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Connections: Middleware and Network. Kittiphan Techakittiroj engktc@au.ac.th. Introduction. Clients: need services Servers: serve the need Middleware: Connection between Clients & Servers software: standard, protocol, commercial software hardware: physical connection, router, gateway.
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Connections:Middleware and Network Kittiphan Techakittiroj engktc@au.ac.th
Introduction • Clients: need services • Servers: serve the need • Middleware: Connection between Clients & Servers • software: standard, protocol, commercial software • hardware: physical connection, router, gateway
Configuration of Client/Server • tiny shops or individual • small shops or departments • intergalactic enterprises • post scarcity world
Configuration of Client/Server Tiny Shops or Individual • Both client and server are on the same machine • Powerful machine: usually the case of current available machine • Robust Operating System
Configuration of Client/Server Small Shops or Deparments • one server/many clients: all clients access one server • Popular architecture of local area networks • Easy for administration • Known clients -> customized for specific needs • Administrator has full control over server
Configuration of Client/Server Intergalactic Enterprises • many servers/one client: client designed to access many servers • Current of Internet/Intranet Application
Configuration of Client/Server Intergalactic Enterprises (cont.) • Expandable, Flexible, Fault Tolerance • Require a good middleware: e.g. security, bandwidth
Configuration of Client/Server Post-Scarcity World • Distributed systems: each individual machine acts as both client and server • Require powerful resources
Configuration of Client/Server Real World • Combination of all • LAN with Internet • Need to consider the advantage, disadvantage • Other arrangement is possible: depends on definition • number of clients or servers • geographical boundary
Inside Middleware • Client Building Block • Server Building Block • Middleware Building Block
Inside the Middleware Client Building Block • Usually built-in OS • Graphical User Interface (GUI) • Object Oriented User Interface (OOUI) • Web Browser • Distributed System Management (DSM) • etc.
Inside the Middleware Server Building Block • SQL Database Servers • TP Monitors • Groupware Servers • Object Servers • Web Server • DSM Component • etc.
Inside the Middleware Middleware Building Block • Transport Stack • Network Operating Systems (NOS) • DSM • Service Specific
Server-to-Server Middleware • For n-tier system • Might be future trend of network application
Network Connection • Size of Network • Local Area Network (LAN) • Wide Area Network (WAN) • Standard Protocol: TCP/IP, NetBIOS, IPX/SPX, AppleTalk • Layer Concept: ISO Layer, Internet Protocol Suite
Network Topology • The way of connect computers together • WAN will be irregular (f) Computer Networks by Andrew S. Tanenbaum
Network Connection Layer Concept • Split to small functionality connect to each other • Easy to implement, maintenance Internet & Intranet Engineering by Daniel Minoli
Network Connection: Layer Concept Internet Suite (TCP/IP protocol) • Link Layer: interconnection(hardware & software) • Network Layer: networking computers • Transport Layer: delivery service • Application Layer: Telnet, FTP, SMTP
Network Connection: Layer Concept Connection Type • Connection-Oriented Service: connection need to be established first • Connectionless Service Computer Networks by Andrew S. Tanenbaum
Network Connection: Layer Concept Specification & Header • Each difference layer contains specification • Physical Layer: signal specification • Other Layers: header containing information Computer Networks by Andrew S. Tanenbaum
Network Connection Interconnecting Devices • Hubs • Bridges • IP Switches • Routers • Gateways
Network Connection: Interconnecting Devices Hubs, Switches, Birdges, Routers • Definition changing with time • Intelligence …: make difference disappered Internet & Intranet Engineering by Daniel Minoli
Transport Stacks Middleware • Logical Network Driver • Stack Sandwich • Protocol Matchmakers (optional) • Transport-Independent APIs
Bandwidth • Cover: Signal, Medium, Data • Absolute Bandwidth: the width of the frequency spectrum of the signal • Effective Bandwidth: less than 3dB power drop • Commonly used as the amount of bits that can be transferred within one unit time (bit-rate)
Bandwidth How much bandwidth is enough? • Depend on Application and Taste
Bandwidth Bandwidth Available • Depend on Location & Media & Cost
Bandwidth: Bandwidth Available Bandwidth for LAN • Depend on Location & Media & Cost
Bandwidth: Bandwidth Available Bandwidth for WAN • Depend on Location & Media & Cost
Bandwidth: Bandwidth Available Bandwidth for WAN cont. • Technology on top of Cable/Physical Technology
Bandwidth: Bandwidth Available Bandwidth from Home to WAN
Reference Books Client/server survival guide 3rd edition by Robert Orfali, Dan Harkey, Jeri Edwards (John Wiley & Sons: 1999) Computer Networks 3rd edition by Andrew S. Tanenbaum (Prentice Hall: 1996) Internet & Intranet Engineering by Daniel Minoli (McGraw Hill: 1997)