-introduction-
a) What are protocols?
b) What is TCP/IP?
-The Internet protocol suite is the set of communications protocol used for the Internet and similar networks, and generally the most popular protocol stack for wide area networks. It is commonly known as TCP/IP, because of its most important protocols: Transmission Control Protocol(TCP) and Internet Protocol (IP), which were the first networking protocols defined in this standard. It is occasionally known as the DoD model due to the foundational influence of the ARPANET in the 1970s
c) How does information travel through the Internet?
-The Internet is based on packet-switched protocols. Information is carried in packets, which can be imagined as small parcels being passed from computer to computer. Large chunks of data are usually broken up into several smaller packets before being sent through the network. The delivery mechanism, or protocol, that is used to encode the packet ensures safe transit, and provides a way of reconstructing the data when it reaches its destination. The protocols used on the Internet are referred to as TCP/IP, standing for Transmission Control Protocol / Internet Protocol.
With a modem and the appropriate software, you can dial up another modem connected to another computer and establish a network connection with it. Usually, this computer is linked into the internet and so you're online.
With an ADSL modem or router, a similar procedure happens but a filter splits the telephone line into voice and data (low and high frequencies) and your router negotiates a connection with the ADSL equipment in the telephone exchange.
If you need portable internet access for a mobile device such as a phone, tablet or laptop, you will need an ISP that offers a service such as 3G, 4G, Wi-Fi or Wi-Max. This would not typically be your primary method of connecting to the internet; you should also have a Dial-up, DSL, cable, or satellite connection.
Typically, broadband connections are delivered through cable, DSL, or fiber-optic wires. If you have access to a fiber-optic connection, this will typically be the fastest, but it also costs the most. Fiber-optic “to the home” connections in particular can offer blazing speeds! Cable is usually faster than DSL, but both are about equally popular.
You should check with your ISP about additional services that are included with your connection. Some of these services might include spam protection, email backup, or customer support. If bundling your services is an option, consider doing so to save money; many ISPs also offer phone and TV service and will give you a discount for subscribing to all of these services through them.
If the ability to use wireless broadband is important to you – those who own laptops or smartphones are often particularly keen on getting Wi-Fi – then you should check out the modems your ISP offers. You might find an option to pay extra for a wireless modem, and sometimes you can even negotiate your pricing plan so this is free.
Ask your friends, coworkers, or neighbors which ISP they would recommend. You will quickly see if any particular ISPs have a reputation for slow installation, frequent downtime, or inaccessible customer service. It’s important to have good support available whenever you have a problem with your broadband internet.
Each ISP will likely promise you a similar speed, so look for one with a good reputation for delivering those speeds. You might not get the exact internet speed you were promised, but you shouldn’t be suffering with half that speed! Ask what happens if you don’t get those speeds, and whether there are any guarantees.
Because ISPs compete so fiercely to attract customers, they are often willing to offer promotional discounts to new customers. Check whether the price you’re getting will be permanent or promotional. You can easily determine an average monthly price over the course of your subscription.
d) Measuring Bandwidth
-Who govern/regulates/controls the Internet?-
Domain names
One form of control that is necessary (and possible) is the name service, which allocates Domain Names on the Internet. These are unique names for subnetworks, which allow easier (human) access to Internet addresses. So, instead of having to remember that Exeter's (numeric) addresses all begin 144.173, you can just use .ex.ac.uk at the end of a name. (We'll explain more about addressing in the next lecture). In the UK, these domain names (all ending in .uk) are managed by an organisation called Nominet.UK. It delegates some UK addresses to other organisations, such as UKERNA (forac.uk and .gov.uk addresses), but manages most itself.
Internet Protocol Adresses
Every computer, server and other device that connects to the internet needs an address to be
found, and these need to be unique across the whole of the network. Managing to keep these
unique and ordered is the job of IANA, the Internet Assigned Numbers Authority.
Other bodies and institutions
• Internet Society (ISOC)
• oversees other Internet organisations
• Internet Architecture Board (IAB)
• manages technical direction of the Internet
• Internet Engineering Task Force (IETF)
• standardises technical developments (through RFCs)
On a global level, things are more complex. Since the Internet grew primarily out of the United States, the bodies that control the Internet worldwide are organised from there. The main body is IANA, and as previously mentioned, this has overall control for assigning numeric addresses. Recently, a new corporation, called ICANN, the Internet Corporation for Assigned Names and Numbers, was set up to oversee this role and other important aspects of Internet governance. All of these organisations, and many more governing and researching aspects of the Internet, are members of the Internet Society, as shown in Figure 1.3, “The Internet Society Structure”.
-Who owns the Internet?-
a) What are protocols?
