Tài liệu TCP/IP Tutorial and Technical Overview ppt

ibm.com/redbooks
TCP/IP Tutorial and
Technical Overview
Lydia Parziale
David T. Britt
Chuck Davis
Jason Forrester
Wei Liu
Carolyn Matthews
Nicolas Rosselot
Understand networking fundamentals
of the TCP/IP protocol suite
Introduces advanced concepts
and new technologies
Includes the latest
TCP/IP protocols
Front cover

TCP/IP Tutorial and Technical Overview
December 2006
International Technical Support Organization
GG24-3376-07
© Copyright International Business Machines Corporation 1989-2006. All rights reserved.
Note to U.S. Government Users Restricted Rights -- Use, duplication or disclosure restricted by GSA ADP
Schedule Contract with IBM Corp.
Eighth Edition (December 2006)
Note: Before using this information and the product it supports, read the information in
“Notices” on page xvii.
© Copyright IBM Corp. 1989-2006. All rights reserved.
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Contents

Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xviii
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
The team that wrote this redbook. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx
Become a published author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxii
Comments welcome. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii
Part 1. Core TCP/IP protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 1. Architecture, history, standards, and trends . . . . . . . . . . . . . . . 3
1.1 TCP/IP architectural model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1.1 Internetworking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1.2 The TCP/IP protocol layers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.3 TCP/IP applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.2 The roots of the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.2.1 ARPANET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.2.2 NSFNET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.2.3 Commercial use of the Internet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.2.4 Internet2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.2.5 The Open Systems Interconnection (OSI) Reference Model . . . . . . 20
1.3 TCP/IP standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.3.1 Request for Comments (RFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
1.3.2 Internet standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.4 Future of the Internet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.4.1 Multimedia applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.4.2 Commercial use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.4.3 The wireless Internet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.5 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Chapter 2. Network interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.1 Ethernet and IEEE 802 local area networks (LANs) . . . . . . . . . . . . . . . . . 30
2.1.1 Gigabit Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.2 Fiber Distributed Data Interface (FDDI). . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.3 Serial Line IP (SLIP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.4 Point-to-Point Protocol (PPP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.4.1 Point-to-point encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
2.5 Integrated Services Digital Network (ISDN) . . . . . . . . . . . . . . . . . . . . . . . 38
2.6 X.25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
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2.7 Frame relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.7.1 Frame format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.7.2 Interconnect issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2.7.3 Data link layer parameter negotiation . . . . . . . . . . . . . . . . . . . . . . . . 43
2.7.4 IP over frame relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
2.8 PPP over SONET and SDH circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.8.1 Physical layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.9 Multi-Path Channel+ (MPC+) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.10 Asynchronous transfer mode (ATM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.10.1 Address resolution (ATMARP and InATMARP) . . . . . . . . . . . . . . . 47
2.10.2 Classical IP over ATM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
2.10.3 ATM LAN emulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
2.10.4 Classical IP over ATM versus LAN emulation. . . . . . . . . . . . . . . . . 59
2.11 Multiprotocol over ATM (MPOA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
2.11.1 Benefits of MPOA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
2.11.2 MPOA logical components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
2.11.3 MPOA functional components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
2.11.4 MPOA operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
2.12 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Chapter 3. Internetworking protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
3.1 Internet Protocol (IP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.1.1 IP addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.1.2 IP subnets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

3.1.3 IP routing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
3.1.4 Methods of delivery: Unicast, broadcast, multicast, and anycast . . . 84
3.1.5 The IP address exhaustion problem . . . . . . . . . . . . . . . . . . . . . . . . . 86
3.1.6 Intranets: Private IP addresses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
3.1.7 Network Address Translation (NAT) . . . . . . . . . . . . . . . . . . . . . . . . . 89
3.1.8 Classless Inter-Domain Routing (CIDR) . . . . . . . . . . . . . . . . . . . . . . 95
3.1.9 IP datagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
3.2 Internet Control Message Protocol (ICMP) . . . . . . . . . . . . . . . . . . . . . . . 109
3.2.1 ICMP messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
3.2.2 ICMP applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
3.3 Internet Group Management Protocol (IGMP) . . . . . . . . . . . . . . . . . . . . 119
3.4 Address Resolution Protocol (ARP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
3.4.1 ARP overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
3.4.2 ARP detailed concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
3.4.3 ARP and subnets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
3.4.4 Proxy-ARP or transparent subnetting . . . . . . . . . . . . . . . . . . . . . . . 123
3.5 Reverse Address Resolution Protocol (RARP) . . . . . . . . . . . . . . . . . . . . 124
3.5.1 RARP concept. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
3.6 Bootstrap Protocol (BOOTP). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
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3.6.1 BOOTP forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
3.6.2 BOOTP considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
3.7 Dynamic Host Configuration Protocol (DHCP) . . . . . . . . . . . . . . . . . . . . 130
3.7.1 The DHCP message format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
3.7.2 DHCP message types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
3.7.3 Allocating a new network address. . . . . . . . . . . . . . . . . . . . . . . . . . 134
3.7.4 DHCP lease renewal process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
3.7.5 Reusing a previously allocated network address . . . . . . . . . . . . . . 138
3.7.6 Configuration parameters repository. . . . . . . . . . . . . . . . . . . . . . . . 139

