ENGI 4557 Digital Communications Practice Problems 2017 (Part 2)
|
|
- Hugo Curtis
- 6 years ago
- Views:
Transcription
1 ENGI 4557 Digital Communications Practice Problems 207 (Part 2) H = n p i log 2 ( ) p i C = W log 2 ( + S N ) SNR = 6m + 0 log 0 ( 3σ2 x V ) 2 SNR = 6m 0 ( ) n n! = k k!(n k)! x = σ 2 = + + x p(x)dx (x x) 2 p(x)dx ( p) n exp( np) η = n o /n f ( P f ) + n a /n f + (2t p R)/n f η = n o /n f ( P f ) + (W s )P f η = ( P f )( n o /n f ) S max = G exp( 2G) or G exp( G) ρ max = E(X ) E(X ) + (2e )t p. Consider a (7,4) Hamming code with the following check matrix: H = Justify your answers for full credit: (a) Show a triple error vector that is not detected. (b) Suppose the following vector is received: (00) T. What bit is most likely to be in error? (c) Estimate the probability of error correction failure if the error rate in the channel is A linear code consists of codewords nine bits long, four information bits and five check bits. Check bits are calculated as follows: b 5 = b + b 2 b 6 = b 2 + b 3 b 7 = b 3 + b 4 b 8 = b + b 4 b 9 = b + b 3 + b 4.
2 (a) Show the check matrix (H) for this code. (b) Show the list of codewords. (c) What is the minimum distance of this code? How many errors can be forward-corrected? 3. Consider a (8,4) linear code with the following check matrix: Justify your answers for full credit: H = (a) Suppose the following vector is received: (0000) T. Is any error detected? Justify. (b) List all undetected error vectors. (c) Estimate the probability of error detection failure if the bit error rate in the channel is A linear code has the following check matrix: H = (a) How many information and check bits are there in this code? (b) Write the equation to calculate b 6 from the information bits. (c) What is the minimum distance of this code? Can this code be used for forward error correction? Justify your answer. (d) What is the probability of error-detection failure if the bit error rate is 0 5? 5. An asynchronous TDM is fed by three channels. Each channel has a nominal bit rate of 5 Mbps. Output frames have 26 bits: 40 data bits plus one flag and one data/stuff bits per each input channel. (a) What nominal bit rate is required at the output to use the stuff bits half of the time when input bit rates are nominal? (b) What are the absolute maximum and minimum input bit rates that can be accommodated, assuming that the output bit rate is nominal. 6. An asynchronous TDM is fed by three channels. Each channel has a nominal bit rate of 0 Mbps. Output frames have 69 bits: 9 bits from each input plus two flag and two data/stuff bits per each input channel. The output bit rate is 35 Mbps (a) Assume input bit rates are nominal. How many data bits per channel are used on average? (b) What are the absolute maximum and minimum input bit rates that can be accommodated? 7. In ADSL, why is the total available channel bandwidth divided in many sub-channels? 2
3 8. Explain what is the difference between frequency- and wavelength- division multiplexing. 9. Briefly explain what is SONET. 0. What is the main advantage of synchronous multiplexing used in SONET networks compared to the asynchronous multiplexing used in the traditional digital multiplexing hierarchy?. A cellular phone network has total allocated bandwidth of 25 MHz. Each one-way radio channel needs 40 khz and can carry 4 digital channels. Assume 5% of channels are reserved for setup and control and the reuse factor is 7. The expected load in each cell is 00 Erlangs and the average call duration is 5 minutes. (a) How many two-way channels are available for user traffic in each cell? (b) Is the number of available channels enough for a low blocking probability? Explain why. (c) How many calls per minute are received on average in one cell? 2. Explain why a frame sequence number is necessary for stop-and-wait ARQ. 3. Briefly explain how the ENQ (enquire) frame can help to improve efficiency of stop-and-wait ARQ. 4. Data is transmitted using an ARQ protocol over a channel with a nominal bit rate of 3 Mbps, a propagation time of 2 ms and a bit error rate of 0 6. Assume information frames have 2500 information bytes and 32 bytes overhead, ACK frames are 32 bytes long and processing time is negligible. (a) Calculate the effective bit rate with stop-and-wait ARQ. (b) Is there any way to improve the stop-and-wait ARQ efficiency? Explain. (assume the physical channel can not be changed). (c) Calculate the effective bit rate achieved with go-back-n ARQ. What window size should be used? 5. Derive the formula for the effective bit rate with stop-and-wait ARQ protocol. Assume the following parameters are known: frame failure probability (P f ), propagation time (t p ), number of bits and overhead in information frame (n f, n o ), number of bits in ACK frame (n a ), physical bit rate in channel (R). Assume processing time is negligible and consider the following results valid for α < : iα i = ( α) 2, α i = α ( α) 6. A channel has a bit rate of 0 Gbps and distance of 0 km. Propagation speed in the link is m/s, processing time at both ends is 0. µs, header overhead and ACK frames are 20 bytes long. Information frames (including overhead) are 2048 bytes long. If Go-back-N ARQ is used. (a) What is the minimum window size for maximum effective bit rate? Justify your answer. (b) Calculate the effective bit rate in the line if the bit error rate is 0 4 and the window size is set to 00. 3
