Understanding Networked Applications A First Course Chapter 5

Understanding Networked Applications: A First Course Chapter 5 by David G. Messerschmitt

Client host Server host Understanding Networked Applications 2 A First Course

Part of the rationale • Specialization: – Clients specialize in user interface – Servers specialize in managing data and application logic • Sharing: – Many clients can be supported by few servers – Often data and logic are shared among applications and users Understanding Networked Applications 3 A First Course

“I want to collaborate with my colleague” “I want to access some information” Client Peer-to-peer Server Client/server Understanding Networked Applications 4 A First Course

Distinctions • Client-server – Asymmetric relationship – Client predominately makes requests, server makes replies • Peer-to-peer – Symmetric relationship Understanding Networked Applications 5 A First Course

Email application Server Client Email client sends message to server Client Message is stored on POP server Understanding Networked Applications 6 Later, recipient’s email client retrieves message from server A First Course

Chat application Server Client Chat clients send user’s typing to server Chat server aggregates typing from all users and sends to all clients Understanding Networked Applications 7 Other user’s clients display aggregated typing from chat server A First Course

Three-tier client/server Local-area network Application logic Presentation Note: many clients per application server, several application servers per data server Understanding Networked Applications Shared data 8 A First Course

Client Host architecture Web browser Web server Application logic Common gateway interchange Databases and DBMS Understanding Networked Applications Application partition 9 A First Course

Practice in defining tiers • Online bookseller (e. g. amazon. com) • Stock trading system (e. g. Schwab or Etrade) Understanding Networked Applications 10 A First Course

amazon. com Understanding Networked Applications 11 A First Course

Schwab Understanding Networked Applications 12 A First Course

Question • What types of social applications would be appropriate for a client/server architecture? Understanding Networked Applications 13 A First Course

Departments Enterprise-to-enterprise Commerce Consumer Enterprise Understanding Networked Applications 14 A First Course

software 4 u. com Customers Customer-service department Consumer Understanding Networked Applications Technical-support department Enterprise 15 A First Course

Consumer application Enterprise application Customer care Web browser Web server Customer logic Agent logic Technician logic Databases Customer audit Software documentation Understanding Networked Applications Problem knowledge base 16 A First Course

Customers Customer logic Agents Technicians Agent logic Technician logic Databases Accounts Products Understanding Networked Applications Orders 17 A First Course

Financial institution Book distribution centers Customers books 4 u. com Consumer Enterprise Understanding Networked Applications Inter-enterprise 18 A First Course

Book merchant Web browser Consumer e-commerce Inter-enterprise e-commerce Web server Customer logic Fullfillment logic Outside links Databases Customers Merchandise Acquirer Book bank distributors Orders Understanding Networked Applications 19 A First Course

Clients Acquirer bank Customer logic Fullfillment logic Databases Customers Merchandise Understanding Networked Applications Orders 20 Book distributors A First Course

Information providers Customers Stock market stocks 4 u. com Consumer Enterprise Understanding Networked Applications Inter-enterprise 21 A First Course

Stock trader Web browser Consumer e-commerce Inter-enterprise e-commerce Web server Customer logic Trading logic Outside links Databases Accounts Products Information providers Orders Understanding Networked Applications 22 Financial markets A First Course

Clients Information providers Customer logic Trading logic Databases Accounts Products Understanding Networked Applications Orders 23 Financial markets A First Course

Financial institution Customers flowers 4 u. com Consumer Local florists Enterprise Understanding Networked Applications Inter-enterprise 24 A First Course

Consumer e-commerce Inter-enterprise e-commerce Florist delivery Web browser Push server Web server Push client Customer logic Fullfillment logic Outside link Databases Accounts Products Acquirer bank Orders Understanding Networked Applications 25 A First Course

Customers Florists Fullfillment logic Customer logic Acquirer bank Databases Accounts Products Understanding Networked Applications Orders 26 A First Course

Shortcomings of client/server • Departmental solution • Proliferates non-interoperable technologies and applications • Hardwired applications lose flexibility What are some goals and likely characteristics of future enterprise architectures? Understanding Networked Applications 27 A First Course