Networking Essentials Mark A. Sportack / SÄNiS PUBLISHING 201 West 103rd Street Indianapolis, IN 46290
Introduction xxiii Part I Network Fundamentals 1 A Networking Primer 3 Evolution of Networks 4 Standards Organizations 6 ANSI 6 IEEE 7 The ISO 7 ThelEC 7 IAB 7 The OSI Reference Model 8 Layer 1: The Physical Layer 9 Layer 2: The Data Link Layer 10 Layer 3: The Network Layer 11 Layer 4: The Transport Layer 11 Layer 5: The Session Layer 12 Layer 6: The Presentation Layer 12 Layer 7: The Application Layer 12 The Model's Usage 12 Networking Basics 14 Hardware Components 15 Software Components 17 Making Networks from Components 18 Summary 22 2 LAN Types and Topologies 23 LAN-Attached Devices 24 Types of Servers 24 Network Type 28 Peer-to-Peer Networks 28 Server-Based Networks 31 Combination Networks 33 LAN Topologies 33 Bus Topology 34 Ring Topology 35 Star Topology 37 Switched Topology 38 Complex Topologies 39 Daisy Chains 39 Hierarchies 40
Networking Essentials VÜi " LAN Functional Areas 43 Station Connectivity 43 Server Connectivity 44 WAN Connectivity 44 Backbone Connectivity 45 Summary 50 3 The Physical Layer 51 Layer 1: The Physical Layer 52 Physical Layer Functions 53 Distance Implications 58 Physical Transmission Media 61 Coaxial Cable 61 Twisted Pair Wire 63 Fiber Optic Cable 68 Summary 72 4 The "Not-so-Physical" Physical Layer 73 The Electromagnetic Spectrum 74 Spectral Characteristics 76 Bandwidth and the Spectrum 77 What Does This Mean? 78 Wireless LANs 79 Wireless Station Connectivity 79 Wireless Peer-to-Peer Connectivity 80 Wireless Hub Interconnection 80 Wireless Bridges 81 Transmission Technologies 82 Spread Spectrum Radio Frequency 82 Single Band Radio Frequency 87 Infrared 88 LASER 89 The IEEE 802.11 90 Media Access 91 Physical Layers 91 Summary 92 5 The Data Link Layer 95 OSILayer2 96 Frames 97 Typical Frame Components 97 Frame Summary 99 Evolution of Proprietary Frame Structures 99 Xerox's PARC Ethernet Frame 99 DIX Ethernet Frame 100
IEEE Project 802 102 IEEE 802.2 Logical Link Control (LLC) 103 IEEE 802.2 Sub-Network Access Protocol (SNAP) 105 IEEE 802.3 Ethernet Frame 106 IEEE 802.5 Token Ring 110 FDDI Ill Concept of Media Access Control 114 Contention-Based Media Access 114 Demand Priority Media Access 115 Token-Based Media Access 116 Selecting a LAN Technology 117 802.3 Ethernet 118 802.5 Token Ring 118 FDDI 118 802.12 VG-AnyLAN 118 Summary 119 6 The Mechanics of Media Access 121 Media Access 122 Contention-Based Media Access 122 Token-Based Media Access 128 Demand-Priority Media Access 131 Accessing Media in a Switched LAN 132 Summary 134 Part II Building Local Area Networks 7 Ethernet 137 The Various Ethernets 138 Supported Hardware 140 Layered Functions 142 Data Link Layer Functions 142 Physical Layer Functions 144 The Physical Layer's Medium Dependent Interfaces 146 10Base2 147 10Base5 147 lobaset 147 lobasefl 151 lobasefoirl 151 Mixing Media Types 152 IEEE 802.3 Ethernet Frame 152 Delay Budgets 157 Estimates of Propagation Delays 157 Calculating Delay Budgets 158 Summary 158
Networking Essentials UNLEASHED 8 Faster Ethernets 159 Fast Ethernet 160 Fast Ethernet's Media Choices 161 100BaseTX 162 100BaseFX 162 100BaseT4 163 Signaling Schemes 163 Maximum Network Diameter 165 Fast Ethernet Summary 165 Gigabit Ethernet 165 The Physical Interfaces 166 What Else Is New? 169 Too Good to Be True? 171 Summary 171 9 Token Ring 173 Overview 174 Standardization of Token Ring 175 Token Ring Frame Structures 176 The Token Frame 176 The Data Frame 178 The Fill Sequence 180 Understanding Token Ring 181 The Hardware 182 Topology 184 Dynamic Ring Membership 185 The Active Monitor 187 What's Ahead for Token Ring? 188 Switching and Dedicated Token Ring 188 Increasing the Transmission Speed 189 Will It Work? 190 Summary 191 Benefits of Token Ring 191 Limitations of Token Ring 192 10 FDDI 193 FDDI 194 The Functional Components, 195 Building FDDI Networks 197 Port Types and Attachment Methods 197 Valid Connections 199 Topologies and Implementations 200 Network Size 206
