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SERVER ARCHITECTUREServer Architecture is nothing but the way our server layers(server ,network connectivity and other components connected to it) are connected to one another. It depends on :-1.The architecture depends on type of application and network layer.2.based on targeted users.3.Firmware and midware.4.Any 3rd party application usage.
Objectives• Explain the essential principles of client-
server architecture.• Explain the differences between 2-tier, 3-tier,
and multitier architectures, including their features and relative capacities.
• Recognize 2-tier, 3-tier, and multi-tier architectures.
• Contrast the client-server architecture with centralized and distributed architectures.
Types of application:- 1.Stand-alone application – usually has
single tier architecture. 2.Client-Server architecture – usually has
two tier(client and server) to multi-tier(n-tier) architecture depending on concurrent load.
3.Web-server architecture - usually has single tier to multi-tier(n-tier) architecture depending on concurrent load.
System Architecture• The architecture of a computer system is the
high-level (most general) design on which the system is based.
Architectural features include:• Components.• Collaborations (how components interact)• Connectors (how components communicate)
SYSTEM ARCHITECTURE
Common architectural patterns include• Client-Server• Layered• Peer-to-peer• Pipes and Filters• etc.
Client-Server Architecture• Each component of a client-server system has
the role of either client or server.
–Client: a component that makes requestsclients are active initiators of transactions
–Server: a component that satisfies requestsservers are passive and react to client requests
Representation of client-server
ClientPresentation Logic
Business Logic
ServerBusiness LogicDatabase Logic
DBMS
DataBase
Centralized / Distributed• The client-server architecture can be thought
of as a median between
–Centralized processing: computation is performed on a central platform, which is accessed using “dumb” terminals.–Distributed processing: computation is
performed on platforms located with the user.
Centralized Client / Server Distributed
• The Web is a client-server system• Web browsers act as clients, and make
requests to web servers• Web servers respond to requests with
requested information and/or computation
Client-Server Architecture
Server
Server
ServerClient
Client
ClientClient
Client request
Tiered Web Architectures• Web applications are usually
implemented with 2-tier, 3-tier, or multitier (N-tier) architectures
• Each tier is a platform (client or server) with a unique responsibility
2-Tier C-S Architecture• Tier 1: Client platform, hosting a web
browser• Tier 2: server platform, hosting all server
software components
2-Tier Characteristics
• Typical application– 10-100 users.– Small company or organization, e.g., law office, medical
practice, local non-profit.
• Advantage:– Inexpensive (single platform)
• Disadvantages– Interdependency (coupling) of components.– No redundancy.– Limited scalability.
3-Tier C-S Architecture• Tier 3 takes over part of the server function from tier
2, typically data management.
3-TIER CHARACTERISTICS
• Advantage:– Improved performance, from specialized hardware. – Decreased coupling of software components.– Improved scalability.
• Disadvantages– No redundancy.
• Typical application– 100-1000 users.– Small business or regional organization, e.g., specialty
retailer, small college
MULTITIER C-S ARCHITECTURE
• A multitier (N-tier) architecture is an expansion of the 3-tier architecture, in one of several different possible ways– Replication of the function of a tier. – Specialization of function within a tier.– Portal services, focusing on handling incoming web traffic.
REPLICATION
• Application and data servers are replicated.• Servers share the total workload.
SPECIALIZATION
• Servers are specialized• Each server handles a designated part of the
workload, by function.
PORTAL SERVICES
• Portal servers handle incoming traffic, reducing application server load.– e.g., firewall, load balancer, transaction processing
manager.
MULTI-TIER CHARACTERISTICS
• Advantage:– Decoupling of software components. – Flexibility to add/remove platforms in response to load.– Scalability.– Redundancy.
• Disadvantages– Higher costs (maintenance, design, electrical load,
cooling)
• Typical Application– 1000+ users.– Large business or organization.
CHARACTERISTICS SUMMARY
2-Tier
3-Tier
N-Tier
10
100
1000users
•Large e-commerce, business, or organization
•Small e-commerce, regional business or organization
•Local business or organizationCapacity
ScalabilityRedundancyCost
SAMPLE ARCHITECTURE
SAMPLE ARCHITECTURE
TYPICAL DETAILS OF WINDOWS IIS SERVER AND APACHE SERVER