124 Exams

Overview

The final can cover any material presented in class, on the slides, in the assigned reading, the projects, homework, etc. However, I wanted to provide you with a set of topics, terms, and sample questions to give you extra practice in preparing for the exam. What is below is not designed to be comprehensive, but rather designed to help you.

You may discuss these questions and ideas for answers on Piazza and/or with your classmates.

Note that the relative length of each of the following sections isn't indicative of their relative importance.

Networking programming fundamentals

• network sockets API: open(), connect(), send(), recv(), etc?
• How names are resolved to IP addresses in DNS
• to query a dns server, you need to know at least one IP address without using DNS. explain.

• Internet Protocol (IP) What is the IP service model?

• End to end protocols

  • Move from host-to-host to process-to-process communication model
  • UDP – thin layer on top of IP
  • TCP – provide abstraction of reliable in-order byte stream on top of IP protocol
• Signals and timeouts
• Concurrency, multi-tasking, multiplexing
• Locking, mutexes, sharing state between threads/processes

Protocol design and anlysis

• Framing vs. parsing
• Delimiter vs. length-value
• Graphing data, axes labels, error bars

Data Centers

• round-robin DNS vs load balancers. advantages and disadvantages of each
• replication vs partitioning: advantages and disadvantages
• terms: MTTR, MTBF, availability, yield, harvest, DQ principle
• terms: top of rack switch, PUE, SPUE
• tail latency vs. average latency
• Energy and power

Application-layer protocols: HTTP and Email

• purpose of the MTA, UA, MIME, SMTP, POP, IMAP
• what are the two parts of an email?
• terms for http: proxy server, request header, response header, status code

Remote procedure calls

• explain concept of 'idempotent'
• maybe vs at least once vs at most once semantics; how to implement each of these?
• Thrift
• Role of stub compiler, RPC runtimes
• Discuss whether the following operations are idempotent:
  • Pressing a lift (elevator) request button
  • Writing data to an offset in a file
  • Appending data to the end of a file (assuming there are no other writers in the system)

Overlay networks, P2P, Chord

• Compare and contrast aspects of flooding queries, supernodes, vs structured. Tradeoffs--which is better for joining, leaving, advertising content, querying for content.

• Assume you have a Chord system of 5 nodes with identifiers 0, 1, 2, 6, and 7.

  1. Draw the identifier circle and show which nodes the following keys will be assigned to 0, 4, 5, 8. You can assume the identifier space is 0-9.

  2. Each chord node must maintain routing state.

  Describe exactly what routing state must be maintained at each node to ensure correct function. Show what this state would be for node 6. What is the expected lookup time of an object?

  Describe what routing state must be maintained at each node to ensure fast lookup times. Show what this state would be for node 6. what is the expected lookup time of an object?

IPSec, VPNs, Tunnels

• How does IPSec ensure authentication? Encryption of traffic?
• How can you use tunnels to connect two networks together?
• What is IP-in-IP encapsulation?

Last updated: 2016-03-06 15:55:45 -0800 [validate xhtml]