Midterm Exam
The class has chosen to write the midterm exam.
Each student is required to submit four unique, suitable exam questions. They should be “thinking” questions that are not too long for an exam. One can be homework (state which one that is). One should be easy, two of medium difficulty, and one difficult. Submit questions and answers.
Questions should be submitted to exam@csci6433.org.
The questions need to be unique. If a question is submitted that has already been approved, the submitter will be told and given a chance to resubmit.
All questions are to be submitted and approved by October 18, to provide time to study before the midterm.
Although the answers will not be posted, you are encouraged to study together in any way you wish, including posting and assembling a list of questions and answers.
Topic | Question |
---|---|
ARP | ARP is often cited as a security weakness. Explain why. |
ARP | Explain the main difference between ARP and RARP. |
ARP | Can ARP be used on a network that does not provide broadcast? Why or why not? |
ARP | Not using checksums can be dangerous. Explain how a single corrupted ARP packet broadcast by machine P can make it impossible to reach another machine, Q. |
ARP | ARP spoofing attack is a security issue in switching network environment, can you find a method to mitigate this? |
BGP | Suppose BGP router A sends a BGP path vector to BGP peer router B. BGP peer B is connected to BGP peer C. Must B advertise that path to C? |
DHCP | You want to implement a mechanism that automates the IP configuration, including IP address, subnet mask, default gateway, and DNS information. Which protocol will you use to accomplish this and is that done? |
Ethernet | How does what an Ethernet switch does differ from what an Ethernet hub does? |
Ethernet | What is the difference in terms of network traffic between two Ethernet segments connected by a bridge and two segments connected by an adaptive bridge? Why? |
Ethernet | Is it necessary to use an IP checksum when sending packets over an Ethernet? Why or Why not? |
Ethernet | If a switch receives a frame and the source MAC address is not in the MAC address table but the destination address is, what will the switch do with the frame? |
Ethernet | Using network hubs may put your online credentials at risk of getting stolen, do you know why? Can you explain? |
General | What are checksum field used for? |
General | Could we use a single checksum for complete IP message without using UDP checksum? |
General | What is the Good Citizen Principle? |
General | From the standpoint of protocol design, what is the most critical resource on the Internet? |
General | Suppose each person on the planet had a smart phone, laptop computer, and ten other devices that each had an IPv6 address. What percentage of the IPv6 address space would be required? |
General | What are four general principles of designing Internet Protocols? Briefly explain each. |
General | Which is better for data networks: circuit switching or packet switching? Why? |
General | Why is it that voice and video traffic is often sent over TCP rather than UDP in today’s Internet? |
General | Which layers in the Internet protocol stack does a host process? Which layers does a router process? |
General | What is the difference between direct and indirect delivery? |
General | Layered protocols hide all underlying details from applications. Could application software be optimized if an application knew about the underlying networks being used? |
General | Which is better, UDP or TCP? Why? |
General | What is one advantage and one disadvantage of layered network protocol? |
General | Internet protocols sometimes violate the layering principle. Why? Give two examples. |
General | Why is the Internet so successful? Give two reasons. |
General | Which condition is better, LAN MTU higher than WAN MTU, or WAN MTU higher than LAN MTU? Why? |
General | If you had network adapters with changeable MAC addresses, and you set the MAC address to be the same as the IP address for each adapter, would the Internet still work? What would change? |
ICMP | How does traceroute use ICMP message (suppose traceroute is implemented by ICMP)? How many messages involve in this process totally (without considering duplicated sent messages)? |
ICMP | How does ping use ICMP messages, and which ones does it use? |
ICMP | How will you ping the loopback address of your local host with IPv4 and IPv6? |
ICMP | Can an IP datagram carrying an ICMP message, if it causes an error, cause another IP datagram to be sent with an ICMP message about the first ICMP message? Why? |
ICMP | Who sends ICMP messages and what is the destination? |
IP | How does the IP addressing scheme differ from the U.S. telephone numbering scheme? |
IP | What are the advantages of doing reassembly of fragments at the ultimate destination, rather than after the datagram traverses a single network? |
IP | Each IP address has a subnet mask that can help determine which subnet is it in. We can do and operation (&) on each IP address with its subnet mask, and if the result is the same, then we know that this two IP address is in the same subnet. |
IP | What is the role of IP in the TCP/IP protocol suite? |
IP | How many IP address can one host have? |
IP | Why should datagrams be fragmented? |
IP | How can a host find the MAC address of another computer on the same network? |
IP | How many computers can be setup with the network address 192.168.1.0/24 network. |
IP | Suppose the internet design was changed to allow routers along a path to reassemble datagrams. How would the change affect security? |
IP | You want to implement a mechanism that automates the IP configuration, including IP address, subnet mask, default gateway, and DNS information. Which protocol will you use to accomplish this and is that done? |
IP | Fragmentation and reassembly are different for IPv4 and IPv6. Which is better? Why? |
IP | How is the TTL field used to prevent indefinite looping of IP datagrams? |
IPv6 | What are some of the modifications of IPv6, from the IPv4, that allow a router to process a packet quicker? |
IPv6 | Explain three important reasons for the new approach to fragmentation taken by IPv6. |
MPLS | What is the significance of MPLS? |
MPLS | How do LSRs change MPLS headers? |
MPLS | In what ways does CISCO's Multi- Layer switching, MLS differ from MPLS? |
Multicast | What happens when I ping a multicast address? Why? |
Multicast | What are three applications that can benefit from IP multicast. |
NAT | What kinds of applications cannot run through a NAT box? |
NAT | Can a local address in a network behind a NAT box be the same as a globally unique address? Explain. |
NAT | NAT is a very important feature of IPv4. Does IPv6 need NAT? Why or why not? |
NAT | Give two important advantages of NAT and two important disadvantages of NAT |
Routing | Should the routing table contain IP address or MAC address of next machine? Why? |
Routing | Routers send HELLO datagram->Building neighbor relation->Generating link state->Getting the best path by SPF algorithm->Getting a routing table |
Routing | Why do link state protocols have better convergence rate than distance vector protocols? |
Routing | When does a router modify the hop limit (or time-to-live) field in a datagram header? |
Routing | How does a router know whether an incoming datagram carries a routing update message? |
TCP | A single lost TCP acknowledgement does not necessarily force a retransmission. Explain why. |
TCP | What is the minimum value for the timeout of a reliable transmission protocol? Why is there a minimum value? |
TCP | Can two programs both use the same TCP port on the same machine at once? |
UDP | Why is UDP checksum separate from IP checksum? |
UDP | Suppose that I have decided to use UDP to transfer data to my application. My application needs to receive the data in the order it was transmitted. Will this be a problem with UDP? If it is, how can I solve the problem? |
UDP | UDP is unreliable and connectionless protocol. Why do we use it? |
Final Exam
The class has chosen to write the final exam.
