabled Manual Swact = enabled Communications = Up client count = 115Operating Redundancy Mode = RPR. SSO is supported in Cisco IOS Release 12. If the router is configured for SSO mode, and the active RP fails before the standby is ready to switch over, the router will recover through a full system reset. When you configure the controller for HA SSO, the Cisco 600 Series OfficeExtend Access Points are not supported. San Jose, California 95134-1706. SSO HSRP. A router in SSO redundancy mode checkpoints Layer 2 protocol states and line card operation. Example: Device(config-red)# mode sso: Configures stateful switchover. Step 8: exit. 39. • With a Supervisor Engine 720, if all the installed switching modules have DFCs, enter the fabric switching-mode allow dcef-only command to disable the Ethernet ports on both supervisor engines, which ensures that all modules. 05-25-2012 08:56 AM - edited 03-07-2019 06:54 AM. Step 6. Enters redundancy configuration mode. If active supervisor fails, then standby sup will perform following in sequence: Layer3 protocol initialized, routing tables. The first two octets are always 169. The SSO model monitors the health of the active controller via a redundant (HA) port. 1. Operating Redundancy Mode = RPR. After this the WLC will reboot and come back as Primary and Standby WLC again. after reboot ASR can used single processer but, when I show redundancy configure still mode sso I used in config t and redundancy and default-exit and enter and save non reboot after then show config again config in redundacy mode noneUse the power redundancy-mode {combined. 5. Heres the redundancy cfg: redundancy. SSO provides RP redundancy by establishing one of the RPs as the active processor and the other RP as. Note • The two Gigabit Ethernet interfaces on the redundant supervisor engine are always active unless you enter the fabric switching-mode allow dcef-only command. Example: Device(config-red)# mode sso: Configures stateful switchover. Router(config-red)# end. Sets the router in SSO redundancy mode. Configures SSO. Step 5. Step 5:. The default mode for the Cisco 7304 router and Cisco 10000 series routers is SSO. For Enterprise Services or IP Base mode, use ISSU to upgrade software for both RPR and SSO redundant mode. 130，称为WLC1; 第二个地址为IP地址10. The following is a sample output of the show redundancy rpr command run on the Cisco StackWise Virtual active supervisor:SSO is supported in Cisco IOS Release 12. Example: Device (config-red)# endWith SSO redundancy, the StackWise Virtual standby switch is always ready to assume control if a fault occurs on the StackWise Virtual active switch. configure redundancy unit secondary. Maintenance Mode = Disabled. Enters configuration mode. config redundancy mode sso. Step 3. Configuration Examples for DHCP High Availability. Step 7: mode sso. 133，稱為WLC2。. Cisco Public HA SSO behavior Redundancy Port (RP) BRKEWN-2846 19 Redundancy Port (RP) • Syncs configuration and AP/Client databases between Active and Standby • Monitors status of the chassis • Possible single point of. When a redundant supervisor engine runs in SSO mode, the redundant supervisor engine starts up in a fully-initialized state and synchronizes with the persistent configuration and the running configuration of the active supervisor engine. Enters redundancy configuration mode. redundancy Router(config)# redundancy. The time required by the device to switch over from the active RP to the standby RP varies by platform: Although the newly active processor takes over almost immediately following a switchover, the time required for the device to begin operating again in full redundancy (SSO) mode can be several minutes, depending on the platform. The SSO/ISSU feature supports only the Cisco ASR 1000 Series Aggregation Services Routers intrachassis (RP-to-RP) SSO, but not the interchassis (Cisco ASR1K-to-Cisco ASR1K) SSO. Router#show redundancy Redundant System Information : ----- Available system uptime = 6 days, 4 hours, 17 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. WLC のステータスや設定を確認する. ) To minimize down time during software changes on the supervisor engine, load the new image onEnters redundancy configuration mode. Example: Device(config-red)# exit: Exits redundancy. mode sso. SSO HSRP. The mode sso command can be entered only from within redundancy configuration mode. SSO is supported in Cisco IOS Release 12. Step 6. † Software. mode sso. 0 10. . Step 5. SSO pair connected to upstream VSS pair with split links and RP connected back to back. Example: Device (config-red)# mode sso: Configures SSO. I will show you how to make a wireless-controller-cluster. Example: Device (config-red)# mode sso: Configures SSO. Switches can run multiple route processors (supervisors) in 3 modes: RPR (Route Processor Redundancy) RPR+ (Route Processor Redundancy plus) SSO (Stateful Switchover) While RPR was the 1 st one to be introduced, RPR+ came in later and the latest offering was SSO. SSO refers to the implementation of Cisco IOS software that allows applications and features to maintain a defined state between an active and standby Route Processor (RP). 