Deliver Maximum Uptime with Simplicity Using VSS Quad Supervisor RPR for Cisco Catalyst 4500-E Switches

Transcription

1 White Paper Deliver Maximum Uptime with Simplicity Using VSS Quad Supervisor RPR for Cisco Catalyst 4500-E Switches What Is VSS Quad Supervisor (Sup) RPR? The Cisco IOS XE 3.4.xSG software release supports dual supervisors in both chassis of the Cisco Catalyst 4500 Series Switches. When a chassis is running in virtual switching system (VSS) mode, it supports a second supervisor engine. However, support occurs only in rommon mode, by disabling auto-boot with the confreg command. Beginning with Cisco IOS XE release 3.8.0E, a Catalyst 4500-E switch configured with Supervisor 7E, 7-LE, or 8E supports quad-supervisor VSS Route Processor Redundancy (RPR) mode. This mode enhances the VSS with support for Redundant Supervisor Module (RSM) within a single chassis. This functionality is also called in-chassis standby (ICS). The two supervisor modules use RPR technology to establish an RPR standby cold-redundancy relationship within each local chassis, and Stateful Switchover (SSO) technology to establish an SSO active/standby redundancy relationship across the chassis. In the unlikely event that the active supervisor should fail within the chassis, the standby cold supervisor will transition to the active role (in-chassis active [ICA]). This transition occurs by fully booting up the ICS supervisor; it remains non-operational until the SSO redundancy is re-established with the VSS active supervisor across the chassis. Key Benefits of VSS Quad Sup RPR When you support an in-chassis standby supervisor, the resiliency of the individual chassis increases, as well as the performance of the VSS, during a supervisor failure event. The main benefits are: Increased chassis resiliency Automated and deterministic recovery of a failed supervisor without human intervention The standby supervisor will automatically boot in an event of active supervisor failure 2016 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 1 of 13

2 Adding redundant components is the most direct method to increase device resiliency for standalone devices. Adding redundant power supplies, fans, and redundant supervisor modules increases the overall predicted availability rating of the chassis. The greatest advantage of including quad-supervisor VSS with ICS supervisors in RPR mode is that, in the event of an inter-chassis SSO failover, the inter-chassis redundancy is restored faster. The reason for this is that the VSS standby supervisor becomes the new VSS active supervisor, and the partially-booted ICS within the failed chassis boots up completely, providing chassis-level redundancy. This setup should also result into faster convergence and load-balancing across the multichassis EtherChannel (MEC). The supervisor recovery and replacement procedure is a more automated process with VSS Quad Sup RPR mode. The recovery process is based on SSO technology across the chassis and its switchover is sub-second compared to RPR mode within the chassis. It takes as little as two minutes for the ICS supervisor to take over the ICA state. SSO Technology Review SSO technology is essentially a group of Cisco IOS Software processes that provide for supervisor module redundancy to transparently failover certain Layer 2 protocols and certain Cisco IOS Software applications when a supervisor switchover occurs. These protocols and Cisco IOS Software applications that are synchronized between the active and standby supervisor modules are called high-availability-aware applications. Not all protocols and Cisco IOS Software applications are synchronized; these are referred to as non-high-availability-aware applications. Software images between the active and standby supervisors must be the same version. A redundant supervisor engine running in SSO mode starts up in a fully-initialized state, synchronizing the running configuration, forwarding tables, and high-availability-aware applications to the active supervisor engine. In an event that the active supervisor engine fails, the redundant supervisor engine becomes active. This newly active supervisor engine uses existing Layer 2 switching information to continue forwarding traffic. Layer 3 forwarding will be delayed until the routing tables have been repopulated in the newly active supervisor engine. SSO data-plane switchover time is zero to three seconds. RPR Technology Review RPR is the first redundancy mode of operation introduced in Cisco IOS Software. In RPR mode, the startup configuration and boot registers are synchronized between the active and standby supervisors. The standby software is not fully initialized. An important distinction of RPR mode is that the software images between the active and standby supervisors do not need to be the same version. Upon switchover, the standby supervisor becomes active automatically, but it must complete the boot process. In addition, all line cards are reloaded and the hardware is reprogrammed. The RPR switchover time is one or more minutes. VSS Quad Sup RPR How It Works Catalyst 4500-E VSS supports Quad Supervisor RPR mode (Figure 1), where one of the supervisors in a given chassis would play a role of either VSS-active or VSS-standby, and another supervisor within the chassis would obtain a role of in-chassis standby. As explained earlier, the ICS supervisor is not fully booted, but it does get the startup configuration from the ICA supervisor. The ICS supervisor in this case will load the image, run the power-on self-test (POST) and loopback tests, and will wait for switchover. This may have repercussions in terms of elongated failover time when the active supervisor fails. In this mode, the supervisor doesn t possess any of the control plane states and it starts all over. In due time, it not only becomes the local active supervisor; it also acquires the role of VSS-standby when a peer is present. If a peer is not present, it assumes the role of VSSactive Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 2 of 13