3.7.7 DHCP considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
3.7.8 BOOTP and DHCP interoperability. . . . . . . . . . . . . . . . . . . . . . . . . 140
3.8 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Chapter 4. Transport layer protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
4.1 Ports and sockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
4.1.1 Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
4.1.2 Sockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
4.2 User Datagram Protocol (UDP). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
4.2.1 UDP datagram format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
4.2.2 UDP application programming interface . . . . . . . . . . . . . . . . . . . . . 149
4.3 Transmission Control Protocol (TCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
4.3.1 TCP concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
4.3.2 TCP application programming interface . . . . . . . . . . . . . . . . . . . . . 164
4.3.3 TCP congestion control algorithms . . . . . . . . . . . . . . . . . . . . . . . . . 165
4.4 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Chapter 5. Routing protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
5.1 Autonomous systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
5.2 Types of IP routing and IP routing algorithms . . . . . . . . . . . . . . . . . . . . . 174
5.2.1 Static routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
5.2.2 Distance vector routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
5.2.3 Link state routing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
5.2.4 Path vector routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
5.2.5 Hybrid routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
5.3 Routing Information Protocol (RIP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
5.3.1 RIP packet types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
5.3.2 RIP packet format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
5.3.3 RIP modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
5.3.4 Calculating distance vectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
5.3.5 Convergence and counting to infinity . . . . . . . . . . . . . . . . . . . . . . . 185
5.3.6 RIP limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

5.4 Routing Information Protocol Version 2 (RIP-2) . . . . . . . . . . . . . . . . . . . 189
5.4.1 RIP-2 packet format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
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5.4.2 RIP-2 limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
5.5 RIPng for IPv6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
5.5.1 Differences between RIPng and RIP-2 . . . . . . . . . . . . . . . . . . . . . . 193
5.5.2 RIPng packet format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
5.6 Open Shortest Path First (OSPF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
5.6.1 OSPF terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
5.6.2 Neighbor communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
5.6.3 OSPF neighbor state machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
5.6.4 OSPF route redistribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
5.6.5 OSPF stub areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
5.6.6 OSPF route summarization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
5.7 Enhanced Interior Gateway Routing Protocol (EIGRP). . . . . . . . . . . . . . 212
5.7.1 Features of EIGRP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
5.7.2 EIGRP packet types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
5.8 Exterior Gateway Protocol (EGP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
5.9 Border Gateway Protocol (BGP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
5.9.1 BGP concepts and terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
5.9.2 IBGP and EBGP communication . . . . . . . . . . . . . . . . . . . . . . . . . . 218
5.9.3 Protocol description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
5.9.4 Path selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
5.9.5 BGP synchronization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
5.9.6 BGP aggregation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
5.9.7 BGP confederations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
5.9.8 BGP route reflectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
5.10 Routing protocol selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
5.11 Additional functions performed by the router. . . . . . . . . . . . . . . . . . . . . 234

5.12 Routing processes in UNIX-based systems . . . . . . . . . . . . . . . . . . . . . 235
5.13 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
Chapter 6. IP multicast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
6.1 Multicast addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
6.1.1 Multicasting on a single physical network . . . . . . . . . . . . . . . . . . . . 238
6.1.2 Multicasting between network segments . . . . . . . . . . . . . . . . . . . . 240
6.2 Internet Group Management Protocol (IGMP) . . . . . . . . . . . . . . . . . . . . 241
6.2.1 IGMP messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
6.2.2 IGMP operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
6.3 Multicast delivery tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
6.4 Multicast forwarding algorithms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
6.4.1 Reverse path forwarding algorithm . . . . . . . . . . . . . . . . . . . . . . . . . 252
6.4.2 Center-based tree algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
6.4.3 Multicast routing protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
6.5 Distance Vector Multicast Routing Protocol (DVMRP) . . . . . . . . . . . . . . 254
6.5.1 Protocol overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
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6.5.2 Building and maintaining multicast delivery trees . . . . . . . . . . . . . . 256
6.5.3 DVMRP tunnels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
6.6 Multicast OSPF (MOSPF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
6.6.1 Protocol overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
6.6.2 MOSPF and multiple OSPF areas . . . . . . . . . . . . . . . . . . . . . . . . . 260
6.6.3 MOSPF and multiple autonomous systems . . . . . . . . . . . . . . . . . . 260
6.6.4 MOSPF interoperability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
6.7 Protocol Independent Multicast (PIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
6.7.1 PIM dense mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
6.7.2 PIM sparse mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
6.8 Interconnecting multicast domains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
6.8.1 Multicast Source Discovery Protocol (MSDP). . . . . . . . . . . . . . . . . 266

