DATA COMMUNICATIONS 10-1 Communication Basics Computer communications is at three levels – Application level – Computer level – Communication channel Protocol – Set of rules for communications – OSI Standard 10-2 OSI Reference Model Layer 7 6 5 4 3 2 1 Name Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer Purpose Application-to-application communication Manage data representation
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telephone or cable companies‚ but a LAN does not. ← All WAN implementations generally use the same Layer 2 protocol but there are many accepted LAN Layer 2 protocols in use. 1.1.3 The Evolving Network Model Which statement is true of the functionality of the layers in the hierarchical network model? ← The purpose of the access layer is to provide very high bandwidth communications between network devices. ← Most security screening to prevent unauthorized entry to the network happens at
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Transmission Control Protocol and Internet Protocol Currently‚ About 2.4 billion people use the internet‚ yet there probably is only a small percentage who understands how the internet sends information or where the technology to send the data originated. (Miniwatts Marketing Group‚ 2008) In 1973‚ a paper titled "A Partial Specification of an International Transmission Protocol" was written by Vint Cerf. This paper included a system for more efficiently transmitting information across a network
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CCNA Chapter 1 OSI 7 layer model Application File‚ Print‚ database‚ apps‚web Presentation Encryption‚ compression‚ translations‚ ebdic etc. Session Dialog control - nfs‚ sql‚ rpc ‚ Connection establishment‚ data transfer‚ connection release Transport End to end connection‚ Flow control‚ Data integrity‚ Retransmissions Segments re-ordered before delivery‚ Make / tear down virtual circuits Network Routing ‚ Map of network (logical) Data Link Framing Ensures messages delivered to correct
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• Question 1 5 out of 5 points Which of the following files is edited to block a search engine’s bots from indexing an organizational Web site? Selected Answer: robots.txt Answers: lmhosts.txt robots.txt host.txt index.txt • Question 2 5 out of 5 points Web resources used to footprint a company include all but which one of the following? Selected Answer: Request for Comments (RFC) archive Answers: Internet archive SEC EDGAR Company Web site Request for Comments
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Christopher C. Johnson Course: NT1210 – “Introduction to Networking” Assignment: Unit 3 Assignment 1: Networking Models Review Due Date: 7/17/2014 Instructor: Mr. Greg Tarver Chapter # 3 / Review 1.) A. 2.) A. / C. 3.) A. / C. 4.) C. / D. 5.) C. / B. 6.) A. / B. 7.) D. 8.) B. 9.) B. 10.) B. 11.) C. 12.) B. 13.) C. 14.) A. / C. 15.) C. 16.) C. / D. 17.) D. 18.) A. / C. 19.) A. / C. 20.) B. / C. / D. Key Terms TCP/IP network - is the basic communication language
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Security and the OSI Model Network security is a topic that reaches far beyond the realm of firewalls‚ passwords‚ and user ID accounts. For a network and data to remain secure there must be protective measures at each level in the OSI interconnect model. While each layer basically operates autonomously of the other it is important to ensure that the data being transmitted from the host to destination has not been tampered with or is being prevented from reaching its destination. There are
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DEPARTMENT OF ECE Year /SEM : III / VI SUBJECT : COMPUTER COMMUNICATION AND NETWORKS Question Bank UNIT I 1. Write about the Evolution of data networks. 2. Explain the various topologies in networking. 3. Explain the ISO – OSI layer model of data communications. 4. Explain the Physical layer functions and various Wired media in detail. 5. Differentiate the connection oriented and connection less data service. 6. Explain the radio wave communications in detail. UNIT II 1
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a laser as a light source. Multimode fiber cables carry signals from multiple connected sending devices. SC-ST patch cords are used with multimode fiber cables. SC-SC patch cords are used with multimode fiber cables.* 3 Which layer of the OSI model is responsible for specifying the encapsulation method used for specific types of media?
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circuit. O 313-315 Switched circuit is created on demand as needed. Dedicated Circuit – Constant Circuit between two specific devices. 5. What is the purpose of a router? O 318 Forward Packets at Layer 3 6. At what layer of the OSI model does a router function? O 318 Layer 3 7. What is the process of adding headers and trailers called? O 319-320 Encapsulation 8. Name the three main categories of WAN topologies. O 321-324 Point-to-point‚ HUB and Spoke/Star‚
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