131. To reload the standby switch if a parser return code (PRC) failure occurs during configuration synchronization, use the policy config-sync reload command in redundancy configuration. Catalyst 4500 series switches allow a standby supervisor engine to take over if the active supervisor engine fails. In an HA environment using FlexConnect locally switched clients, the client information might not show the username. 0. Check the Boot Mode 3. My routers only show redundancy mode as none. 0SG and later releases. auto-sync config-register. To reload the standby switch if a parser return code (PRC) failure occurs during configuration synchronization, use the policy config-sync reload command in redundancy configuration. core-7606-01#show redundancy . Router# copy running-config. Sw-4510R (config-red)#>redundancy Sw-4510R (config-red)#mode sso Changing to sso mode will. end. For Enterprise Services or IP Base mode, use ISSU to upgrade software for both RPR and SSO redundant mode. Enters redundancy configuration mode. 48. Step 5: exit. Hardware Mode = Simplex. end. 除了這些IP地址外. Configured Redundancy Mode = sso Operating Redundancy Mode = sso Maintenance Mode = Disabled Communications = Up Current Processor Information :-----Active Location = slot 1 Current Software state = ACTIVE Uptime in current state = 23 hours, 52 minutes Image Version = Cisco IOS Software [Fuji], Catalyst L3 Switch Software. main-cpu. Step 5. and the redundant supervisor engine boots into a partially-initialized state in RPR mode and a fully-initialized state in SSO mode. Step 2 Router(config-red)# mode sso Configures SSO. RPR redundancy mode is used. If the router is configured for SSO mode, and the active RP fails before the standby is ready to switch over, the router will recover through a full system. Cisco 3504 Controllers. When this command is entered, the redundant supervisor engine is reloaded and begins to work in SSO mode. Enabling SSO reboots the controllers to negotiate the HA role as per the configuration performed. When this command is entered, the standby switch is reloaded and begins to work in SSO mode. Follow these guidelines when configuring your system to SSO mode: You must use identical Cisco IOS images on the switches in the stack to support SSO mode. The SSO HSRP feature enables the Cisco IOS HSRP subsystem software to detect that a standby RP is installed and the system is configured in SSO redundancy mode. The software will prompt to reboot the Standby Supervisor (in slot 5) - confirm to reboot - exit configuration mode and save the configuration. auto-sync startup-config. When a redundant supervisor engine runs in SSO mode, the redundant supervisor engine starts up in a fully-initialized state and synchronizes with the persistent configuration and the running configuration of the active supervisor engine. Cisco Employee. The mode sso command can be entered only from within redundancy configuration mode. Once config is bulk-synced the primary unit is now in HOT STANDBY. Router(config-red)# end. Redundancy State = sso . In Cisco Wireless LAN Controllers, redundancy is achieved in two ways— n+1 and AP SSO redundancy. restart the Wireless controller in maintenance mode. Configuration Examples for DHCP High. x. Step 4. Image Version = Cisco IOS Software, IOS-XE Software, Catalyst 3 850 L3 Switch Software (CAT3850-UNIVERSALK9-M), Version 03. HSRP is SSO aware on interfaces that are configured for HSRP and the standby RP is automatically reset. Router(config)# mode sso. Step 5. Wrong handling can happen and. Redundancy Mode Support in Cisco IOS Releases Platform Mode 12. Step 2: mode sso. 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. Router# show redundancy Operating mode is sso redundancy mode sso hw-module slot 6 image disk0:rsp-pv-mz hw-module slot 7 image disk0:rsp-pv-mz Active in slot 6 Standby in slot 7 The system total uptime since last reboot is 2 weeks, 23 hours 41. Enters redundancy configuration mode. Stateful Switchover enabled routers will always checkpoint line card. 61 /24. 6. Step 3:. # redundancy Switch(config-red)# mode sso Switch(config-red)# end Switch# show redundancy states my state = 13 -ACTIVE peer. Step 5: end. Follow these guidelines when configuring your system to SSO mode: You must use identical Cisco IOS images on the supervisor modules to support SSO mode. Router# configure terminal. Book Contents Book Contents. 1. The processing of mirroring this information between route processors is known as checkpointing. 