-a protocol is the special set of rules that end points in a telecommunication connection use when they communicate. Protocols specify interactions between the communicating entities. Protocols exist at several levels in a telecommunication connection. For example, there are protocols for the data intercharge at the hardware device level and protocols for data intercharge at the application program level. In the standard model known as Open Systems Interconnection (OSI), there are one or more protocols at each layer in the telecommunication exchange that both ends of the exchange must recognize and observe. Protocols are often described in an industry or international standard.
b) What is TCP/IP?
-The Internet protocol suite is the set of communications protocol used for the Internet and similar networks, and generally the most popular protocol stack for wide area networks. It is commonly known as TCP/IP, because of its most important protocols: Transmission Control Protocol(TCP) and Internet Protocol (IP), which were the first networking protocols defined in this standard. It is occasionally known as the DoD model due to the foundational influence of the ARPANET in the 1970s
c) How does information travel through the Internet?
-The Internet is based on packet-switched protocols. Information is carried in packets, which can be imagined as small parcels being passed from computer to computer. Large chunks of data are usually broken up into several smaller packets before being sent through the network. The delivery mechanism, or protocol, that is used to encode the packet ensures safe transit, and provides a way of reconstructing the data when it reaches its destination. The protocols used on the Internet are referred to as TCP/IP, standing for Transmission Control Protocol / Internet Protocol.
As a switched network, the physical connections between computers do not matter as far as Internet traffic is concerned - the protocols ensure that guaranteed information delivery is more important than speed or use of a particular route. This means that a sequence of packets might arrive out of order, with some travelling through the net by a faster, shorter route than others. TCP/IP provides the means for your software to piece together those packets into meaningful data. The ability to take different routes through the network is a fundamental part of the original design of TCP/IP, as it allows the internet to route around damaged areas of the network.
d) How does the connection work from home?
-1) Modems and routers
2) Negotiating a connection
To connect from home you need several things. Apart from a computer you'll need a phone connection, a modem or ADSL router and some internet software. Things will be easier if use a relatively recent operation system, such as Windows Vista/XP or MacOSX but it's possible to connect with older or more obscure systems.
With a modem and the appropriate software, you can dial up another modem connected to another computer and establish a network connection with it. Usually, this computer is linked into the internet and so you're online.
With an ADSL modem or router, a similar procedure happens but a filter splits the telephone line into voice and data (low and high frequencies) and your router negotiates a connection with the ADSL equipment in the telephone exchange.
- ISP (Internet Service Provider)-
a) What is ISP?
-is an Internet Service Provider (ISP) is a company that provides you with access to the Internet, usually for a fee. The most common ways to connect to an ISP are by using a phone line (dial-up) or broadband connection (cable or DSL). Many ISPs provide additional services such as e‑mail accounts, web browsers, and space for you to create a website. ISP is sometimes used as an abbreviation for independent service provider to distinguish a service provider that is an independent, separate company from a telephone company.
b) Connecting using ISP and how to choose an ISP: Dialup, broadband or mobile?
-Most ISPs use either an existing phone line (for dial-up or DSL), a cable television line, or a satellite connection to connect you to the internet. Depending on your area, some connections may not be available.
DIAL-UP
- slower than other internet connection types
- connects through existing phone lines using a dial-up modem
- generally the cheapest option but requires phone service
- must "dial-up" to connect to the internet and disconnect when done
- cannot use phone and internet at the same time (unless there are multiple phone lines)
DSL
- broadband - much faster than dial-up
- connects through phone lines but does not necessarily require phone service
- "always on" - does not require dialing up
- internet and phone can be used at the same time
- unavailable in many locations, even where there are phone lines
CABLE
- broadband - much faster than dial-up; can be faster than DSL
- uses cable connection but does not necessarily require cable TV subscription
- "always on" - does not require dialing up
- only available where cable is available
SATELLITE
- broadband - faster than dial-up but data is delayed so it is not good for real-time applications like gaming or videoconferancing
- connects via satellites orbiting the earth
- can be affected by rain or snow
- does not require phone or cable lines; can be used almost anywhere in the world
3G AND 4G
- available for mobile phones, computers and tablet computers
- connects wirelessly through your provider's 3G or 4G network
- allows you to acces the internet away from home, even when there is no Wi-Fi connection
- 3G maybe not be as fast as DSL or Cable connection
- Dial-up
If you only want to use the internet every now and then, do not mind waiting a few minutes to connect and disconnect each time you want to use the internet, and do not need wireless access, then dial-up may be right for you. Dial-up can also be a good option for those who are traveling and want to occasionally check email or browse some web pages. Keep in mind that you need access to a land-line telephone service in order to use Dial-up. - DSL or Cable
If you regularly use the internet, you will probably want a DSL or cable connection. Cable can be faster than DSL, but most people can find what they need from either one of these services. Also, for those who want a reliable wireless connection, you can connect to DSL or cable internet wirelessly with a wireless router. - Satellite
If you regularly use the internet, but live in an area where DSL or cable connections are not available, a satellite connection may be your best option. Satellite connections are wireless and much faster than dial-up, but they are limited in their ability to connect to streaming content, can be affected by the weather, and their price is comparable to DSL or cable connections.
c) Choosing a broadband providerc)
-1. What type of internet connection do they offer?