4 7. Derive the formula for the effective bit rate with selective repeat ARQ protocol. Assume the following parameters are known: window size (W s ), frame failure probability (P f ), propagation time (t p ), number of bits and overhead in information frame (n f, n o ), number of bits in ACK frame (n a ), physical bit rate in channel (R). Assume processing time is negligible and consider the following results valid for α < : iα i = ( α) 2, α i = α ( α) 8. Data is transmitted using an ARQ protocol over a channel with a nominal bit rate of 30 Mbps, a propagation time of 2 ms and a bit error rate of 0 6. Assume information frames have 2500 information bytes of which 64 bytes are overhead. ACK frames are 64 bytes long. Processing time is 0. ms. (a) Calculate the effective bit rate (in bps) achieved with go-back-n ARQ. What window size should be used? (b) Suppose go-back-n with a window size of 6 is used. How many bits on the header should be used to represent the frame sequence? 9. Data is transmitted using an ARQ protocol over a channel with a nominal bit rate of 00 Mbps, a propagation time of 2 ms. Assume the frame overhead (header, CRC, etc.) is equal to 64 bytes, independently of the frame length. ACK frames are 64 bytes long and processing time is negligible. (a) How long (in bytes) should the frame length be set to achieve an efficiency of 80% with stop-and-wait ARQ? Assume there are no transmission errors. (b) Calculate the effective bit rate achieved with selective repeat ARQ, a bit error rate of 0 4 and a frame lenght of 52 bytes. What window size should be used and why? 20. A communication link uses selective-repeat ARQ. Information frames have a fixed overhead of 256 bits and the bit error rate in the line is 0 8. Assume that the window size is large enough to keep the channel busy at all times. What is the optimum frame length that maximizes efficiency? 2. Workstations are connected in a LAN with a star topology using the CSMA-CD protocol. The centre of the star is a hub that repeats incoming frames to all ports. The distance between workstations and the hub is 00 m and the propagation speed is m/s. The bit rate in the bus is 00 Mbps. What is the frame size (in bits) that results in the same throughput as the Slotted Aloha protocol? 22. A wireless LAN uses polling to communicate 30 stations to a base station. Assume all stations are 80 m away from the base station. The bit rate in the channel is 0 Mbps, propagation speed is m/s, information frames are 024 bytes long. Polling messages (and responses if station has no data to transmit) are 64 bytes long. Stations are allowed to transmit 2 frames/poll. (a) What is the maximum possible data frame arrival rate? (b) What is the maximum data frame arrival rate if only one station has frames to transmit? (c) Suppose that the LAN protocol is changed to Slotted Aloha. Is the maximum possible frame arrival rate improved? 4
5 23. Forty terminals are connected to a bus. The maximum distance between terminals is 2.5 km (assume a propagation velocity of m/s). The bit rate in the bus is 00 Mbps. Frames are 500 bytes (not bits) long. (a) What protocol would you choose to maximise the frame throughput (Slotted Aloha or CSMA- CD)? Justify your answer. (b) If you can adjust the frame size from a minimum of 500 bytes to a maximum of 4500 bytes, what size and protocol would you choose to to maximise the frame throughput? What is the value of the maximum throughput in bits per second? 24. Explain the multi token operation in token ring networks. Can a collision occur in a token ring network? 25. Twenty terminals are connected to a bus. The maximum distance between terminals is 25 km (assume a propagation velocity of m/s). The bit rate in the bus is 00 Mbps. (a) What protocol and what frame size would you choose to maximise the throughput (Slotted Aloha or CSMA-CD)? Justify your answer. Note: assume any improvement above 95 % is considered negligible. (b) If you can adjust the frame size from a minimum of 200 bytes to a maximum of 000 bytes, what size and protocol would you choose to to maximise the throughput? What is the value of the maximum throughput in bits per second? 26. Briefly describe how reservation systems work. What can be done to improve the throughput if there are many stations? 27. A wireless network uses a reservation system over a 20 Mbps radio channel. The frame is composed of 500-byte data slots and a 200-byte reservation slot. Reservation mini-slots are 8-byte long. The Slotted Aloha protocol is used during the reservation period and each station can reserve data slot per frame. (a) What is the maximum normalized throughput that the system can achieve? (b) What is the normalized throughput when only two stations are active? (c) If stations are allowed to reserve 4 data slots per frame. What is the maximum normalized throughput? 28. Explain the difference between a datagram and a connection-oriented packet network. Mention at least one pro and con for each type. 29. Ten packets are transmitted over 3 hops of a store-and-forward datagram network. Each packet is 800 bytes long and the bit rate in all lines is 00 Mbps. The delay in each hop is 2 ms. Calculate the total elapsed time from the transmission start to the time that the last bit is received. 30. Briefly explain why the IP network uses hierarchical addressing. 3. What is the purpose of a switch/router? 32. Give one example of a connection-oriented packet network 33. Give one example of a connectionless packet network 5