3 Figure 1. VSS RPR Initialization Process for VSS Quad Sup RPR When a VSS-configured chassis powers up, and there are two supervisor modules installed in the chassis, each supervisor module will start its boot process. Very early on during this initialization process, the supervisor will determine two key factors: first, that it is a VSS configuration, and second, that an in-chassis redundant supervisor module is installed in the same chassis. Table 1 shows excerpts from system console messages that indicate a VSS mode is detected and then that role resolution is identified. Table 1. Excerpts from System Console Messages Supervisor Module Switch 1 Slot 3 Supervisor Module Switch 2 Slot 3 Loading gsbu64atomic as gdb64atomic Using 3 for MTS slot Platform Manager: starting in VSS mode (chassis id 1, in-chassis active) Restricted Rights Legend Use, duplication, or disclosure by the government is subject to restrictions as set forth in subparagraph (c) of the Commercial Computer Software - Restricted Rights clause at FAR sec and subparagraph (c) (1) (ii) of the Rights in Technical Data and Computer Software clause at DFARS sec Cisco Systems, Inc. 170 West Tasman Drive San Jose, California Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500es8-universalk9-m), Version E RELEASE SOFTWARE (fc2) Technical Support: Copyright (c) by Cisco Systems, Inc. Compiled Tue 29-Sep-15 02:39 by prod_rel_team Cisco IOS-XE software, Copyright (c) by cisco Systems, Inc. All rights reserved. Certain components of Cisco IOS-XE software are licensed under the GNU General Public License (GPL) Version 2.0. The software code licensed under GPL Version 2.0 is free software that comes with ABSOLUTELY NO WARRANTY. You can redistribute and/or modify such GPL code under the terms of GPL Version 2.0. ( For more details, see the documentation or "License Notice" file accompanying the Cisco IOS-XE software, or the applicable URL provided on the flyer accompanying the Cisco IOS-XE software. Loading gsbu64atomic as gdb64atomic Using 13 for MTS slot Platform Manager: starting in VSS mode (chassis id 2, in-chassis active) Restricted Rights Legend Use, duplication, or disclosure by the government is subject to restrictions as set forth in subparagraph (c) of the Commercial Computer Software - Restricted Rights clause at FAR sec and subparagraph (c) (1) (ii) of the Rights in Technical Data and Computer Software clause at DFARS sec Cisco Systems, Inc. 170 West Tasman Drive San Jose, California Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500es8-universalk9-m), Version E RELEASE SOFTWARE (fc2) Technical Support: Copyright (c) by Cisco Systems, Inc. Compiled Tue 29-Sep-15 02:39 by prod_rel_team Cisco IOS-XE software, Copyright (c) by cisco Systems, Inc. All rights reserved. Certain components of Cisco IOS-XE software are licensed under the GNU General Public License (GPL) Version 2.0. The software code licensed under GPL Version 2.0 is free software that comes with ABSOLUTELY NO WARRANTY. You can redistribute and/or modify such GPL code under the terms of GPL Version 2.0. ( For more details, see the documentation or "License Notice" file accompanying the Cisco IOS-XE software, or the applicable URL provided on the flyer accompanying the Cisco IOS-XE software Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 3 of 13

