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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 5 Configuring Virtual Switching Systems
In-Service Software Upgrade (ISSU) on a VSS
Stored Information
The stored compatibility matrix contains a list of other IOS XE software releases for the Catalyst 4500
platform that are compatible with this release. This information is precomputed and stored inside the IOS
XE image.
When an ISSU upgrade is attempted, the software looks up the Stored Compatibility Matrix on the
supervisor engine that is running the higher (that is, later) IOS XE version. In this matrix, the software
tries to locate the IOS XE version number that is running on the other supervisor engine (that is, the
lower or earlier version number). If this information is missing, the ISSU upgrade cannot proceed.
All current IOS XE releases on the Catalyst 4500 platform support Dynamic Image Version Capability
(DIVC). This means that the ISSU compatibility for the specified version is dynamically computed, as
illustrated with the following example:
Switch#
show issu comp-matrix stored
Number of Matrices in Table = 1
(1) Matrix for cat4500e-UNIVERSAL-M(182) - cat4500e-UNIVERSAL-M(182)
==========================================
Start Flag (0xDEADBABE)
My Image ver: 03.03.01.SG
Peer Version Compatibility
------------ -------------
03.02.00.SG Dynamic(0)
03.02.01.SG Dynamic(0)
03.02.00.XO Dynamic(0)
03.02.02.SG Dynamic(0)
03.02.03.SG Dynamic(0)
03.02.04.SG Dynamic(0)
03.03.00.SG Dynamic(0)
03.03.01.SG Comp(3)
The above Stored Compatibility Matrix is for IOS XE version 03.03.01.SG.
The "Comp(3)" entry shows that IOS XE version 03.03.01.SG is compatible with this version, and the
end result is guaranteed to succeed.
The "Dynamic(0)" entry against IOS XE version 03.02.04.SG means that an ISSU upgrade from or to
IOS XE version 03.02.04.SG is e permitted. However, the end result will depend upon the ability of
individual software features comprising the two versions to successfully complete the ISSU negotiation.
IOS XE version 03.01.01.SG is not in the list. This means that an ISSU upgrade from that version to this
IOS XE version (03.03.01.SG) is not possible.
Negotiated Information
While the Stored compatibility matrix information is used before an ISSU upgrade is attempted, the
Negotiated compatibility matrix information pertains to the ISSU state after or during an ISSU upgrade
attempt. It contains information about how the different software components comprising the IOS XE
images on the two supervisor engines were able to negotiate their states. So, this data is useful for
troubleshooting failed ISSU upgrade operations.
To display information about the ISSU compatibility matrix, perform this task:
Summary of Contents for Catalyst 4500 Series
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