Communication and Networks. Problems
Electrical and Information Technology Communication and Networks Problems Link Layer 2016 Problems 1. Consider a network applying a slotted Aloha access system. The assumption for this is that all nodes
More informationTopics. Link Layer Services (more) Link Layer Services LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS. flow control: error detection:
1 Topics 2 LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS Multiple access: CSMA/CD, CSMA/CA, token passing, channelization LAN: characteristics, i basic principles i Protocol architecture Topologies
More informationUNIVERSITI TUN HUSSEIN ONN MALAYSIA FINAL EXAMINATION SEMESTER I SESSION 2009/10
UNIVERSITI TUN HUSSEIN ONN MALAYSIA FINAL EXAMINATION SEMESTER I SESSION 2009/10 SUBJECT NAME SUBJECT CODE COURSE DATA COMMUNICATION BEP4223 4BEE EXAMINATION DATE NOVEMBER 2009 DURATION INSTRUCTION 3 HOURS
More informationECSE-4670: Computer Communication Networks (CCN) Informal Quiz 3
ECSE-4670: Computer Communication Networks (CCN) Informal Quiz 3 : shivkuma@ecse.rpi.edu Biplab Sikdar: sikdab@rpi.edu 1 T F Slotted ALOHA has improved utilization since the window of vulnerability is
More informationMedium Access Protocols
Medium Access Protocols Summary of MAC protocols What do you do with a shared media? Channel Partitioning, by time, frequency or code Time Division,Code Division, Frequency Division Random partitioning
More informationSample Solution to Problem Set 3
College of Computer & Information Science Fall 2007 Northeastern University Handout 6 CSG250: Wireless Networks 25 October 2007 Sample Solution to Problem Set 3 (The problem numbers from the text are the
More informationSummary of MAC protocols
Summary of MAC protocols What do you do with a shared media? Channel Partitioning, by time, frequency or code Time Division, Code Division, Frequency Division Random partitioning (dynamic) ALOHA, S-ALOHA,
More informationECE 4450:427/527 - Computer Networks Spring 2017
ECE 4450:427/527 - Computer Networks Spring 2017 Dr. Nghi Tran Department of Electrical & Computer Engineering Lecture 5.4: Multiple Access Protocols Dr. Nghi Tran (ECE-University of Akron) ECE 4450:427/527
More informationReminder: Datalink Functions Computer Networking. Datalink Architectures
Reminder: Datalink Functions 15-441 15 441 15-641 Computer Networking Lecture 5 Media Access Control Peter Steenkiste Fall 2015 www.cs.cmu.edu/~prs/15-441-f15 Framing: encapsulating a network layer datagram
More informationCSE 461: Multiple Access. Homework: Chapter 2, problems 1, 8, 12, 18, 23, 24, 35, 43, 46, and 58
CSE 461: Multiple Access Homework: Chapter 2, problems 1, 8, 12, 18, 23, 24, 35, 43, 46, and 58 Next Topic Key Focus: How do multiple parties share a wire? This is the Medium Access Control (MAC) portion
More informationCOMP476 Networked Computer Systems. Polling. Sharing the Wire. LAN Technologies. COMP476 Networked Computer Systems 1
Media Access Control Sub Layer COMP476 Networked Computer Systems Sharing Common Media There are several ways to share common media. Some methods are: Frequency division multiplexing Time division multiplexing
More informationMultiple Access Links and Protocols
Multiple Access Links and Protocols Two types of links : point-to-point PPP for dial-up access point-to-point link between Ethernet switch and host broadcast (shared wire or medium) old-fashioned Ethernet
More informationSubject Data Communication. Subject Code 15CS46. Module 2 (Part 2) Multiplexing and Switching
1. What is multiplexing? What are types of multiplexing? (Dec 2012) Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link. If the
More informationHigh Level View. EE 122: Ethernet and Random Access protocols. Medium Access Protocols
High Level View EE 122: Ethernet and 802.11 Ion Stoica September 18, 2002 Goal: share a communication medium among multiple hosts connected to it Problem: arbitrate between connected hosts Solution goals:
More informationModule 10 Frame Relay and ATM
Module 10 Frame Relay and ATM Lesson 34 ATM: Concepts And Header 10.2.1 INTRODUCTION IP has a varying packet size which causes no problem while multiplexing but makes switching difficult. ATM uses a fixed
More informationCS 43: Computer Networks. 27: Media Access Contd. December 3, 2018
CS 43: Computer Networks 27: Media Access Contd. December 3, 2018 Last Class The link layer provides lots of functionality: addressing, framing, media access, error checking could be used independently
More informationLink Layer and Ethernet
Link Layer and Ethernet 14-740: Fundamentals of Computer Networks Bill Nace Material from Computer Networking: A Top Down Approach, 6 th edition. J.F. Kurose and K.W. Ross traceroute Data Link Layer Multiple
More informationSwitching CHAPTER 8. Solutions to Review Questions and Exercises. Review Questions
CHAPTER 8 Switching Solutions to Review Questions and Exercises Review Questions 1. Switching provides a practical solution to the problem of connecting multiple devices in a network. It is more practical
More informationCommunication Networks
Communication Networks Chapter 3 Multiplexing Frequency Division Multiplexing (FDM) Useful bandwidth of medium exceeds required bandwidth of channel Each signal is modulated to a different carrier frequency
More information1/29/2008. From Signals to Packets. Lecture 6 Datalink Framing, Switching. Datalink Functions. Datalink Lectures. Character and Bit Stuffing.
