Networking is communicating or linking people, groups, activities or devices in order to form networks that make it easy to exchange information or services.
Networking as defined in Merriam Webster dictionary is the exchange of information or services among individuals, groups, or institutions; specifically : the cultivation of productive relationships for employment or business.
Networking application
A list of familiar use of network and networking comprises:
Modern global business and thirsty global market made business professionals anxious to inventing ways that improve their business practice. One efficient practice they found consists of organizing themselves into group networks in every activity as we mentioned in the listed network examples above.
Consequently, a network can be defined as interconnected number of people, objects, businesses, services, etc…
This definition applies to computer networking since computers are tools used by individuals and business decision makers to hold and process information.
Following this logic we can say that modern computer networking is in fact business networking as it is hard to imagine business information networks that don’t evolve around computers and computer information systems.
It is needless to mention that business networking or computer networking or any other networking wouldn’t be this easily possible and profitable without the abundance of advanced telecommunication media and telecommunication technology.
We use to consider two or more computers linked together as a computer network but practically a computer network consists of at least 3 computers linked together by means of telecommunication media.
Computer networks are usually tailored to match the structure of a given establishment, business or any organization.
Because this structure includes a lot of ramifications and substructures, business network usually is a network of sub-networks looking like the metaphor of the tree structure.
Each computer in the network is known as a node or workstation.
If the network has a server all other nodes are considered as clients to the server, by the way this is the most commonly used structure in computer networking.
Network classification by size:
Local area network (LAN) covers a limited geographical area (a building or few small buildings), the network in your computer lab is a LAN with around 30 nodes.
Personal area network (PAN) is a specific LAN designed to connect computer devices for one person or household or office in very limited geographical area and ultimately connect them to the Internet.
Metropolitan area network (MAN) is a larger network that may include several LANs and PANs. This network covers larger geographical area like a whole city or a large campus (university, college, military base, business campus).
Wide area network (WAN) is the largest network structure that may include several interconnected LANs, MANs and PANs. This network covers large areas like a state, a country or several countries or even a continent.
The largest area network is the Internet because it is the collection of all networks connected together by the Internet backbone.
Network classification by physical structure (physical topology):
Star network:
Consists of several computer nodes connected to a central hub.
The central server offer services to the other nodes that are considered as client nodes.
Most used structure in business computer networking.
Node1
Node2
Node4
Bus network:
Bus (backbone)
Node3
Consists of a backbone cable extended all along the network area.
Several computers connected in parallel to the same backbone which is called a bus because of this type of connection.
No server in a bus network. Nodes share files and other information.
Easy to connect and monitor network.
Ring network:
Consists of a specific bus network that has both ends linked together.
Used in locations where the computers are physically located very close to a ring
Message always flows clockwise and priorities are also established in the order clockwise.
No server involved. Nodes connect and share files as they configure them depending on who needs what?
Mesh networking topology:
Consists of several computers where each node is connected with all other nodes.
Expensive structure if we need to lay a huge quantity of cables or implement other media for this purpose.
No server is usually needed. Exchange of files and information as previously configured by nodes (who needs what?).
Access authorization for sharing files should be strictly controlled
Rarely used without Internet backbone connection
Peer-to-peer (P2P) network:
Special mesh structure that uses the Internet backbone as a communication medium with each node in the network.
Very flexible structure as it may connect unlimited number of nodes that may include every computer that has Internet connection.
Eliminates the need of a server by using the file sharing technology that allows every node to share files with all other nodes.
Tree network:
Consists of a combination of a bus network with several star networks
This network fits a department that comprises several divisions where each division has a star network and all stars are connected via a bus.
Priorities and message flow control are more complicated in this network structure.
Network protocol (network logical topology)
Network protocol is a set of rules designed to control all network functions by assuming the following responsibilities:
Establishing network priorities and enforcing them.
Maintaining strict communication discipline in the network.
Controlling network access and network security.
Establishing communications with network nodes from internal nodes and external messages applying the handshaking technology
Handshaking technology consists of the following steps achieved by the network protocol:
Protocol intercepts the message and inspects its validity and security status and make sure it doesn’t collide with other network messages.
Protocol warns node B about the message by checking if it is available and willing to receive it.
