This website uses cookies to ensure you have the best experience. Learn more

Data Communications Essay

1198 words - 5 pages

COMP2330 Data Communications and Networking
Written Assignment 1

Sample Solutions
1. Which of the OSI layers handles each of the following: (a) Dividing the transmitted bit stream into frames. (b) Determining which route through the subnet to use.
(10 marks)
(a) Data Link Layer
(b) Network Layer
2. An image is 1024x768 pixels with 3 bytes/pixel. Assume the image is uncompressed. How long does it take to transmit it over a 56-kbps modem channel? Over a 1-Mbps cable modem? Over a 10-Mbps Ethernet? Over 100-Mbps Ethernet? ...view middle of the document...

5. We have a message D = 1010001101 (10 bits). Using a predetermined divisor P = 110011 (6 bits), please find the FCS (frame check sequence) using CRC technique. (15 marks)
The FCS is 01110.
Remark: if your answer is “1110”, you will be wrong because the length of FCS is exactly 5 bits, i.e., one bit less than the length of the divisor P.

6. Isn Sliding-Window flow control, suppose k bits are used to specify the sequence
numbers of frames. It can support the range of sequence numbers from 0 to 2k-1.
Explain, by an example, why the maximum window size can not exceed 2k-1.

Ans: We consider the Go-back-N scheme which is based on sliding window flow control. Suppose k=3, i.e., a 3-bit sequence number is used to denote the frames. Suppose a sender sends frame 0 and gets back an RR1 from the receiver. Suppose window size is 23=8. The sender continues to send frames 1, 2, 3, 4, 5, 6, 7, 0 in its window and get another RR1. However, the sender does not know the meaning of this RR1. It could mean that all eight frames are received correctly and the RR1 is a cumulative acknowledgement. It could also mean that all eight frames are damaged or lost in transmit, and the receiver is repeating its previous RR1. Therefore, window size should be less than 23.

7. A channel has a data rate of R bps and a propagation delay of t s/km. The distance between the sending and receiving nodes is L km. Nodes exchange fixed-size frames of B bits.
What is the propagation time?
What is the frame transmission time?
How to set the window size to achieve the maximum channel utilization in the Sliding-Window flow control? (15 marks)
Propagation time (in seconds): t*L
Frame transmission time (in seconds): B/R
In order to achieve the maximum channel utilization, the window size should be at least . The notation means the smallest integer greater than or equal to x.

8. Suppose Selective-Reject ARQ is employed in error control. Explain, by example, how to deal with the case that RR message is damaged.
Suppose receiver gets frame i and replies sender RR-(i+1) which is lost or damaged. If sender receives the next acknowledgement, i.e., RR-(i+n), before its timer expires, transmission resumes without errors. If sender’s timer expires, it sends a request to receiver asking for instructions. The receiver receiving this request will send sender a new RR which indicates the next frame it expects.

9. Explain the basic idea of the Statistical Time Division Multiplexing.

Other Papers Like Data Communications

Distributed Database Essay

885 words - 4 pages Distributed database is one in which multiple database sites are linked by a communications system in such a way that the data at any site is available to users at other sites. Depending on the needs of an organization the following reasons would be why they would have the needs of distributed databases: * Improved reliability. A distributed system is more reliable than a centralized one, because processing is done at several sites, so

Data Management Policy Essay

2611 words - 11 pages       Responsible for understanding legislation and University policies surrounding data e.g., privacy, protected disclosures, communications, official information, records management, as well as consequences of misuse of data, the legal and administrative consequences of maintaining and disseminating data within their custody. Responsible for corporate use of data, in both uploading and downloading data. Responsible for data quality. Responsible for

Reliance Plan

952 words - 4 pages problematic. Compared to Reliance’s previous database system, the Greenplum system reduced the average time to load a day’s worth of data by over 90 percent, from 2 hours to under 10 minutes. Deploying the Greenplum solution improved response times and mitigated Reliance’s risk of non-compliance. Reliance Communications has established a panIndia, next generation, integrated (wireless and wireline), convergent (voice, data and video) digital network

Verizon Wireless

1515 words - 7 pages Department of Justice.  The merger combined the extensive infrastructure of Bell Atlantic with the advanced data communications ability of GTE (“(History Of Verizon Communications, 2007) Verizon Communications was created on a scale to compete as a top-level telecommunications company.  The business was divided into four separate sectors that included a separate sector for domestic wireless communications and international communications. On April 3

