Internet Protocol And Transmission Control Protoco

Published Date: 02 Nov 2017

Kantiyok D

School of Engineering, Design and Technology

University of Bradford

d

Abstract - The internet is the most common means by which information is shared. The internet from its inception functions using Transmission Control Protocol/Internet Protocol (TCP/IP) which is the basic communication language it understands. TCP/IP while distributing packets to and from different devices on the internet also assigns addresses to the devices for easy identification. The IP has been modified and restructured over the years to suit the activities they perform and improve effectiveness in the way information is distributed over the internet. These modifications and reconstructions have led to the introduction of various versions that handle different operations. The IP version currently in use is the IPv4. With the ever growing number of computers and mobile devices joining the internet community, Internet Protocol version 6 (IPv6) is fast becoming a welcome solution to the shortcomings of the existing internet protocols. This is because the addressing system IPv6 offers is large enough to accommodate more devices compared to the IPv4.

This work analyses the Internet Protocol (IP) and the shortcomings IPv6 has been developed to address. This will be done by analysing the IP to grasp the need for IPv6

Keywords: IPv6, IPv4, Internet, TCP/IP, Addresses

INTRODUCTION

As of 2012 a survey by Microsoft Tag revealed that there are over 4 billion mobile phone users around and this does not include the numerous laptops and desktops in use [12]. Imagine 4 billion mobile phones on the internet, now include the numerous laptops, desktops, androids and other internet devices also connected to the internet. With today’s multiplicity of Internet-connected devices per person, 4 billion IP addresses available is clearly not enough. Although IPv4 was effective and robust at the time of its inception it did not anticipate the need for security at the IP level, easier configuration, the on-going exponential growth of the internet and support for real time delivery of data in terms of quality of service [3].

IPv6 is not a new protocol instead it is an evolution of IPv4. It has been around since the early 2000s. It was developed for addressing the shortage of the IPv4’s address system that was not deemed possible at that time [1]. IPv4 is a 32-bit addressing system that was sufficient for internet use from its inception but due to the fast growing population of internet users and devices, the need for a larger addressing system arose. This led to the emergence of IPv6.

INTERNET PROTOCOL AND TRANSMISSION CONTROL PROTOCOL (TCP/IP)

Over the years, TCP/IP has continued to evolve to meet the needs of the Internet and also smaller, private networks that use the technology. The history of TCP/IP and the Internet are closely related. It is not possible to talk about one without the other because they were developed together by the United States Defence Advanced Research Projects Agency (DARPA or ARPA). TCP/IP was initially developed in the 1970s as part of an attempt to define a set of technologies to operate the immature Internet [5]. Though TCP and IP are two protocols with some differences they are commonly referred to as TCP/IP. This is because TCP is an upper-layer protocol from the IP point of view, TCP is one of the two original components of the suite that complements the Internet Protocol (IP) and provides the mechanism for implementing the internet. Though TCP and IP function as a team they have some differences that enable them operate independently. While IP transmit data between individual devices on the internet, TCP transfers data between two actual applications running on these two devices. IP assigns addresses to computer's network interface, TCP uses a port number as its address. TCP is connection oriented while IP is connectionless, meaning no connection is needed to be established between devices before data can be sent [5]. TCP/IP are used by major internet applications like the World Wide Web (WWW), file transfer, email and remote administration [3]. For the purpose of this paper, we are more interested in IP.

Fig 1 TCP/IP model

INTERNET PROTOCOL (IP)

The acronym Internet Protocol was derived from the name InterNet Protocol, that is, a protocol connecting different network interfaces. Internet Protocol is the core protocol of the internet protocol suite. IP is the main protocol at the network layer in the TCP/IP structure. It is the means by which data is sent between devices on an internetwork with help from other protocols. IP has multiple functions and characteristics with the main function being its ability to assign addresses and deliver data known as datagram between devices on unconnected networks. This process is sometimes called internetwork datagram delivery [2]. Here are the major functions of IP:

I. Addressing

Just like in real life cases where a courier service company like DHL delivers parcels to different clients, they need the recipient’s address for easy location and delivery. Without the appropriate address the parcel may likely not get to its destination. IP system is structured to assign unique addresses for devices across large networks and facilitate delivery of packets when necessary [2] [4].

II. Data Encapsulation and Packaging

As part of the TCP/IP network layer protocol, IP receives data from the TCP protocol, encapsulates the data into datagrams using a unique format and sends the datagram to its destination across the network. This function enables IPv4 datagrams transmissible on IPv6 protocols.

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III. Fragmentation and Reassembly

The maximum size required for packets to pass through different layers varies. IP fragments the packets into little bits, so that they can be accommodated on the network. The destination host then reassembles the packets back to its original size [5].

IV. Routing and Indirect Delivery

IP routes datagrams from source to destination host on the same network. In cases where the source and destination hosts are on different network interfaces, the datagram is delivered indirectly. IP, using the support of Internet Control Message Protocol (ICMP) and other protocols accomplishes through intermediate devices [2].