To complete the handshaking process, protocol connects the sender with the receiver allowing the message to flow from origin to destination.
If node B is busy with other messaging business the handshaking process will be postponed as long as necessary.
Ethernet protocol: Was commercially released in 1980 and it is until today the most popular protocol among LAN users
Ethernet technology is known as CSMA/CD which stands for (Carrier Sense Multiple Access/Collision Detection.
This technology is based on the principle of polite conversation between a group of civilized people with the following scenario:
Many people start talking at the same time.
They stop talking because each one of them will leave the turn to others.
When an absolute silence is achieved, some guys will restart talking and again if more than one is talking they will stop.
The process will continue until only one is talking and all others listening
Ethernet protocol assumes the enforcement of the courtesy role by stopping all messages if more than one station is trying to send.
Ethernet sends the message to all nodes but none can receive it except the addressees.
Token ring protocol:
This protocol is designed for the ring network
A signal called token that may be a code is sent to the station that has the sending priority
When that station finishes it passes the token to the station that has the next priority and so forth
In a ring network priorities are clockwise in the order and the message flows clockwise exactly.
Some networks use the Internet protocol which we will see along with many other protocols of Internet services ahead.
Wireless networking:
WLAN network connects nodes via radio-waves instead of cables. It is known as Wi-Fi network and the latest wireless technology is the Wi-Max network.
Wi-Fi network stands for (Wireless-Fidelity) and is known by its IEEE code 802.11 where we must distinguish from 802.11a, 802.11b, 802.11g, and 802.11n
802.11 was released in 1997 uses a 2.4 GHz and bandwidth 20 MHz can be used over a distance of 20 meter indoor and 100 meter outdoor
802.11a released on the eve of the 3rd millennium SEPT-OCT 1999 uses a 3.7 GHz frequency and 20 MHz bandwidth that improved the range to 35 meters indoor and 120 meters outdoor.
802.11b uses 2.4 GHz and same bandwidth of 20 MHz with the improvement of the outdoor working distance to 140 meters.
802.11g similar to the 802.11b and data rate between 6 and 54 (Mbit/s) and was released in June 2003.
802.11n released in OCT 2009 used a 2.4/5 GHz frequency and bit stream between 7.2 Mbit/s and 72.2 Mbit/s the working range was improved to 70 meters indoor and 250 meters outdoor.
Other scheduled releases for 2013 (802.11ad) and 2014 (802.11ac) that will introduce new improvements to the WLAN technology.
Wi-MAX (Worldwide interoperability for Microwave Access).
Wireless broadband Internet access designed to replace the DSL as more convenient mobile and fixed Internet access.
Wi-MAX influence on Internet access may be compared tp cellphone impact on the telephone networking and telephone industry.
The IEEE 802.16 and 802.16e standard enable to use 2.3 GHz, 3.3 GHz, 2.5 GHz and 3.5 GHz.
Wi-MAX range may reach 50 Kilometers about 31 miles (enough to cover a big city or a county).
Designed to provide 30-40 Mbit/s that was updated in 2011 to 1 Gbit/s for fixed stations.
However Wi-MAX has the limitation of not being able to deliver the maximum speed at the maximum range (speed in bit/s is inversely proportional to the distance from the base station).
Wi-MAX 802.16 started the 4th generation (4G) of smart phones and mobile Internet access that evolved as follow:
LTE (Long Term Evolution) is defined as a 4G standard was effectively first launched in 2009 in Scandinavia (Oslo and Stockholm).
Wi-MAX 1, 1.5 and 2 were all designed as wireless MAN (Metropolitan area Network).
Wi-MAX 2nd release core technology (802.16m) provides data speed 4 times faster than the first release 802.16 and 802.16e.
802.16m release 2 is backward compatible with Wi-MAX release 1 so the migration from Wi-MAX 1 to Wi-MAX 2 needs only to update the software or upgrade the channel cards.
By the start of 2012 Wi-MAX networks around the world were estimated to have more than one billion subscribers.