/9/008 From Signals to Packets Lecture Datalink Framing, Switching Peter Steenkiste Departments of Computer Science and Electrical and Computer Engineering Carnegie Mellon University Analog Signal Digital
More informationEE 122: Ethernet and
EE 122: Ethernet and 802.11 Ion Stoica September 18, 2002 (* this talk is based in part on the on-line slides of J. Kurose & K. Rose) High Level View Goal: share a communication medium among multiple hosts
More informationCS 123: Lecture 12, LANs, and Ethernet. George Varghese. October 24, 2006
CS 123: Lecture 12, LANs, and Ethernet George Varghese October 24, 2006 Selective Reject Modulus failure Example w = 2, Max = 3 0 0 1 3 0 A(1) A(2) 1 0 retransmit A(1) A(2) buffer Case 1 Case 2 reject
More informationContent. Deterministic Access Polling(1) Master-Slave principles: Introduction Layer 2: Media Access Control
Content Introduction Layer 2: Frames Error Handling Media Access Control General approaches and terms Network Topologies Media Access Principles (Random) Aloha Principles CSMA, CSMA/CD, CSMA / CA Media
More informationChapter 6 Medium Access Control Protocols and Local Area Networks
Chapter 6 Medium Access Control Protocols and Local Area Networks Part I: Medium Access Control Part II: Local Area Networks CSE 3213, Winter 2010 Instructor: Foroohar Foroozan Chapter Overview Broadcast
More informationLANs. Local Area Networks. via the Media Access Control (MAC) SubLayer. Networks: Local Area Networks
LANs Local Area Networks via the Media Access Control (MAC) SubLayer 1 Local Area Networks Aloha Slotted Aloha CSMA (non-persistent, 1-persistent, p-persistent) CSMA/CD Ethernet Token Ring 2 Network Layer
More informationData Link Layer: Multi Access Protocols
Digital Communication in the Modern World Data Link Layer: Multi Access Protocols http://www.cs.huji.ac.il/~com1 com1@cs.huji.ac.il Some of the slides have been borrowed from: Computer Networking: A Top
More informationSIMON FRASER UNIVERSITY SCHOOL OF ENGINEERING SCIENCE. Spring 2013 ENSC 427: COMMUNICATION NETWORKS. Midterm No. 2(b) Monday, March 18, 2013
SIMON FRASER UNIVERSITY SCHOOL OF ENGINEERING SCIENCE Spring 2013 ENSC 427: COMMUNICATION NETWORKS Midterm No. 2(b) Monday, March 18, 2013 Duration: 50 minutes. Attempt all problems. Questions may not
More informationRAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY
RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING QUESTION BANK SUBJECT NAME: COMPUTER NETWORKS SUBJECT CODE: CST52 UNIT-I 2 MARKS 1. What is Network? 2.
More informationReview. Error Detection: CRC Multiple access protocols. LAN addresses and ARP Ethernet. Slotted ALOHA CSMA/CD
Review Error Detection: CRC Multiple access protocols Slotted ALOHA CSMA/CD LAN addresses and ARP Ethernet Some slides are in courtesy of J. Kurose and K. Ross Overview Ethernet Hubs, bridges, and switches
More informationChapter 6 Local Area Networks and Media Access Control. School of Info. Sci. & Eng. Shandong Univ.
Chapter 6 Local Area Networks and Media Access Control School of Info. Sci. & Eng. Shandong Univ. 6.1 MULTIPLE ACCESS COMMUNICATIONS FIGURE 6.1 Multiple access communications FIGURE 6.2 Approaches to sharing
More informationIntroductory to Computer Networks Local Area Networks. Lecture 16 Fall Isfahan University of technology Dr.
