The Illustrated Network- P2 docx

IEEE 802.11 MAC Layer Protocol 100 The IEEE 802.11 Frame 102 Questions for Readers 105 Part II Core Protocols CHAPTER 4 IPv4 and IPv6 Addressing 109 IP Addressing 112 The Network/Host Boundary 117 The IPV4 Address 118 Private IPv4 Addresses 122 Understanding IPv4 Addresses 122 The IPv6 Address 123 Features of IPv6 Addressing 124 IPv6 Address Types and Notation 125 IPv6 Address Prefi xes 126 Subnetting and Supernetting 127 Subnetting in IPv4 127 Subnetting Basics 128 CIDR and VLSM 131 IPV6 Addressing Details 135 IP Address Assignment 138 Questions for Readers 141 CHAPTER 5 Address Resolution Protocol 143 ARP and LANs 146 ARP Packets 153 Example ARP Operation 155 ARP Variations 157 Proxy ARP 157 Reverse ARP 158 ARPs on WANs 158 ARP and IPv6 159 Neighbor Discovery Protocol 160 ND Address Resolution 161 Questions for Readers 163 CHAPTER 6 IPv4 and IPv6 Headers 165 Packet Headers and Addresses 168 The IPv4 Packet Header 170 Fragmentation and IPv4 172 Fragmentation and MTU 175 Contents ix Fragmentation and Reassembly 176 Path MTU Determination 176 A Fragmentation Example 177 Limitations of IPv4 179 The IPv6 Header Structure 179 IPv4 and IPv6 Headers Compared 182 IPv6 Header Changes 183 IPv6 and Fragmentation 184 Questions for Readers 187 CHAPTER 7 Internet Control Message Protocol 189 ICMP and Ping 192 The ICMP Message Format 196 ICMP Message Fields 197 ICMP Types and Codes 198 Sending ICMP Messages 203 When ICMP Must Be Sent 204 When ICMP Must Not Be Sent 204 Ping 204 Traceroute 205 Path MTU 206 ICMPv6 208 Basic ICMPv6 Messages 209 Neighbor Discovery and Autoconfi guration 211 Routers and Neighbor Discovery 212 Interface Addresses 212 Neighbor Solicitation and Advertisement 213 Questions for Readers 215 CHAPTER 8 Routing 217 Routers and Routing Tables 220 Hosts and Routing Tables 222 Direct and Indirect Delivery 226 Routing 229 Direct Delivery without Routing 230 Indirect Delivery and the Router 231 Questions for Readers 235 CHAPTER 9 Forwarding IP Packets 237 Router Architectures 242 Basic Router Architectures 243 Another Router Architecture 246 x Contents Router Access 248 The Console Port 248 The Auxiliary Port 248 The Network 248 Forwarding Table Lookups 249 Dual Stacks, Tunneling, and IP V6 251 Dual Protocol Stacks 252 Tunneling 252 Tunneling Mechanisms 255 Transition Considerations 256 Questions for Readers 257 CHAPTER 10 User Datagram Protocol 259 UDP Ports and Sockets 262 What UDP Is For 266 The UDP Header 267 IPv4 and IPv6 Notes 268 Port Numbers 269 Well-Known Ports 269 The Socket 273 UDP Operation 274 UDP Overfl ows 274 Questions for Readers 277 CHAPTER 11 Transmission Control Protocol 279 TCP and Connections 282 The TCP Header 282 TCP Mechanisms 285 Connections and the Three-Way Handshake 286 Connection Establishment 288 Data Transfer 289 Closing the Connection 291 Flow Control 292 TCP Windows 293 Flow Control and Congestion Control 294 Performance Algorithms 294 TCP and FTP 296 Questions for Readers 299 CHAPTER 12 Multiplexing and Sockets 301 Layers and Applications 301 The Socket Interface 304 Contents xi Socket Libraries 305 TCP Stream Service Calls 306 The Socket Interface: Good or Bad? 307 The “Threat” of Raw Sockets 308 Socket Libraries 309 The Windows Socket Interface 309 TCP/IP and Windows 310 Sockets for Windows 310 Sockets on Linux 311 Questions for Readers 317 Part III Routing and Routing Protocols CHAPTER 13 Routing and Peering 321 Network Layer Routing and Switching 324 Connection-Oriented and Connectionless