Performing an In Service Software Upgrade
First Published: March 16, 2006
Last Updated: February 11, 2011
This module describes the In Service Software Upgrade (ISSU) process and provides configuration examples for ISSU on Cisco ASR 1000 Series routers.
Finding Feature Information
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 for Performing an XE ISSU" section.
Use Cisco Feature Navigator to find information about platform support and Cisco IOS XE Software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
•Information About Performing an ISSU
•How to Perform an ISSU
•Configuration Examples for Performing an ISSU
•Feature Information for Performing an XE ISSU
Information About Performing an ISSU
•ISSU Process Overview
•ISSU and the Cisco ASR 1000 Series Router
ISSU Process Overview
ISSU allows Cisco software to be upgraded or downgraded, at a router level, while the system continues to forward packets. ISSU takes advantage of the Cisco high availability infrastructure—Cisco NSF with SSO and hardware redundancy—and eliminates downtime associated with software upgrades or version changes by allowing updates while the system remains in service. Cisco high availability features combine to lower the impact that planned maintenance activities have on network service availability, with the results of less downtime and better access to critical systems.
SSO mode supports configuration synchronization. When images on the active and standby RPs are different, this feature allows the two Route processors (RPs) to remain synchronized although they may support different sets of commands.
An ISSU-capable router consists of two RPs (active and standby) and one or more line cards. Before initiating the ISSU process, you must copy the Cisco IOS software into the file systems of both RPs
After you have copied the Cisco IOS software to both file systems, load the new version of Cisco IOS software onto the standby RP.
After switchover, the standby RP takes over as the new active RP.
Then, the former active RP, which is now the new standby RP, is loaded with the new software.
The two RPs in a system can be in one of three different states during ISSU:
•Active—One RP is actively forwarding packets with old software. After the ISSU process is performed, the original active RP becomes the standby RP.
•Standby—Perform ISSU on the standby RP, loading it with new software. After the ISSU process is performed, the original standby RP is the new active RP.
•Hot standby—After the original standby RP becomes the new active RP, load the new software image into the new standby RP. Doing so makes the standby RP a hot standby RP.
Figure 1 shows the ISSU states during the ISSU process.
Figure 1 ISSU States During the ISSU Process
ISSU and the Cisco ASR 1000 Series Router
See the Cisco ASR 1000 Series Aggregation Services Routers Software Configuration Guide for information about ISSU and Cisco ASR 1000 Series routers.
How to Perform an ISSU
Unlike SSO, which is a mode of operation for the device and a prerequisite for performing ISSU, the ISSU process is a series of steps performed while the router or switch is in operation. The steps result in the implementation of new or modified Cisco software, and have a minimal impact to traffic.
For information on performing Cisco IOS XE ISSU upgrades on the Cisco ASR 1000 Series Router, see the "In Service Software Upgrade (ISSU)" module in the Cisco ASR 1000 Series Aggregation Services Routers Software Configuration Guide.
Configuration Examples for Performing an ISSU
•Example: Verifying Redundancy Mode Before Beginning the ISSU Process
•Example: Verifying the ISSU State
Example: Verifying Redundancy Mode Before Beginning the ISSU Process
The following examples display verification that the system is in SSO mode and that slot R0 is the active RP1 and slot R1 is the standby RP1. Both RPs are running the same Cisco IOS XE Software image.
Router# show redundancy states
peer state = 8 -STANDBY HOT
Redundancy Mode (Operational) = sso
Redundancy Mode (Configured) = sso
Maintenance Mode = Disabled
client_notification_TMR = 30000 milliseconds
Slot Type State Insert time (ago)
--------- ------------------- --------------------- -----------------
0 ASR1000-SIP10 ok 02:48:56
0/0 SPA-2X1GE-V2 ok 02:46:38
0/1 SPA-2XOC3-POS ok 02:46:38
R0 ASR1000-RP1 ok, active 02:48:56
R1 ASR1000-RP1 ok, standby 02:48:56
F0 ASR1000-ESP10 ok, active 02:48:56
F1 ASR1000-ESP10 ok, standby 02:48:56
P0 ASR1006-PWR-AC ok 02:47:55
P1 ASR1006-PWR-AC ok 02:47:55
Slot CPLD Version Firmware Version
--------- ------------------- ---------------------------------------
Example: Verifying the ISSU State
The following example displays and verifies the ISSU state:
Router# show issu state detail
--- Starting installation state synchronization ---
Finished installation state synchronization
No ISSU operation is in progress
The new version of the Cisco IOS XE Software must be present on both of the RPs. The directory information displayed for each of the RPs shows that the new version is present.
11 drwx 16384 Jul 24 2008 15:04:47 +00:00 lost+found
1114113 drwx 65536 Nov 25 2008 16:58:36 +00:00 tracelogs
294913 drwx 4096 Jul 24 2008 15:14:39 +00:00 core
12 -rw- 225308932 Nov 12 2008 15:50:37 +00:00
13 -rw- 209227980 Aug 20 2008 17:31:59 +00:00 asr1000special
14 -rw- 222240972 Sep 8 2008 17:13:22 +00:00 rp_super.ppc.bin
15 -rw- 209985740 Nov 25 2008 16:50:39 +00:00
39313059840 bytes total (38439649280 bytes free)
Router# dir stby-harddisk:
Directory of stby-harddisk:/
11 drwx 16384 Jul 24 2008 15:05:35 +00:00 lost+found
1507329 drwx 73728 Nov 25 2008 16:58:50 +00:00 tracelogs
2424833 drwx 4096 Jul 24 2008 15:22:04 +00:00 core
12 -rw- 225308932 Sep 8 2008 04:48:39 +00:00
13 -rw- 209227980 Aug 20 2008 17:41:21 +00:00 asr1000special
14 -rw- 222240972 Sep 8 2008 18:04:26 +00:00 rp_super.ppc.bin
15 -rw- 209985740 Nov 25 2008 16:55:11 +00:00
39313059840 bytes total (38438928384 bytes free)
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.
To locate and download MIBs for selected platforms, Cisco IOS XE Software releases, and feature sets, use Cisco MIB Locator found at the following URL:
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.
To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.
Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.
Feature Information for Performing an XE ISSU
Table 1 lists the features in this module and provides links to specific configuration information.
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 Table 1 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.
Table 1 Feature Information for Performing an ISSU
In Service Software Upgrade (ISSU)
Cisco IOS XE Release 2.1
The following features were introduced:
•Dual IOS processes on the same RP
•In Service Software Upgrade (ISSU)
–ISSU - ARP
–ISSU - Frame Relay
–ISSU - GLBPv6
–ISSU - HSRPv6
–ISSU - HDLC
–ISSU - IGMP snooping
–ISSU - IPv6 uRPF
–ISSU - IS-IS
–ISSU - Managed LNS MPLS
–ISSU - MLD Access Group
–ISSU - NAT
–ISSU - PPP/MLP
–ISSU - QoS
–ISSU - SNMP
The following commands were introduced or modified issu abortversion, issu acceptversion, issu commitversion, issu loadversion, issu runversion, issu set rollback timer, show issu clients, show issu comp-matrix, show issu rollback timer, show issu sessions, show issu state, show redundancy.
ISSU - ATM
Cisco IOS XE Release 2.3
This feature was introduced.
ISSU - HSRPv6 on VRF interfaces
Cisco IOS XE Release 3.1S
This feature was introduced for Cisco ASR 1000 Series Aggregation Services Routers.
ISSU - Multicast MPLS VPN
Cisco IOS XE Release 2.5
This feature was introduced.
Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.
© 2006-2010 Cisco Systems, Inc. All rights reserved.