data-communication-and-networking-forouzan-5th-ed. FIFTH EDITION Data Communications and Networking Data Communications and Networking McGraw-Hill Forouzan Networking Series Titles by Behrouz A. Networks Models: Protocol Layering, TCP/IP Protocol suite, The OSI model Behrouz A. Forouzan, Data Communications and Networking 5E, 5th Edition, Tata.
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Technologies related to data communications and networking are among the MD Data Communications and Networking FIFTH EDITION Behrouz A. Forouzan. DATA. COMMUNICATIONS. AND. NETWORKING. Fourth Edition. Behrouz A. Forouzan. DeAnza College with. Sophia Chung Fegan. #. Higher Education. by Behrouz A. Forouzan will find a wide variety of resources available at the Online DATA COMMUNICATIONS AND NETWORKING, FOURTH EDITION The fifth part is devoted to the discussion of the transport layer of the Internet model.
This book presents highly technical subjects with more than figures from level 0 to level upper, without relying on complex formulations. This book starts with the described content of the network model and provides the user with a perfect introduction to data transfer. There's a lot of talks here about protocols and network physical structures. Data communication and networking are provided in a descriptive manner. Data communication and networking technologies may be the fastest growing in contemporary culture. This claim is demonstrated by the appearance of some new social networking applications.
A frame is a link-layer data unit. It encapsulates a data unit coming from the network layer. In this case, the data unit is a datagram. A user datagram is a transport-layer data unit.
It decapsulates a data unit going to the application layer. In this case, the data unit is a message. The data unit should belong to layer 4. In this case, it is a user datagram. The transport-layer packet needs to include two port numbers: source and destination port numbers.
The transport-layer header needs to be at least 32 bits four bytes long, but we will see in Chapter 24 that the header size is normally much longer because we need to include other pieces of information. At the application layer, we normally use a name to define the destinationcomputer name and the name of the file we need to access.
An example is something somewhere. At the network layer, we use two logical addresses source and destination to define the source and destination computers.
These addresses are unique universally. At the data-link layer, we use two link-layer addresses source and destination to define the source and destination connections to the link. The answer is no. It only means that each of the transport-layer protocols such as TCP or UDP can carry a packet from any application-layer protocol that needs its service. However, a transport-layer packet can carry one, and only one, packet from an application-layer protocol.
We do not need a link-layer switch because the communication in this case is automatically one-to-one. A link-layer switch is needed when we need to change a one-to-many communication to a one-to-one.
We do not need a router in this case because a router is needed when there is more than one path between the two hosts; the router is responsible for choosing the best path at each moment. Problems The services provided in part a and part b are the opposite of each other.
Layer 1 takes the ciphertext from layer 2, inserts encapsulates it in an envelope and sends it. Layer 1 receives the mail, removes decapsulates the ciphertext from the envelope and delivers it to layer 2. The services provided in part a and part b are the opposite of each other. Layer 2 takes the plaintext from layer 3, encrypts it, and delivers it to layer 1.
Ho wever, a tr an spor t-l a y e r packet can carry one, and on ly on e, pack et from an appli catio n-l a yer prot ocol. We do not need a link-layer sw itch because the communication in this case is au to ma ti call y on e- to -o ne. A link-layer switch is needed when we need to chang e a one-to-m a ny com mun icati on to a one-to-one. We do not need a router in this case because a router is needed when there is mo re t han one p a th between th e two ho st s; th e ro uter is responsi ble for choo s- ing the best path at each moment.
The se rvices provided in part a and part b are the opposite of each other. Layer 1 takes the ci phertext fro m l ay e r 2, in serts en capsulat es it i n an envel ope and sends it.
Layer 1 receives the mail, removes decap sulates the ciphertext from the envel ope and del ivers it t o layer 2. Layer 2 takes the plai ntex t fro m layer 3 , encrypts it, and deli vers it to lay er 1. Layer 2 takes th e ciph ertex t from la yer 1, decrypt s i t, and d e livers it t o layer 3. In 10 years, t he n um ber of hos ts becomes about si x times 1.
Thi s m eans the nu mber of ho sts co nnected t o the Internet is mo re than t hree bi lli on. The system tran smit s bytes for a byt e message.
The advantage of using large packets is less overhead. When using large pack- ets, the number of packets to be se nt for a huge file beco mes small. Since we are adding three headers to each pack et , we are sending fewer extra bytes than in the case in whic h the number of pac k ets is la rg e.
The disadva ntage manifests itself when a packet is lost or co rru pted du rin g the tran sm issio n; we need to resen d a large amo unt of data.
The netwo rk la yer is respon sible for ro ute determ inati on. The physical layer i s th e onl y l a yer that is co nnected to th e transmi ssio n med ia. The appl icat ion la yer provi des services for the end users. User datagrams are created at the tran sport laye r.
The da ta-lin k layer is responsible for handling frames between adjacent nod es. The physical layer is respo nsibl e for tran sformi ng bi ts to elect rom a gn et ic signals. There should be an upper- layer identifier in the header of th e IP p ro tocol t o defi ne to which u pper- layer prot ocol t h e encapsul a t e d packet b e long s. The iden tifier i s call ed t he protoco l fiel d See Figu re