6.8.2 Border Gateway Multicast Protocol. . . . . . . . . . . . . . . . . . . . . . . . . 269
6.9 The multicast backbone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
6.9.1 MBONE routing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
6.9.2 Multicast applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
6.10 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Chapter 7. Mobile IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
7.1 Mobile IP overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
7.1.1 Mobile IP operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
7.1.2 Mobility agent advertisement extensions . . . . . . . . . . . . . . . . . . . . 278
7.2 Mobile IP registration process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
7.2.1 Tunneling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
7.2.2 Broadcast datagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
7.2.3 Move detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
7.2.4 Returning home. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
7.2.5 ARP considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
7.2.6 Mobile IP security considerations . . . . . . . . . . . . . . . . . . . . . . . . . . 286
7.3 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
Chapter 8. Quality of service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
8.1 Why QoS?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
8.2 Integrated Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
8.2.1 Service classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
8.2.2 Controlled Load Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
8.2.3 Guaranteed Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
8.2.4 The Resource Reservation Protocol (RSVP) . . . . . . . . . . . . . . . . . 296
8.2.5 Integrated Services outlook. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
8.3 Differentiated Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
8.3.1 Differentiated Services architecture . . . . . . . . . . . . . . . . . . . . . . . . 310
8.3.2 Organization of the DSCP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
8.3.3 Configuration and administration of DS with LDAP. . . . . . . . . . . . . 322
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8.4 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Chapter 9. IP version 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
9.1 IPv6 introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
9.1.1 IP growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
9.1.2 IPv6 feature overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
9.2 The IPv6 header format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
9.2.1 Extension headers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
9.2.2 IPv6 addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
9.2.3 Traffic class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345
9.2.4 Flow labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
9.2.5 IPv6 security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
9.2.6 Packet sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
9.3 Internet Control Message Protocol Version 6 (ICMPv6) . . . . . . . . . . . . . 352
9.3.1 Neighbor discovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
9.3.2 Multicast Listener Discovery (MLD) . . . . . . . . . . . . . . . . . . . . . . . . 365
9.4 DNS in IPv6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
9.4.1 Format of IPv6 resource records. . . . . . . . . . . . . . . . . . . . . . . . . . . 368
9.5 DHCP in IPv6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
9.5.1 DHCPv6 messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
9.6 IPv6 mobility support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372
9.7 IPv6 new opportunities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
9.7.1 New infrastructure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
9.7.2 New services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
9.7.3 New research and development platforms . . . . . . . . . . . . . . . . . . . 378
9.8 Internet transition: Migrating from IPv4 to IPv6 . . . . . . . . . . . . . . . . . . . . 379
9.8.1 Dual IP stack implementation: The IPv6/IPv4 node . . . . . . . . . . . . 380
9.8.2 Tunneling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
9.8.3 Interoperability summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
9.9 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389

Chapter 10. Wireless IP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
10.1 Wireless concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
10.2 Why wireless? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
10.2.1 Deployment and cost effectiveness . . . . . . . . . . . . . . . . . . . . . . . 395
10.2.2 Reachability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
10.2.3 Scalability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
10.2.4 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
10.2.5 Connectivity and reliability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
10.3 WiFi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
10.4 WiMax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
10.5 Applications of wireless networking. . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
10.5.1 Last mile connectivity in broadband services . . . . . . . . . . . . . . . . 402
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10.5.2 Hotspots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
10.5.3 Mesh networking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
10.6 IEEE standards relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . 403
Part 2. TCP/IP application protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
Chapter 11. Application structure and programming interfaces . . . . . . 407
11.1 Characteristics of applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
11.1.1 The client/server model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
11.2 Application programming interfaces (APIs) . . . . . . . . . . . . . . . . . . . . . . 410
11.2.1 The socket API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410
11.2.2 Remote Procedure Call (RPC) . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
11.2.3 The SNMP distributed programming interface (SNMP DPI) . . . . . 419
11.2.4 REXX sockets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
11.3 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
Chapter 12. Directory and naming protocols . . . . . . . . . . . . . . . . . . . . . . 425
12.1 Domain Name System (DNS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
12.1.1 The hierarchical namespace. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426

