Mid-term Study Guide Autumn 1999 TDC 463 Format ------ The format of the mid-term exam will be closed book, closed notes. No calculators or electronic devices will be allowed. Only basic math skills are required for the exam. You will have as much paper as you need to complete the exam. Text Readings ------------- All the reading we have covered up to this point. However, the outline below lists the most important concepts and topics. Lecture notes and weblink readings should be referred to as appopriate. Topics ------ I. Fundamentals A. Numbering system concepts 1. Binary to decimal conversion 2. Decimal to binary conversion 3. Uses for hexadecimal, binary and decimal numbering B. Serial versus parallel transmission C. Asynchronous versus synchronous timing II. Intro to Computer Networking A. The concepts of protocols and layers B. The OSI Reference Model C. Standards organizations D. Basic differences between computer networks and the PSTN III. Transmission Media A. Types of media B. Limitations IV. Layer 1 Network Devices A. Functions of a Repeater B. Functions of a Hub V. Data Link Networking A. Medium Access Control Concepts 1. Addressing 2. Centralized versus distributed 3. CRCs B. Frame Formats 1. Ethernet/802.3 2. Token Ring/802.5 C. Operation and performance of LANs D. LAN Bridges 1. Transparent Bridging 2. Source Route Bridging C. LAN Bridges versus LAN Switches VI. The Network Layer A. Addressing Concepts B. Routing Concepts C. Internet Protocol (IP) 1. Addressing 2. Routing C. Basics of BOOTP/DHCP D. Basics of DNS E. IPv6 versus IPv4 F. How Mobile IP works G. ICMP H. Traceroute VII. The Transport Layer A. Error Control B. Flow Control C. Congestion Control D. UDP versus TCP Sample Questions ---------------- 1. 100Mb/s is 10 to what power? a. 8 b. 10 b. 100,000,000 c. 100,000,000,000 2. If '1001' is a binary number, it equals ___ in hex. 3. The diagram is a representation of ___ transmission. a. Serial b. Parallel 10010011----> 10000111----> Flow of 00101001----> Data 01111000----> 4. Which is not a layer 3 protocol? a. IPX b. CLNP c. IP d. TCP 5. The MAC layer would fit into the ___ layer of the OSI Reference Model. 6. In the original class hierarchy of the Internet, the IP address of 172.34.3.245 is a: a. Class A address b. Class B address c. Class C address d. Cannot be determined without a subnet mask 7. Match the terms/acronyms with the descriptions. ___ IP 1. End-to-end flow/error control ___ 802.3 2. Hop based routing algorithm ___ Category 5 3. Internet's layer 3 protocol ___ Asynchronous 4. 1000 ___ Transport 5. Address scheme for a group ___ 1KB 6. Common data cabling standard ___ Multicast 7. IEEE layer 2 standard ___ LAA 8. 1024 ___ 1Kb 9. Manually assigned address at layer 2 ___ Distance Vector 10. Character based timing mechanism 8. If you are assigned an IP address range of 140.192.128.0/25: a. How many total addresses do you have to work with? (show math) b. What is the directed broadcast address assuming you do not divide this address space up further? c. What is the subnet mask in decimal for this network? Answer questions 9-12 based on the following the diagram. |A| |B| |C| |D| | | | | | | | | o--+--------+------| Hub |--------+-------------+---o | | | IP Network 10.50.15.0/20 | |E|-------------| Switch |------|F| | | | Router | LAN gateway IP: 10.50.15.1 9. If A and B are on a Ethernet segment, C and D ____ be on a Token Ring segment. a. Must b. Can c. Cannot 10. If the switch uses transparent bridging and it does not currently know about station B in it's bridge table, where does a frame from A go if it's destined for B? a. Just to station B directly b. To all stations B, C and D only. c. To all stations on the hub, plus the switch. d. To all stations including E, F and the router. 11. On this IP network, would it be legal for station B to have IP address 10.50.1.50 and station F IP address 10.50.12.243? a. No b. Yes 12. Would it be legal for any station to have the IP address of 10.50.12.255 in this IP network? a. No b. Yes 13. Which group is not involved in networking standards? a. IEEE b. MTU c. IETF d. ISO 14. Describe how the Spanning Tree algorithm avoids loops in the network. 15. Which is not a limitation of RIPv1? a. Single metric b. Convergence time c. Maximum packet size d. Lack of subnet mask information 16. What is the difference between a static route and a default route? 17. Which of the following protocols has the most bits assigned to it's layers address scheme? a. IPv4 b. IPv6 d. Token Ring/802.5 d. Ethernet/802.3 18. Draw a picture of a physical star wired, token ring network. Draw 4 stations and clearly show the transmission of a data packet from one station to the next. 19. Ethernet collisions: a. are generally rare events. b. typically indicate errors on the network. c. are normal events used to arbitrate access. d. are measured to determine the utilization of the network. 20. Which is not a function of the physical layer? a. Coding scheme used to represent bits on the wire. b. Defines connector shapes and sizes. c. Provides bit level transport for the data link layer. d. Frames bits into packets for transmission on the wire. From the following diagram, answer the next question. |R1| |R2| |R3| \ | / \ | / \ | / |R4| |R5| / \ | / \ | / \ | / \ | / \ | / \ | / \ | / \ | / -------- Router 6 -------- R1 to R4 is network 10.1.0.0 R2 to R5 is network 20.1.0.0 R3 to R6 is network 30.1.0.0 R4 to R6 is network 40.1.0.0 R5 to R6 is network 50.1.0.0 21. If directly attached networks are 0 hops, what does the RIPv1 routing table of Router 6 look like? The first one has been done for you. Network Hops ------- ---- 10.1.0.0 1 22. Explain how IP is able to reassemble packets that are fragmented in transit. 23. A station has a choice of two links with which to transmit a packet. What would be a situation when it would be better to take the slower (in bps) path? 24. Draw a TCP/IP internet that consists of two data link networks. One datalink network is token ring, the other is ethernet. Put a picture of a router between the two. Show the protocol stacks in use for each data link and the router. 25. Assume two IP routers have been misconfigured to form a routing loop for some destination 'D'. Will the packet go around forever? Explain.