This is a Clilstore unit. You can .
Internet Protocol (IP) addresses are the unique numbers assigned to every computer or device that is connected to the Internet. Among other important functions, they identify every device connected to the Internet, whether it is a web server, smartphone, mail server, or laptop. After years of rapid Internet expansion, the pool of available unallocated addresses for the original Internet Protocol, known as IPv4, has been fully allocated to Internet Services Providers (ISPs) and users. That’s why we need IPv6, the next generation of the Internet protocol that has a massively bigger address space than IPv4.
What is an IP address ?
“IP address” is a shorter way of saying “Internet Protocol address.” IP addresses are the numbers assigned to computer network interfaces. Although we use names to refer to the things we seek on the Internet, such as www.example.org, computers translate these names into numerical addresses so they can send data to the right location. So when you send an email, visit a web site, or participate in a video conference, your computer sends data packets to the IP address of the other end of the connection and receives packets destined for its own IP address.
Why do we need IP addresses ?
IP addresses are the numbers that enable our computers, servers, telephones, cameras, printers and sensors to communicate with each other. Without IP addresses, we would have to copy data from device to device manually, using CDs, DVDs, hard disks or flash storage, such as a USB drive. But more importantly, our devices could not send data to each other without human intervention. Without the IP addresses assigned to our computers, we would have to send paper letters and memos instead of sending emails. There would be no streaming video sites. Instead, we would have to send each other discs and tapes. Worst of all, we would not be able to order items online and would have to go to stores to buy them in person. It would be horrific, like the 1970s all over again.
Activity 1. Watch the following video and answer:
What is the di fference between a private IP address and a unique IP address ?
Private addresses are the addresses people use on private networks, such as many home and office networks. At a protocol level there is no difference between the addresses, but organizationally, private addresses are distinct because they can only be used within a single administration and not on the wider Internet. This is because private addresses are set aside for use by anyone without any global coordination. You can know an address is from a block of private addresses if it:
■ Begins with 10. (i.e. 10.0.0.0 through 10.255.255.255)
■ Begins with 172.16. through 172.31.
■ Begins with 192.168.
These addresses are the defaults used in a lot of plug’n’play networking equipment, like that sold to residential Internet users. Unique addresses are different only in that their distribution is managed by a set of registries. Because the registries manage the distribution of the other addresses, it is possible to know who an address is assigned to and how to get in contact with them. These types of addresses allow data to be routed across the whole Internet.
If your computer is assigned a private address, but you can still access services over the Internet, then your computer is probably behind a Network Address Translator (NAT), which lets lots of computers share a single unique IP address.
Activity 2.
Find information about NAT and write down a brief explanation about its use.
Why does every device need an IP address?
IP addresses are the numbers that identify devices connected to a network. If your device only needs access to a local network, it can be identified with an address that has only a local context. These are called private addresses. But when your device needs to access services on other networks, it needs to use a unique address. In some cases, this is done by translating a private address into a unique address at the border between your network and your ISP’s network. This technology is called Network Address Translation, or NAT.
NAT has the advantage of allowing multiple devices to share a single, unique address, but it also has disadvantages. One of these is that the device doing the NAT must understand the protocol being used by the devices communicating through it. If the protocol you want to use is not supported by the NAT, you cannot use it.
This can cause frustration when, for instance, you are unable to use your Voice over IP (VoIP) servicefrom a hotel or airport lounge while travelling. But there is also a second problem. If a new NAT device does not support a protocol, it will stop the people using the network it serves from also using that protocol, unless it is replaced. This stifles innovation in the services that can be provided over the Internet. Losing innovation means losing access to new services that could enrich our lives. But the variability in the protocols supported by NATs means that services often either work or break depending on the equipment used by the network operator, not by the setup on the individual user’s computer.
When IP was first standardized in September 1981, the specification required that each system attached to an IP-based Internet be assigned
a unique, 32-bit Internet address value. Systems that have interfaces to more than one network require a unique IP address for each network
interface. The first part of an Internet address identifies the network on which the host resides, while the second part identifies the particular
host on the given network.
Class A Networks (/8 Prefixes)
Each Class A network address has an 8-bit network prefix, with the highest order bit set to 0 (zero) and a 7-bit network number, followed by a 24-bit host number. Today, Class A networks are referred to as “/8s” (pronounced “slash eight” or just “eights”) since they have an 8-bit network prefix.
A maximum of 126 (27 -2) /8 networks can be defined. The calculation subtracts two because the /8 network 0.0.0.0 is reserved for use as the default route and the /8 network 127.0.0.0 (also written 127/8 or 127.0.0.0/8) is reserved for the “loopback” function. Each /8 supports amaximum of 224 -2 (16,777,214) hosts per network. The host calculation subtracts two because the all-0s (all zeros or “this network”) and all-1s (all ones or “broadcast”) host numbers may not be assigned to individual hosts.
Since the /8 address block contains 231 (2,147,483,648 ) individual addresses and the IPv4 address space contains a maximum of 232 (4,294,967,296) addresses, the /8 address space is 50 percent of the total IPv4 unicast address space.
Class B Networks (/16 Prefixes)
Each Class B network address has a 16-bit network prefix, with the two highest order bits set to 1-0 and a 14-bit network number, followed by a 16-bit host number. Class B networks are now referred to as “/16s” since they have a 16-bit network prefix.
A maximum of 16,384 (214 ) /16 networks can be defined with up to 65,534 (216-2) hosts per network. Since the entire /16 address block contains 230 (1,073,741,824) addresses, it represents 25 percent of the total IPv4 unicast address space.
Class C Networks (/24 Prefixes)
Each Class C network address has a 24-bit network prefix, with the three highest order bits set to 1-1-0 and a 21-bit network number, followed by an 8-bit host number. Class C networks are now referred to as “/24s” since they have a 24-bit network prefix.
A maximum of 2,097,152 (221 ) /24 networks can be defined with up to254 (28-2) hosts per network. Since the entire /24 address block contains 229 (536,870,912) addresses, it represents 12.5 percent (or oneeighth) of the total IPv4 unicast address space.
Activity. Go on and try Classful IP Exercises 2.
Short url: https://multidict.net/cs/5271