Each student is required to submit four unique, suitable exam questions. They should be “thinking” questions that are not too long for an exam. One can be homework (state which one that is). One should be easy, two of medium difficulty, and one difficult. Two are to be from period before the midterm, two after the midterm. Submit questions and answers.
Questions should be emailed to exam@csci6433.org.
The questions need to be unique. If a question is submitted that has already been approved, the submitter will be told and given a chance to resubmit.
All questions are to be submitted and approved by November 29, to provide time to study before the midterm.
Although the answers will not be posted, you are encouraged to study together in any way you wish, including posting and assembling a list of questions and answers.
Topic | Question |
---|---|
HTTP | What is the difference between PUT and POST? |
HTTP | What are the differences between PUT and POST in HTTP? |
IP | Why is the UDP checksum different from the IP checksum? |
IP | How is TTL used to prevent router loops? |
SNMP | Is the command from the SNMP control center to restart the same for a UNIX machine and for a Windows machine? |
PING | What does a successful response from PING tell you about the machine that sent the response? |
Ethernet | Is the Good Citizen Principle used by ethernet? Explain. |
Security | What is a firewall? Explain. |
UDP | Without changing UDP, how could an application use UDP to obtain reliable communications? |
UDP | How does UDP handle an undeliverable IP datagram? Is this different from other protocols? Explain |
UDP | How would you change UDP so that it could provide reliable communication? |
ICMP | What happens if an ICMP message is undeliverable? |
Addressing | How is a MAC address different from an IP address? |
SMTP | What are the key steps for SMTP to transmit a message? |
SMTP | Does SMTP provide assured dellivery of messages to users? |
DNS | Give 3 important advantages and 3 important disadvantages of DNS caching. |
DNS | Describe the step-by-step process of DNS resolution when a user enters a domain name into a web browser. |
DNS | Would you recommend changing DHCP to deliver the URL instead of the IP address of the DNS server? |
Routing | When will the split horizon technique prevent slow convergence? |
IoT | How can IoT devices use SMTP? Explain. |
SNMP | What is the role of the MIB in SNMP and how does it contribute to machine independence? |
NAT | Compare how NAT works for outbound and inbound communication. |
General | Why can packets arrive out of order? |
General | What's the difference between the roles of a router and switch in a local network? |
General | Suppose you have to send an email to your aunt in ASIA from the us. Draw a diagram to show how the packets will reach its destination if NAT is involved on both ends. Show all addresses within the data that is transferred. |
General | Why is the Good Citizen Principle important? |
General | Explain the soft state principle |
General | From the standpoint of protocol design, what is the scarcest resource on the Internet? |
General | Why use port numbers when we could identify processes by the process ID on each machine? |
SMTP | What is the role of the MX record in email transmission? |
IP | How does IP forwarding alter the original datagram? |
Ethernet | How does a switch reduce broadcast traffic and ARP traffic? |
DNS | Explain how a DNS poisoning attack works and outline measures that can be taken to prevent it. |
VPN | What are the comparative advantages and disadvantages of split tunneling and full tunneling VPN implementations? |
FTP | What protocols does FTP use? |
FTP | Why does FTP use two TCP connections for a transfer? |
FTP | How many connections does FTP use? Why? |
FTP | Compare active and passive FTP with regard to security and data transfer and NAT. |
Telnet | Compare Telnet and SSH for remote terminal access. |
SMTP | What protocol does SMTP use to transmit messages? Explain. |
IMAP | What's the difference in server resource utilization between IMAP and POP? |
DHCP | List four items of information that a host needs upon connection to the internet. |
Addressing | What is the primary purpose of using subnetting in IP addressing? |
TCP | In what scenario would UDP be preferred over TCP? Give a specific example. |
VPN | How does a VPN contribute to secure mobile communications? |
Sockets | How does a program specify a process to connect to? |
HTTP | Why was HTTP designed as a stateless protocol? |
ICMP | How does ICMP violate the layering principle? |