In-Service Software Upgrade (ISSU)

Information About In-Service Software Upgrade (ISSU)

ISSU is a process that upgrades an image to another image on a device while the network continues to forward packets. ISSU helps network administrators avoid a network outage when performing a software upgrade. ISSU is supported in install mode.


Note
Refer to the release notes and check the list of unsupported commands across releases before initiating an ISSU upgrade, as the upgrade may fail when unsupported commands are present.

ISSU Support between Releases

EM: extended maintenance

SM: standard maintenance

For information on IOS XE Software Lifecycle, see the following link: https://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ios-xe-16/bulletin-c25-2378701.html

Supported Scenarios

Unsupported Scenarios

  • Within a major release train (17.x or 18.x ), ISSU is supported between any two EMs that are released not more than 3 years apart.

  • Within a major release train, ISSU is supported from:

    • Any EM (EM1, EM2, EM3) to another EM (EM1, EM2, EM3)

      Example: 17.3.x to 17.6.x, 17.6.x to 17.9.x

    • Any release within the same EM

      Example: 17.3.1 to 17.3.2 or 17.3.3 or 17.3.x

  • Between major release trains, ISSU is not supported from:

    • An EM of a major release train to an EM of another major release train

      Example: 16.x.x to 17.x.x or 17.x.x to 18.x.x is not supported

    • An SM to EM or EM to SM

      Example: 17.3.x or 17.4.x to 17.5.x is not supported

  • ISSU is not supported on engineering special releases and .s (or similar) images.

  • ISSU is not supported between Licensed Data Payload Encryption (LDPE) and No Payload Encryption (NPE) Cisco IOS XE software images.

  • ISSU downgrades are not supported.

Note

 

No configuration changes should be performed while ISSU is being performed.

Release Support Matrix

The following tables show ISSU support within the same EM.

  • For Cisco Catalyst 9800 Series Wireless Controllers, ISSU support starts from Cisco IOS XE Amsterdam 17.3.1.

For a comprehensive list of supported ISSU upgrade matrices across multiple releases for the Cisco Catalyst 9800 Series Wireless Controllers, see the following link: https://www.cisco.com/c/dam/td-xml/en_us/wireless/vewlc/issu/ISSU.xlsx

Cisco Catalyst 9800 Series Wireless Controllers

Table 1. Cisco Catalyst 9800 Series Wireless Controllers - 17.3.x Release

From/To

17.3.1

17.3.2a

17.3.3

17.3.4

17.3.4c

17.3.5

17.3.5a

17.3.5b

17.3.6

17.3.7

17.3.8

17.3.1

—

✓

✓

✓

✓

✓

✓

✓

✓

✓

✓

17.3.2a

x

—

✓

✓

✓

✓

✓

✓

✓

✓

✓

17.3.3

x

x

—

✓

✓

✓

✓

✓

✓

✓

✓

17.3.4

x

x

x

—

✓

✓

✓

✓

✓

✓

✓

17.3.4c

x

x

x

x

—

✓

✓

✓

✓

✓

✓

17.3.5

x

x

x

x

x

—

✓

✓

✓

✓

✓

17.3.5a

x

x

x

x

x

x

—

✓

✓

✓

✓

17.3.5b

x

x

x

x

x

x

x

—

✓

✓

✓

17.3.6

x

x

x

x

x

x

x

x

—

✓

✓

17.3.7

x

x

x

x

x

x

x

x

x

—

✓

17.3.8

x

x

x

x

x

x

x

x

x

x

—
Table 2. Cisco Catalyst 9800 Series Wireless Controllers - 17.6.x Release

From/To

17.6.1

17.6.2

17.6.3

17.6.4

17.6.5

17.6.6

17.6.1

—

✓

✓

✓

✓

✓

17.6.2

x

—

✓

✓

✓

✓

17.6.3

x

x

—

✓

✓

✓

17.6.4

x

x

x

—

✓

✓

17.6.5

x

x

x

x

—

✓

17.6.6

x

x

x

x

x

—
Table 3. Cisco Catalyst 9800 Series Wireless Controllers - 17.9.x Release

From/To

17.9.1

17.9.2

17.9.3

17.9.4

17.9.1

—

✓

✓

✓

17.9.2

x

—

✓

✓

17.9.3

x

x

—

✓

17.9.4

x

x

x

—