12.1.2 Fully qualified domain names (FQDNs) . . . . . . . . . . . . . . . . . . . . 428
12.1.3 Generic domains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428
12.1.4 Country domains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
12.1.5 Mapping domain names to IP addresses . . . . . . . . . . . . . . . . . . . 429
12.1.6 Mapping IP addresses to domain names: Pointer queries . . . . . . 430
12.1.7 The distributed name space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
12.1.8 Domain name resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
12.1.9 Domain Name System resource records . . . . . . . . . . . . . . . . . . . 436
12.1.10 Domain Name System messages. . . . . . . . . . . . . . . . . . . . . . . . 439
12.1.11 A simple scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445
12.1.12 Extended scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
12.1.13 Transport. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
12.1.14 DNS applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451
12.2 Dynamic Domain Name System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
12.2.1 Dynamic updates in the DDNS . . . . . . . . . . . . . . . . . . . . . . . . . . . 454
12.2.2 Incremental zone transfers in DDNS. . . . . . . . . . . . . . . . . . . . . . . 456
12.2.3 Prompt notification of zone transfer . . . . . . . . . . . . . . . . . . . . . . . 457
12.3 Network Information System (NIS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
12.4 Lightweight Directory Access Protocol (LDAP) . . . . . . . . . . . . . . . . . . . 459
12.4.1 LDAP: Lightweight access to X.500 . . . . . . . . . . . . . . . . . . . . . . . 460
12.4.2 The LDAP directory server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
12.4.3 Overview of LDAP architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
12.4.4 LDAP models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
12.4.5 LDAP security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
12.4.6 LDAP URLs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
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12.4.7 LDAP and DCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
12.4.8 The Directory-Enabled Networks (DEN) initiative . . . . . . . . . . . . . 477
12.4.9 Web-Based Enterprise Management (WBEM) . . . . . . . . . . . . . . . 478

12.5 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
Chapter 13. Remote execution and distributed computing. . . . . . . . . . . 483
13.1 Telnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484
13.1.1 Telnet operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484
13.1.2 Network Virtual Terminal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
13.1.3 Telnet options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
13.1.4 Telnet command structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
13.1.5 Option negotiation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491
13.1.6 Telnet basic commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
13.1.7 Terminal emulation (Telnet 3270) . . . . . . . . . . . . . . . . . . . . . . . . . 492
13.1.8 TN3270 enhancements (TN3270E) . . . . . . . . . . . . . . . . . . . . . . . 493
13.1.9 Device-type negotiation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
13.2 Remote Execution Command protocol (REXEC and RSH) . . . . . . . . . 495
13.3 Introduction to the Distributed Computing Environment (DCE). . . . . . . 496
13.3.1 DCE directory service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498
13.3.2 Authentication service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
13.3.3 DCE threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505
13.3.4 Distributed Time Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
13.3.5 Additional information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
13.4 Distributed File Service (DFS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
13.4.1 File naming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
13.4.2 DFS performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
13.5 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512
Chapter 14. File-related protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513
14.1 File Transfer Protocol (FTP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
14.1.1 An overview of FTP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
14.1.2 FTP operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
14.1.3 The active data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 520
14.1.4 The passive data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 521
14.1.5 Using proxy transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522

14.1.6 Reply codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523
14.1.7 Anonymous FTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525
14.1.8 Using FTP with IPv6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525
14.1.9 Securing FTP sessions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527
14.2 Trivial File Transfer Protocol (TFTP) . . . . . . . . . . . . . . . . . . . . . . . . . . . 529
14.2.1 TFTP usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530
14.2.2 Protocol description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
14.2.3 TFTP packets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
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14.2.4 Data modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 532
14.2.5 TFTP multicast option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 532
14.2.6 Security issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533
14.3 Secure Copy Protocol (SCP) and SSH FTP (SFTP). . . . . . . . . . . . . . . 533
14.3.1 SCP syntax and usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533
14.3.2 SFTP syntax and usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
14.3.3 SFTP interactive commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
14.4 Network File System (NFS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
14.4.1 NFS concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
14.4.2 File integrity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542
14.4.3 Lock Manager protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
14.4.4 NFS file system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
14.4.5 NFS version 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
14.4.6 Cache File System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545
14.4.7 WebNFS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545
14.5 The Andrew File System (AFS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546
14.6 Common Internet File System (CIFS) . . . . . . . . . . . . . . . . . . . . . . . . . . 548
14.6.1 NetBIOS over TCP/IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 548
14.6.2 SMB/CIFS specifics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550
14.7 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552

