Follow the guidelines in the "Guidelines and Limitations for ISSU" section to ensure that the ISSU works smoothly.

Make sure that the network is stable and no changes are made while the ISSU is in progress.

Ensure feature compatibility between the current running release and the target release.

Make sure that interfaces are not in a spanning-tree designated forwarding state. Also, make sure that bridge assurance is not configured on any interface. The vPC peer-link is an exception to these requirements.

Verify that the current STP topology is consistent with the ISSU requirements. Use the show spanning-tree issu-impact command to display the STP configuration and whether or not there are potential STP issues.

Use the show lacp issu-impact command to display if a port or a peer switch is configured in the rate fast mode. The ISSU process is aborted if the system has any LACP fast timers configured.

The following is a list of important guidelines and limitations for ISSU:

• An ISSU can be performed only from a Cisco NX-OS 7.0(3)I3(1) or a later image to a later image.

• Beginning with Cisco NX-OS Release 7.0(3)I4(1), you can perform an ISSU for VXLAN.

• ISSUs for segment routing are supported on Cisco Nexus 3000 series switches from Cisco NX-OS Release 7.0(3)I4(1) onwards.

• ISSUs are supported on the following platforms:

  • Cisco Nexus 3172PQ, 3172TQ, 3172PQ-XL, and 3172TQ-XL switches

  • Cisco Nexus 3132Q, 3132Q-X, and 3132Q-XL switches

  • Cisco Nexus 3064, 3064-X, and 3064-T switches

  • Cisco Nexus 3048 switches

  • Cisco Nexus 3016 switches

• Beginning with Cisco NX-OS Release 7.0(3)I5(1), Cisco Nexus 3000 series platforms with 16 GB of memory or higher support enhanced ISSU. The upgrade will be disruptive.

• Beginning with Cisco NX-OS Release 7.0(3)I7(3), the minimum free bootflash space that is required to perform an ISSU is as follows:

  • For compact image: 200 MB

  • For non-compact image: 300 MB

• For Cisco NX-OS Release 7.0(3)I7(1) and Cisco NX-OS Release 7.0(3)I7(2), the minimum free bootflash space that is required to perform ISSU is 550 MB.

• Cisco Nexus 3048, 3064, 3132, and 3172 switches with a model number that does not end in -XL must run a compact NX-OS software image due to limited bootflash space. This compact image can be created using the NX-OS Compact Image procedure; alternatively, a compact NX-OS software image can be downloaded directly from Cisco's Software Download website. This requirement does not apply to any other model of Nexus 3000 or 3100 series switch.

  • The MD5/SHA512 checksum published on Cisco's Software Download website for a compact NX-OS software image may not match the MD5/SHA512 checksum of a compact image created through the NX-OS Compact Image procedure.