Introductory to Computer Networks Local Area Networks Lecture 16 Fall 2010 Isfahan University of technology Dr. Faramarz Hendessi What is a LAN? Local area means: Private ownership freedom from regulatory
More informationCS 421: COMPUTER NETWORKS FALL FINAL January 5, minutes. Name: Student No: TOT
S 421: OMPUTR NTWORKS ALL 2006 INAL January 5, 2007 150 minutes Name: Student No: Q1 Q2 Q3 TOT 1) a) (6 pts) iven the following parameters for a datagram packet switching network: N: number of hops between
More informationEL Wireless and Mobile Networking Spring 2002 Mid-Term Exam Solution - March 6, 2002
Instructions: EL 604 - Wireless and Mobile Networking Spring 2002 Mid-Term Exam Solution - March 6, 2002 Be sure to write your name on your submission. This is an open book test. Use your class notes,
More information2. Modelling of telecommunication systems (part 1)
2. Modelling of telecommunication systems (part ) lect02.ppt S-38.45 - Introduction to Teletraffic Theory - Fall 999 2. Modelling of telecommunication systems (part ) Contents Telecommunication networks
More informationLecture 9: Bridging. CSE 123: Computer Networks Alex C. Snoeren
Lecture 9: Bridging CSE 123: Computer Networks Alex C. Snoeren Lecture 9 Overview Finishing up media access Ethernet Contention-free methods (rings) Moving beyond one wire Link technologies have limits
More informationDepartment of EECS - University of California at Berkeley EECS122 - Introduction to Communication Networks - Spring 2005 Final: 5/20/2005
Name: SID: Department of EECS - University of California at Berkeley EECS122 - Introduction to Communication Networks - Spring 2005 Final: 5/20/2005 There are 10 questions in total. Please write your SID
More informationLink Layer and Ethernet
Link Layer and Ethernet 14-740: Fundamentals of Computer Networks Bill Nace Material from Computer Networking: A Top Down Approach, 6 th edition. J.F. Kurose and K.W. Ross traceroute Data Link Layer Multiple
More informationChapter 3. Underlying Technology. TCP/IP Protocol Suite 1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 3 Underlying Technology TCP/IP Protocol Suite 1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. OBJECTIVES: To briefly discuss the technology of dominant
More informationLocal Area Networks (LANs) SMU CSE 5344 /
Local Area Networks (LANs) SMU CSE 5344 / 7344 1 LAN/MAN Technology Factors Topology Transmission Medium Medium Access Control Techniques SMU CSE 5344 / 7344 2 Topologies Topology: the shape of a communication
More informationProblem Set Name the 7 OSI layers and give the corresponding functionalities for each layer.
Problem Set 1 1. Why do we use layering in computer networks? 2. Name the 7 OSI layers and give the corresponding functionalities for each layer. 3. Compare the network performance of the 3 Multiple Access
More informationCOS 140: Foundations of Computer Science
COS 140: Foundations of Computer Science ALOHA Network Protocol Family Fall 2017 Homework 2 Introduction 3 Network Protocols.......................................................... 3 Problem.................................................................
More informationOutline. Introduction to Networked Embedded Systems - Embedded systems Networked embedded systems Embedded Internet - Network properties
Outline Introduction to Networked Embedded Systems - Embedded systems Networked embedded systems Embedded Internet - Network properties Layered Network Architectures - OSI framework descriptions of layers
More informationMultiple Access in Cellular and Systems
Multiple Access in Cellular and 802.11 Systems 1 GSM The total bandwidth is divided into many narrowband channels. (200 khz in GSM) Users are given time slots in a narrowband channel (8 users) A channel
More informationJaringan Komputer. Broadcast Network. Outline. MAC (Medium Access Control) Channel Allocation Problem. Dynamic Channel Allocation
Broadcast Network Jaringan Komputer Medium Access Control Sublayer 2 network categories: point-to-point connections broadcast channels Key issue in broadcast network: how to determine who gets to use the
More informationChapter 6 Medium Access Control Protocols and Local Area Networks
Chapter 6 Medium Access Control Protocols and Local Area Networks Part I: Medium Access Control Part II: Local Area Networks Chapter Overview Broadcast Networks All information sent to all users No routing
More informationLecture 9 November 12, Wireless Access. Graduate course in Communications Engineering. University of Rome La Sapienza. Rome, Italy
Lecture 9 November 12, 2018 Wireless Access Graduate course in Communications Engineering University of Rome La Sapienza Rome, Italy 2018-2019 Medium Access Control Scheduled access Classification of wireless
More informationCOMPUTER NETWORKS MODEL QUESTION PAPER WITH SOLUTION. (c) Peer-to-peer processes are processes on two or more devices communicating at a
