1. Dammam Community College
Network Overview
Ref: Text, Ch 14, pages

2. Advantages of networks
Enable sharing of files
Enables sharing of resources
It saves time
Internet access

3. What is a Network ?
Two or more computers connected together by a cable.
LAN - Local Area Network
MAN - Metropolitan Area Network
WAN - Wide Area Network

4. Basic Network Components
Network Interface Cards - NIC
Network cabling & connections
Servers & Workstations
Network Operating System – NOS

5. Extending a LAN
Repeaters
Bridges
Routers
Gateways

6. Network Interface Card
Interrupt (IRQ) request line
Base I/O port address
Base memory address
Direct memory access (DMA) request line

7. Basic Types of LAN’s
Peer-to-Peer: Two computers participating equally in the network.
Server Based: Security and other network functions are provided by a dedicated server.

8. Network Elements Sending Computer Receiving Computer Protocol
Media - Wire or Wireless

9. Network Protocols
A protocol is a set of rules that govern network communication.
A protocol suite is a group of protocols that can be used together.
The standard protocols are
Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX)
Networked Basic Input/Output System/NetBIOS Enhanced User Interface (NetBEUI)
Transmission Control Protocol/Internet Protocol (TCP/IP)
AppleTalk
Data Link Control (DLC)

10. Protocols Summary Protocols - A set of rules for a network Examples:
TCP/IP
TELNET
IPX/SPX
NET BEUI
To cater for the following types of networking technology:
Ethernet
Fast Ethernet
Token Ring
FDDI

11. Main Types of Cable
Coaxial Cable
Twisted Pair
Fiber Optic

12. Network Cabling

13. Cabling types and advantages
Three different types of network cabling and their advantages are:
1. Twisted pair cable is readily available, easy to install and inexpensive
2. Coaxial cable is standard technology that resists rough treatment and EMI, can transmit over longer distance than twisted pair
3.Fibre Optic cable is immune to EMI and detection outside and provides reliable and secure media with high bandwidth

14. Types of Cable Connectors
BNC Connector
RJ-45 Connector
Duplex SC Connector

15. Ethernet Cable Summary
Specification Cable Type Maximum length
10BaseT Unshielded Twisted Pair 100 meters
10Base2 Thin Coaxial meters
10Base5 Thick Coaxial 500 meters
10BaseF Fiber Optic meters

16. LAN Communication
Ethernet uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) as well as bus topology.
Token ring allows only the station holding the token to transmit data.

17. LAN Topology
Topology is the way the network is connected physically. Following are topologies:
Bus Topology
Ring Topology
Star Topology
Mesh Topology
Hybrid Topology

18. BUS TOPOLOGY PRINTER WORKSTATION 1 WORKSTATION 2 WORKSTATION 3 SERVER
T-CONNECTOR
TERMINATOR

19. RING TOPOLOGY Workstation 5 Workstation 4 server Workstation 3 printer

20. HUB STAR TOPOLOGY SERVER WORKSTATION 1 WORKSTATION 2 WORKSTATION 3
PRINTER
STAR TOPOLOGY

21. MESH TOPOLOGY Workstation 5 Workstation 4 server Workstation 3 printer

22. HYBRID TOPOLOGY STAR TOPOLOGY HUB Workstation 5 Workstation 4 server
PRINTER
STAR TOPOLOGY
Workstation 1
Workstation 2
Workstation 3
Workstation 4
Workstation 5
server
printer
RING
TOPOLOGY

23. Networking Essentials
Local Area Network (LAN)
Usually limited to short distances
Owned by the organization that uses it
Usually employs solid cable
Transmission rates tend to be high in the range of 1Mbps to 100Mbps

24. Networking Essentials
Local Area Network

25. Networking Essentials
Wide Area Network (WAN)
Usually owned by major telephone companies
Cover extremely large areas
Most common WAN protocol is TCP/IP (common for internet)
Transmission rates are usually slower than LAN or MAN rates (2400bps to 128Kbps)
Technology such as ATM is improving data transmission rates

26. Networking Essentials
Wide Area Network

27. Networking Essentials
Network Components
Network Interface Card (NIC)
Usually found in the form of an expansion card
Can have multiple connector types
Can be integrated into the motherboard
Can be 8-bit, 16-bit ISA, VLBus or PCI
Is used to connect the computer or PC to the network