4 Supervisor Module Switch 1 Slot 3 Supervisor Module Switch 2 Slot 3 Initializing as Virtual Switch ACTIVE processor Initializing as Virtual Switch STANDBY processor STANDBY SUPERVISOR REDUNDANCY mode is SSO Continue bootup Supervisor Module Switch 1 Slot 4 Supervisor Module Switch 2 Slot 4 Loading gsbu64atomic as gdb64atomic IN-CHASSIS STANDBY SUPERVISOR REDUNDANCY mode is RPR Waiting for Switchover Activity Loading gsbu64atomic as gdb64atomic IN-CHASSIS STANDBY SUPERVISOR REDUNDANCY mode is RPR Waiting for Switchover Activity Both supervisor modules will then arbitrate and determine which supervisor module will become the ICA, and which will become the ICS. During a normal boot-up sequence, the supervisor module in the lowest slot number will become the ICA. If a supervisor module is inserted after a previous supervisor module has already established itself as the ICA, then the second supervisor module will assume the ICS role. Next, the ICA will continue the initialization process by attempting to establish communication over the virtual switch link (VSL) and negotiate a SSO redundancy across the chassis. Only the ICA supervisor from each chassis will participate in the SSO negotiation process. If the ICA supervisor is not able to communicate with the ICA of the peer chassis after a specified period of time it will progress to the active role. The supervisor module that becomes the SSO active supervisor will continue the boot-up process and start to initialize the line cards and execute the startup configuration file. The supervisor module that becomes the ICS will load the image, run the POST and loopback tests, and will wait for switchover in RPR (standby cold) mode. Supervisor Switchover Events The failure of the VSS-active supervisor causes an SSO switchover to the standby chassis. Other failures invoke an RPR switchover. Table 2 shows the types of switchover against a supervisor failure. Table 2. Type of Switchover Against a Supervisor Failure Supervisor Failure SW1 ICA fail SW1 ICS fail SW2 ICA fail SW2 ICS fail Type of Switchover -VSS-standby to VSS-active - SSO -SW1 ICS to SW1 ICA - RPR - No switchovers; SW1 ICS reboots and comes back up as ICS in RPR mode -SW2 ICS to SW2 ICA or VSS-standby - RPR -No switchovers; the replaced supervisor reboots in RPR mode With inter-chassis SSO, the total switchover time depends upon the time taken to detect a VSL failure, either through link-down events or through time-out of the Virtual Switch Link Protocol (VSLP). When a chassis fails or during a switchover event, all the links on that chassis go down. External switches that are single-homed into the failed chassis experience an outage. It is recommended to dual-home all connections to the VSS pair using MEC technology, which primarily load-balances traffic across links, and keeps the traffic impact minimal in the event of chassis or link failure Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 4 of 13