Networks 325 Quality of Service 326 Host Routing Tables 328 Routing Tables and FreeBSD 329 Routing Tables and RedHat Linux 330 Routing and Windows XP 331 The Internet and the Autonomous System 332 The Internet Today 334 The Role of Routing Policies 336 Peering 338 Picking a Peer 340 Questions for Readers 343 CHAPTER 14 IGPs: RIP, OSPF, and IS–IS 345 Interior Routing Protocols 353 The Three Major IGPs 354 Routing Information Protocol 355 Distance-Vector Routing 355 Broken Links 356 Distance-Vector Consequences 357 RIPv1 358 RIPv2 359 RIPng for IPv6 362 A Note on IGRP and EIGRP 364 Open Shortest Path First 365 Link States and Shortest Paths 365 xii Contents What OSPF Can Do 366 OSPF Router Types and Areas 368 OSPF Designated Router and Backup Designated Router 370 OSPF Packets 371 OSPFv3 for IPv6 372 Intermediate System–Intermediate System 372 The IS–IS Attraction 373 IS–IS and OSPF 373 Similarities of OSPF and IS–IS 374 Differences between OSPF and IS–IS 374 IS–IS for IPv6 376 Questions for Readers 377 CHAPTER 15 Border Gateway Protocol 379 BGP as a Routing Protocol 379 Confi guring BGP 382 The Power of Routing Policy 384 BGP and the Internet 386 EGP and the Early Internet 386 The Birth of BGP 387 BGP as a Path-Vector Protocol 388 IBPG and EBGP 389 IGP Next Hops and BGP Next Hops 390 BGP and the IGP 391 Other Types of BGP 392 BGP Attributes 393 BGP and Routing Policy 395 BGP Scaling 395 BGP Message Types 396 BGP Message Formats 397 The Open Message 397 The Update Message 397 The Notifi cation Message 399 Questions for Readers 401 CHAPTER 16 Multicast 403 A First Look at IPV4 Multicast 406 Multicast Terminology 408 Contents xiii Dense and Sparse Multicast 410 Dense-Mode Multicast 410 Sparse-Mode Multicast 410 Multicast Notation 411 Multicast Concepts 411 Reverse-Path Forwarding 411 The RPF Table 412 Populating the RPF Table 412 Shortest-Path Tree 413 Rendezvous Point and Rendezvous-Point Shared Trees 414 Protocols for Multicast 415 Multicast Hosts and Routers 415 Multicast Group Membership Protocols 416 Multicast Routing Protocols 417 Any-Source Multicast and SSM 418 Multicast Source Discovery Protocol 419 Frames and Multicast 420 IPv4 Multicast Addressing 421 IPv6 Multicast Addressing 423 PIM-SM 425 The Resource Reservation Protocol and PGM 425 Multicast Routing Protocols 426 IPv6 Multicast 428 Questions for Readers 429 CHAPTER 17 MPLS and IP Switching 431 Converging What? 435 Fast Packet Switching 435 Frame Relay 435 Asynchronous Transfer Mode 438 Why Converge on TCP/IP? 441 MPLS 442 MPLS Terminology 446 Signaling and MPLS 447 Label Stacking 448 MPLS and VPNs 449 MPLS Tables 449 Confi guring MPLS Using Static LSPs 450 The Ingress Router 450 The Transit Routers 450 The Egress Router 451 xiv Contents Traceroute and LSPs 452 Questions for Readers 455 Part IV Application Level CHAPTER 18 Dynamic Host Confi guration Protocol 459 DHCP and Addressing 462 DHCP Server Confi guration 462 Router Relay Agent Confi guration 464 Getting Addresses on LAN2 465 Using DHCP on a Network 466 BOOTP 468 BOOTP Implementation 469 BOOTP Messages 469 BOOTP Relay Agents 471 BOOTP “Vendor-Specifi c Area” Options 471 Trivial File Transfer Protocol 472 TFTP Messages 473 TFTP Download 473 DHCP 475 DHCP Operation 475 DHCP Message Type Options 478 DHCP and Routers 479 DHCPv6 479 DHCPv6 and Router Advertisements 479 DHCPv6 Operation 480 Questions for Readers 481 CHAPTER 19 The Domain Name System 483 DNS Basics 486 The DNS Hierarchy 486 Root Name Servers 487 Root Server Operation 487 