Blue tooth networking: (Blootooth.com)
Bluetooth networking technology was developed in 1994 in the labs of ERICSSON (the Scandinavian communication giant company) by 2 employees Jaap Haartsen and Sven Mattisson
It was called by this name after the Scandinavian king Harald (935 – 985) who was very productive in building bridges and making all Scandinavian tribes communicate with each other. This king was nicknamed “BLUETOOTH” because his front teeth were blue colored affected by his love of eating berries.
Bluetooth is a full wireless networking technology using low power transmitters that are designed to link computing devices in PAN (Personal Area Network) over short distances (10 meters = 33 feet or less).
Newer Bluetooth technology using more powerful transmitters can be used for up to 100 meters or 330 feet.
The frequency band used is 2402-2480 MHz divided into 79 channels one MHz apart assigned by the ISM (Industrial Scientific Medical) agency.
In 1998 Bluetooth SIG (Bluetooth Special Interest Group) was established by Ericsson, Nokia, IBM, Toshiba and INTEL this group is monitoring the use of protocol stack and Bluetooth qualification requirements for electronic devices and equipment.
In 2002 Bluetooth enabled devices were around 250 million. Today it is estimated that more than a billion devices are using the technology.
Computers who are not equipped with Bluetooth adaptor can be Bluetooth connected thru wireless adapter.
One Bluetooth adapter can connect several Bluetooth devices.
Characteristics of Bluetooth network:
The basic network in a Bluetooth system is the “Pico-net” where the number of nodes cannot exceed 8 devices because the address is 3 digits (2^3 = 8).
Each device in Pico-net is a peer device (it can act a master or a slave so at a given time we have one master and 7 slaves.
Two or more Pico-nets form a scatter-net and the name is meaningful in this networking technology because a scatter happens when one slave of any Pico-net elects to behave as master or slave in another one.
This interconnectivity is very important because it enables Bluetooth devices to reach far beyond the short range limitation of Bluetooth networking.
Bluetooth protocol: because of the diversity of Bluetooth devices the technology has a stack of several protocols to handle diverse services and provide for implementation flexibility. These protocols are:
LMP (Link Management protocol) establishes and manages links and ability to query.
BNEP (Bluetooth Network Encapsulation Protocol) used by Bluetooth PNA to manage packet switching and transmission in the network.
HCI (Host Controller Interface) establishes and controls communication between operating system of computer devices and Bluetooth IC (Integrated Circuit).
SDP (Service Discovery Protocol) enables any Bluetooth device to discover services offered by other devices and their characteristics and parameters.
TCS and TCS-BIN (Telephony Control Protocol allows voice and data calls between devices of Bluetooth network.
WAP (Wireless Application Protocol) provides necessary access to telephone and computer networks for mobile users who are connecting thru Bluetooth network.
Samples of Bluetooth apps: Here are some applications:
PROFINET: Bridge that connects two Ethernet networks.
Wii of Nintendo and PS3 of Sony game consoles use Bluetooth to accommodate their game controllers.
Personal security application: Bluetooth tag (marker) attached to protected objects and has constant communication with a phone. If the communication is interrupted a warning signal is activated.
RTLS (Real Time Location System) app that enables user to track and locate objects by attaching or embedding Bluetooth markers or tags and using readers to intercept and process signals sent by the tags. Bluetooth OBEX (Object Exchange) is an application that allows exchange of information and transfer of files within all devices of Bluetooth network.
The Internet
Internetworking:
The basic idea behind Internet invention is connecting networks with each other creating a network of networks (MAN or WAN).
This process is known as internetworking and several technological steps were already set up that guided to the Internet.
Networks may have different topologies and different protocols and to connect them we need to set up a conversion or translation service between them.
Connecting networks:
Two similar networks (same protocol) are connected by means of a bridge whose job is to connect 2 or more segments and control packet flow between them.
Two dissimilar networks (have different protocols) are connected by means of gateway device which provide assistance to make sure the message flows uniformly in both networks
Network switch links segments of the network to bridges or gateways. Basic switches don’t process data.
A switch that does process data is called multilevel switch because it will be working at a level 3 processing.
Packet switching/circuit switching:
Internetworking technology will be impossible with circuit switching technology that reserves a circuit for each message until it is done.
This technology allows fewer messages to use the network pathways simultaneously.
Packet switching, on the other hand, optimizes the use of network pathways by dividing each message into parcels of data called packets whose trip takes short time.