5 With intra-chassis RPR, all the line cards in the chassis are reset on switchover. After switchover, the ICS supervisor becomes ICA. If the failure is on VSS active (SW1), the intra-chassis RPR switchover then triggers the inter-chassis SSO switchover and the VSS-standby becomes the VSS-active as part of the switchover event. ICS on SW1 upon complete boot up becomes the VSS-standby after the VSL is established and the role is negotiated. If the supervisor failure is on the VSS-standby chassis (SW2), the ICS supervisor becomes the new ICA after the intra-chassis RPR switchover, and eventually assumes the role of VSS-standby. Configuring and Monitoring VSS Quad Sup RPR From a configuration standpoint, no additional configuration commands are required to enable the VSS quad sup RPR mode. The only requirement is that the supervisor modules run a software image version capable of supporting the quad sup RPR redundancy mode. When a second supervisor is inserted into an operational VSS pre-loaded with a quad sup-supported image, the ICA will detect that the new supervisor does not have the VSS configuration variables set. The ICA will configure the ICS with the appropriate VSS variables, including the VSS switch ID, and then reload the ICS. Use the copy running-config startup-config command to save the configuration from the ICA to ICS. As with redundant supervisor operations in a standalone chassis, the SSO active supervisor module automatically synchronizes the startup-config and running-config files with the SSO standby hot; this is part of SSO operation. Apart from the configuration files, the software image files and any other files located on the supervisor module file systems must be managed manually. In other words, one uses the command-line interface (CLI) for copy, delete, and other functions to move files between the various supervisor module file systems. The VSS quad sup RPR implementation creates some new file system names. The new names are based on the active/standby relationship; alternatively admins can reference the switch number or slot number. The new switchnumber or slot-number naming convention allows the admin to reference a file system without consideration of the redundancy state of VSS. Table 3 shows a subset of new file system names supported with the VSS quad sup RPR implementation. Table 3. Subset of File System Names Supported with a VSS Quad Sup RRP Implementation File System Name bootflash: bootflash-ics: slavebootflash: slavebootflash-ics: Description Bootflash on a VSS active supervisor (SW1 Slot3) Bootflash on an ICS supervisor of a VSS active chassis (SW1 Slot4) Bootflash on a VSS standby supervisor (SW2 Slot3) Bootflash on an ICS supervisor of a VSS standby chassis (SW2 Slot4) For viewing and monitoring the state of the individual supervisor modules, certain VSS-related CLIs can be used to view the redundancy roles and states. An example of the show switch virtual redundancy command is shown in the output following this paragraph. Notice that the output of this command will always list the current active supervisor module first, therefore the order that the modules are displayed will vary as the redundancy modes change on the supervisors. Show Switch Virtual Redundancy Command Output 4507-VSS#show switch virtual redundancy Executing the command on VSS member switch role = VSS Active, id = 1 My Switch Id = 1 Peer Switch Id = 2 Last switchover reason = none 2016 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 5 of 13

6 Configured Redundancy Mode = Stateful Switchover Operating Redundancy Mode = Stateful Switchover Switch 1 Slot 3 Processor Information : Current Software state = ACTIVE Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500es8-universalk9-m), Version 15.2(4.0.97)E, EARLY DEPLOYMENT [PROD IMAGE] ENGINEERING NOVA_WEEKLY BUILD, synced to V152_4_1_E Technical Support: Copyright (c) by Cisco Systems, Inc. Compiled Mon 07-Sep-15 17:32 by sasyamal BOOT = bootflash:cat4500es8- universalk9.spa e e.bin,1; CONFIG_FILE = BOOTLDR = Configuration register = 0x2101 Fabric State = ACTIVE Control Plane State = ACTIVE Switch 2 Slot 3 Processor Information : Current Software state = STANDBY HOT (switchover target) Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500es8-universalk9-m), Version 15.2(4.0.97)E, EARLY DEPLOYMENT [PROD IMAGE] ENGINEERING NOVA_WEEKLY BUILD, synced to V152_4_1_E Technical Support: Copyright (c) 1 BOOT = bootflash:cat4500es8-universalk9.spa e e.bin,1; CONFIG_FILE = BOOTLDR = Configuration register = 0x2101 Fabric State = ACTIVE Control Plane State = STANDBY Executing the command on VSS member switch role = VSS Standby, id = 2 show virtual switch redundancy is not supported on the standby 4507-VSS#sh module Switch Number: 1 Role: Virtual Switch Active Chassis Type : WS-C4507R+E Power consumed by backplane : 40 Watts Mod Ports Card Type Model Serial No /100/1000BaseT UPOE E Series WS-X4748-UPOE+E CAT1638L11W 3 8 Sup 8-E 10GE (SFP+), 1000BaseX (SFP) WS-X45-SUP8-E CAT1751L Sup 8-E 10GE (SFP+), 1000BaseX (SFP) /100/1000BaseT UPOE E Series WS-X4748-UPOE+E CAT1735L3QD 2016 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 6 of 13

