Evolution of PC_LANS and
Networks
Prithvi N. Rao
Carnegie Mellon University
Objectives

Describe the evolution of corporate management structures.

List the characteristics of a centralized network system.


Recognize the challenges of building an enterprise-wide
network.
List some of the critical issues facing network managers.
Introduction





Communication is fundamental to organizational effectiveness.
Management structure determines structural requirements for
communication.
Evolution from function oriented steep hierarchies to flatter
process focused structures.
Functional structures require hierarchical communication based
on centralized architectures.
Process structures require more de-centralized communication.
Steep Functional Hierarchy
Manufacturing
Sales
Executive Management
Executive Management
Senior Management
Senior Management
Middle Management
Middle Management
Staff
Staff
Line
Line
Flat Process Orientation
Executive Management
Project Leader
Team Members:
Sales/Marketing/Mfg./Operations/Customer
Svc.
Introduction




Effective organizations must have a communication system that
links all of its resources: people, information and tools.
Evolution of roles increases the importance of communications.
Creates new demands on systems for supporting complex
organizations and communications requirements.
Computers link people, information and tools.



Meet flat process structural standard.
Vendors must communicate with each other.
Software tool compatibility is important.
Evolution

Networks facilitate effective communicate using computers.



Information on networked computers must be accessible.
Vendors work closely with customers and each other to ensure that
an open communications environment is maintained.
Open environment facilitates the use of heterogeneous hardware
and software infrastructures as well as various types of cabling.

Network operating systems facilitate sharing.

Database Systems, Electronic mail systems facilitate sharing.
Computer System Evolution

Move towards smaller, faster, cheaper hardware.



Applications are demanding more resources.


Audio, Video, Speech….
Operating systems have also evolved.


PCs are getting cheaper and faster
Memory speed is increasing.
Operating systems cannot keep up with hardware advances.
Result over 20 years is inversion of cost/performance.


Vacuum tube -> high cost, low performance.
VLSI -> low cost, high performance.
Computer System Evolution

Evolution of computer systems occurred in distinct phases
Phase
Type of MIS
Environment
Equipment
Justification
Phase 1
Centralized
Mainframes
Organizationalwide Functional
Automation
Phase 2
Distributed/Depa Personal/Departm
rtmental
ental
Effectiveness
PC’s/Minis
Phase 3
Distributed/Enter Workgroup
prise Networks
Productivity
Mainframe Architecture

Mainframe based network systems were centralized.


Tightly controlled of computer and shared peripherals.
Terminal devices connected (dumb terminals).

Star networking design.

Few computer to computer integration requirements.
Mainframe Architecture
Mainframe
Channel-to-Channel
Mainframe
Or Link Attached
FEP
Channel-to-Channel
Or Link Attached
Dumb Terminals
FEP
Distributed Networks



First networks enabled simple file and resource sharing
(printers).
PC networks used originally to support communication at
departmental level.
PC networks contrasted mainframe phase:





Local area network
Shared resources: data, programs, peripherals
Distributed processing
Intelligent workstations
Bus or ring network topology
Network Topology: Token Ring
Shared Resource
(printers)
Server
PC
Token Ring
PC
PC
Network Topology: Ethernet
WS
WS
Ethernet
Thinnet: 185 meters (~600 feet)
terminator
terminator
Thicknet: 500 meters (~1700 feet)
WS
WS
Enterprise Networking



Places tremendous demands on the communication systems
within organization.
Cause is related to rising importance of networking multiple
systems
New demands that must be addressed are:
 Increasing importance of wide are networking
 Combining LAN and WAN technologies
 Support for multi-protocol based networks
 Multiple topology networks
 Application interface requirements
Enterprise Networking


Networking technology plays a major role in corporate
communication
Information technology managers faced with numerous issues:






Continued expansion of current networks
Increased interconnectivity requirements
Distributed applications
Client – Server based computing
Importance of open systems standards
Managing the network
Enterprise Networking
Remote
WAN
Remote Bus
Local Bus
Local Ring
Mainframe
Current Network Management
Network Manager Support System
SERVER
Database
database
Application
application
Communication
printing
email