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Explore hidden costs, security considerations, and hardware/software technologies for efficient remote access. Learn about logical and physical topology, wireless transmission, and mobile computing functions. Discover the selection criteria and pros of wireless WAN services.
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Chapter 10Remote Access and Wireless Networking • Business Issues • Logical & Physical Topology • Technology: Hardware & Software, & Wireless • Personnel Communication Services
Business Issues • Needs • Costs • Functions
Business Needs • Telecommuting or Small Office Home Office (SOHO) • Mobile computing for field representatives • Remote technical support for customers
Hidden Costs • Communication carriers service costs • Wiring & bandwidth • Management problems
Functions • Exchange e-mail • Upload & download files • Remote access application programs • Share LAN-attached resources
Logical Topology • Remote node or remote access • Full client/server application • Use remote hard drive • Remote control • Keystrokes and screen image • Input or output device for local PC • Use local PC hard drive
Security Consideration • Password and its management • Intrusion response • Partitioning of data • Encryption • Dial-back systems • Authentication protocol
Token Authentication- Types • Types • Token response • Private identification number (client) • Challenge number (server) • Challenge response number (client) • Time-synchronous authentication • Private identification number (client) • Random authentication number (client) • Random authentication number (server)
Token Authentication - Management • Encrypt data, ID, & password between client and server • Auditable for failed attempts • Limited remote access (time & day) • Interoperate authentication server & communication server
Physical Topology • Wire or wireless • Serial port of a LAN-attached PC • Communication server • LAN modem (dial-in server) with four to eight PC Card (PCMCIA) slots
Hardware • Communication servers • Offer application • Serial ports, CPU(s), & network interface card(s) • Remote node servers (gateway) • Offer remote node connection service • Application servers offer application • Compatibility, LAN & WAN services, call management issue
Software Types • Remote node software • Remote control software • Mobile-aware OS • Mobile-aware application • Mobile middleware
Remote Node Software • Consideration: • Protocols, modem, & client support • Management • Security • Types: Windows NT RAS & NetWare Connect • PPP clients work with different server NOS
Remote Control Software • Guest (remote) & host (local) • Consideration • Compatibility (protocol, LAN) • Applications (file transfer etc.) • Security (virus etc.) • Avoid lock of host PC
Mobile-aware OS Functions • Auto-detection of multiple configurations • Built-in multiprotocol remote node client • Direct cable connection • File transfer and file/directory synchronization • Deferred printing • Power management • Infrared connection
Mobile-aware ApplicationsOracle Mobile Agents (Oracle-in-Motion) • 50:1 performance increase • Client/agent/server architecture • Message manager (client): tracking pending requests on various servers through LAN links or PPP-based dial-up links • Message gateway(server): message holding station between message manager and intelligent agent on server to minimize overhead • Agent event manager (intelligent agent on server): represents mobile client during entire processing on server to save bandwidth and transmission time
Mobile Middleware • Function: consolidate multiple client application request into a single transmission • Pros: • Flexibility • Performance
Improve Remote Software Performance • V.34 modems • ISDN services • 16550 UARTs and matching serial port drivers • Data compression software/hardware • Communication software • Compatibility
Mobile MIB • Balance between bandwidth & information • Information: • Current user location • Type and speed of connection device • Type of remote client or remote control software • Battery power • Memory
Wireless • Transmission technology • Spread spectrum transmission • Infrared transmission • Standards • IEEE 802.11 • Mobil IP (client, home agent)
Spread Spectrum Transmission • Frequency-hopping spread spectrum (FHSS) • Hops within the frequency range • Less interference • Good for mobile computing • Direct-sequence spread spectrum (DSSS) • 10 bits to data message for id • Complexity, cost, overhead to processing id • superior throughput
Wireless WAN Service • Circuit-switched analog cellular • CDPD (Cellular digital packet data) • Private packet radio • Enchanced paging and two-way messaging • ESMR (enhanced specialized mobile radio) • Microcellular spread spectrum • PCS (personal communications services)
Selection Criteria of WAN Services • Content • Geographic scope • Amount of data • Urgency • Compatibility with LAN
CDPD • Transaction processing and database queries • Pros: • Fast call setup • Inexpensive for short messages • Cons: • Limited availability • Expensive for large file transfers
Circuit-switched Cellular • Large file transfers and faxes • Pros: • Widely available • Reasonable price for longer transaction • Cons: • Longer call setup time • Expensive for short message
Private Packet Radio • Short bursty messages and e-mail • Pros: • Wide area • Connect to e-mail system • Cons: • Proprietary networks • Expensive for large file transfer
Enhanced Paging or Two-way Messaging • Guaranteed delivery • Return receipt • McCaw Cellular
Enhanced Specialized Mobile Radio • One or two way • Voice, paging, or message
Microcell Spread spectrum • Internet • E-mail
Analog Cellular • Modems support cellular transmission at both ends • Cellular enhanced modem at mobile telephone switching office (MTSO) • Advanced mobile phone service • 800 MHz
Digital CellularPersonal Communications Services • Personal phone number PPN • Standards • Time division multiple access (TDMA) • Code division multiple access (CDMA) • No modem • Social impact and changes
Assignment • Review chapters 8-10 • Read chapter 11