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.
| Topic | Question |
|---|---|
| Addressing | Does the internet need to have two different address spaces? |
| Addressing | How do switches help reduce traffic in a network? |
| Addressing | What are the differences between an IP address and a MAC address? |
| Addressing | What’s the difference between a public IP address and a private IP address? |
| Addressing | Which address spaces we have discussed are physical and which are virtual? |
| Addressing | What is subnetting and why is it useful? |
| Addressing | |
| Addressing | Why does the internet have two different address spaces for host devices? |
| ARP | In what special cases does a host connected to an ethernet not need to use ARP or an ARP cache before transmitting an IP datagram? |
| AS | What is the purpose of autonomous system routing? |
| BGP | How does BGP differ from interior gateway protocols? |
| DHCP | Suppose 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 reporting | If 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? |
| Errors | IP headers and data payloads incorporate checksums. Why have this redundancy? Which are checked by the router and which by the destination device? |
| General | Resources on the Internet are not limited, so when resources are scarce, what principle should be followed? |
| General | From the standpoint of internet protocol design, what is the scarcest resource on the internet? |
| General | Why are internet protocols layered? |
| General | Who is responsible for the day to day operation of the overall internet? |
| General | Match each protocol with its function: a. TCP b. UDP c. ICMP 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 |
| General | What is end-to-end operation in internet networking? What is the advantage of this principle? |
| General | Suppose 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. |
| General | What is the internet? |
| ICMP | How does traceroute use ICMP? |
| ICMP | Which ICMP messages does ping use, and how does it use them? |
| ICMP | Why would you use UDP for traceroute instead of ICMP? |
| IP | Fragmentation and reassembly are different for IPv4 and IPv6. Which is better? Why/ |
| IP | What is meant my MTU? |
| IP | What does a router do with an IP packet that has a TTL of -2? |
| IP | Why use port numbers when we could identify processes by the process ID on each machine? |
| IP | What is an IP datagram? |
| IPV6 | What is the major problem addressed by IPV6? |
| IPV6 | What is the primary motivation for the changes made in IPV6, and how does it address the limitations of IPV4? |
| MPLS | How does MPLS achieve higher speed than traditional IP routing? |
| MPLS | How do MPLS routers make forwarding decions based on labels. |
| Multicast | What will be the result of a ping to a multicast IP address? |
| Multicast | For multicast routing, how is TTL used to control the scope of multicast traffic? |
| Multicast | How is multicast different from broadcast and unicast? |
| NAT | How does NAT allow an organiztion to extend the life of its IPv4 address allocation? |
| NAT | What is the role of the port number in NAT? |
| Routing | What is the primary purpose of a router in the internet? |
| Routing | What’s the difference between a router and a switch in a local area network? |
| Routing | When is a datagram considered undeliverable? |
| Routing | Simply describe how link-state routing works, in terms of the router information exchange that begins when a new router is connected to a network. |
| Routing | Simply 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. |
| Routing | Why is there a default route in the router table? |
| TCP | TCP 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 UDP | When would you choose UDP instead of TCP for network communication? |
| TCP | TCP 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? |
| TCP | Why can packets arrive out of order? |
| TCP | Can we design a new version of TCP that doesn’t have sequence number? Explain. |
| TCP | How 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. |
| TTL | Suppose 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? |
| TTL | How is the TTL field used to prevent indefinite looping of IP datagrams? |