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Mạng và viễn thông P29

Network Numbering and Addressing Plans Thenetworknumbering or addressingplanis an important part ofthenetworkrouting plan, because the network address is the identification used by a caller to identify the customer or network port to which he wishes to be connected. Based on the network address, switched connectionswithinalltypesofnetwork are established.Inthischapterwediscussthefive basicnumbering and addressing schemes, and the principles that goalongwiththem | Networks and Telecommunications Design and Operation Second Edition. Martin P. Clark Copyright 1991 1997 John Wiley Sons Ltd ISBNs 0-471-97346-7 Hardback 0-470-84158-3 Electronic 29 Network Numbering and Addressing Plans The network numbering or addressing plan is an important part of the network routing plan because the network address is the identification used by a caller to identify the customer or network port to which he wishes to be connected. Based on the network address switched connections within all types of network are established. In this chapter we discuss the five basic numbering and addressing schemes and the principles that go along with them. These schemes are international telephone service ISDN numbering plan according to ITU-T recommendations E.163 and E.164 recently combined into one recommendation E.164 international public data network numbering scheme according to ITU-T recommendation X.121 international telex service numbering according to ITU-T recommendation F.69 addressing scheme for the message handling service ITU-T recommendations X.500 Internet addressing scheme 29.1 THE INTERNATIONAL TELEPHONE NUMBERING PLAN The international telephone numbering plan was originally defined in 1964 by ITU-T s recommendation E.163 which laid down the principles of numbering pertinent to public telephone networks. It remains substantially the same but has recently been combined with the subsequent recommendation E.164 numbering for the ISDN era into a single recommendation E.164. Recommendation E.164 defines the recommended prefixes for international calls 00 and trunk calls 0 the allocation of country codes and the maximum number length excluding international prefix 15 digits . Figure 29.1 illustrates an E.164 number or network address. 513 514 NETWORK NUMBERING AND ADDRESSING PLANS international prefix 00 country code CO national significant number NSN trunk area code subscriber number maximum 15 digits structure of an international telephone .