Exam Questions

The class has decided to write the midterm themselves. These are the approved questions. The midterm will be taken from these questions. Exam questions may have different wording, but the subject of every question on the exam will match a subject listed here.

AddressingDoes the internet need to have two different address spaces?
AddressingHow do switches help reduce traffic in a network?
AddressingWhat are the differences between an IP address and a MAC address?
AddressingWhat’s the difference between a public IP address and a private IP address?
AddressingWhich address spaces we have discussed are physical and which are virtual?
AddressingWhat is subnetting and why is it useful?
AddressingWhy does the internet have two different address spaces for host devices?
ARPIn what special cases does a host connected to an ethernet not need to use ARP or an ARP cache before transmitting an IP datagram?
ASWhat is the purpose of autonomous system routing?
BGPHow does BGP differ from interior gateway protocols?
DHCPSuppose you have a piece of hardware with a MAC address that has an assigned IP to it. You need to replace that hardware but you want the IP to be the same on this. Is this doable? If not why not? If so what would you need to do?
Error reportingIf a packet being transmitted isn’t lost, for two protocols, a destination not found message will not be sent. What are they, and why not?
ErrorsIP headers and data payloads incorporate checksums. Why have this redundancy? Which are checked by the router and which by the destination device?
GeneralResources on the Internet are not limited, so when resources are scarce, what principle should be followed?
GeneralFrom the standpoint of internet protocol design, what is the scarcest resource on the internet?
GeneralWhy are internet protocols layered?
GeneralWho is responsible for the day to day operation of the overall internet?
GeneralMatch each protocol with its function:
a. TCP
b. UDP
d. DNS
1. reliable, connection-oriented data transfer
2. connectionless, data transfer
3. low-overhead data transfer
4. error reporting
5. resolves domain names to IP addresses
GeneralWhat is end-to-end operation in internet networking? What is the advantage of this principle?
GeneralSuppose you’re creating the internet from scratch. What changes would you make knowing what you know now about IP addresses, MAC addesses, and other protocols.
GeneralWhat is the internet?
ICMPHow does traceroute use ICMP?
ICMPWhich ICMP messages does ping use, and how does it use them?
ICMPWhy would you use UDP for traceroute instead of ICMP?
IPFragmentation and reassembly are different for IPv4 and IPv6. Which is better? Why/
IPWhat is meant my MTU?
IPWhat does a router do with an IP packet that has a TTL of -2?
IPWhy use port numbers when we could identify processes by the process ID on each machine?
IPWhat is an IP datagram?
IPV6What is the major problem addressed by IPV6?
IPV6What is the primary motivation for the changes made in IPV6, and how does it address the limitations of IPV4?
MPLSHow does MPLS achieve higher speed than traditional IP routing?
MPLSHow do MPLS routers make forwarding decions based on labels.
MulticastWhat will be the result of a ping to a multicast IP address?
MulticastFor multicast routing, how is TTL used to control the scope of multicast traffic?
MulticastHow is multicast different from broadcast and unicast?
NATHow does NAT allow an organiztion to extend the life of its IPv4 address allocation?
NATWhat is the role of the port number in NAT?
RoutingWhat is the primary purpose of a router in the internet?
RoutingWhat’s the difference between a router and a switch in a local area network?
RoutingWhen is a datagram considered undeliverable?
RoutingSimply describe how link-state routing works, in terms of the router information exchange that begins when a new router is connected to a network.
RoutingSimply describe how shortest-path-first routing works, in terms of the router information exhange that begins when a new router is connected to a network.
RoutingWhy is there a default route in the router table?
TCPTCP is reliable, yet it transmits over ethernet, that is not reliable. How can a protocol be reliable if it uses an unreliable protocol for transmission?
TCP and UDPWhen would you choose UDP instead of TCP for network communication?
TCPTCP ensures that every packet is delivered. But waiting for each packet to be acknowledged and then sending another is inefficient. How is this problem solved?
TCPWhy can packets arrive out of order?
TCPCan we design a new version of TCP that doesn’t have sequence number? Explain.
TCPHow does TCP ensure reliable delivery?
TCP and UDP Discuss a scenario where using UDP would be advantageous over TCP and vice versa. Justify your choice based on the requirements of each scenario.
TTLSuppose that there was one router that, instead of decrementing TTL by one, increased it by 5 for every datagram that it routed. What would be the overall effect on traffic on networks connected to this router?
TTLHow is the TTL field used to prevent indefinite looping of IP datagrams?