Chapter 15. Mail applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555
15.1 Simple Mail Transfer Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556
15.1.1 How SMTP works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559
15.1.2 SMTP and the Domain Name System . . . . . . . . . . . . . . . . . . . . . 565
15.2 Sendmail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 568
15.2.1 Sendmail as a mail transfer agent (MTA) . . . . . . . . . . . . . . . . . . . 568
15.2.2 How sendmail works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569
15.3 Multipurpose Internet Mail Extensions (MIME) . . . . . . . . . . . . . . . . . . . 571
15.3.1 How MIME works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 574
15.3.2 The Content-Transfer-Encoding field . . . . . . . . . . . . . . . . . . . . . . 582
15.3.3 Using non-ASCII characters in message headers . . . . . . . . . . . . 587
15.4 Post Office Protocol (POP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589
15.4.1 Connection states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589
15.4.2 POP3 commands and responses . . . . . . . . . . . . . . . . . . . . . . . . . 590
15.5 Internet Message Access Protocol (IMAP4) . . . . . . . . . . . . . . . . . . . . . 591
15.5.1 Fundamental IMAP4 electronic mail models. . . . . . . . . . . . . . . . . 591
15.5.2 IMAP4 states. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592
15.5.3 IMAP4 commands and response interaction . . . . . . . . . . . . . . . . 594
15.5.4 IMAP4 messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597
15.6 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599
Chapter 16. The Web. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
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TCP/IP Tutorial and Technical Overview
16.1 Web browsers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
16.2 Web servers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
16.3 Hypertext Transfer Protocol (HTTP) . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
16.3.1 Overview of HTTP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
16.3.2 HTTP operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 606
16.4 Content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615
16.4.1 Static content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615

16.4.2 Client-side dynamic content . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616
16.4.3 Server-side dynamic content. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617
16.4.4 Developing content with IBM Web application servers . . . . . . . . . 621
16.5 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621
Chapter 17. Network management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623
17.1 The Simple Network Management Protocol (SNMP) . . . . . . . . . . . . . . 624
17.1.1 The Management Information Base (MIB) . . . . . . . . . . . . . . . . . . 625
17.1.2 The SNMP agent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630
17.1.3 The SNMP manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
17.1.4 The SNMP subagent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
17.1.5 The SNMP model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633
17.1.6 SNMP traps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 638
17.1.7 SNMP versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639
17.1.8 Single authentication and privacy protocol . . . . . . . . . . . . . . . . . . 647
17.2 The NETSTAT utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 648
17.2.1 Common NETSTAT options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649
17.2.2 Sample NETSTAT report output . . . . . . . . . . . . . . . . . . . . . . . . . . 649
17.3 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651
Chapter 18. Wireless Application Protocol. . . . . . . . . . . . . . . . . . . . . . . . 655
18.1 The WAP environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657
18.2 Key elements of the WAP specifications. . . . . . . . . . . . . . . . . . . . . . . . 657
18.3 WAP architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658
18.4 Client identifiers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663
18.5 Multimedia messaging system (MMS) . . . . . . . . . . . . . . . . . . . . . . . . . 663
18.6 WAP push architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 664
18.6.1 Push framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 664
18.6.2 Push proxy gateway (PPG). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665
18.6.3 Push access control protocol (PAP) . . . . . . . . . . . . . . . . . . . . . . . 667
18.6.4 Service indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 668
18.6.5 Push over-the-air protocol (OTA) . . . . . . . . . . . . . . . . . . . . . . . . . 668

18.6.6 Client-side infrastructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 668
18.6.7 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 669
18.7 The Wireless Application Environment (WAE2) . . . . . . . . . . . . . . . . . . 670
18.8 User Agent Profile (UAProf) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 671
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18.9 Wireless protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 672
18.9.1 Wireless Datagram Protocol (WDP) . . . . . . . . . . . . . . . . . . . . . . . 672
18.9.2 Wireless Profiled Transmission Control Protocol (WP-TCP) . . . . 674
18.9.3 Wireless Control Message Protocol (WCMP) . . . . . . . . . . . . . . . . 678
18.9.4 Wireless Transaction Protocol (WTP) . . . . . . . . . . . . . . . . . . . . . . 679
18.9.5 Wireless Session Protocol (WSP). . . . . . . . . . . . . . . . . . . . . . . . . 682
18.9.6 Wireless profiled HTTP (W-HTTP) . . . . . . . . . . . . . . . . . . . . . . . . 695
18.10 Wireless security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 696
18.10.1 Wireless Transport Layer Security (WTLS). . . . . . . . . . . . . . . . . 696
18.10.2 Wireless Identity Module (WIM) . . . . . . . . . . . . . . . . . . . . . . . . . 701
18.11 Wireless Telephony Application (WTA). . . . . . . . . . . . . . . . . . . . . . . . 702
18.12 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
18.13 Specifications relevant to this chapter. . . . . . . . . . . . . . . . . . . . . . . . . 703
Chapter 19. Presence over IP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 707
19.1 Overview of the presence service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710
19.2 Presence Information Data Format (PIDF) . . . . . . . . . . . . . . . . . . . . . . 714
19.3 Presence protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 716
19.3.1 Binding to TCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
19.3.2 Address resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
19.4 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
Part 3. Advanced concepts and new technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 721
Chapter 20. Voice over Internet Protocol . . . . . . . . . . . . . . . . . . . . . . . . . 723
20.1 Voice over IP (VoIP) introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 724
20.1.1 Benefits and applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 724

