This objects indicates whether the IPv6 topology is enabled for the IS-IS process:
disable(0): disables the IPv6 topology of the IS-IS process.
standard(1): specifies the topology type as the standard mode.
ipv6(2): enables IPv6 for the IS-IS process in the IPv6 topology.
compatible(3): specifies the topology type as the compatible mode.
compatibleenablemtspf(4): indicates that SPF calculation is performed in the IPv6 topology in compatible mode.
By default, the IPv6 topology is not enabled for the IS-IS process.