HP FlexNetwork 3600 v2 Series Command Reference Manual page 198

Description
Use virtual-system to configure a virtual system ID for the IS-IS process. Use undo virtual-system
to remove a virtual system ID.
Up to 50 virtual system IDs can be configured for the IS-IS process.
Examples
# Set a virtual system ID of 2222.2222.2222 for IS-IS process 1.
<Sysname> system-view
[Sysname] isis 1
[Sysname-isis-1] virtual-system 2222.2222.2222
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