7 M MAC addresses Hw Fw Sw Status cf5.af64 to cf5.af Ok c80.9c80 to c80.9c (1r)SG E.97 Ok c80.9c88 to c80.9c8f Provision 5 c067.afe4.bb30 to c067.afe4.bb5f 1.1 Ok Mod Redundancy role Operating mode Redundancy status Active Supervisor SSO Active 4 In-Chassis Standby RPR Standby cold Switch Number: 2 Role: Virtual Switch Standby Chassis Type : WS-C4507R+E Power consumed by backplane : 40 Watts Mod Ports Card Type Model Serial No /100/1000BaseT Premium POE E Series WS-X4748-RJ45V+E CAT1749L20K 3 8 Sup 8-E 10GE (SFP+), 1000BaseX (SFP) WS-X45-SUP8-E CAT1751L5FB 4 8 Sup 8-E 10GE (SFP+), 1000BaseX (SFP) M MAC addresses Hw Fw Sw Status c08.f630.b4c0 to 3c08.f630.b4ef 1.3 Ok 3 3c08.f6da.dbc0 to 3c08.f6da.dbc (1r)SG E.97 Ok 4 3c08.f6da.dbc8 to 3c08.f6da.dbcf Provision Mod Redundancy role Operating mode Redundancy status Standby Supervisor SSO Standby hot 4 In-Chassis Standby RPR Standby cold How to Migrate to VSS Quad Sup RPR Migrating an existing traditional VSS setup to a VSS quad sup RPR configuration is a straightforward process. The main requirements are that all supervisors run Cisco IOS XE 3.8.0E or a newer Cisco IOS XE software version, and that the newly-inserted redundant supervisor module is configured to boot the same image as the ICA supervisor. The redundant supervisor can simply be inserted into the operational VSS chassis; the newly inserted supervisor will be automatically provisioned for VSS (VSS switch ID is configured to match the ICA) and will negotiate itself to the ICS redundancy mode. There is no impact to data-plane switching when the second supervisor is inserted. Key steps to migrate to VSS quad sup RPR mode: 1. Upgrade the existing VSS to Cisco IOS XE 3.8.0E Software Release or newer. 2. Prepare the first ICS supervisor module to boot the same image version as the active VSS Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 7 of 13

8 3. Insert the redundant supervisor module into the chassis (it does not matter which VSS chassis the redundant supervisor is inserted into first, whether the VSS active or VSS standby) with same license level as the active supervisor. 4. Establish a console connection for each supervisor module in the VSS. 5. Verify the newly inserted supervisor boots as the ICS. 6. Save the configuration on the VSS active to synchronize the configuration to the newly inserted supervisor (ICS). 7. Configure and connect the new ICS supervisor s 10-Gb uplink ports into the VSL (this optional step is recommended). You must upgrade the redundant supervisor to Cisco IOS XE version 3.8.0E or newer prior to inserting the supervisor in order to support quad sup RPR mode. One option is to use a spare chassis to prepare the redundant supervisor to be inserted into the VSS. When using the spare chassis method you can configure the supervisor to boot Cisco IOS XE 3.8.0E or newer image. It is not necessary to convert the supervisor module to VSS mode or configure the VSS switch number as this configuration is synchronized from the ICA supervisor. If it is not possible to use a spare chassis to prepare the redundant supervisor module, then you can insert the redundant supervisor module. Then, use either the console connection to interrupt the boot process to force the supervisor to rommon, or simply allow the supervisor to abort the Cisco IOS Software initialization and drop to rommon. Nither of these two approaches will cause an interruption in data-plane switching of the VSS. Use a USB device or SD card to copy the new image from the ICA supervisor to the ICS supervisor and boot the redundant supervisor using the image available on the USB device or SD card. Once the redundant supervisor is booted with the newer image and has joined as ICS, that newer image can be copied into the ICS bootflash, either from the ICA bootflash or by using the image available on the USB device or SD card. An example of the CLI to boot the supervisor from the external file system is provided in the output that follows. CLI Commands to Boot the Second Supervisor from Rommon rommon 4 >dir slot0: Date Time Attribute Size Name ========== ===== ========= ========== ================ 2015/11/01 23: A VSS.cfg 2015/10/17 03: A cat4500es8- universalk9.spa e e.bin Total space = KB Available = KB rommon 5 >dir usb0: Date Time Attribute Size Name ========== ===== ========= ========== ================ 2015/10/17 03: A cat4500es8- universalk9.spa e e.bin 2015/11/01 23: A VSS.cfg Total space = KB 2016 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 8 of 13