20.1.2 VoIP functional components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 726
20.2 Session Initiation Protocol (SIP) technologies. . . . . . . . . . . . . . . . . . . . 730
20.2.1 SIP request and response. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 732
20.2.2 Sample SIP message flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 733
20.2.3 SIP protocol architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 734
20.3 Media Gateway Control Protocol (MGCP) . . . . . . . . . . . . . . . . . . . . . . 736
20.3.1 MGCP architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737
20.3.2 MGCP primitives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 737
20.4 Media Gateway Controller (Megaco). . . . . . . . . . . . . . . . . . . . . . . . . . . 738
20.4.1 Megaco architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 738
20.5 ITU-T recommendation H.323. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 739
20.5.1 H.323 architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 739
20.5.2 H.323 protocol stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741
20.6 Summary of VoIP protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 742
20.7 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 743
Chapter 21. Internet Protocol Television. . . . . . . . . . . . . . . . . . . . . . . . . . 745
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TCP/IP Tutorial and Technical Overview
21.1 IPTV overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 746
21.1.1 IPTV requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 747
21.1.2 Business benefits and applications. . . . . . . . . . . . . . . . . . . . . . . . 749
21.2 Functional components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750
21.2.1 Content acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750
21.2.2 CODEC (encode and decode) . . . . . . . . . . . . . . . . . . . . . . . . . . . 750
21.2.3 Display devices and control gateway . . . . . . . . . . . . . . . . . . . . . . 751
21.2.4 IP (TV) transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 752
21.3 IPTV technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 752
21.3.1 Summary of protocol standards . . . . . . . . . . . . . . . . . . . . . . . . . . 753
21.3.2 Stream Control Transmission Protocol . . . . . . . . . . . . . . . . . . . . . 753
21.3.3 Session Description Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . 754

21.3.4 Real-Time Transport Protocol (RTP) . . . . . . . . . . . . . . . . . . . . . . 756
21.3.5 Real-Time Control Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762
21.3.6 Moving Picture Experts Group (MPEG) standards . . . . . . . . . . . . 767
21.3.7 H.261. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 769
21.4 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 770
Chapter 22. TCP/IP security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 771
22.1 Security exposures and solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 772
22.1.1 Common attacks against security . . . . . . . . . . . . . . . . . . . . . . . . . 772
22.1.2 Solutions to network security problems. . . . . . . . . . . . . . . . . . . . . 772
22.1.3 Implementations of security solutions . . . . . . . . . . . . . . . . . . . . . . 774
22.1.4 Network security policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 776
22.2 A short introduction to cryptography . . . . . . . . . . . . . . . . . . . . . . . . . . . 777
22.2.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777
22.2.2 Symmetric or secret-key algorithms . . . . . . . . . . . . . . . . . . . . . . . 779
22.2.3 Asymmetric or public key algorithms. . . . . . . . . . . . . . . . . . . . . . . 780
22.2.4 Hash functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785
22.2.5 Digital certificates and certification authorities . . . . . . . . . . . . . . . 791
22.2.6 Random-number generators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792
22.2.7 Export/import restrictions on cryptography . . . . . . . . . . . . . . . . . . 793
22.3 Firewalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
22.3.1 Firewall concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795
22.3.2 Components of a firewall system . . . . . . . . . . . . . . . . . . . . . . . . . 796
22.3.3 Types of firewalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
22.4 IP Security Architecture (IPSec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809
22.4.1 Concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 810
22.4.2 Authentication Header (AH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 813
22.4.3 Encapsulating Security Payload (ESP). . . . . . . . . . . . . . . . . . . . . 817
22.4.4 Combining IPSec protocols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 823
22.4.5 Internet Key Exchange (IKE) protocol. . . . . . . . . . . . . . . . . . . . . . 829
22.5 SOCKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 846