0. . To enable Cisco StackWise Virtual on a switch, use the stackwise-virtual command in the global configuration mode. To disable Cisco StackWise Virtual, use the no form of this command. Route Processor Redundancy (RPR) refers to the provision of support for the redundancy feature. The sku on the box for the HA should have this part number: air-ct5508-ha-k9. Follow these guidelines when configuring your system to SSO mode: You must use identical Cisco IOS images on the switches in the stack to support SSO mode. after reboot ASR can used single processer but, when I show redundancy configure still mode sso I used in config t and redundancy and default-exit and enter and save non reboot after then show config again config in redundacy mode none Bias-Free Language. Convert RPR to SSO mode, this will force a reboot on standby supervisor. Step 4: show running-config Example:Enters redundancy configuration mode. On primary controller, disable SSO using the command: Config redundancy mode disable The Active and Standby WLCs. 2. The switch is supports route processor redundancy (RPR). When this command is entered, the standby supervisor module is reloaded and begins to work in SSO mode. When this command is entered, the standby switch is reloaded and begins to work in SSO mode. Switchover Process Restrictions † If any changes to the fabric configuration happen simultaneously with an RP switchover, the chassis is reset and all line cards are reset. When this command is entered, the standby switch is reloaded and begins to work in SSO mode. Check if Auto-Boot is Enabled 6. Check if Switches are in SSO Mode 5. SSO HSRP alters the behavior of HSRP when a device with redundant Route Processors (RPs) is configured for stateful switchover (SSO) redundancy mode. Step 5. Router# show running-config. Example: Device(config-red)# end: Exits redundancy configuration mode and returns to. (CSCec05612)Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide, Release 12. Router# show redundancy states. Example: Device(config-red)# end: Exits redundancy configuration mode and returns to. ATM SSO is not configurable and runs by default on networking devices configured with ATM and Redundancy Mode SSO. Example: Router(config-red)# mode sso. Step 2 Router(config-red)# mode sso Configures SSO. Step 6. Router# configure terminal. Now if the HA unit is indeed an HA sku, then you don't need to have any license and all you have to do is enable secondary unit: config redundancy unit secondary. Step 6. Stateful Switchover is particularly useful in conjunction with Nonstop Forwarding. When the redundant supervisor engine is inserted, the active supervisor engine detects its presence, and the redundant supervisor engine boots into a partially-initialized state in RPR mode and a fully-initialized state in SSO mode. In an HA environment using FlexConnect locally switched clients, the client information might not show the username. Step 3. Since we couldnt afford downtime I rebooted standby controller that was in maintenance mode and it was able to boot in sso redundant mode. SSO checkpointing is the process of mirroring information between RPs. SSO is supported in Cisco IOS Release 12. Redundancy Mode (Configured) = sso Redundancy State = sso Maintenance Mode = Disabled Manual Swact = enabled Communications = Up client count = 115Cisco NSF は、SSO 対応のデバイスにおけるルーティング フラップを抑止することによって、ネットワークの安定性を保ちます。 Cisco NSF と SSO により、スイッチオーバー後にルーティング プロトコル情報が復元される間も、既知のルートでデータ パケットの. シングル構成しているのが片方電源を抜いてもトラップがとばないのです。在本示例中，高可用性 (HA)狀態切換 (SSO)配置在兩個9800-CL例項之間，這些例項運行相同的Cisco IOS軟體版 本，這些例項已配置有獨立的WMI，並且可以通過以下網址訪問的GUI. show redundancy Redundant System Information :-----Available system uptime = 11 hours, 31 minutes Switchovers system experienced = 0 Standby failures = 0 Last switchover reason = none. Maintenance Mode = Disabled . This mode utilizes two electrical grids, each one powering a half module within each power supply. This example shows how to set the redundancy mode to SSO: Device(config)# redundancy Device(config-red)# mode sso Device(config-red)# policy config-sync prc reload. Device # show redundancy Redundant System Information : ----- Available system uptime = 6 days, 9 hours, 23 minutes Switchovers system experienced = 0 Standby failures = 0 Last switchover reason = not known Hardware Mode = Simplex Configured Redundancy Mode = SSO Operating Redundancy Mode = SSO Maintenance Mode =. 