7.5. Reserved MT ID Values Certain MT topologies are assigned to serve predetermined purposes: - MT ID #0: Equivalent to the "standard" topology. - MT ID #1: Reserved for IPv4 in-band management purposes. - MT ID #2: Reserved for IPv6 routing topology. - MT ID #3: Reserved for IPv4 multicast routing topology. - MT ID #4: Reserved for IPv6 multicast routing topology. - MT ID #5: Reserved for IPv6 in-band management purposes. - MT ID #6-#3995: Reserved for IETF consensus. - MT ID #3996-#4095: Reserved for development, experimental and proprietary features [RFC3692]. On Spirent TestCenter, we can config this value to "0", "2", "0,2" or empty. regarding to RFC5120 different value means:
Identifier Description 0 IPv4 routing topology 2 IPv6 routing topology If this field is empty then the multi topology field will be included in the ISIS PDU.