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22.5.1 SOCKS Version 5 (SOCKSv5) . . . . . . . . . . . . . . . . . . . . . . . . . . . 848
22.6 Secure Shell (1 and 2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 853
22.6.1 SSH overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 853
22.7 Secure Sockets Layer (SSL). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854
22.7.1 SSL overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854
22.7.2 SSL protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 856
22.8 Transport Layer Security (TLS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861
22.9 Secure Multipurpose Internet Mail Extension (S-MIME) . . . . . . . . . . . . 861
22.10 Virtual private networks (VPNs) overview . . . . . . . . . . . . . . . . . . . . . . 861
22.10.1 VPN introduction and benefits. . . . . . . . . . . . . . . . . . . . . . . . . . . 862
22.11 Kerberos authentication and authorization system . . . . . . . . . . . . . . . 864
22.11.1 Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 865
22.11.2 Naming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 865
22.11.3 Kerberos authentication process. . . . . . . . . . . . . . . . . . . . . . . . . 866
22.11.4 Kerberos database management . . . . . . . . . . . . . . . . . . . . . . . . 870
22.11.5 Kerberos Authorization Model. . . . . . . . . . . . . . . . . . . . . . . . . . . 871
22.11.6 Kerberos Version 5 enhancements. . . . . . . . . . . . . . . . . . . . . . . 871
22.12 Remote access authentication protocols. . . . . . . . . . . . . . . . . . . . . . . 872
22.13 Extensible Authentication Protocol (EAP) . . . . . . . . . . . . . . . . . . . . . . 874
22.14 Layer 2 Tunneling Protocol (L2TP) . . . . . . . . . . . . . . . . . . . . . . . . . . . 875
22.14.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 876
22.14.2 Protocol overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 877
22.14.3 L2TP security issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 879
22.15 Secure Electronic Transaction (SET) . . . . . . . . . . . . . . . . . . . . . . . . . 880
22.15.1 SET roles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 880
22.15.2 SET transactions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 881
22.15.3 The SET certificate scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . 883
22.16 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885

Chapter 23. Port based network access control . . . . . . . . . . . . . . . . . . . 889
23.1 Port based network access control (NAC) overview . . . . . . . . . . . . . . . 890
23.2 Port based NAC component overview . . . . . . . . . . . . . . . . . . . . . . . . . 891
23.3 Port based network access control operation . . . . . . . . . . . . . . . . . . . . 892
23.3.1 Port based network access control functional considerations. . . . 904
23.4 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906
Chapter 24. Availability, scalability, and load balancing . . . . . . . . . . . . . 907
24.1 Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
24.2 Scalability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909
24.3 Load balancing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 910
24.4 Clustering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 910
24.5 Virtualization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 912
24.6 Virtual Router Redundancy Protocol (VRRP) . . . . . . . . . . . . . . . . . . . . 914
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TCP/IP Tutorial and Technical Overview
24.6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 914
24.6.2 VRRP definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916
24.6.3 VRRP overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 916
24.6.4 Sample configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 918
24.6.5 VRRP packet format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 919
24.7 Round-robin DNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 921
24.8 Alternative solutions to load balancing . . . . . . . . . . . . . . . . . . . . . . . . . 921
24.8.1 Network Address Translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 922
24.8.2 Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 923
24.9 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 924
Appendix A. Multiprotocol Label Switching . . . . . . . . . . . . . . . . . . . . . . . 925
A.1 MPLS: An introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 926
A.1.1 Conventional routing versus MPLS forwarding mode. . . . . . . . . . . 926
A.1.2 Benefits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 927
A.1.3 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 929

A.2 MPLS network processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 932
A.2.1 Label swapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 932
A.2.2 Label switched path (LSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 934
A.2.3 Label stack and label hierarchies . . . . . . . . . . . . . . . . . . . . . . . . . . 934
A.2.4 MPLS stacks in a BGP environment. . . . . . . . . . . . . . . . . . . . . . . . 936
A.2.5 Label distribution protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 938
A.2.6 Stream merge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 939
A.3 Emulating Ethernet over MPLS networks . . . . . . . . . . . . . . . . . . . . . . . . 939
A.4 Generalized Multiprotocol Label Switching (GMPLS). . . . . . . . . . . . . . . 941
A.4.1 Benefits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 941
A.4.2 MPLS and GMPLS comparison in OTN environment. . . . . . . . . . . 942
A.4.3 How does GMPLS work? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 943
A.4.4 Link Management Protocol (LMP) . . . . . . . . . . . . . . . . . . . . . . . . . 944
A.4.5 Signaling for route selection and path setup. . . . . . . . . . . . . . . . . . 947
A.4.6 GMPLS considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 949
A.4.7 GMPLS examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 950
A.5 RFCs relevant to this chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 952
Abbreviations and acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 953
Related publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959
IBM Redbooks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959
Other publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959
Online resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959
How to get IBM Redbooks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 961
Help from IBM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 961
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 963
© Copyright IBM Corp. 1989-2006. All rights reserved.
xvii
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xviii
TCP/IP Tutorial and Technical Overview
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xix