Packets are sent from A to B using most available pathways between them instead of only one like in circuit switching. Consider the following scenario of 9 packets going from A to B.
Packet1 takes itinerary I1
Packet2 takes Itinerary I2 and so on…
Packet9 takes Itinerary I9
Upon arrival to B, a guide will gather them regroup them and deliver them altogether one message as they initially were.
An internetwork is basically a small Internet the biggest internetwork of all networks and internetworks is the Internet that controls our daily life (as individual, community, society, business, government and so on…)
Evolution of the Internet:
Because Internet changed the way we live and the way we do business, it is very important that you know how this miraculous technology evolved and be literate about its too many services and how to put them in action for improving our life and our business while contributing to serving our nation and the global society.
DOD (Department of Defense) started the Internet development journey in February 1958 (right after the Soviet union successfully launched Sputnik orbiter in 1957):
A committee of scientists called ARPA (Advanced Research Project Agency) also named DARPA (Defense Advanced Research Project Agency).
DARPA’s mission was to create a network that enables scientists to network without interruption even in case of nuclear warfare.
DARPA hired high tech companies mainly BBN (Bolt Beranek Neuman) as contractors to work on the project.
MERIT (Michigan Educational Research Information Triad) is packet switching network that was created in 1966 by many universities in Michigan for research collaboration
ARPANET (Advanced Research Project Agency Network) was started by DARPA in December 1969 connecting 4 university nodes:
UCLA (Network Measurement Center (NMC))
Stanford (Stanford Research Institute (SRI))
University of Utah
University of California-Santa Barbara
1971-1972: Computer engineer Ray Tomlinson invented the E-mail while working for BBN and implemented it on ARPANET which was developed by BBN.
Email was the first and most important service using the Internet backbone and attracted the attention of political and economy leaders about the importance of that tool in the global business.
1981 the number of host computers reached 213 and growing by 20/year approximately this number grews several folds after the addition of other services and especially the WWW service to the Internet.
1981 IBM released the first PC and Time magazine choses the computer as “Man of the year” 1981.
1984 Apple released its MAC with the user friendly GUI (Graphical User Interface). All that gave huge push to the Internet drive.
1985 NSFNET (National Science Foundation Network) was created based on MERIT network and evolved into the modern Internet in 1995.
1990, the year when ARPANET shuts down, 300000 hosts were connected to the Internet using PCs, MACs.
Other large computers used as servers for networks connected to the Internet whose number grow from 3000 in 1986 to more than 30000 in 1987 and continue growing with the advance of computer hardware and software technology and networking protocol software technology.
Internet protocol
Since its implementation in 1969 till its shut down in 1990 ARPANET used a variant of packet switching protocol known as IMP (Interface Message Processor).
The message is cut into parcels of data called PDUs (Protocol Data Unit) where the packet or PDU cannot exceed 1008 bits
IMP protocol slowness (acknowledge receipt of each packet) wasn’t able to face the large number of networks and hosts that exceeds today the billion and was about 500000 even before the invention of the WWW (World Wide Web) as predominant service provided by the Internet.
Internet protocol TCP/IP (Transmission Control Protocol/Internet Protocol) was the right solution where each part fulfills a specific job making the process very fast to handle the huge number of exchanged packets:
TCP (Transmission Control Protocol) is the part that takes care of the packet at the origin and destination making sure they are well prepared at the origin and assemble them prior to the correct delivery at the destination.
TCP cuts the message into packets below 1500 bytes each because Ethernet protocol in LANs cannot take more than 1500 bytes.
IP (Internet Protocol) is the part that takes care of addressing the packets and directs them thru their proper itineraries.
Internet backbone:
Internet backbone can be compared to human backbone or spine because it connects Internet host user to other users like human backbone connect to every organ and cell of the human body.
This backbone comprises all fast and broad band networks and connections all around the world including:
Under ocean cables installed by submarines and known as submarine cables that link most continents.
Satellites owned and operated by large telecommunications companies because the private sector took over in 1994.
Ground high speed telecommunication and networking infrastructure including wired and wireless infrastructure.
