Transcript Network Topology and Internetworking

Network Components and
Equipment
Organizational Communications and
Technologies
Prithvi N. Rao
H. John Heinz III School of Public
Policy and Management
Carnegie Mellon University
Readings
High Speed and Wireless LANs(Stallings
and van Slyke) Chapter 10
Objectives
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Identify the main components of a network
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Describe the types of servers that can exist on a LAN
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Discuss differences between deterministic and nondeterministic media access protocols
Describe the features of LAN media and be familiar
with LAN equipment
Network Components
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Networks are constructed with 3 main components
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Computers
Media
Communication equipment
Assembly of components depends on requirements of
network
Incorrect design and implementation results in
expensive re-engineering of network
Computers
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Various hardware and software platforms
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DOS
OS/2
Macintosh
Unix
Some platforms are pure clients others can be both
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Performance
Software availability
End-user
Computers
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Network server can represent any computer
providing services to other computers on network
Server can provide services to other clients, hosts, or
other servers
Servers
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File Servers are centralized file system
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Mechanism for storing and retrieving data for applications
Mechanism for protecting data through record locking
Provide database transaction tracking and security
Communication servers
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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
Servers
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Print servers
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Permit sharing of printers
Permits multiple users to share single printer
Print jobs are spooled
Database server
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Provides dedicated and centralized source for all users and
LAN to access a common database
Servers
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Application servers provide a vast array of services
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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
Client Workstations
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Workstations make up majority of computers on
network
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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
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Terminate and stay resident (TSR)
Enable interaction with servers and other workstations
Client Workstations
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Peer hosts are independent network node units
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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
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DOS is limited because of single tasking
Unix typically can be peer hosts
LAN Media
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Including type of media following are important
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Topology or physical layout of cable plant (token ring,
ethernet)
Media access technique
Encoding scheme
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
Broadcast – CSMA/CD
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Carrier Sense Multiple Access with Collision Detection
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STP shielded and twisted pair
UTP unshielded twisted pair
Network Interface Card (NIC)
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Responsible for
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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
Concentrators / Hubs
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Concentrator hubs simple multiport repeaters
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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
Hub Benefits
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Facilitate fault detection
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Support for different protocols
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Ethernet, token ring, FDDI can all be combined in a single
hub
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Can be easily linked to backbone
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Support different media using similar protocol
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Thinnet, thicknet and 10-Base T Ethernet segments can be
combined in a single hub
Summary
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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
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Topology
Type of access scheme