Introduction to Computer Networks and Data
Communications
The Language of Computer Networks
The Big Picture of Networks
Computer Networks—Basic Configurations
Terminal/microcomputer-to-mainframe computer configurations
Microcomputer-to-local area network configurations
Microcomputer-to-internet configurations
Local area network-to-local area network configurations
Personal area network-to-workstation configurations
Local area network-to-metropolitan area network configurations
Local area network-to-wide area network configurations
Wide area network-to-wide area network configurations
Sensor-to-local area network configurations
Satellite and microwave configurations
Wireless telephone configurations
Network Architectures
The Open Systems Interconnection (OSI) model
The TCP/IP protocol suite
Logical and physical connections

Data and Signals
Analog vs. digital
Fundamentals of signals
Loss of signal strength
Omnidirectional signals vs. unidirectional signals
Frequencies and data rates
Converting Data into Signals
Transmitting analog data with analog signals
Transmitting digital data with digital signals: digital encoding schemes
Transmitting digital data with analog signals
Transmitting analog data with digital signals
Spread Spectrum Technology: direct sequence and frequency hopping
Data Codes
EBCDIC
ASCII
Unicode
Data and Signal Conversion in Action: Two Examples

Conducted and Wireless Media
Conducted Media
Twisted Pair wire
Coaxial cable
Fiber-Optic cable
Wiring connectors/jacks
Protected distribtuion system to protect wireline
Wireless Media
Terrestrial microwave transmission
Line-of site transmissions
Satellite microwave transmission
Cellular telephones, wireless devices, and low power transmissions
Infrared transmissions
Wireless Application Protocol
Broadband wireless systems
Bluetooth
Wireless local area networks
Free space optics and ultra-wideband
Media Selection Criteria
Cost
Speed
Distance and expandability
Environment

Making Connections
Dial-up Modems
Basic modem operating principles
Data transmission rate
Standard telephone operations
Connection negotiation
Error correction and data compression
Facsimile
Security
Self-Testing (loop back)
Internal vs. external models
Modems for laptops
Blacklisting, callback security, backdoor entry with password protection
The 56k Digital Modem
Alternatives to Dial-Up Modems
Channel Service Unit/Data Service Unit (CSU/DSU)
Cable modems
ISDN modems
DSL modems
Modem Pools
Interfacing a Computer to Modems and Other Devices
Data Terminal Equipment and Data Circuit-Terminating Equipment
Interface standards
High-Speed Interface Protocols
Fire Wire
Universal Serial Bus (USB)
SCSI and iSCSI
InfiniBand and Fibre Channel
Data-Link Connections
Asynchronous connections
Synchronous connections
Half-duplex, full-duplex, and simplex connections
Terminal-to-Mainframe Computer Connections

Multiplexing: Sharing a Medium
Frequency Division Multiplexing
Time Division Multiplexing
Synchronous time division multiplexing (aka optical time divsiion multiplexing)
Statistical time division multiplexing (aka optical spatial division multiplexing)
Wavelength Division Multiplexing
Discrete Multitone
Code Division Multiplexing
Comparison of Multiplexing Techniques

Errors, Error Detection, and Error Control
Noise and Errors
White noise
Impulse noise
Crosstalk
Echo
Jitter
Delay distortion
Attenuation
Electromagnetic interference and jamming
Error Prevention (including TEMPEST)
Attentuation, amplification, amplifiers and repeaters
Multiplexers and guardbands
Cables and cable testing
Filters to descrease signal irregularities
Telephone line conditioning
Grounding to avoid damage from static electricity discharges
Shielding to descrease electromagnetic interference, crosstalk, and unintended electrical emissions
Locating equipment to minimize electronic emissions between them

Error Detection
Parity checks
Cyclic redundancy checksum
Error Control
Do nothing
Return a message
Correct the error

Local Area Networks: The Basics
Primary Function of Local Area Networks
Role of supercomputer, mainframe and minicomputer in a predominantly microcomputer environment
Advantages and Disadvantages of Local Area Networks
Basic Local Area Network Topologies
Bus/tree topology
Star-wired bus topology
Star-wired ring topology
Wireless LANs
Comparison of bus, star-wired bus, star-wired ring, and
wireless topologies
Circuit boards in LAN topologies
Medium Access Control Protocols
Contention-based protocols
Round robin protocols
IEEE 802
IEEE 802.3 and 802.5 frame formats
Local Area Network Systems
Ethernet
IBM Token Ring
Fiber Distributed Data Interface (FDDI)

Local Area Networks: Internetworking
Why Segment or Internetwork Local Area Networks?
Hubs
Bridges
Transparent bridge
Remote bridge
Switches
Virtual LANs
Isolating traffic patterns and providing multiple access
Full-duplex switches
Routers

