Knowledge

X.121

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88:
The DNIC has three digits to identify the country (one to identify a zone and two to identify the country within the zone) and one to identify the PDN (allowing only ten in each country). The NTN identifies the exact network device (DTE,
100:
IPv4 addresses can be mapped to X.121 as described in RFC 1236. The 14.0.0.0/8 block used to be reserved for X.121 use but was returned to IANA in 2008 to stave off
42: 170: 160: 165: 101: 94: 90: 140: 50: 46: 8: 38: 97:(PSN) and is often provided as an NUA. There are no rules to the structure of the NTN. 34: 30: 175: 154: 113: 23: 120: 27: 33:used as part of call setup to establish a switched 152: 53:(PLP) after the packet type identifier (PTI). 69:), which consists of two fields: the 4 digit 45:(NUAs). It consists of a maximum of fourteen 153: 13: 14: 187: 71:data network identification code 171:ITU-T X Series Recommendations 133: 61:The address is made up of the 56: 1: 141:"Public Data Network Numbers" 126: 49:digits and is sent over the 7: 107: 77:) and the (up to) 10 digit 10: 192: 63:international data number 79:national terminal number 161:Network layer protocols 102:IPv4 address exhaustion 95:packet-switched network 91:data terminal equipment 41:(PDNs), connecting two 43:network user addresses 26:address format of the 166:ITU-T recommendations 51:Packet Layer Protocol 47:binary-coded decimal 39:public data networks 16:ITU-T recommendation 183: 145: 144: 137: 191: 190: 186: 185: 184: 182: 181: 180: 151: 150: 149: 148: 139: 138: 134: 129: 110: 59: 35:virtual circuit 17: 12: 11: 5: 189: 179: 178: 173: 168: 163: 147: 146: 131: 130: 128: 125: 124: 123: 117: 116: 109: 106: 58: 55: 31:protocol suite 15: 9: 6: 4: 3: 2: 188: 177: 174: 172: 169: 167: 164: 162: 159: 158: 156: 142: 136: 132: 122: 119: 118: 115: 112: 111: 105: 103: 98: 96: 92: 86: 84: 80: 76: 72: 68: 64: 54: 52: 48: 44: 40: 36: 32: 29: 25: 21: 135: 99: 87: 82: 78: 74: 70: 66: 62: 60: 19: 18: 57:Description 155:Categories 127:References 93:) in the 114:Videotex 108:See also 37:between 22:is the 24:ITU-T 20:X.121 176:X.25 121:X.75 75:DNIC 28:X.25 85:). 83:NTN 67:IDN 157:: 104:. 143:. 81:( 73:( 65:(

Index

ITU-T
X.25
protocol suite
virtual circuit
public data networks
network user addresses
binary-coded decimal
Packet Layer Protocol
data terminal equipment
packet-switched network
IPv4 address exhaustion
Videotex
X.75
"Public Data Network Numbers"
Categories
Network layer protocols
ITU-T recommendations
ITU-T X Series Recommendations
X.25

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