Preface
The TCP/IP protocol suite has become a staple of today's international society
and global economy. Continually evolving standards provide a wide and flexible
foundation on which an entire infrastructure of applications are built. Through
these we can seek entertainment, conduct business, make financial
transactions, deliver services, and much, much more.
However, because TCP/IP continues to develop and grow in order to meet the
changing needs of our communities, it might sometimes be hard to keep track of
new functionality or identify new possibilities. For this reason, the TCP/IP Tutorial
and Technical Overview provides not only an introduction to the TCP/IP protocol
suite, but also serves as a reference for advanced users seeking to keep their
TCP/IP skills aligned with current standards. It is our hope that both the novice
and the expert will find useful information in this publication.
In Part I, you will find an introduction to the core concepts and history upon which
TCP/IP is founded. Included is an introduction to the history of TCP/IP and an
overview of its current architecture. We also provide detailed discussions about
the protocols that comprise the suite, and how those protocols are most
commonly implemented.
Part II expands on the information provided in Part I, providing general
application concepts (such as file sharing) and specific application protocols
within those concepts (such as the File Transfer Protocol, or FTP). Additionally,
Part II discusses applications that might not be included in the standard TCP/IP
suite but, because of their wide use throughout the Internet community, are
considered de facto standards.
Finally, Part III addresses new concepts and advanced implementations within
the TCP/IP architecture. Of particular note, Part III examines the convergence of
many formerly disparate networks and services using IP technology. Conjointly,
this section reviews potential dangers of this IP convergence and approaches
the ever-growing standards used to secure and control access to networks and
networked resources.

We purposely kept this book platform independent. However, we recognize that
you might have a need to learn more about TCP/IP on various platforms, so the
following Web sites might assist you in further researching this topic:
 TCP/IP and System z:
/>xx
TCP/IP Tutorial and Technical Overview
 TCP/IP and System p:
/> TCP/IP and System i:
/> TCP/IP and System x:
/>lling.html
The team that wrote this redbook
This redbook was produced by a team of specialists from around the world
working at the International Technical Support Organization, Poughkeepsie
Center.
Lydia Parziale is a Project Leader for the ITSO team in
Poughkeepsie, New York with domestic and international
experience in technology management including software
development, project leadership, and strategic planning.
Her areas of expertise include e-business development
and database management technologies. Lydia is a
Certified IT Specialist with an MBA in Technology
Management and has been employed by IBM for 23 years in various
technology areas.
David T. Britt is a Software Engineer for IBM in Research
Triangle Park, NC, working specifically with the z/OS®
Communications Server product. He is a subject matter
expert in the Simple Networking Management Protocol
(SNMP) and File Transfer Protocol (FTP), and has written
educational material for both in the form of IBM
Technotes, Techdocs, and Webcasts. He holds a degree

in Mathematical Sciences from the University of North
Carolina in Chapel Hill, and is currently pursuing a master
of science in Information Technology and Management
from the University of North Carolina in Greensboro.
Preface
xxi
Chuck Davis is a Security Architect in the U.S. He has 12
years of experience in IT security field. He has worked at
IBM for nine years. His areas of expertise include IT
security and privacy. He has written extensively about
UNIX/Linux® and Internet security.
Jason Forrester is an IT Architect for IBM Global
Technology Services in Boulder, CO. He has more than 12
years of experience with network communications.
Specializing in IT strategy and architecture, Jason has
designed large-scale enterprise infrastructures. He holds a
CCIE certification and his work has lead to multiple patents
on advanced networking concepts.
Dr. Wei Liu received his Ph.D. from Georgia Institute of
Technology. He has taught TCP/IP networks in the
University of Maryland (UMBC campus) and he has
participated in ICCCN conference organization
committees. Dr. Liu has given lectures at Sun™ Yat-Sen
University and Shantou University in Next Generation
Networks (NGNs). With more than 30 technical
publications (in packet networks, telecommunications, and
standards), he has received several awards from ATIS
committees. Dr. Wei Liu has more than 10 years of telecom industry
experience, having participated in various network transformation projects and
service integration programs. Currently, he is investigating new infrastructure

opportunities (virtualization, network, services, security, and metadata models)
that can lead to future offering and new capabilities.
xxii
TCP/IP Tutorial and Technical Overview
Thanks to the following people for their contributions to this project and laying the
foundation for this book by writing the earlier version:
Adolfo Rodriguez, John Gatrell, John Karas, Roland Peschke, Srinath Karanam,
and Martín F. Maldonado
International Technical Support Organization, Poughkeepsie Center
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Carolyn Matthews is an IT Architect for IBM Global
Technology Services in South Africa. She is an
infrastructure architect for one of South Africa’s largest
accounts. She also acts as a consultant, using various
IBM techniques. Carolyn holds an honors degree in
Information Systems and is currently pursuing her
master’s degree in Information Systems. Her areas of
expertise include TCP/IP networks, IT architecture, and
new technologies.
Nicolas Rosselot is a Developer from Santiago, Chile.

He has most recently been teaching an “Advanced
TCP/IP Networking” class at Andres Bello University.
Preface
xxiii
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