Most important cables of internet and internetwork backbone are T1 and T3 lines that we have seen in the previous telecommunications chapter.
T 1 line:
Reserved circuit that uses copper or fiber optic cables to operate over various networking distances.
Monthly Cost is about $1000 and more and mostly used by hotels, apartment buildings and subdivision and some business and college campuses where the cost can be justified.
T3 line:
Use copper and fiber optic cables to operate as a reserved circuit equivalent to an aggregation of 28 T1 lines.
Data rate is about 44.7 Mbps.
Monthly cost is about $3000 - $12000 or more that’s why it is used as a backbone of large business network or the headquarters of big businesses and large size campuses and military bases.
Routers
Different Internet pathways are connected together thru the use of huge number of routers that are responsible of:
Monitoring and easing Internet traffic
Monitoring packets itineraries and direct them to thei correct destination
Apply Internet protocol to all services that use the Internet.
Internet operation
Nobody own the Internet, however big telecommunication companies own parts of the Internet backbone and make profit by charging use fees so Internet providers can be divided into 3 tiers:
Tier 1: comprises huge ISP (Internet Service Provider) companies that don’t need to pay anything to access all nodes of the Internet. Qwest, AT&T, Verizon, sprint, French telecom, Finn telecom etc…
Tier 2: comprises ISP companies that need to pay for some access from Tier 1 companies.
Tier 3: Comprises ISP companies that lease Internet access from Tier 1 or Tier 2 companies provide services to subscribers and don’t own connections by themselves.
Tier 1, Tier 2 and Tier 3 companies are all Internet service providers (ISP)s and that’s why the quality of Internet service is normally better with Tier 1 companies then Tier 2 then Tier 3.
Internet Access: Five most important characteristics of Internet access are:
Reliability: Connection is available when needed without unexpected interruption due to coverage and weather
Speed: Download speed and upload speed in Mbps.
Cost should be reasonable and justified.
Customer satisfaction oriented help and assistance service
Free array of popular general information
News
Weather
Gaming
Travel and entertainment.
ISP (Internet Service Provider) supplies a modem (modulator demodulator) that is able to accommodate all services provided.
A splitter modem is provided by the CTV provider that routes TV channels to the TV and Internet service to the computer or the wireless router if you want to install a WI-FI network.
You can watch TV and access Internet and its services simultaneously.
Very fast connection up to 8 Mbps and may reach up to 50 Mbps in case businesses want speed beyond what is offered for the public.
Slightly higher cost than DSL
Very reliable (not affected by weather condition.
Satellite access: direct satellite access is provided by many companies that operate and manage satellites like HughesNet, MyBlueDish and Wild blue in the USA.
Provides fast Internet in rural areas where only dial-up connection or no connection at all is available.
Always ON connection
Speed may go up to 18 Mbps.
Very reliable Internet access
Most expensive Internet service.
Important Business special networks we need to cover in this chapter include:
VPN (Virtual Private Network):
Very important business network that uses client server topology and has no physical installed structure.
May have partly installed local structure.
Operates using public networks (mainly the Internet) to exchange private data and make private communications
To enforce and enhance communication security a protocol known as “Tunneling” protocol is used.
Tunneling protocol usually does the following:
Authenticate the client requesting communication to the VPN
Create a secured tunnel (pathway).
Complete and control the communication thru that tunnel.
VPN is used by businesses to create connection possibilities for their Intranet and Extranet as we will see below.
Intranet:
Internetwork of many private networks in a company designed to accommodate teamwork and enhance communication and file sharing in a company
Uses the Internet protocol TCP/IP
Hi security network in a business.
Only authorized executives, managers and employees can access it (no outsiders allowed in)
An Intranet consists of:
Internal e-mail system
Database loaded with important information and news about the company and its working environment.
Websites and some other services as needed.
Secured and firewalled Internet access
VPN connection to support remote access for company’s staff.
Extranet:
Internetwork like Intranet but with strictly controlled outside access
Uses VPN (Virtual Private Network) to connect with another network in a different organization.
Extranets are widely used by medium and large companies because of the simplicity and convenience they add to business – customer relationship and easiness of communication between businesses.
VAN (Value Added Network):
considered as a competitor to the post office for business documents and file exchange between businesses.
