2.1 Transport

[C706] specifies two protocol variants within connection-oriented RPC and connectionless RPC. This specification maintains categorization for the descriptions of the RPC protocol variants.

These extensions update the protocol identifiers that are specified in [C706] Appendix I which specifies that the protocol identifier can be one of three types:

1. An octet string derived from an interface UUID combined with a version number.

2. An octet string derived from OSI object identifiers (OIDs).

3. Single octet identifiers that are registered by the Open Software Foundation for commonly used protocols.

The extensions specified in this document mandate that the third type MUST be used for all communications.

Unless explicitly stated otherwise, the protocol identifier used by each protocol sequence specified in sections 2.1.1 and 2.1.2 is as specified in the table in [C706] Appendix I.

The RPC protocol sequence strings for the RPC transports defined by these extensions are specified in the following table.<1>

RPC transport	RPC protocol sequence string
SMB	ncacn_np (see section 2.1.1.2)
TCP/IP (both IPv4 and IPv6)	ncacn_ip_tcp (see section 2.1.1.1)
UDP	ncadg_ip_udp (see section 2.1.2.1)
SPX	ncacn_spx (see section 2.1.1.3)
IPX	ncadg_ipx (see section 2.1.2.2)
NetBIOS over IPX	ncacn_nb_ipx (see section 2.1.1.4)
NetBIOS over TCP	ncacn_nb_tcp (see section 2.1.1.5)
NetBIOS over NetBEUI	ncacn_nb_nb (see section 2.1.1.6)
AppleTalk	ncacn_at_dsp (see section 2.1.1.7)
RPC over HTTP	ncacn_http (see section 2.1.1.8)