Contents xi FDDI Frames 207 Data Frame 207 LLC Data Frame 209 LLC SNAP Data Frame 210 The Token Frame 211 SMT Frames 212 The Mechanics of FDDI 212 Station Initialization 212 Ring Initialization 214 Summary 214 11 ATM 215 The Fundamentals of ATM 216 Virtual Connections 217 Connection Types 217 Transmission Rates 218 Topology 219 ATM Interfaces 220 ATM Reference Model 221 Physical Layer 222 ATM Adaptation Layer 223 The ATM Layer 228 The Cell 229 Local Area Network Emulation (LANE) 232 Summary 234 12 Network Protocols 235 Protocol Stacks 236 The Internet Protocol, Version 4 (IPv4) 238 Dissecting TCP/IP 238 The Internet Protocol, Version 6 (IPv6) 245 IPv6 Unicast Address Structures 246 IPv6 Transitional Unicast Address Structures 247 IPv6 Anycast Address Structures 248 IPv6 Multicast Address Structures 249 IPv6 Conclusion 249 Novell's IPX/SPX 249 Dissecting IPX/SPX 249 Data Link and Medium Access Layers 253 IPX Addressing 253 IPX/SPX Conclusion 254 Apple Corporation's AppleTalk Protocol Suite 255 Dissecting AppleTalk 255
Networking Essentials UNLEASHED NetBEUI 260 NetBEUI Conclusion 261 Summary 261 Part III Building Wide Area Networks 13 Wide Area Networking 265 Understanding WAN Technologies 266 Using Transmission Facilities 267 Circuit Switched Facilities 267 Packet Switched Facilities 269 Cell-Switched Facilities 272 Choosing Communications Hardware 272 Customer-Provided Equipment (CPE) 273 Premises Edge Vehicles 274 Understanding Internetwork Addressing 275 Ensuring Unique Addressing 275 Internetworking with Different Protocols 276 Using Routing Protocols 277 Distance-Vector Routing 278 Link-State Routing 278 Hybridized Routing 279 Static Routing 279 Selecting a Protocol 280 Understanding WAN Topologies 280 Peer-to-Peer Topology 281 Ring Topology 282 Star Network Topology 283 Full Mesh Topology 285 Partial Mesh Topology 286 Two-Tiered Topology 286 Three-Tiered Topology 288 Hybrid Topologies 289 Designing Your WAN 290 WAN Performance Criteria 290 Costs of the WAN 294 Summary 295 14 Leased Lines 297 Overview of Leased Lines 298 Multiplexing Techniques 298 Benefits and Drawbacks of Leased Lines 300 Topology of Leased Lines 301
Contents xiii Digital Signal Standards 304 ANSI's Digital Signal Hierarchy 304 ITU's Digital Signal Hierarchy 306 SONET's Carrier Systems 307 The T-Carrier System 308 T-Carrier Services 309 Line Encoding 310 Framing Formats 312 Summary 313 15 Circuit Switched Transmission Facilities 315 Switched 56 316 Common Uses for Switched 56 316 Switched 56 Technologies 317 Frame Relay 317 Frame Relay Versus Leased Lines 318 Extended Frame Relay 321 Permanent Virtual Circuits Versus Switched Virtual Circuits..321 The Format of Basic Frame Relay 321 Designing Frame Relay Networks 322 UNI Versus NNI 323 Going Above the CIR 323 Flow Control in the Frame Relay Network 325 Voiceover Frame Relay (VoFR) 325 Private, Public and Hybrid Networks 326 Internetworking with ATM 328 ATM 329 History of ATM 330 The Nitty-Gritty of ATM 331 VPIsandVCIs 335 ATM Connections 335 Quality of Service 336 Signaling 336 Provisioning ATM Circuits 337 Interoperating with LANE 337 Migrating to ATM 338 Summary 338 16 Packet Switched Transmission Facilities 339 X.25 340 The History of X.25 341 Pros and Cons of X.25 341 Common Uses 341 Comparison to OSI Reference Model 341
Networking Essentials UNLEASHED Different Types of Networks 345 X.25 Specifications (RFC 1356) 346 Migrating from X.25 347 Summary 348 17 Modems and Dial-Up Technologies 349 How Modems Work 350 Bits and Bauds 352 Modem Modulation Types 353 Asynchronous and Synchronous 355 Standard Modem Interfaces 357 ITU-T (CCITT) Modem Standards 359 Modems and Microsoft Networking 361 Summary 363 18 Remote Access Services (RAS) 365 The History of Remote Access Networking 366 The 1970s 367 The 1980s 367 The Craze of the 90s 368 Establishing Remote Connections 368 Developing Protocol Standards 369 The AT Command Set 370 RAS Connection Protocols 371 Establishing a Session 371 TCP/IP Access Protocols 371 Remote Access Transport Services 374 How RAS Users Are Currently Connecting 374 Windows NT RAS Capabilities 381 Using RAS as an Internet Gateway/Router for a LAN 381 Using RAS to Provide Internet Access for Dial-In Users 383 Novell NetWare Connect Software's RAS Capabilities 385 Banyan Systems' RAS Capabilities 385 RAS Security Issues 386 Passwords 387 Dialers 387 Callback Systems 388 Summary 388 19 Intranets and Extranets 389 Intranets 390 What's So Special About the Web? 391 What About Intranets? 392
