A    Conformance to Internet Host Requirements

This appendix addresses the conformance of Digital UNIX to Internet host requirements as specified by Request for Comments (RFC) 1122: Requirements for Internet Hosts - Communication Layers and RFC 1123: Requirements for Internet Hosts - Applications and Support, and the RFCs that they reference. (RFCs 1122 and 1123 are referred to as Host Requirements RFCs throughout this appendix.)

Note

Although there are RFCs that specify internetworking protocols not referenced in the Host Requirements RFCs, the conformance of Digital UNIX to the requirements specified in those RFCs is beyond the scope of this appendix. The Digital UNIX Software Product Description (SPD) contains additional technical information about the networking component of Digital UNIX and a complete list of RFCs implemented in Digital UNIX.

This appendix contains the following information:

• Background information that briefly describes what RFCs are and, in particular, describes the Host Requirements RFCs.

• Tables that list the RFCs that the Host Requirements RFCs reference and against which Digital UNIX was validated. Associated with each table is a pointer to information in the Host Requirements RFCs that discusses requirements for each Internet layer or protocol.

• A discussion of how Digital UNIX systems can be configured conditionally to comply to Internet Host Requirements when acting as a host.

A.1    Background

The Internet Architecture Board (IAB) issues specifications, and updates to the specifications, in the form of RFCs. RFCs describe protocols (as well as other information) of interest to the Internet community.

The Host Requirements RFCs are a statement of requirements for host system implementations of the Internet protocol suite, when these host systems are connected to the Internet. They do the following:

• Reference other RFCs and documents describing the current specifications for the Internet protocols

• State a set of requirements for each referenced protocol

• Clarify issues where the source document may be confusing

• Correct errors in the referenced documents

• Describe specific provisions overriding the original documents

The Host Requirements RFCs also indicate whether the requirements they discuss are must, must not, should, should not, or may level requirements. If an implementation complies with all must and should level requirements, it is considered unconditionally compliant. If an implementation complies with all must level requirements, but not necessarily all should requirements, it is considered conditionally compliant.

Note

This appendix describes Digital UNIX's conformance to must and must not level requirements only. Although Digital UNIX complies with the vast majority of should, should not, and may level requirements described in the Host Requirements RFCs, compliance with should, should not, and may level requirements is beyond the scope of this appendix.

RFCs are frequently issued or updated. When updates are issued, earlier versions of the RFC are rendered obsolete. The Host Requirements RFCs were issued in October 1989. Where RFCs referenced by the Host Requirements RFCs have been updated since October 1989, the RFC number of the updated version, as well as the number of the version it rendered obsolete, are noted.

The following two RFCs are of general importance to the Internet community because they contain information that has an impact on all implementations of all protocols:

• RFC 1780: Internet Official Protocol Standards Describes the state of standardization of protocols used in the Internet. It lists recent changes in protocols, and also indicates a status of required, recommended, elective, limited use, or not recommended for each protocol described. Digital UNIX was validated against RFC 1600. RFC 1600 renders RFCs 1540, 1500, 1410, 1360, 1280, 1250, 1200, 1140, 1130, 1100, and 1083 obsolete.

• RFC 1780: Assigned Numbers Lists the assigned values of the parameters used in the various protocols, for example, IP codes, TCP port numbers, TELNET option codes, ARP hardware types, and terminal type names. The Host Requirements RFCs reference RFC 1010, an earlier version of this RFC. Digital UNIX was validated against RFC 1340. RFC 1340 renders RFC 1060, 1010, as well as many earlier RFCs, obsolete.

A.2    The Host Requirements RFCs (RFC 1122 and RFC 1123)

RFC 1122 covers requirements for communication protocols for the data link, internetworking, and transport layers of host Internet software. RFC 1123 covers requirements for the application and support protocols for Internet host software.

This section contains tables that list and briefly describe the RFCs that Digital UNIX was validated against and that are referenced in the Host Requirement RFCs. Additionally, Table A-8 and Table A-9 list the total must/must not level requirements explicitly stated by the Host Requirements RFCs.

Table A-1 lists the RFCs that RFC 1122 references for the link layer. For a discussion of link layer requirements, see Chapter 2 of RFC 1122.

Table A-1: Referenced RFCs for the Link Layer

ip:
       1831450 total packets received
       0 bad header checksums
       0 with size smaller than minimum
       0 with data size < data length
       0 with header length < data size
       0 with data length < header length
       3542 fragments received
       0 fragments dropped (dup or out of space)
       10 fragment dropped after timeout
       0 packets forwarded
       0 packets not forwardable
       0 redirects sent

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