IV. Routing and Indirect Delivery

IP routes datagrams from source to destination host on the same network. In cases where the source and destination hosts are on different network interfaces, the datagram is delivered indirectly. IP, using the support of Internet Control Message Protocol (ICMP) and other protocols accomplishes through intermediate devices [2].

Fig2.IP interfaces for common network devices [2]

IP Versions

There are two versions of the IP: version 4 and 6.

A. Internet Protocol version 4 (IPV4)

IPv4 is the version that has been in use since the inception of the internet. Some characteristics of IPv4 are addressing, address type, routing, classful network and configuration among others.

Addressing

The total number of IPv4 addresses available is 232 or 4,294,967,296 addresses [6]. The IPv4 addresses have been able to last this long because they are reused and reassigned as devices were connected and disconnected from a network.

Network Interface Identification

IP addressing is regarded as the most important function of the IP because it delivers datagrams across an internetwork and it does so using addresses. With IP addressing unique identification is provided for every interface between a device and network. In order not to get things mixed up, it is important to note that IP is a protocol that is strictly associated with the network layer and so addresses various network interface not physical devices [6].

Size and Format

IP address is a 32-bit binary number that can be represented in decimal, hexadecimal or binary form. They are commonly expressed by dividing the 32 bits into four bytes with a dot used to separate them. The dotted notations provide a convenient way to operate with IP addresses especially when communicating with people. Computers understand no other language except that of zeros and ones, hence the need for binary expressions. In order to function properly when configuring IP addresses, this binary numbers have to be converted to decimal and hexadecimal. The IP address is structured to identify a local network and a computer in the local network [5].

Fig 3. IPv4 address representation [2]

Classful Network

IP address consists of two parts: one which identifies the network and the other, the host or node. There are five address classes namely class A, B ,C, D and E;

Class A

Class A binary addresses begins with 0, therefore, the decimal number can be from 1 to 126.

The first octet of an IP address identifies the network while the remaining three octet indicates the host within the network. The total number of networks will be 128 (27) and 16,777,216 (224) addresses per network.

For example, if 102.168.212.226 is a class A address, 102 addresses the network while 168.212.226 is for the hosts within the network.

Class B

The binary addresses for B begins with 10, therefore, the decimal number can be from 128 to 191. The first two octet identify the network while the remaining two identify hosts within the network. The total number of networks will be 16,384 (214) and 65,536 (216) addresses.

Using the address above, 102.168 identifies the network. While 212.226 is for hosts in the network [8].

Class C

Here the binary addresses start with 10 which allows the decimal number from 192 to 223. The first three octet identify the network, while the last octet identifies the host. The total number of networks will be 2,097,152 (221) and 256 (28) addresses.

Using the same address as classes A and B, 102.168.212 represents the network while 226 represents the host.

Class D

The binary addresses begin with 1110, therefore, the decimal number can be from 224 to 239. The class D networks are used mainly to support multicasting.

Class E

The binary addresses start with 1111, therefore the decimal number can be anywhere from 240 to 255. This class networks are used for experimental purposes and have never been used in a standard way. [5][10]

Routing

When addresses have been assigned, the datagrams are sent to their destinations. In cases where the source and destination are not on the same network, intermediate systems are used to deliver the datagrams. This is where routing comes in. The device used for routing on the internet is called a Router. IP addressing ensures that devices such as computers, laptops and printers get one IP address except routers, bridges and other network devices that get more than one address due to multiple functions performed [2][5].

Configuration

At this point it is imperative you know that addresses can be set up as either configures static or dynamic.

Static configuration - in the sense that each device is manually configured with an address that doesn’t change and is adopted by organizations that run small networks [2].

Dynamic configuration - is used by organisations that function on larger networks. The thought of manually setting IP addresses for every single device is exhausting. Dynamic configurations permit addresses to be assigned automatically and changed under software controls. BOOTP and DHCP are host configuration protocols that were created to perform the latter function [2].

Address Types

Unicast - Communication between a single sender and a receiver is known as Unicast. Datagrams sent to a unicast address are delivered to the node containing the interface identified by the address.

Multicast – Communication between a sender and multiple receivers is Multicast. They are addresses that belong to a group of host on a network. A message sent goes to all the host.

Anycast – communication between a sender to the nearest group of receivers in a network is Anycast. It is used when a packet must be sent to any host of a group, but does not need to be sent to all of them. The packet usually gets to the nearest host of the group [7].

IP Header

The IPv4 header includes checksum, which is a mechanism for protecting packets against data corruption during transmission.

Fig 4 IPv4 header.