Typically, broadband connections are delivered through cable, DSL, or fiber-optic wires. If you have access to a fiber-optic connection, this will typically be the fastest, but it also costs the most. Fiber-optic “to the home” connections in particular can offer blazing speeds! Cable is usually faster than DSL, but both are about equally popular.
2. Are any additional services included?
You should check with your ISP about additional services that are included with your connection. Some of these services might include spam protection, email backup, or customer support. If bundling your services is an option, consider doing so to save money; many ISPs also offer phone and TV service and will give you a discount for subscribing to all of these services through them.
3. Is your modem wireless or not?
If the ability to use wireless broadband is important to you – those who own laptops or smartphones are often particularly keen on getting Wi-Fi – then you should check out the modems your ISP offers. You might find an option to pay extra for a wireless modem, and sometimes you can even negotiate your pricing plan so this is free.
4. How is their reputation? Do they provide good support?
Ask your friends, coworkers, or neighbors which ISP they would recommend. You will quickly see if any particular ISPs have a reputation for slow installation, frequent downtime, or inaccessible customer service. It’s important to have good support available whenever you have a problem with your broadband internet.
5. What speeds do they promise?
Each ISP will likely promise you a similar speed, so look for one with a good reputation for delivering those speeds. You might not get the exact internet speed you were promised, but you shouldn’t be suffering with half that speed! Ask what happens if you don’t get those speeds, and whether there are any guarantees.
6. Are they new or established?
Sometimes, the phone lines are controlled or owned by a major ISP, and smaller ISPs have to pay them to do installations or maintenance work. You can often get a cheaper rate by going with a lesser-known ISP, but make sure that you’re going to benefit in terms of speed and customer service if you sacrifice the reliability of an established company.
7. Is their pricing promotional or permanent?
Because ISPs compete so fiercely to attract customers, they are often willing to offer promotional discounts to new customers. Check whether the price you’re getting will be permanent or promotional. You can easily determine an average monthly price over the course of your subscription.
- asic unit is the bit per second
- megabits per second (Mb/s) more commonly used
- a megabit is around a million bits
- Don't confuse with megabytes per second (MB/s)
- divide Mb/s by 8 to get MB/s
-Who govern/regulates/controls the Internet?-
Domain names
- map numeric addresses to mnemonic names
- Allocated first-come, first served (usually)
- One of first areas of dispute over control
One form of control that is necessary (and possible) is the name service, which allocates Domain Names on the Internet. These are unique names for subnetworks, which allow easier (human) access to Internet addresses. So, instead of having to remember that Exeter's (numeric) addresses all begin 144.173, you can just use .ex.ac.uk at the end of a name. (We'll explain more about addressing in the next lecture). In the UK, these domain names (all ending in .uk) are managed by an organisation called Nominet.UK. It delegates some UK addresses to other organisations, such as UKERNA (forac.uk and .gov.uk addresses), but manages most itself.
Internet Protocol Adresses
- System of unique numbers needed to find each host
- Managed by the internet Assigned Numbers Authority (IANA)
Every computer, server and other device that connects to the internet needs an address to be
found, and these need to be unique across the whole of the network. Managing to keep these
unique and ordered is the job of IANA, the Internet Assigned Numbers Authority.
Other bodies and institutions
• Internet Society (ISOC)
• oversees other Internet organisations
• Internet Architecture Board (IAB)
• manages technical direction of the Internet
• Internet Engineering Task Force (IETF)
• standardises technical developments (through RFCs)
On a global level, things are more complex. Since the Internet grew primarily out of the United States, the bodies that control the Internet worldwide are organised from there. The main body is IANA, and as previously mentioned, this has overall control for assigning numeric addresses. Recently, a new corporation, called ICANN, the Internet Corporation for Assigned Names and Numbers, was set up to oversee this role and other important aspects of Internet governance. All of these organisations, and many more governing and researching aspects of the Internet, are members of the Internet Society, as shown in Figure 1.3, “The Internet Society Structure”.
-Who owns the Internet?-
- ISPs are charged by network providers for use of backbone
- ISPs sometimes own parts of backbone
- Government bodies also own parts (e.g. JANET)
- Internet traffic travels over many networks, separately owned.
