"Introduction and Motivation The concepts of an RPC (defined in RFC 5531 [4]) Network Identifier (netid) and an RPC Universal Address (uaddr) were introduced in RFC 1833 [1] for distinguishing network addresses of multiple protocols and representing those addresses in a canonical form. RFC 1833 states that a netid ""is defined by a system administrator based on local conventions@ and cannot be depended on to have the same value on every system"". (The netid is contained in the field r_netid of the data type rpcb_entry@ and the uaddr is contained in the field r_addr of the same data type@ where rpcb_entry is defined in RFC 1833.) Since the publication of RFC 1833@ it has been found that protocols like Network File System version 4 (NFSv4.0) [5] and RPC/ RDMA (Remote Direct Memory Access) [6] depend on consistent values of netids and representations of uaddrs. Current practices tend to ensure this consistency. Thus@ this document identifies the considerations for IANA to establish registries of netids and uaddr formats for RPC and specifies the initial content of the two registries."