28. Networking Essentials
Network Components (cont.)
Network cable
Coaxial cable
Thinnet (10Base-2) and Thicknet (10Base-5)
RG-59 used in broadband networks to support video and data
Twisted pair
Is used by dial-up modems for dial up connection to the internet
Unshielded and Shielded twisted pair (UTP and STP)
Category 1 to 5
Fiber optic

29. Networking Essentials
Network Protocols
TCP/IP
Transmission Control Protocol/Internet Protocol
The most widely used protocol suite in the world
Most major NOSs support the use of TCP/IP
Originally designed for WAN use
Routable protocol that offers true internetworking and interoperability between disparate NOSs

30. Common Topologies Bus Topology
Computers in the network are connected to a single cable
Main cable is called the backbone
Signals from computers travel in both directions
Cable must be properly terminated at both ends
Only a single computer can transmit a signal at any given time

31. Common Topologies
Bus Topology

32. Common Topologies Bus Topology Advantages Easy to apply and maintain
Requires minimal amount of cabling
Easy to extend by adding cable or adding repeaters
Can be extended with the addition of hubs connected to the bus

33. Common Topologies Bus Topology Disadvantages
The speed of the network is directly related to the number of computers connected to the bus
Damage to the cable at any location may bring down the entire network
The network usually has to be taken down to add additional computers
It may be difficult to locate a break or short in the cable without specialized equipment

34. Common Topologies Star Topology
All computers are connected to a central device called a hub
Each signal is initially sent to the central hub and then either out to all computers (broadcast star network) or to the recipient computer (switched star network)
Several star networks can be linked together

35. Common Topologies
Star Topology

36. Common Topologies Star Topology Advantages Easy to expand
If one computer fails or one cable connecting a computer fails, the rest of the network stays up
Hubs can support different types of cable
UTP is the least expensive type of cable

37. Common Topologies Star Topology Disadvantages
Failure of the central hub results in failure of the entire network
Separate cables are required to connect each workstation to a hub
The initial cost of the equipment is more than with a straight bus topology due to the added expense of the hubs and running separate cables to each computer

38. Common Topologies Ring Topology
All computers in the network are joined in a logical ring
The actual appearance may look like the star topology
The central network device, called an MAU, has a loop inside of it, which creates the ring
utilises token-ring to transmit data around the network. If a token is free of data a transmitting computer grabs it to send data by it and on the receiving end the data is removed and free token passed on to the network

39. Common Topologies Ring Topology Advantages
Ring networks handle collisions more efficiently than bus networks
No single computer can end up using the network all the time. This is theoretically possible in the bus topology.
It is faster than the star topology
Can be very long because each computer reinforces the message

40. Common Topologies Ring Topology Disadvantages
On a physical ring network, you must down the entire network to add or remove computers
On a physical ring network, if a computer goes down the entire network may go down
It may not be easy to locate a faulty computer or device on the physical ring network

41. Common Topologies
Ring Topology

42. Connectivity Within Networks
Hubs
Hubs can be used to connect networks but are more commonly used to extend a network
Most hubs will simply rebroadcast signals to all ports
Intelligent hubs rebroadcast signals only to the actual destination port

43. Connectivity Within Networks
Repeaters
Amplify signals on networks
Most commonly used to increase the length of the network backbone
Normally signals should not pass through more than two repeaters before reaching their destination

44. Connectivity Within Networks
Bridges
Selectively sends signals from one segment to the other
Can filter signals based on the protocol type
Transparent bridges contain the addresses of each computer and calculate the shortest route to the destination computer
Source-routing bridges—sender determines the proper route

46. Connectivity Between Networks
Routers
Connect independent networks
Dynamic and static routers
Distance-vector routing
Each router sends its table to all other routers at regular intervals
Link-state routing
Instead of sending the entire table, only the changes are sent

47. Connectivity Between Networks
Gateways
Provides all the connectivity, and even greater functionality of routers and bridges
usually resides on a dedicated computer and acts as a translator between two completely dissimilar systems or applications
Are slower than bridges or routers
Also provide access to special services such as or fax functions

48. Maintaining and Troubleshooting Networks
Reduced bandwidth
Loss of data
Slow loading of programs and files
Unauthorized software
Traffic overloads
Common mode failures
Network security violations

49. Cisco 1601
Cisco 2503

50. Summary A network provides connections, communications, and services.
Networks are either peer-to-peer or server-based.
Network topology types are star, bus, and ring.
A NIC connects the computer to the network.
Network cable types are twisted-pair, coaxial, and fiberoptic.
A network protocol provides the rules for network communications.
Networks can be extended with repeaters, bridges, routers, and gateways.