📄 rfc1020.txt
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Network Working Group S. RomanoRequest for Comments: 1020 M. StahlObsoletes RFCs: 997, 990, 960, 943, SRI923, 900, 870, 820, 790, 776, 770, 762, November 1987758, 755, 750, 739, 604, 503, 433, 349Obsoletes IENs: 127, 117, 93 INTERNET NUMBERSSTATUS OF THIS MEMO This memo is an official status report on the network numbers used in the Internet community. Distribution of this memo is unlimited.Introduction The responsibility for the assignment of IP numbers and ASNs has been assumed by Hostmaster at the DDN Network Information Center (NIC). The Hostmaster staff are indebted to Dr. Jon Postel and Ms. Joyce Reynolds of the Information Sciences Institute at the University of Southern California for their ongoing assistance. This Network Working Group Request for Comments documents the currently assigned network numbers and gateway autonomous systems. This RFC will be updated periodically, and in any case current information can be obtained from Hostmaster. Hostmaster DDN Network Information Center SRI International 333 Ravenswood Avenue Menlo Park, California 94025 Phone: 1-800-235-3155 ARPA mail: HOSTMASTER@SRI-NIC.ARPA Most of the protocols used in the Internet are documented in the RFC series of notes. Some of the items listed are undocumented. Further information on protocols can be found in the memo "Official Internet Protocols" [32]. The more prominent and more generally used are documented in the "DDN Protocol Handbook" [12] prepared by the NIC. Other collections of older or obsolete protocols are contained in the "Internet Protocol Transition Workbook" [13], or in the "ARPANET Protocol Transition Handbook" [14]. For further information on ordering the complete 1985 DDN Protocol Handbook, contact the Hostmaster.Romano & Stahl [Page 1]RFC 1020 Internet Numbers November 1987 The entries below contain the name and network mailbox of the individuals responsible for each registered network or autonomous system. The bracketed entry, e.g., [nn,iii], at the right hand margin of the page indicates a reference for the listed network or autonomous system, where the number ("nn") cites the document and the letters ("iii") cites the handle of the responsible person. The NIC Handle is a unique identifier that is used in the NIC WHOIS (NICNAME) service. People sometimes change electronic mailboxes. To find out the latest mailbox or phone number of a contact, use the NIC WHOIS/NICNAME server or contact HOSTMASTER@SRI-NIC.ARPA. The convention used for the documentation of Internet Protocols is to express numbers in decimal and to picture data in "big-endian" order [31]. That is, fields are described left to right, with the most significant octet on the left and the least significant octet on the right. The order of transmission of the header and data described in this document is resolved to the octet level. Whenever a diagram shows a group of octets, the order of transmission of those octets is the normal order in which they are read in English. For example, in the following diagram the octets are transmitted in the order they are numbered. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 1 | 2 | 3 | 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 5 | 6 | 7 | 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 9 | 10 | 11 | 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Transmission Order of Bytes Whenever an octet represents a numeric quantity the left most bit in the diagram is the high order or most significant bit. That is, the bit labeled 0 is the most significant bit. For example, the following diagram represents the value 170 (decimal). 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ |1 0 1 0 1 0 1 0| +-+-+-+-+-+-+-+-+ Significance of BitsRomano & Stahl [Page 2]RFC 1020 Internet Numbers November 1987 Similarly, whenever a multi-octet field represents a numeric quantity the left most bit of the whole field is the most significant bit. When a multi-octet quantity is transmitted the most significant octet is transmitted first. NETWORK NUMBERS The network numbers listed here are used as internet addresses by the Internet Protocol (IP) [11,21]. The IP uses a 32-bit address field and divides that address into a network part and a "rest" or local address part. The division takes 4 forms or classes. The first type of address, or class A, has a 7-bit network number and a 24-bit local address. The highest-order bit is set to 0. This allows 128 class A networks. 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0| NETWORK | Local Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Class A Address The second type of address, class B, has a 14-bit network number and a 16-bit local address. The two highest-order bits are set to 1-0. This allows 16,384 class B networks. 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1 0| NETWORK | Local Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Class B Address The third type of address, class C, has a 21-bit network number and a 8-bit local address. The three highest-order bits are set to 1-1-0. This allows 2,097,152 class C networks. 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1 1 0| NETWORK | Local Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Class C AddressRomano & Stahl [Page 3]RFC 1020 Internet Numbers November 1987 The fourth type of address, class D, is used as a multicast address [10]. The four highest-order bits are set to 1-1-1-0. 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1 1 1 0| multicast address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Class D Address Note: No addresses are allowed with the four highest-order bits set to 1-1-1-1. These addresses, called "class E", are reserved. One commonly used notation for internet host addresses divides the 32-bit address into four 8-bit fields and specifies the value of each field as a decimal number with the fields separated by periods. This is called the "dotted decimal" notation. For example, the internet address of VENERA.ISI.EDU in dotted decimal is 010.001.000.052, or 10.1.0.52. The dotted decimal notation will be used in the listing of assigned network numbers. The class A networks will have nnn.rrr.rrr.rrr, the class B networks will have nnn.nnn.rrr.rrr, and the class C networks will have nnn.nnn.nnn.rrr, where nnn represents part or all of a network number and rrr represents part or all of a local address. There are four catagories of users of Internet Addresses: Research, Defense, Government (Non-Defense), and Commercial. To reflect the allocation of network identifiers among the categories, a one- character code is placed to the left of the network number: R for Research, D for Defense, G for Government, and C for Commercial (see Appendix A for further details on this division of the network identification). Network numbers are assigned for networks that are connected to the research Internet and operational Internet, and for independent networks that use the IP family protocols (these are usually commercial). These independent networks are marked with an asterisk preceding the number. The administrators of independent networks must apply separately for permission to interconnect their network with the Internet. Independent networks should not be listed in the working tables of the Internet hosts or gateways. For various reasons, the assigned numbers of networks are sometimes changed. To ease the transition the old number will be listed for aRomano & Stahl [Page 4]RFC 1020 Internet Numbers November 1987 transition period as well. These "old number" entries will be marked with a "T" following the number and preceding the name, and the network name will be suffixed "-TEMP". Special Addresses:
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