Chapter 10 Remote 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 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 Applications Oracle 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 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 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 Pros: –Wide area –Connect to 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

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 Cellular Personal 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