9 Available = KB rommon 6 >boot slot0:cat4500es8-universalk9.spa e e.bin Loading image!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Checking digital signature... [mem:/cat4500es8-firmware] Digitally Signed Release Software with key version A Rommon reg: 0x00084F80 Reset2Reg: 0x0C ######## Conan controller 0x37AFB010..0x37D57C35 Size: #### Radtrooper controller 0x3795F474..0x37AFB00E Size: Link: 0x x Program Done! Checking digital signature... [mem:/cat4500es8-base] Digitally Signed Release Software with key version A ########### pci 0000:00:00.0: ignoring class b20 (doesn't match header type 01) pci 0001:02:00.0: ignoring class b20 (doesn't match header type 01) pci 0002:04:00.0: ignoring class b20 (doesn't match header type 01) audit: cannot initialize inotify handle All packages are Digitally Signed Starting System Services devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=4,mode=600,ptmxmode= diagsk10-post version prod: WS-X45-SUP8-E part: serial: CAT1751L587 Power-on-self-test for Module 4: WS-X45-SUP8-E CPU Subsystem Tests... seeprom: Pass Traffic: L3 Loopback... Test Results: Pass Traffic: L2 Loopback... Test Results: Pass post done(72 secs) Exiting to ios... Loading gsbu64atomic as gdb64atomic IN-CHASSIS STANDBY SUPERVISOR REDUNDANCY mode is RPR Waiting for Switchover Activity 2016 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 9 of 13

10 The first time the ICS is inserted into the VSS chassis, the ICA will detect that the new supervisor does not have the VSS configuration variables set. The ICA will configure the ICS with the appropriate VSS variables, including the VSS switch ID, and then reload the ICS. This is a one-time step; upon any subsequent reloads the supervisor module will have the relevant VSS information to boot directly as the ICA or ICS supervisor. Configuring the Virtual Switch Link in VSS Quad Sup RPR The VSL is the dedicated port-channel between the two VSS chassis that is used for passing control-plane and data-plane traffic between the chassis. There are a number of variables to consider when determining the number of interfaces and which interfaces to use to build the VSL. Some of these considerations, such as VSL bandwidth sizing, link diversification, and QoS mechanisms, are relevant considerations to all VSS designs and are beyond the scope of this paper. These topics are discussed in existing documentation and other white papers, including design guides 1. It is recommended to directly and physically link VSL between the VSS active supervisor and both supervisor modules in the peer VSS chassis. In other words, at a minimum, every supervisor should connect to the supervisor on the peer chassis for maximum resiliency, as shown in Figure 2. Figure 2. VSL Connectivity Across the VSS Chassis The CLI output below provides details of the show switch virtual link detail command. It indicates the VSL links and their connected peers. CLI Output from Show Switch Virtual Link Detail Command 4507-VSS#sh switch virtual link detail Executing the command on VSS member switch role = VSS Active, id = 1 VSL Status : UP VSL Uptime : 3 hours, 4 minutes VSL Control Link : Te1/3/1 VSL Encryption : Configured Mode - Off, Operational Mode - Off 1 Cisco Validated Design guides Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 10 of 13

