This object reports the address format, typically IPv4 or IPv6, of the router-id configured or automatically selected for this EIGRP autonomous system. This is a supporting type field for correctly interpreting cEigrpAsRouterId; an admin needs it when reading router-id values programmatically to know whether to parse that address as IPv4 or IPv6, especially on a dual-stack router running both EIGRP address families. On a router running both EIGRP for IPv4 and EIGRPv6, an admin comparing router-ids across the two AS instances would check this type field to correctly interpret each AS's respective router-id format.