COMPUTER NETWORKS MODEL QUESTION PAPER WITH SOLUTION Q-1(a) In half-duplex transmission, only one entity can send at a time; in a full-duplex transmission, both entities can send at the same time. (b)
More informationInternetworking Part 1
CMPE 344 Computer Networks Spring 2012 Internetworking Part 1 Reading: Peterson and Davie, 3.1 22/03/2012 1 Not all networks are directly connected Limit to how many hosts can be attached Point-to-point:
More informationGoals. Fundamentals of Network Media. More topics. Topics. Multiple access communication. Multiple access solutions
Fundamentals of Network Media Local Area Networks Ursula Holmström Goals Learn the basic concepts related to LAN technologies, for example use of shared media medium access control topologies Know the
More informationLecture 6 Datalink Framing, Switching. From Signals to Packets
Lecture 6 Datalink Framing, Switching David Andersen Department of Computer Science Carnegie Mellon University 15-441 Networking, Spring 2005 http://www.cs.cmu.edu/~srini/15-441/s05/ 1 From Signals to
More informationMultiple Access Protocols
Multiple Access Protocols Computer Networks Lecture 2 http://goo.gl/pze5o8 Multiple Access to a Shared Channel The medium (or its sub-channel) may be shared by multiple stations (dynamic allocation) just
More informationDirect Link Communication II: Wired Media. Multi-Access Communication
Direct Link Communication II: Wired Media Multi-Access Communication Two classes: contention-based e.g., CSMA/CD, CSMA/CA used in Ethernet, WLAN contention-free e.g., TDM, FDM, TDMA, CDMA, token ring one
More information(a) Client server model (b) MAN (c) Interfaces and services. [4+6+6] FirstRanker
Code No: N0421/R07 Set No. 1 IV B.Tech I Semester Supplementary Examinations, March 2013 COMPUTER NETWORKS ( Common to Electronics & Communication Engineering, Electronics & Instrumentation Engineering,
More informationCS1302 / Computer Networks
CS1302 / Computer Networks Year/Sem : III/VI UNIT I- DATA COMMUNICATIONS 1. Define Data communication 2. List out the characteristics of data communication 3. What are the components of data communication?
More informationECSE 414 Fall 2014 Final Exam Solutions
ECSE 414 Fall 2014 Final Exam Solutions Question 1 a. The five main layers of the internet protocol stack, along with the service provided by each, and the place where each is implemented are as follows:
More informationCS 43: Computer Networks Media Access. Kevin Webb Swarthmore College November 30, 2017
CS 43: Computer Networks Media Access Kevin Webb Swarthmore College November 30, 2017 Multiple Access Links & Protocols Two classes of links : point-to-point dial-up access link between Ethernet switch,
More informationECS 152A Computer Networks Instructor: Liu. Name: Student ID #: Final Exam: March 17, 2005
ECS 152A Computer Networks Instructor: Liu Name: Student ID #: Final Exam: March 17, 2005 Duration: 120 Minutes 1. The exam is closed book. However, you may refer to one sheet of A4 paper (double sided)
More informationCS 455/555 Intro to Networks and Communications. Link Layer
CS 455/555 Intro to Networks and Communications Link Layer Dr. Michele Weigle Department of Computer Science Old Dominion University mweigle@cs.odu.edu http://www.cs.odu.edu/~mweigle/cs455-s13 1 Link Layer
More informationChapter 4. The Medium Access Control Sublayer. Points and Questions to Consider. Multiple Access Protocols. The Channel Allocation Problem.
Dynamic Channel Allocation in LANs and MANs Chapter 4 The Medium Access Control Sublayer 1. Station Model. 2. Single Channel Assumption. 3. Collision Assumption. 4. (a) Continuous Time. (b) Slotted Time.
More informationWireless Communications
4. Medium Access Control Sublayer DIN/CTC/UEM 2018 Why do we need MAC for? Medium Access Control (MAC) Shared medium instead of point-to-point link MAC sublayer controls access to shared medium Examples:
More informationCS/ECE 438: Communication Networks for Computers Spring 2018 Midterm Examination Online
1 CS/ECE 438: Communication Networks for Computers Spring 2018 Midterm Examination Online Solutions 1. General Networking a. In traditional client-server communication using TCP, a new socket is created.
More informationAdaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols
Link Layer: Introduction daptors ommunicating Terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are links wired links wireless links LNs
More informationElectrical and Computer Engineering Technology
ECET 3400 Spring 2012 Data Communications Southern Polytechnic State University Electrical and Computer Engineering Technology Instructor Information Instructor: Dr. Craig A. Chin, Assistant Professor
More informationDCN Questions CHAPTER 1:- NETWORKING FUNDAMENTALS
DCN Questions CHAPTER 1:- NETWORKING FUNDAMENTALS Q1. What are the four fundamental Characteristics of Data Communication? On which effectiveness of data communication is depended? Q2. Define data communication?