9. Router# show redundancy Operating mode is sso redundancy mode sso hw-module slot 6 image disk0:rsp-pv-mz hw-module slot 7 image disk0:rsp-pv-mz Active in slot 6 Standby in slot 7 The system total uptime since last reboot is 2 weeks, 23 hours 41 minutes. HA_CONFIG_SYNC-6-BULK_CFGSYNC_SUCCEED: Bulk Sync succeeded Switchover Process Restrictions. Cisco 5500 Series WLCs . Router# copy running. Example: Device(config-red)# mode sso: Configures stateful switchover. The DHCP high availability features are enabled by default when the redundancy mode of operation is set to SSO. If you perform an online insertion and removal (OIR) of the module, the switch resets during the. Step 2. Step 3:. Note After configuring SSO mode, the standby RP will automatically reset. Connected to network with 4x10G links. For Enterprise Services or IP Base mode, use ISSU to upgrade software for both RPR and SSO redundant mode. Sets the redundancy configuration mode to SSO on both the active and standby RP. Example: Router(config)# end. 2. 147 as the Redundancy Management IP and controller2 with 9. Step 5. The New High Availability feature i. +1 is the power supply module reserved for redundancy. The following example displays verification that the system is in SSO mode and that slot A—RP A is the active R, and slot B—RP B is the standby RP. Configure SSO redundancy mode at this time. Step 3. NSF and SSO must be configured before attempting an ISSU. Both RPs must run the same Cisco IOS image. Exits redundancy configuration mode and returns the switch to privileged EXEC mode. Hardware Mode = Duplex Configured Redundancy Mode = sso Operating Redundancy Mode = sso Maintenance Mode =. If SSO mode cannot be established between the active and standby switches because of an incompatibility in the configuration file, a mismatched command list (MCL) is generated at the active switch and a reload into route processor redundancy (RPR) mode is forced for the standby switch. Standby failures = 3. The. 0. while restarting the secondary WLC that was in maintenance mode, check the "Bulksync status" of redundancy summary in primary WLC and wait for until it turn as. Cisco SSO (frequently used with NSF) minimizes the time a network is unavailable to its users following a switchover while continuing to forward IP packets. Redundancy may not work due to differences between the Cisco IOS releases. insrc-redundant. One switch is running 3. Sets the redundancy configuration mode to SSO on both the active and standby RP. (Cisco Controller) >show redundancy summary. 168. Usage Guidelines. Enters redundancy configuration mode. 1. The VSS runs stateful switchover (SSO) between the VSS active and standby supervisor engines (see Figure 5. RF debug mask = 0x0. Step 5: end. 12. For Enterprise Services or IP Base mode, use ISSU to upgrade software for both RPR and SSO redundant mode. The switch is. (See the “Performing a Software Upgrade” section on page 8-12. Step 5. n+1 redundant Mode—n number of power supply modules are active (n can be one to seven pput ower supply modules). end. Usage Guidelines. I have 2x 5508 in SSO mode. 150. Information About Redundancy. Cisco NSF with SSO allows for the forwarding of data packets to continue along known routes while the routing protocol information is being restored following a switchover. Go to solution. Step 2: mode sso. Step 4 Router# show redundancy states Displays the operating redundancy. 3. When this command is entered, the standby switch is reloaded and begins to work in SSO mode. The software upgrade procedure supported by supervisor engine redundancy allows you to reload the Cisco IOS software image on the redundant supervisor engine, and once complete, reload the active supervisor engine. Redundancy Mode (Operational) = sso Redundancy Mode (Configured) = sso Redundancy State = sso Maintenance Mode = Disabled Manual Swact = enabled Communications = Up. Step 4: mode sso. mode sso. Usage Guidelines. 2. Step 2: mode sso Example: Switch (config-red)# mode sso Configures SSO. Enters redundancy configuration mode. SSO is supported in Cisco IOS Release 12. When this command is entered, the standby switch is reloaded and begins to work in SSO mode. Specify a standby slot, by entering the power redundancy-mode redundant n+1 standby-PSslot command. Redundancy Mode (Configured) = sso Redundancy State = sso Maintenance Mode = Disabled Manual Swact = enabled Communications = Up client count = 115Enters global configuration mode. The mode sso command can be entered only from within redundancy configuration mode. 255. Configures SSO. redundancy Router(config)# redundancy. Step 2: mode sso. RPR+-The show module command displays Warm. The default standby power supply slot is PS8. Example: Router>enable Router#configure terminal Router(config)#redundancy Router(config-r)#mode none Router(config-red)#application redundancy Router(config-red-app)#group 1 Configure a name for the redundancy group. 