11 LMP summary Link info: Configured: 4 Operational: 4 Peer Peer Peer Peer Timer(s)running Interface Flag State Flag MAC Switch Interface (Time remaining) Te1/3/1 vfsp operational vfsp c80.9c80 2 Te2/3/1 T4(144ms) T5(29.93s) Te1/3/2 vfsp operational vfsp c80.9c80 2 Te2/4/2 T4(284ms) T5(29.95s) Te1/4/1 vfsp operational vfsp c80.9c80 2 Te2/4/1 T4(332ms) T5(29.95s) Te1/4/2 vfsp operational vfsp c80.9c80 2 Te2/3/2 T4(676ms) T5(29.99s) Flags: v - Valid flag set f - Bi-directional flag set s - Negotiation flag set p - Peer detected flag set Timers: T4 - Hello Tx Timer T5 - Hello Rx Timer Software Upgrades with VSS Quad Sup RPR Upgrading the Cisco IOS XE Software image on the VSS quad sup RPR setup is supported primarily through two methods: the manual software upgrade process and the In-Service Software Upgrade (ISSU) process. Manual Software Upgrade Process Following is the sequence of steps to take to upgrade the software manually on the VSS quad sup RPR setup: 1. Copy the newer image onto all four supervisors bootflash. 2. Modify the switch configuration to set the boot image to the new Cisco IOS XE Software image. 3. Copy the running configuration to the startup configuration. It will save the configuration on all supervisors. 4. Verify the Cisco IOS XE Software image is set to boot on the next reload using the show boot command. 5. Reload both switches to boot the new image using the redundancy reload command. ISSU Software Upgrade Process There are two ways to perform an ISSU upgrade. Both options are supported for VSS quad sup RPR. ISSU, using a four-command sequence Automatically, using a single command 2016 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 11 of 13

12 ISSU Using the Four-Command Sequence The manual ISSU upgrade process (Figure 3) involves issuing four distinct ISSU EXEC commands in sequence: issu loadversion The ISSU process begins with the loadversion command. When the user enters the ISSU loadversion command the process will begin with an upgrade of both supervisor modules (SW2 Slot3 and SW2 Slot4) on the standby chassis. Both supervisor modules on the standby chassis reload to boot the new Cisco IOS image, which resets all the line cards on the standby chassis affecting traffic (originated locally or traffic traversing through the VSS standby switch). There is no impact to traffic switched through the VSS active switch. issu runversion At the runversion stage, the intention is move the VSS active role to the supervisor running the new software version. In this case that is the VSS standby (SW2 Slot 3). This is accomplished by reloading both supervisors in the VSS active chassis (SW1 Slot3 and SW1 Slot4). All line cards in the VSS active switch reset. issu acceptversion The acceptversion command halts the rollback timer and helps to ensure the new Cisco IOS XE ISSU process is not automatically aborted during the ISSU process. Enter the issu acceptversion command within the time period specified by the rollback timer to acknowledge that the supervisor engine has achieved connectivity to the outside world. Otherwise, the ISSU process is terminated, and the system reverts to the previous version of Cisco IOS XE Software by switching to the standby supervisor engine. The ISSU abortversion command is the only command needed to revert the system back to the original software version and end the ISSU upgrade process. The ISSU abortversion command will force the supervisor module in SW2 to reload and boot the original version of the software. There is no impact to traffic on either of the chassis with execution of this command. issu commitversion The final stage in the upgrade process is the ISSU commitversion command. The commitversion step reloads the standby supervisor engine with the post-upgrade image. Traffic originated or passing through Switch1 is impacted until both the Switch 1 supervisors boot and line cards are online. There is no traffic interruption for Switch2 local traffic or traffic traversing through Switch2. Figure 3. ISSU Process 2016 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 12 of 13

13 ISSU Using a Single Command issu commitversion The issu changeversion command launches a single-step, complete ISSU upgrade cycle. It performs the logic for all four of the standard commands (issu loadversion, issu runversion, issu acceptversion, and issu commitversion) without user intervention, streamlining the upgrade through a single CLI step. Similar to the normal ISSU upgrade procedure, the in-progress upgrade procedure initiated by the issu changeversion command can be aborted with the issu abortversion command. For More Information To learn more about information covered in this white paper, read: Borderless Campus 1.0 Overview and Framework Enterprise Campus 3.0 Design Guide 4500E High-Avalability White Paper Printed in USA C / Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. Page 13 of 13