More informationMedia Access Control (MAC) Sub-layer and Ethernet
Media Access Control (MAC) Sub-layer and Ethernet Dr. Sanjay P. Ahuja, Ph.D. Fidelity National Financial Distinguished Professor of CIS School of Computing, UNF MAC Sub-layer The MAC sub-layer is a sub-layer
More informationCSC 4900 Computer Networks: The Link Layer
CSC 4900 Computer Networks: The Link Layer Professor Henry Carter Fall 2017 Last Time We talked about intra-as routing protocols: Which routing algorithm is used in RIP? OSPF? What techniques allow OSPF
More informationLinks. Error Detection. Link Layer. Multiple access protocols. Nodes Links Frame. Shared channel Problem: collisions How nodes share a channel
Link Layer Error Detection Nodes Links Frame R yclic Redundancy hecksum Parity its More about this in exercise! Data Link Layer -1 Data Link Layer -2 Links Two types of links : point-to-point broadcast
More informationNETWORK PROBLEM SET Due Date 6/28/2014
NETWORK PROBLEM SET Due Date 6/28/2014 Problem 1 Consider a packet-switched network of N nodes connected by the following topologies: Star: one central node (hub) and all other nodes are attached to the
More informationMobile Communications Chapter 3 : Media Access
Mobile Communications Chapter 3 : Media Access 2. Motivation 3. SDMA, FDMA, TDMA 1. Aloha and contention based schemes 4. Reservation schemes 5. Collision avoidance, MACA 6. Polling CDMA (Lecture 6) Prof.
More informationLinks Reading: Chapter 2. Goals of Todayʼs Lecture. Message, Segment, Packet, and Frame
Links Reading: Chapter 2 CS 375: Computer Networks Thomas Bressoud 1 Goals of Todayʼs Lecture Link-layer services Encoding, framing, and error detection Error correction and flow control Sharing a shared
More informationCPE 548 Exam #1 (50 pts) February 17, 2016
Name Class: 548 All answers must have supporting work. Any answer without support will receive no credit 1) (4 pts) Answer the following short answer questions. a) Explain the stop and wait ARQ (automatic
More informationKing Fahd University of Petroleum and Minerals College of Computer Sciences and Engineering Department of Computer Engineering
Student Name: Section #: King Fahd University of Petroleum and Minerals College of Computer Sciences and Engineering Department of Computer Engineering COE 344 Computer Networks (T072) Final Exam Date
More informationCHAPTER 15 LOCAL AREA NETWORKS ANSWERS TO QUESTIONS
CHAPTER 15 LOCAL AREA NETWORKS ANSWERS TO QUESTIONS 15.1 Computer room networks require very high data rates and usually are concerned with transfer of large blocks of data. 15.2 Backend LAN: Backend networks
More informationCARRIER SENSE MULTIPLE ACCESS (CSMA):
Lecture Handout Computer Networks Lecture No. 8 CARRIER SENSE MULTIPLE ACCESS (CSMA): There is no central control management when computers transmit on Ethernet. For this purpose the Ethernet employs CSMA
More informationData Link Layer, Part 3 Medium Access Control. Preface
Data Link Layer, Part 3 Medium Access Control These slides are created by Dr. Yih Huang of George Mason University. Students registered in Dr. Huang's courses at GMU can make a single machine-readable
More informationAdaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols
Link Layer: Introduction daptors ommunicating hosts and routers are nodes links connect nodes wired links wireless links layer-2 packet is a frame, encapsulates datagram datagram controller sending host
More informationCOMPUTER NETWORKS UNIT 3
COMPUTER NETWORKS UNIT 3 1. Illustrate about Reservation, Polling and Token Passing. [10 marks] Controlled access: In controlled access, the stations consult one another to find which station has the right
More informationMULTIPLE ACCESS PROTOCOLS 2. 1
MULTIPLE ACCESS PROTOCOLS AND WIFI 1 MULTIPLE ACCESS PROTOCOLS 2. 1 MULTIPLE ACCESS LINKS, PROTOCOLS Two types of links : point-to-point broadcast (shared wire or medium) POINT-TO-POINT PPP for dial-up
More informationComputer Facilities and Network Management BUS3150 Tutorial - Week 13
Computer Facilities and Network Management BUS3150 Tutorial - Week 13 *** FOR TUTORS ONLY *** The answers provided here are only brief guides. If you have any comments or suggestions for improvement to
More informationLecture 6. Data Link Layer (cont d) Data Link Layer 1-1
Lecture 6 Data Link Layer (cont d) Data Link Layer 1-1 Agenda Continue the Data Link Layer Multiple Access Links and Protocols Addressing Data Link Layer 1-2 Multiple Access Links and Protocols Two types
More informationLAN PROTOCOLS. Beulah A AP/CSE
LAN PROTOCOLS Beulah A AP/CSE IEEE STANDARDS In 1985, the Computer Society of the IEEE started a project, called Project 802, to set standards to enable intercommunication among equipment from a variety
More informationUNIT-II OVERVIEW OF PHYSICAL LAYER SWITCHING & MULTIPLEXING
1 UNIT-II OVERVIEW OF PHYSICAL LAYER SWITCHING & MULTIPLEXING Syllabus: Physical layer and overview of PL Switching: Multiplexing: frequency division multiplexing, wave length division multiplexing, synchronous
More informationECE/CSC 570 Section 001. Final test. December 11, 2006
ECE/CSC 570 Section 001 Final test December 11, 2006 Questions 1 10 each carry 2 marks. Answer only by placing a check mark to indicate whether the statement is true of false in the appropriate box, and
More informationCS 421: COMPUTER NETWORKS SPRING FINAL May 8, minutes
CS 421: COMPUTR NTWORKS SPRIN 2016 INL May 8, 2016 150 minutes Name: Student No: Q1 Q2 Q3 TOT 1) a) (6 pts) iven the following parameters for a datagram packet switching network: N: number of hops between
More informationRMIT University. Data Communication and Net-Centric Computing COSC 1111/2061/1110. Lecture 8. Medium Access Control Methods & LAN
RMIT University Data Communication and Net-Centric Computing COSC 1111/2061/1110 Medium Access Control Methods & LAN Technology Slide 1 Lecture Overview During this lecture, we will Look at several Multiple
More informationThere are 10 questions in total. Please write your SID on each page.
