Computer networks

Internet, Intranet, Extranet, Lan, Wan, characteristics and differences.

Paweł Madera

Table of Content

1. Generally about Computer Network2. Network Classification3. Types of Networks4. Network Hardware Componenets5. Local Area Network (LAN)

1.Ethernet2.Star Topology3.Mesh networking4.Wireless Network: Wi-Fi

6. Wide area network

Table of Content

1. Internet1.TCP Protocol2.Packet/Switching3.Client/Server Networking4.Internet Functions

2. Intranet3. Extranet4. LAN & WAN comparison5. Intranet & Extranet comparison

Generally about Computer Network…• group of interconnected computers• allows computers to communicate • share resources and information

Network Classification

Types of Networks

Network Hardware Componenets

Local Area Network (LAN)

• small geographic area (e.g. room, office)• contrast to wide-area networks (WANs)• controlled by one administrative authority• usually high speed• always shared

Ethernet

• developed by Xerox in 1973–1975• standardized as IEEE 802.3• has replaced token ring, FDDI and ARCNET• usually uses twisted pair cable ( RJ-45)

Star Topology

• one of the most common• hub accepts data from a sender and delivers it to the

receiver• reduces the chance of failure by connecting to a central

node• good performance - passing the Data through

unnecessary nodes is prevented

Mesh networking

• continuous connections around blocked paths by “hopping” from node to node until the destination is reached.

• can still operate even when a node breaks down• Wi-Fi mesh is typical

Wireless Network: Wi-Fi

• cheap networking solution• radio waves instead of cables• three standards :• 802.11a, 802.11b and 802.11g• 2 modes – Infrastructure, and Ad-hoc• Hotspots – easy internet access

Wide Area Network (WAN)

• computer network that covers a broad area• crosses metropolitan, regional, or national

boundaries• uses routers and public communications links• Example: Internet

Wide Area Network (WAN)

• used to connect LANs and other types of networks together

• Option for WAN connectivity1. Leased Line2. Circuit switching3. Packet switching4. Cell relay

• Speed from 1200 bits/s to 6 Mbit/s

Wide Area Network (WAN)

• Turning into VPN to interconnect their networks, in that way

Internet

• Vision Appeared first in a 1946 comic science-fiction story “A Logic Named Joe”

• SAGE program connecting, radar systems• On August 6, 1991, CERN, straddled the

border between France and Switzerland• During the 1990s, it was estimated grew

by 100% per year, with boom in 1996 and 1997

Internet

• global system of interconnected computer networks

• consists of millions of private and public networks

TCP Protocol

• TCP= Transmission Control Protocol• Developed by US Department of Defense in 70s• Set of network rules• 4 layers structure

IP protocol

• provides addressing for computers• IP Version 4 is the initial version• ~4.3 billion (109) Internet hosts• IP v6 provides vastly larger addressing

capabilities• IPv6 will be not compatible with IPv4

Packet/Switching

• Slicing digital message into packets (parcels)

• Size of a packet = 128 bytes (X.25)

• Security of the data

Client/Server Networking

• Model of networking• Balanced architecture• one or more Server

Computers• Example: Internet

Internet Functions

• E-mail• File-sharing• Instant messaging• Internet fax• World Wide Web• Voice over IP• Mobile VoIP

Intranet

• Private computer network• secure sharing organization's information or operational

systems with its employees.• The same architecture as in Internet• private version of the Internet

Intranet

• possible access to the Internet, then geteway with firewall is applied

• Intranet delivers1. tools and applications, 2. collaboration (to facilitate working in groups and teleconferencing)3. sophisticated corporate directories4. sales and Customer relationship management tools 5. project management etc

• In large intranets, traffic is often similar to public website traffic

Extranet

• Uses Internet protocols, network connectivity• Share informations as intranet• The number of clients is extended to people

outside the company• interconnections are over a shared network

rather than through dedicated physical lines as in intranet

LAN & WAN comparison

LAN WAN

• Small area covered• Use public communication links• Usually low speed• Uses Wi-Fi, Ethernet cables

• Large area area covered• Use public communication links• Usually fast speed• Uses optic wires, microwaves,

satellites

Intranet and Extranet comparison

Intranet Extranet

• connects users in company

• shared network• single company's

administrator• Don’t need so much

security

• connects user inside and outside company

• Dedicated physical lines• multiple company's

administrator• Requires more securtity

The End