Network Components and Equipment

1
Network Components and Equipment

• Organizational Communications and Technologies
• Prithvi N. Rao
• H. John Heinz III School of Public Policy and
  Management
• Carnegie Mellon University

2
Readings

• High Speed and Wireless LANs(Stallings and van
  Slyke) Chapter 10

3
Objectives

• Identify the main components of a network
• Describe the types of servers that can exist on a
  LAN
• Discuss differences between deterministic and
  non-deterministic media access protocols
• Describe the features of LAN media and be
  familiar with LAN equipment

4
Network Components

• Networks are constructed with 3 main components
• Computers
• Media
• Communication equipment
• Assembly of components depends on requirements of
  network
• Incorrect design and implementation results in
  expensive re-engineering of network

5
Computers

• Various hardware and software platforms
• DOS
• OS/2
• Macintosh
• Unix
• Some platforms are pure clients others can be
  both
• Performance
• Software availability
• End-user

6
Computers

• Network server can represent any computer
  providing services to other computers on network
• Server can provide services to other clients,
  hosts, or other servers

7
Servers

• File Servers are centralized file system
• Mechanism for storing and retrieving data for
  applications
• Mechanism for protecting data through record
  locking
• Provide database transaction tracking and
  security
• Communication servers
• Provide communication services
• Permit other nodes to transmit data on a LAN
• Provide services of a NOS
• Permit access to foreign networks or wide area
  networks

8
Servers

• Print servers
• Permit sharing of printers
• Permits multiple users to share single printer
• Print jobs are spooled
• Database server
• Provides dedicated and centralized source for all
  users and LAN to access a common database

9
Servers

• Application servers provide a vast array of
  services
• Modem pooling
• Electronic mail distribution
• Database services
• Load balancing
• Can be single machine or collection of machines

Novell Netware file server provides file system
services, communication services print services
and application services
10
Client Workstations

• Workstations make up majority of computers on
  network
• Any computer attached to LAN not dedicated to
  providing services to other computers
• Can be clients or peer hosts
• Clients depend on communication server to process
  request for data transmission services
• Clients run shells, redirector or requester
• Can double as non-dedicated servers
• Terminate and stay resident (TSR)
• Enable interaction with servers and other
  workstations

11
Client Workstations

• Peer hosts are independent network node units
• Possess all necessary software to communicate
  with other hosts
• Not dependent on communication server to provide
  NOS software to communicate
• Multi-user computers typically peer hosts
• DOS is limited because of single tasking
• Unix typically can be peer hosts

12
LAN Media

• Including type of media following are important
• Topology or physical layout of cable plant (token
  ring, ethernet)
• Media access technique
• Encoding scheme

13
Media Access Technique
10 base 2, BUS, Thinnet Segment, 185 meters max,
30 nodes
10 Base 5, BUS, Thicknet Segment, 500 meters max,
100 nodes
10 Base T, Star, 1 cable per node (type 1 5)
(STP, UTP)
10 Base F, Star, 1 cable per node, fiber
14
Broadcast CSMA/CD

• Carrier Sense Multiple Access with Collision
  Detection
• STP shielded and twisted pair
• UTP unshielded twisted pair

15
Network Interface Card (NIC)

• Responsible for
• Providing access to media
• Interfacing at the physical level with cabling
  system
• Framing data for transmission
• Error detection of transmission units that have
  been received

16
Concentrators / Hubs

• Concentrator hubs simple multiport repeaters
• Repeaters work to extend cable segments past
  their physical un-repeated limit
• Multiport repeaters create number of physical LAN
  segments and logically combine them together
• Concentrator hubs can maintain a ring or bus
  internally while creating a physical star
  topology

17
Hub Benefits

• Facilitate fault detection
• Support for different protocols
• Ethernet, token ring, FDDI can all be combined in
  a single hub
• Can be easily linked to backbone
• Support different media using similar protocol
• Thinnet, thicknet and 10-Base T Ethernet segments
  can be combined in a single hub

18
Summary

• Servers are any computer providing services to
  other computers on the network
• Workstations make up majority of computers on
  network
• LAN media has specific characteristics
• Topology
• Type of access scheme