Local Area Networks: Software and Support Systems
Network Operating Systems
Current Network Operating Systems
Novell NetWare
Microsoft Windows NT, Windows 2000, and Windows 2003
Unix
Linux
Summary of network operating systems
Network Servers
Client/server networks vs. peer-to-peer networks
Network Support Software
Utilities
Internet software
Software Licensing Agreements
LAN Support Devices
LAN Software In Action
Primary uses of current system
Network maintenance and support
Cost of the NOS
Any unique hardware choices affecting NOS decision
Single location or multiple locations
Political pressures affecting decision
Final decision

Introduction to Metropolitan Area Networks
and Wide Area Networks
Metropolitan Area Network Basics
SONET vs. Ethernet
Wide Area Network Basics
Types of communications networks
Connection-oriented vs. connectionless network applications
Routing
Dijkstra's least-cost algorithm
Flooding
Centralized routing
Distributed routing
Adaptive routing
Routing examples
Network Congestion
The problems with network congestion
Possible solutions to congestion

The Internet
Internet Protocols
The Internet Protocol (IP)
The Transmission Control Protocol (TCP)
Internet Control Message Protocol (ICMP)
User Datagram Protocol (UDP)
Address Resolution Protocol (ARP)
Dynamic Host Configuration Protocol (DHCP)
Network Address Translation (NAT)
Tunneling protocols and virtual private networks (VPNs)
The World Wide Web
Locating a document on the Internet
Creating Web pages
Internet Services
Electronic mail (e-mail)
File Transfer Protocol (FTP)
Remote login (Telnet)
Voice over IP (Internet telephony)
Listservs
Usenet
Streaming audio and video
Instant Messaging
The Internet and Business
Cookies and state information
Intranets and extranets
The Future of the Internet
IPv6
Internet2

Telecommunications Systems
The Basic Telephone System
The telephone network before and after 1984
Telephone networks after 1996
Telephone lines, trunks, and numbers
Limitations of telephone signals
Leased Line Services
Integrated Services Digital Network (ISDN)
Frame Relay
Frame relay setup
Committed information rate (CIR) vs. Burst rates
Frame relay vs. the Internet
Voice over Frame Relay (VoFR)
Frame relay switched virtual circuits
Asynchronous Transfer Mode (ATM)
ATM classes of service
Advantages and disadvantages of ATM
Digital Subscriber Line
DSL basics
DSL formats

Network Security
Standard System Attacks
Physical Protection
Possible causes of physical damage
Locks, antitheft devices, alarms, pagers
Equipment location to avoid flooding, humidity, temperature, human threats
Preventing electrical damage, surge protectors, avoiding power fluctuations, grounding
Sockets layer
Control center: documentation, resource, use, procedures, training manuals, baseline studies, equipment documentation, vendor information, hardware and software needed to monitor and control network and its operations
Protection from flooding, high humidity, and excessive heat
Surge protection
Choice of media based on environment and security
Tools for testing and debugging network hardware
Surveillance cameras
Controlling Access
Expected levels of security
Passwords and ID systems
Rules for creating good passwords
Access rights to files, tapes, printers, data, other devices: who, how, and when
Auditing
Biometrics
Privacy issues
Clarifying staff roles & responsibilities
Levels of security and access badsed on levels of user classification
system-high security
Servers dedicated to security functions
Securing Data
Basic encryption and decryption techniques
Plain text vs. ciphertext
Keys and encryption algorithms
Monoalphabetic substitution-based ciphers
Polyalphabetic substitution-based ciphers
Transposition-based ciphers
Public Key cryptography
Public Key Infrastructure
Digital signatures
Kerberos
Pretty Good Privacy
Data Encryption Standard
Advanced Encryption Standard
Digital signatures
Signature-based scanning
Certificate authentication
Certificate revocation
Modes of operation
IP address masking (subnetting)
Securing Communications
Guarding against viruses
Firewalls--packet filters and proxy servers
Firewall efficacy
Wireless security (including WiFi)
Terminate-and-stay-resident monitoring
Computer simulation for testing
Benchmarking
Creating a baseline on system nodes and operational protocols
Utilization level statistics: average utilization, peak utilization
Network evaluation: mean time between failures, mean time to repair, availability, and reliability
Traffic analyzers
Simple Network Management Protocol (SMNP)
Managing Information Base (MIB)
Remote Network Monitoring
Firewalls: Packet filter and proxy server
Security Policy Design Issues
Security assessment software: open ports, improperly designed shares and trusts, suspicious processes, vulnerabilities
Surveillance: video cameras, monitroing calls, intrusion detection by monitoring data flow and system requests
What is the expected level of security
Who has access to what, when?
Cost of any given level of security
Company committment to security
Entrance and exit points
Clearly defined staff roles and responsibilities
Backdoor access (physical and technical)
Network diagnostic tools
Selecting appropriate statistics for evaluating system performance
Benchmarking
Creating a baseline for system operation
Cost vs. benefits of lowering a threat
TEMPEST security issues
Screening against application layer attacks
Screening with encryption and authentication
Authentication as related to remote access