B. Internet Protocol version 6 (IPv6)

IPv6 is also known as Internet Protocol next generation (IPng). IPV6 is an internet protocol Apart from the larger address space IPv6 has solved, here are some motivations for creating IPv6:

Address Space

Compared to IPv4’s 4,294,967,296 addresses IPv6 provides 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses which would not get exhausted anytime soon. IPv6 addresses are 128 bits long that came along with improved architecture. It is represented as eight groups of four hexadecimal digits separated by colons [11]. Binary and decimal representation of the IPv6 address is long and cumbersome, hence the use of hexadecimal representations.

For example 2001:0db8:85a3:0042:1000:8a2e:0370:7334.

Easier TCP/IP Administration

Resolving some labour intensive functions of IPv4 such as the need to configure IP addresses were what the developers hoped to achieve. Even though tools like DHCP eliminate the need to manually configure many hosts, it only partially solves the problem. IPv6 has been designed to make TCP/IP management more efficient and flexible especially for large installations, through its auto configuration capabilities [14]

Better support for Security

IPv4 was originally designed for remote military activities without security in mind before it was adopted as a public network. As technology advanced, so did the activities and applications on the network which demanded on-time delivery and increased security. Developing and integrating security features into the already functioning IPv4 technology (whose security support was the IP header checksum) was going to be costly, time consuming and error prone hence the need for IPv6 [9]. To support security, IPSEC feature has been built into IPv6 to ensure authentication and encryption of packets.

Support for mobility

IPv6’s mobile IP protocol enables mobile devices remain reachable irrespective of location. When IPv4 was created mobile invasion on the internet was not anticipated. In mobile IP, two addresses bound to each other are assigned to a host: a home address which identifies the host and a care-of address which provides information about the host’s current location. When the mobile moves to a current location, it must send its new address to an agent at home so that the agent can channel all packets to its new address timely [16].

Support for multicasting

IPv6 fully supports multicasting which is optional in IPv4. Multicast allows packets that consume bandwidth flows, for example, multimedia streams to be sent to multiple destinations simultaneously, saving network bandwidth [9].

Support for Quality of Service (QoS)

IPv6 datagrams include QoS features that allow for better support for multimedia and other applications that require QoS. It ensures that high priority is given to certain packets that need to arrive at their destination in a timely manner. For example, music or video streaming or Voice over IP (VoIP) [11].

Internet of Things (IoT)

Mobile devices, laptops and PCs have IP addresses which enable them identify and communicate with each other on the internet. Imagine a community where things and objects also have addresses which enable them communicate and interact with each other though wireless technology. That brings about the concept of the Internet of Things. By being connected, thing’s information can be shared on a global scale. Internet of Things is a new type of Internet application which uses a variety of information sensing identification devices and processing equipment such as Global Positioning Systems (GPS), Radio frequency identification (RFID) and Geographic Information System (GIS) to create an extensive network (Fan and Zhou, 2011). With IPv6 there are many addresses to support the internet of things technology.

TRANSITION FROM IPV4 TO IPV6

Transition from IPv4 to v6 is gradually taking place as plans to fully adopt IPv6 is in motion. Since the early 2000 devices and networking infrastructures have been built to function with IPv6 while still supporting IPv4 software. The two protocols will co-exist for some time before IPv6 fully takes over. As devices are built with both IPv4 and v6 technologies one may wonder how then it is possible for them to interact on the internet. The mechanisms below handle interoperability of devices that support different protocols [5].

Dual Stack Mechanism

This mechanism is based on Dynamic Host Configuration Protocol v6 (DHCPv6) protocol which temporarily assigns IPv4 addresses to IPv6 hosts that wish to communicate with IPv4 host. Any host that needs to communicate in either IPv4 or IPv6 network has to maintain both stacks on its network interface [5] [2].

Tunnelling Mechanism

In this mechanism devices that do not have full IPv6 capable technologies may be able to communicate by encapsulating IPv4 packets into IPv6 and vice versa. Once integrated they are transferred through a DTI interface within the IPv6 network to the Border Router which interconnects with the IPA network [5] [2].

What ever happened to IPv5?

Am sure at some point in this paper one may wonder what happened to IPv5. Over time we have heard a lot about IPv4 and 6, what about 5. Well IPv5 does exists. It is known as Internet Stream Protocol (ST2). IPv5 was compatible with IP at the network layer but was built to provide a Quality of Service for streaming services. It was developed to provide end-to-end guaranteed service across a network, that is, for transmission of voice, video, and distributed simulation. The protocol was never introduced to the public [3] [14].

CONCLUSION

Just like in the car industry, changes have been made on vehicles to suit customer taste. Changes can be made to the tires, interior and even shape of the cars but at the end of the day the cars still have engines, steering and fuel pumps to function more effectively. As much as IPv6 has emerged with better features to enhance communication on the internet, its emergence underwent and is still going through series of transformation to meet up with the high demand for internet efficiency. According to Cisco by the end of 2013, there will be more devices on earth than humans [11], but I am certain that IPv6 is well capable of handling any form of challenges the future internet holds.

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