Q1. Differentiate between internet protocol and transport protocol with the help of examples. (10 Marks)
Solution:-
Internet Protocol
The Internet Protocol (IP) is the principal communications protocol used for relaying datagrams (packets) across an internetwork using the Internet Protocol Suite. Responsible for routing packets across network boundaries, it is the primary protocol that establishes the Internet.
IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering datagrams from the source host to the destination host solely based on their addresses. For this purpose, IP defines addressing methods and structures for datagram encapsulation.
Historically, IP was the connectionless datagram service in the original Transmission Control Program introduced by Vint Cerf and Bob Kahn in 1974, the other being the connection-oriented Transmission Control Protocol (TCP). The Internet Protocol Suite is therefore often referred to as TCP/IP.
The first major version of IP, now referred to as Internet Protocol Version 4 (IPv4) is the dominant protocol of the Internet, although the successor, Internet Protocol Version 6 (IPv6) is in active, growing deployment worldwide.
TRANSPORT PROTOCOLS
Q2. Describe the pros and cons of NAT? (10 Marks)
Solution:-
Network Address Translation (NAT) Pros & Cons
by Kaushik Das
Introduction
Network Address Translation or NAT is a technique that allows the translation of local network addresses or the internal IP addresses (used within an organization) into globally unique IP addresses that help identify an online resource in a unique manner over the Internet.
The process is also referred to as Network Masquerading or the Native Address Translation. Network Address Translation allows multiple resources within an organization or connected to a local LAN to use a single IP address to access the Internet.
The idea of Network Address Translation is very simple indeed. It essentially abstracts internal addressing from the global IP addressing used over the Internet. This abstraction allows helps the network resources to get over a shortage of the address space by mapping relatively few real IP addresses to the abundant local IP addresses created locally by the Proxy server for addressing purposes. It allows the use of different addresses over the local and global level and local sharing of IP addresses over the Internet.
An increasing usage of the Network Address Translation was a direct result of the limited address space offered by the erstwhile Internet protocols such as the IPv4 that carried the bulk of the Internet traffic. NAT became a popular mechanism to overcome the shortage of unique IP addresses for individual network resources over the Internet. The Network Address Translation protocol maps the internal addresses to the real IP addresses that are required for communication process over the Internet.
Types of NAT:
1.Full Cone NAT The term Full Cone NAT is also commonly referred known as one-to-one NAT. Full Cone NAT allows the mapping of various external (non local) address ports to the corresponding internal addresses ports in a symmetrical manner.
2.Restricted Cone NAT This allows the local IP address and port number to be mapped to a particular external IP address and port number respectively. The relative mapping in the internal and external domains is not disturbed in the Restricted Cone network address translation.
3.Port restricted cone NAT As the name suggests, the Port restricted cone NAT restricts the port numbers that are used for communication purposes over the Internet. All the external communication is directed to particular communication port except if there is a continuous communication with an application over a specific communications port.
4.Symmetric NAT The communication process directed outwards is mapped to a unique external IP address along with a port number. This scheme imparts a logical symmetry to the process of external network access by the resources connected to the LAN.
In actual practice a pure NAT implementation is rarely used. Rather, a combination of the above types is implemented to achieve the desired network configuration. NAT offers the following advantages to the network users:
1.The Network Address Translation process offers a simple yet effective solution to the nagging problem of limited address space offered by the contemporary network protocols such as the IPv4. The NAT process generates sufficient IP addresses to be used locally that are subsequently mapped to the real IP addresses for communications over the Internet.
2.A lack of complete bi-directional connectivity offered by NAT is desirable in certain situations as it restricts direct access to the LAN resources. Allocation of a static IP address makes the network resource a potential target for hackers. The presence of an intermediate Proxy server makes the situation tricky.
The usage of NAT also carries certain drawbacks:
1.Network Address Translation does not allow a true end-to-end connectivity that is required by some real time applications. A number of real-time applications require the creation of a logical tunnel to exchange the data packets quickly in real-time. It requires a fast and seamless connectivity devoid of any intermediaries such as a proxy server that tends to complicate and slow down the communications process.
2.NAT creates complications in the functioning of Tunneling protocols. Any communication that is routed through a Proxy server tends to be comparatively slow and prone to disruptions. Certain critical applications offer no room for such inadequacies. Examples include telemedicine and teleconferencing. Such applications find the process of network address translation as a bottleneck in the communication network creating avoidable distortions in the end-to-end connectivity.
