1. Computer Networks & Security
Advantages of a network
Client/server and peer-to-peer networks
Classifications of client/server networks
Client/server network components
Types of servers
Network topologies
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2. Topics Types of transmission media Network software Network adapters
Moving data in a client/server network
Securing networks
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3. Networking Advantages
Networks:
Increase productivity
Enable the sharing of resources
Facilitate Internet connectivity
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4. Client/Server Networks
Server based network:
Clients
Servers
Data flows efficiently
Servers respond to requests from clients
Servers perform specific tasks
Scalable network
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5. Classifications of Client/Server Networks
LAN:
Local area network
Computers linked together over a small geographic region
WAN:
Wide area network
Computers linked together over large diverse geographic locations
MAN:
Metropolitan area network
Computers linked together within a city or county
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6. Classifications of Client/Server Networks
PAN:
Personal area network
Wireless devices connected in close proximity to each other
Intranet:
Private corporate network
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7. Constructing Client/Server Networks
Servers
Network topologies
Transmission media
Network operating system (NOS)
Network adapters
Network navigation devices

8. Servers Number and type of servers depend on network size and workload
Dedicated server:
Perform one specific function
Authentication server:
Keeps track of network logins and services available
File server:
Store and manage files

9. Dedicated Servers Print server: Applications server: Database server:
Manages client-requested printing jobs
Creates print queue (prioritizes print jobs)
Applications server:
Acts as a storage area for application software
Database server:
Provides clients with access to database information
server:
Process and deliver in-coming and outgoing

10. Dedicated Servers Communications server: Web server:
Handles communications between networks including the Internet
Web server:
Hosts a Web site available through the Internet

11. Network Topologies
The physical layout of computers, transmission media, and other components
Types of network topologies include:
Bus topology
Ring topology
Star topology

12. Bus Topology All nodes are connected in sequence on a single cable
Used most often on peer-to-peer networks
Networked computers communicate with each other
One computer transmits data at a time:
Access methods avoid data collisions
Data is transmitted in “packets”

13. Ring Topology Nodes are laid out in a ring
Token (data packet) flows in one direction from device to device

14. Star Topology
Nodes connect to a central communications device (hub/switch)
A node sends a signal to the hub which retransmits it to the other nodes
A node accepts the signal addressed to it

15. Avoiding Data Collisions on a Star Network

16. Transmission Media
The routes data takes to flow between devices on a network:
Wired
Wireless:
Wireless Fidelity (Wi-Fi)
Uses radio waves
standard

17. Choosing a Cable Maximum run length Bandwidth Bend radius Cable cost
Installation costs
Susceptibility to interference
Signal transmission methods

18. Twisted Pair Cable Pairs of copper wire twisted around each other
Twists make the wires less susceptible to interference
Shielded twisted pair (STP)
Layer of foil shielding
Unshielded twisted pair (UTP)
Cat 5E
Bandwidth 1Gbps
Cat 6
Bandwidth 200 Mbps

19. Coaxial Cable Four components: Copper core
Nonconductive insulating material
Braided metal
Plastic cover

20. Fiber-Optic Cable Components include:
Glass or plastic fibers
Cladding
Outer jacket
Uses light impulses to transmit data
Immune to interference

21. Network Operating Systems (NOS)
Provide the protocol that controls the communication between devices on the network
Major network operating systems:
Windows Server 2003
UNIX
Novell NetWare

22. Network Adapters
Devices that enable computers to communicate on a network
Network interface cards (NICs):
Generate network transmission signals
Create data packets
Act as information gatekeepers
Ethernet compliant
Wireless NICs

23. Network Navigation Devices
Media Access Control (MAC) address:
Six 2-digit numbers (01:40:87:44:79:A5)
Physical address of network adapter
Internal network identification
Repeaters and Hubs:
Amplify signals and retransmit them
Switches and Bridges:
Send data on a specific route through the network
Bridges send data between collision domains
Routers:
Send information between two networks

24. Network Security Authentication: Access privileges:
User ID and password used to access the network
Access privileges:
Enable access to certain network systems
Physical protection measures:
Restrict physical access to sensitive network equipment
Magnetic card readers
Biometric access devices
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25. Network Security Firewalls:
Prevent access to the network by unauthorized users
Composed of software and/or hardware
Screens and validates data packets
Bastion host/proxy server
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26. Network Firewall Layout
Perimeter Network
Internal Network
External Screening Router
Bastion Host /Proxy Server
Internal Screening Router