Telco Strategies, Investments and Use Cases of Big Data and Analytics

665 words - 3 pages sector is colossal and there is a clear opportunity for communications service providers (CSPs) to analyze this data themselves and also, subject to legal and regulatory conductions, to sell it to other organizations. Telecoms operators are embracing big data analytics (BDA) with enthusiasm, but while many report that BDA is fully operational and already contributing benefit to their organizations others are still at the exploratory stage of

Data Mining

1029 words - 5 pages and the more people speak up and voice their opinions about personal information being leaked the more changes and regulations that can be made to prevent such things from happening. References Berry, Jonathan.Database Marketing .Business Week (September 5, 1994):56-62 Cipolla, Emil T. Data Mining: Techniques to Gain Insight Into Your Data .Enterprise Systems Journal (December 1995):18-24, 64 Conner, Louis.Mining for Data. Communications Week (February 12, 1996):37-41 Palace, Bill. Data Mining: What is Data Mining. 2011 Data Mining Algorithms, 2012

Central and Eastern Europe Fixed Communications Market to 2015: Access Lines by Technology

1041 words - 5 pages , Broadband Subscriber lines, personal computers, voice telephony subscriber lines, internet users, internet accounts by subscription band, IPTV/Video subscriber lines Total access lines used by Central and Eastern Europe population: PSTN/POTS, ISDN, xDSL, Cable, Fixed Wireless Access, Fiber Optic (FTTH/B), WiMAX Revenue data for Central and Eastern Europe fixed communications service, voice service revenues (Circuit and Packet switched), Internet

Tech 140

648 words - 3 pages |d. |Ethernet | ____ 8. ____ are the distinct units of data that are exchanged between nodes on a network. |a. |Segments |c. |Topologies | |b. |Packets |d. |Protocols | ____ 9

Problem Solution for Global Communications

3714 words - 15 pages Running head: PROBLEM SOLUTION: GLOBAL COMMUNICATIONS Problem Solution: Global Communications Amanda Rodriguez University of Phoenix Problem Solution: Global Communications Global Communications is a telecommunications provider that is facing economical pressure. They are encountering competition with other local, long distance and international markets for the same business. With profitability at a low, Global communications must


996 words - 4 pages Yamane, general manager of the e-KOMATSU Technical Centre. “To ensure we could continue to effectively support the future growth of our global operations, we decided to consolidate and integrate our global infrastructure with a single supplier.” CONSOLIDATING THEIR COMMUNICATIONS AROUND THE GLOBE Data centre consolidation would simplify Komatsu’s extensive application infrastructure and improve communications, enabling the swift delivery of

Networking Concepts and Applications

708 words - 3 pages . From there the Network Layer’s packet is passed on to the Network Layer to be unpacked. The Transport Layers packet is passed on to the Transport Layer which finally passes the Application Layer’s packet on to be processed by the Application Layer. Question 17: Describe two important data communications standards-making bodies. How do they differ? One major data communications standards making body is the Telecommunications Group, or

Related Essays

Determining Databases And Data Communications Essay

1036 words - 5 pages ,Determining Databases and Data Communications Determining Databases and Data Communications BIS-320 Business Information Systems December 12, 2011 Determining Databases and Data Communications Scenario 1 Typical fields that you may want to include for booth components are: number of components, Names of components, size, how long it takes to set up, how long it takes breakdown, weight of each piece, and

Determining Databases And Data Communications Essay

1144 words - 5 pages BIS 320 Week 3 Individual Assignment Determining Databases and Data Communications (Two Scenarios) (1000 Words, References, APA Format) Determining Databases and Data Communications Scenario 1: The methodology of managing a trade show booth is to keep certain things in mind about the components, equipment and each and every item that is to be transported back to the head office, when you are closing the booth. We are in

Nt1310 Physical Networking Essay

328 words - 2 pages NT1310 Physical Networking Assignment 1: Voice vs. Data Cell Phones – Cellular phones are used for both voice and data communications. A person talking on a cellular phone uses voice communications and then gets sent back to the base station. Data technology is also used on smartphones which allow the user to browse the internet and download files. Landline Phones – Landline phones typically only use voice communications. Some newer

Asia Pacific Essay

586 words - 3 pages communications on the Internet for such things as web browsing, e-mail, Internet faxing, instant messaging and other data transfers. There are slight differences between SSL and TLS, but they are substantially the same. ------------------------------------------------- Data representation The purpose of a network is to transmit information from one computer to another. To do this, you first have to decide how to encode the data to be sent, in other