3.NAT acts as a redundant channel in the online communication over the Internet. The twin reasons for the widespread popularity and subsequent adoption of the network address translation process were a shortage of IPv4 address space and the security concerns. Both these issues have been fully addressed in the IPv6 protocol. As the IPv6 slowly replaces the IPv4 protocol, the network address translation process will become redundant and useless while consuming the scarce network resources for providing services that will be no longer required over the IPv6 networks.
by Kaushik Das
Introduction
Network Address Translation or NAT is a technique that allows the translation of local network addresses or the internal IP addresses (used within an organization) into globally unique IP addresses that help identify an online resource in a unique manner over the Internet.
The process is also referred to as Network Masquerading or the Native Address Translation. Network Address Translation allows multiple resources within an organization or connected to a local LAN to use a single IP address to access the Internet.
The idea of Network Address Translation is very simple indeed. It essentially abstracts internal addressing from the global IP addressing used over the Internet. This abstraction allows helps the network resources to get over a shortage of the address space by mapping relatively few real IP addresses to the abundant local IP addresses created locally by the Proxy server for addressing purposes. It allows the use of different addresses over the local and global level and local sharing of IP addresses over the Internet.
An increasing usage of the Network Address Translation was a direct result of the limited address space offered by the erstwhile Internet protocols such as the IPv4 that carried the bulk of the Internet traffic. NAT became a popular mechanism to overcome the shortage of unique IP addresses for individual network resources over the Internet. The Network Address Translation protocol maps the internal addresses to the real IP addresses that are required for communication process over the Internet.
Types of NAT:
1.Full Cone NAT The term Full Cone NAT is also commonly referred known as one-to-one NAT. Full Cone NAT allows the mapping of various external (non local) address ports to the corresponding internal addresses ports in a symmetrical manner.
2.Restricted Cone NAT This allows the local IP address and port number to be mapped to a particular external IP address and port number respectively. The relative mapping in the internal and external domains is not disturbed in the Restricted Cone network address translation.
3.Port restricted cone NAT As the name suggests, the Port restricted cone NAT restricts the port numbers that are used for communication purposes over the Internet. All the external communication is directed to particular communication port except if there is a continuous communication with an application over a specific communications port.
4.Symmetric NAT The communication process directed outwards is mapped to a unique external IP address along with a port number. This scheme imparts a logical symmetry to the process of external network access by the resources connected to the LAN.
In actual practice a pure NAT implementation is rarely used. Rather, a combination of the above types is implemented to achieve the desired network configuration. NAT offers the following advantages to the network users:
1.The Network Address Translation process offers a simple yet effective solution to the nagging problem of limited address space offered by the contemporary network protocols such as the IPv4. The NAT process generates sufficient IP addresses to be used locally that are subsequently mapped to the real IP addresses for communications over the Internet.
2.A lack of complete bi-directional connectivity offered by NAT is desirable in certain situations as it restricts direct access to the LAN resources. Allocation of a static IP address makes the network resource a potential target for hackers. The presence of an intermediate Proxy server makes the situation tricky.
The usage of NAT also carries certain drawbacks:
1.Network Address Translation does not allow a true end-to-end connectivity that is required by some real time applications. A number of real-time applications require the creation of a logical tunnel to exchange the data packets quickly in real-time. It requires a fast and seamless connectivity devoid of any intermediaries such as a proxy server that tends to complicate and slow down the communications process.
2.NAT creates complications in the functioning of Tunneling protocols. Any communication that is routed through a Proxy server tends to be comparatively slow and prone to disruptions. Certain critical applications offer no room for such inadequacies. Examples include telemedicine and teleconferencing. Such applications find the process of network address translation as a bottleneck in the communication network creating avoidable distortions in the end-to-end connectivity.
3.NAT acts as a redundant channel in the online communication over the Internet. The twin reasons for the widespread popularity and subsequent adoption of the network address translation process were a shortage of IPv4 address space and the security concerns. Both these issues have been fully addressed in the IPv6 protocol. As the IPv6 slowly replaces the IPv4 protocol, the network address translation process will become redundant and useless while consuming the scarce network resources for providing services that will be no longer required over the IPv6 networks.
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