Root Server Details 489 DNS in Theory: Name Server, Database, and Resolver 489 Adding a New Host 490 Recursive and Iterative Queries 490 Delegation and Referral 491 Glue Records 493 DNS in Practice: Resource Records and Message Formats 493 DNS Message Header 496 Contents xv DNSSec 496 DNS Tools: nslookup, dig, and host 497 DNS in Action 498 Questions for Readers 507 CHAPTER 20 File Transfer Protocol 509 Overview 512 PORT and PASV 513 FTP and GUIs 516 FTP Basics 518 FTP Commands and Reply Codes 519 FTP Data Transfers 521 Passive and Port 524 File Transfer Types 526 When Things Go Wrong 526 FTP Commands 527 Variations on a Theme 529 A Note on NFS 530 Questions for Readers 533 CHAPTER 21 SMTP and Email 535 Architectures for Email 538 Sending Email Today 540 The Evolution of Email in Brief 544 SMTP Authentication 544 Simple Mail Transfer Protocol 545 Multipurpose Internet Mail Extensions 547 MIME Media Types 548 MIME Encoding 548 An Example of a MIME Message 549 Using POP3 to Access Email 550 Headers and Email 552 Home Offi ce Email 555 Questions for Readers 557 CHAPTER 22 Hypertext Transfer Protocol 559 HTTP in Action 562 Uniform Resources 565 URIs 565 URLs 566 xvi Contents URNs 568 HTTP 569 The Evolution of HTTP 570 HTTP Model 571 HTTP Messages 572 Trailers and Dynamic Web Pages 573 HTTP Requests and Responses 573 HTTP Methods 575 HTTP Status Codes 576 HTTP Headers 576 General Headers 577 Request Headers 577 Response Headers 578 Entity Headers 579 Cookies 580 Questions for Readers 583 CHAPTER 23 Securing Sockets with SSL 585 SSL and Web Sites 585 The Lock 591 Secure Socket Layer 592 Privacy, Integrity, and Authentication 593 Privacy 593 Integrity 593 Authentication 594 Public Key Encryption 595 Pocket Calculator Encryption at the Client 595 Example 596 Pocket Calculator Decryption at the Server 597 Public Keys and Symmetrical Encryption 598 SSL as a Protocol 598 SSL Protocol Stack 599 SSL Session Establishment 599 SSL Data Transfer 601 SSL Implementation 601 SSL Issues and Problems 602 A Note on TLS 1.1 604 SSL and Certifi cates 604 Questions for Readers 605 Contents xvii Part V Network Management CHAPTER 24 Simple Network Management Protocol 609 SNMP Capabilities 612 The SNMP Model 616 The MIB and SMI 618 The SMI 618 The MIB 620 RMON 622 The Private MIB 622 SNMP Operation 623 SNMPv2 Enhancements 627 SNMPv3 628 Questions for Readers 629 Part VI Security CHAPTER 25 Secure Shell (Remote Access) 633 Using SSH 633 SSH Basics 636 SSH Features 637 SSH Architecture 639 SSH Keys 640 SSH Protocol Operation 641 Transport Layer Protocol 642 Authentication Protocol 644 The Connection Protocol 645 The File Transfer Protocol 647 SSH in Action 649 Questions for Readers 657 CHAPTER 26 MPLS-Based Virtual Private Networks 659 PPTP for Privacy 662 Types of VPNs 662 Security and VPNs 664 VPNs and Protocols 665 PPTP 666 L2TP 667 PPTP and L2TP Compared 668 Types of MPLS-Based VPNs 668 Layer 3 VPNs 668 xviii Contents . Simple Network Management Protocol 609 SNMP Capabilities 612 The SNMP Model 616 The MIB and SMI 618 The SMI 618 The MIB 620 RMON 622 The Private MIB 622 SNMP Operation 623 SNMPv2 Enhancements. Routing Tables and RedHat Linux 330 Routing and Windows XP 331 The Internet and the Autonomous System 332 The Internet Today 334 The Role of Routing Policies 336 Peering 338 Picking a Peer. BGP as a Routing Protocol 379 Confi guring BGP 382 The Power of Routing Policy 384 BGP and the Internet 386 EGP and the Early Internet 386 The Birth of BGP 387 BGP as a Path-Vector Protocol