The IS-IS MT=0 extensions consist of supporting the advertising and resolution of the prefix SID sub-TLV within the IP Reach TLV-236 (IPv6), which is defined in RFC 5308.The adjacency SID is still advertised as a sub-TLV of the Extended IS Reachability TLV 22, as defined in RFC 5305, IS-IS Extensions for Traffic Engineering, as in the case of an IPv4 adjacency. The router sets the V-Flag and I-Flag in the SR-Capabilities Sub-TLV to indicate that it is capable of processing SR MPLS encapsulated IPv4 and IPv6 packets on its network interfaces.