Extranets 394 The Trouble with Open Protocols 394 The Trouble with Connectionless Protocols 395 The Trouble with Open Protocols and Extranets 398 Rules for Securing an Extranet 399 Am I Wasting My Time? 401 Virtual Private Networks 401 Carrier-Provided VPNs 402 Tunneling 403 Summary 404 Part IV Operating Networks 20 Network Operating Systems (NOS) 407 History of Network Operating Systems (NOS) 408 Novell Dominates the Market '. 408 New Players Emerge 409 Microsoft Takes Hold 409 What's Happening Now 410 Traditional Services of a NOS 410 Banyan Network Systems 412 Services and Applications of VINES 412 VINES-Supported Standards 413 Strengths and Weaknesses of VINES 414 Novell NetWare 414 Features of NetWare 415 NetWare-Supported Standards 418 Strengths and Weaknesses of NetWare 419 Microsoft Windows NT 419 Features of Windows NT 420 Windows NT-Supported Standards 422 Windows NT Security 423 Strengths and Weaknesses of Windows NT 423 Summary 424 21 Network Administration 425 What Is Network Administration? 426 Managing Network Accounts 427 User Accounts 427 Group Accounts 431 Multiple Logins 434 Managing Resources 434 Hardware Resources 434 Disk Quota 434
Networking Essentials UNLEASHED Files & Directories 435 Software Installation/Upgrades 435 Network Printing 436 Management Tools 437 Microsoft Management Tools 438 Zero Administration 440 Microsoft Management Console 440 Summary 440 22 Managing Network 441 Potential Network Performance Problems 442 Physical Layer Issues 442 Network Traffic Issues 444 Address Resolution Problems 446 Internetworking Issues 447 Tools and Techniques 447 Ping 447 Traceroute 449 Windows NT Performance Monitor 450 Network Analyzers 451 Hardware Troubleshooting 452 Summary 454 23 Data Security 455 Planning for Network and Data Security 456 Levels of Security 456 Security Policies 457 Workgroups, Domains, and Trusts 460 The Four Domain Models 462 Setting up Security in Windows 95 465 Password-Protected Shares 465 Setting up Security in Windows NT 467 C2 Compliance 470 Auditing 471 Diskless Workstations 472 Encryption 472 Virus Shields 473 Summary 474 24 Data Integrity 475 Protecting the Operating System 477 Installation Procedures 478 Maintenance Techniques 480
Contents Protecting Your Hardware 488 Uninterruptible Power Supplies 488 Environmental Factors 492 Physical Security 493 Hardware Redundancy 493 Protecting User Data 494 Backing Up Your Data 494 Redundant Disk Storage 499 Implementing Your Data Integrity Plan 501 A Brief Missive on Data Integrity 501 Summary 503 25 Preventing Problems 505 Proactive Network Control Operations 506 Applications for Proactive Network Control Operations 508 Network Testing, Baselining, and Monitoring 511 Refining Existing Network Control Operations 513 Proactive Network Disaster Operations 514 Applications for Proactive Network Disaster Operations 515 Testing Disaster Recovery Operations and Strategies 517 Refining Existing Network Disaster Operations 518 Summary 518 26 Troubleshooting Problems 519 Logical Fault Isolation 520 Assess the Priority 521 Discover Pertinent Information 521 Justify Probable Causes 523 Unit Test and Isolate 524 Study and Evaluate Results 525 Transcribe Results and Process 525 Common Networking Problems 526 Physical Media 526 Network Interface Cards (NIC) 527 NIC Configuration Parameters 528 Network Protocol Mismatch 529 Network Congestion 530 Broadcast Storms 530 Power Problems 530 Server Problems 531 Tools for Gathering Information 532 Digital Volt Meters 532 Time-Domain Reflectometers 532
Networking xviii UNLEASHED Essentials Part V Appendix Oscilloscopes 532 Advanced Cable Testers 533 Protocol Analyzers 533 Network Monitors 534 Performance Monitors 534 Helpful Resources 534 Vendor Technical Support 534 Internet Newsgroups and Mailing Lists 535 Download Sites 535 Magazines and Technical Journals 535 Microsoft Windows NT Hardware/Software Compatibility Lists 535 Microsoft Technical Information Network 536 The Microsoft Online Knowledgebase 536 Windows NT Server Resource Kit 536 Summary 536 A Technical Glossary 539 Index 553