ISSU Limitations and Considerations

• ISSU is supported on FastIron ICX 7150, ICX 7250, ICX 7450, ICX 7550, ICX 7650, ICX 7750 and ICX 7850 stackable hardware.
• ISSU is supported in a traditional ring stack topology and an SPX topology where control bridges are connected in a ring. PE units can be connected in either linear or ring topologies.
• ISSU works for stacks of two units to the maximum supported twelve units.
• ISSU is supported in SPX configurations with the maximum number of PE units.
• ISSU is supported for upgrades between minor releases only. For example, you can use ISSU to upgrade between FastIron 08.0.90 and FastIron 08.0.90a or between FastIron 08.0.90a and subsequent patch releases but not between FastIron 08.0.80 and FastIron 08.0.90.
• For ISSU to occur with minimal disruption, the customer network connected to the stack and CB units in an SPX system must have redundant uplink and downlink configurations across multiple units.
• If the secondary partition is upgraded, this partition is set as the default boot partition for the stack.
• Most CLI commands, SNMP, and web operations are blocked while ISSU is in progress.
• To make the upgrade seamless, the following administrative operations are blocked while ISSU is in progress:
  • Configuration
  • Image download to flash memory
  • Stack commands or SPX commands that may result in topology change or discovery
  • Initiation of another ISSU
  • New PE join activity

The following additional items are blocked during ISSU in a Campus Fabric system:

• The web interface
• SPX DDM commands
• SPX interactive-setup
• SPX zero-touch provisioning
• Clear commands