COMPUTER NETWORKS
Computer Networks, a subject related to networks is a very interesting subject. Let us know something interesting about this subject which makes you feel comfortable with this. Let us make networks our everyday life which in turn gives an efficient way to use our systems. Go through this with zeal & an attitude to use this knowledge.
Units and description :-
There are total of 5 units in Computer Networks according to UPTU syllabus including basics of networks – the OSI model, the layers of OSI model, i.e., the Data Link Layer, Network Layer, Transport Layer, application Layer. All units of this subject are equally valuable as it helps you to give an overview about how the networks are being created & how data is transferred between systems.
A computer network or data network is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections. The connections (network links) between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.
In the 1st unit of basics about networking, there is an overview of networks, transmission media, the categories of network, i.e., LAN, MAN, & WAN; a brief history of internet; the protocols & standards. This unit gives us knowledge about how resources are shared between systems. After these basic concepts, unit jumps to the models of networks: the OSI (Open Systems Interconnection) model & the TCP/IP reference model. The OSI model has 7 layers:
1. Application Layer: Gives an interface between the sender & the model.
2. Session Layer: Makes a session between the sender & the receiver.
3. Presentation layer: Presents the data in an effective way. The main objective of this layer is data compression & translation.
4. Transport Layer: It is responsible for timely delivery of message from sender to receiver.
5. Network Layer: Main objective of this layer is inter networking & congestion control.
6. Data Link Layer: MAC addressing & error-free delivery of data.
7. Physical layer: Mainly concerned about the physical transmission of data.
8.
After that, the reference model, i.e., TCP/IP model having 4 layers including Application (works as the 3 upper layers of the OSI model), Transport (works same as in the OSI), Internet (the network layer of OSI), & the Network Interface Layer (containing data link & the physical layer of OSI).A huge comparison between these two is a basic & very important question for the basic & also for the examination point of view.
In the 2nd unit, there is a brief concept about the 2nd lowest layer of the OSI model, i.e., the data link layer. There are two layers within this layer: MAC (Medium access layer) & LLC (Logical link layer). The main objective of MAC layer is addressing (MAC address of 48-bit) & that of LLC is checking for timely & error-free delivery of data. Concept of various protocols are also discussed in this unit like ALOHA, FDDI, CSMA/CD & CSMA/CA. There is also a concept of IEEE standards.
3rd unit is about the network layer. This layer has 3 important working: Routing, Internet working, & congestion Control. It gives an idea of IP addressing & sub netting along the networks. This unit has a concept of how route is decided from sender to the receiver & which route is perfect for the data transfer at which time.
In the 4th unit, we have an overview of Transport layer. The purpose of Transport layer is to permit devices on the source and destination hosts to carry on a conversation. Transport layer defines the level of service and status of the connection used when transporting data. This unit also has a concept of cryptography (science of secret writing, transferring data from sender to receiver in such a way that only those can read that data who is intended to be the receiver). The main protocols included at Transport layer are TCP (Transmission Control Protocol) and UDP (User Data gram Protocol). After this, there is also an overview of Session & the Presentation layer. Main motive of Presentation layer is to present the data in a very attractive & effective way. The design issues with these layers are also discussed in this.
The last unit of this subject has a concept about the Application layer. This unit gives an overview of File transfer, Access management, working of e-mail, creating virtual private networks (VPN), virtual terminals. Application layer includes all the higher-level protocols like DNS (Domain Naming System), HTTP (Hypertext Transfer Protocol), Telnet, SSH, FTP (File Transfer Protocol), TFTP (Trivial File Transfer Protocol), SNMP (Simple Network Management Protocol), SMTP (Simple Mail Transfer Protocol) , DHCP (Dynamic Host Configuration Protocol), X Windows, RDP (Remote Desktop Protocol) etc.
This subject is a subject related to the networks which are shown in our everyday life. This needs ample time to clarify your concepts about this. But if anyone can read it with interest it can be completed in a few days but it only depends upon the interest of the reader.
The reference books according to UPTU for this subject are:
1. Forouzen, “Data Communication and Networking”, TMH
2. A.S. Tanenbaum, Computer Networks, Pearson Education
3. W. Stallings, Data and Computer Communication, Macmillan Press
4. Anuranjan Misra,
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