Name: SID: Department of EECS - University of California at Berkeley EECS122 - Introduction to Communication Networks - Spring 2005 to the Final: 5/20/2005 There are 10 questions in total. Please write
More informationChapter 5 Link Layer and LANs
Chapter 5 Link Layer and LANs Computer Networking: A Top Down Approach 4 th edition. Jim Kurose, Keith Ross Addison-Wesley, July 2007. All material copyright 1996-2007 J.F Kurose and K.W. Ross, All Rights
More informationTCOM 370 NOTES 99-1 NETWORKING AND COMMUNICATIONS
TCOM 370 NOTES 99-1 NETWORKING AND COMMUNICATIONS Communication Networks Allow Exchange of Information between Users telephone network for voice communication interconnected computers and peripherals,
More informationSample solution to Midterm
College of Computer & Information Science Spring 2007 Northeastern University Handout 10 CSG250: Wireless Networks 27 February 2007 Sample solution to Midterm Part I (4 4 = 16 points) 1. Explain how the
More informationThe Link Layer and LANs. Chapter 6: Link layer and LANs
The Link Layer and LANs EECS3214 2018-03-14 4-1 Chapter 6: Link layer and LANs our goals: understand principles behind link layer services: error detection, correction sharing a broadcast channel: multiple
More informationDistributed Queue Dual Bus
Distributed Queue Dual Bus IEEE 802.3 to 802.5 protocols are only suited for small LANs. They cannot be used for very large but non-wide area networks. IEEE 802.6 DQDB is designed for MANs It can cover
More informationComputer Networks Medium Access Control. Mostafa Salehi Fall 2008
Computer Networks Medium Access Control Mostafa Salehi Fall 2008 2008 1 Outline Issues ALOHA Network Ethernet Token Ring Wireless 2 Main Issues Local Area Network (LAN) : Three or more machines are physically
More informationData Communication & Computer Networks INFO
Data Communication & Computer Networks INFO Instructor: Dr. A. SARI Department: Management Information Systems Course Code: MIS 305 Academic Term: 2013/2014 Fall Title: Data Communication & Computer Networks
More informationCSMA/CD (Collision Detection)
CSMA/CD (Collision Detection) CD (collision detection): easy in wired LANs: measure signal strengths, compare transmitted, received signals difficult in wireless LANs: received signal strength overwhelmed
More informationLink Layer and LANs 안상현서울시립대학교컴퓨터 통계학과.
Link Layer and LANs 안상현서울시립대학교컴퓨터 통계학과 ahn@venus.uos.ac.kr Data Link Layer Goals: understand principles behind data link layer services: error detection, correction sharing a broadcast channel: multiple
More informationData Link Layer Technologies
Chapter 2.2 La 2 Data Link La Technologies 1 Content Introduction La 2: Frames Error Handling 2 Media Access Control General approaches and terms Aloha Principles CSMA, CSMA/CD, CSMA / CA Master-Slave
More informationCPSC 441 Tutorial-19. Department of Computer Science University of Calgary
CPSC 441 Tutorial-19 Department of Computer Science University of Calgary Problem-1 Consider n nodes that use the slotted CSMA/ CD with binary exponential back-off to access a shared broadcast channel.
More information5105: BHARATHIDASAN ENGINEERING COLLEGE NATTARMPALLI UNIT I FUNDAMENTALS AND LINK LAYER PART A
5105: BHARATHIDASAN ENGINEERING COLLEGE NATTARMPALLI 635 854. NAME OF THE STAFF : R.ANBARASAN DESIGNATION & DEPARTMENT : AP/CSE SUBJECT CODE : CS 6551 SUBJECT NAME : COMPUTER NETWORKS UNIT I FUNDAMENTALS
More informationData Link Layer, Part 5. Medium Access Control
CS 455 Medium Access Control, Page 1 Data Link Layer, Part 5 Medium Access Control These slides are created by Dr. Yih Huang of George Mason University. Students registered in Dr. Huang s courses at GMU
More informationLecture 5 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it
Lecture 5 The Data Link Layer Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Link Layer: setting the context two physically connected devices: host-router, router-router, host-host,
More information