11 peer-redundancy-management 10. Usage Guidelines. The software upgrade procedure supported by supervisor engine redundancy allows you to reload the Cisco IOS software image on the redundant supervisor engine, and once complete, reload the active supervisor engine. Cisco Stateful Switchover (SSO) is one of the redundancy mechanisms used in networking. Note Enabling SSO initiates a controller reboot. For Enterprise Services or IP Base mode, use ISSU to upgrade software for both RPR and SSO redundant mode. Step 4: mode sso. Step 5. end. Copy the New Image to be Upgraded / Downgraded ISSU Workflows - Actual Upgrade One Step Work Flow Three Step Work Flow Post ISSU Checklist Action. Router# copy running-config. hw-switch switch 1 logging onboard message level 3 redundancy mode sso The new High Availability (HA) feature (that is, AP SSO) set within the Cisco Unified Wireless Network software release version 7. Redundancy may not work due to differences between the Cisco IOS releases. hw-switch switch 1 logging onboard message level 3. For Enterprise Services or IP Base mode, use ISSU to upgrade software for both RPR and SSO redundant mode. Verify the redundancy status using command : show redundancy summary 5. x [S2C-build-v16x_throttle-4064-/. Step 4: mode SSO Example: Router(config)# mode SSO: Configures SSO. If SSO mode cannot be established between the active and standby switches because of an incompatibility in the configuration file, a mismatched command list (MCL) is generated at the active switch and a reload into route processor redundancy (RPR) mode is forced for the standby switch. Connect with console to it and check which state it is in. LACP and PAGP is not supported in HA mode in releases until, and including, Cisco IOS XE Gibraltar 16. What is stateful switch over? Stateful Switchover (SSO) is a redundancy feature that allows a Cisco device with two route processors to synchronise router configuration and control plane state information. Router(config)# mode sso. sso not available as redundancy mode option Go to solution Scott Chauncey Beginner Options 11-01-2012 01:23 PM - edited 03-07-2019 09:48 AM Any idea why rpr. When this command is entered, the standby switch is reloaded and begins to work in SSO mode. Configured Redundancy Mode = sso Operating Redundancy Mode = sso Maintenance Mode = Disabled Communications = Up Current Processor Information :----- Active Location = slot 1 Current Software state = ACTIVE Uptime in current state = 30 minutes Image Version = Cisco IOS Software [Fuji], Catalyst L3 Switch Software (CAT9K_IOSXE), Version 16. HA_CONFIG_SYNC-6-BULK_CFGSYNC_SUCCEED: Bulk Sync succeeded Switchover Process Restrictions. Router (config)# redundancy. 2(20)EWA and later releases. Router# copy running. Router(config-red)# end. Example: Device(config-red)# mode sso: Configures stateful switchover. (Cisco Controller) >show redundancy summary. Check if Switches are in SSO Mode 5. Cisco 3504 WLCs. Step 5: end. The mode sso command can be entered only from within redundancy configuration mode. Redundancy may not work due to differences between the Cisco IOS. redundancy mode sso. Current Processor Information :-----Active Location = slot 1/3 Current Software state = ACTIVE Uptime in current state = 23 hours, 58 minutes Image Version = Cisco IOS Software, s2t54 Software (s2t54. end. Configures SSO. Step 5. Running the Supervisor card in RPR or SSO operating mode enables Supervisor redundancy. 39. Redundancy may not work due to differences between the Cisco IOS releases. Exits redundancy configuration mode and returns the switch to privileged EXEC mode. 2(20)EWA and later releases. Recovery Mode Yes Yes Default GW Check Yes Yes LACP, PAGP with SSO No Yes SMU for controller patching No Yes. This command supports Route Processor Redundancy Plus (RPR+) with the Cisco uBR10012 router. Hope that helps! -Bradley Selzer. To reload the standby switch if a parser return code (PRC) failure occurs during configuration synchronization, use the policy config-sync reload command in redundancy configuration. mode SSO 5. Active WLC 上で SSO の mode を disable にする. Enters redundancy configuration mode. To reload a single supervisor in the Quad-Supervisor setup enter the hw-module switch switch-number subslot subslot-number oir power-cycle command in privileged. The following guidelines and restrictions apply to supervisor engine redundancy: •If SSO mode cannot be established between the active and standby supervisor engines because of an incompatibility in the configuration file, a mismatched command list (MCL) is generated at the active supervisor engine and a reload into RPR. Step 2: mode sso Example: Switch (config-red)# mode sso Configures SSO. Example: Device(config-red)# end: Exits redundancy configuration mode and returns to privileged EXEC mode. This example shows how to set the redundancy mode to SSO: Device(config)# redundancy Device(config-red)# mode sso Device(config-red)# policy config-sync prc reload. Switch-1(config)# platform hardware vsl pfc mode non-xl (Optional) Sets the PFC operating mode to PFC4 on Chassis A. Step 4: mode sso. To do this, we will use “redundancy” command under global configuration mode and after that we will select mode with “mode sso” command.