Chapter 1 Notes
transmission rate: bandwidth (bits per second)
hosts = end systems
protocols define format, order of msgs sent and received among network entities, and
actions taken on msg transmission, receipt
network edge: hosts: clients and servers
Midterm 1 Fall 09
1 OOP (10 points)
The following denitions have been entered into the Python shell:
x = 0
y = 10
def _init_(self, y):
self.x = y
def a1(self, y):
self.x = max(self.x, y)
self.x = max(self.x, self.y)
6.033 Lecture 12
End to End Layer
Last time: network layer - how to deliver a packet across a network of multiple links
Recall that network layer is best effort, meaning:
- packets may be lost, reordered, garbled
- losses due to no route, queue
Building Fault Tolerant Systems from Unreliable Components
So far what have we seen:
Client / server
Seen a few examples of dealing with faults - e.g., providing exactly on
6.033 Spring 2008, Quiz 1
Page 2 of 12
1. [6 points]: Which of the following statements are true of the X Window System (as described in
the X Windows paper, reading #5)?
(Circle True or False for each choice.)
A. True / False The only
Networks: Lecture 3
Erds-Renyi random graph model
Phase transitions and threshold function
Jackson, Sections 4.1.1 and 4.2.1-4.2.3.
Networks: Lecture 3
Lecture 1: Introduction
Daron Acemoglu and Asu Ozdaglar
September 9, 2009
Networks: Lecture 1
What are networks?
Economic and social networks.
Network e ects.
Networks as graphs.
6.033 Lecture 13
Last time, we saw how the end to end layer ensures exactly once delivery,
using windows to efciently make use of the network.
Couple of loose ends:
- Reordering - packets may arrive at the receiver out of ord
Networks: Lecture 4
Emergence and size of a giant component
An application: contagion and di usion
Jackson, Sections 4.2.2-4.2.5, and 4.3.
Networks: Lecture 4
Phase Transitions for Erds-Renyi Mod
What is the relationship between a domain name (e.g., youtube.com) and an IP
DNS is the system that determines this mapping.
You contact a DNS server, give it a query
It responds with the answer, or
6.033 Spring 2009, Quiz 1 Solutions
Page 2 of 16
I Reading Questions
The following questions refer to Herbert Simons paper, The Architecture of Complexity (reading #2).
1. [2 points]: Simons notion of hierarchy organizes a collection of components by thei
Lecture notes for 15.564: Information Technology I
15.564 Information Technology I
Computer Security (Parts I & II)
Lecture notes for 15.564: Information T
6.01 Midterm 1
1 Di erence Equations (16 points)
System 1: Consider the system represented by the following di erence equation
y[n] = x[n] +
5y[n - 1] + 3y[n - 2]
where x[n] and y[n] represent the nth samples of the input and output si
designing a quizzer
want a console program that
reads a le of questions
displays them one by one
accepts user responses
prompts again if out of bounds
reports a total and message
Daniel Jackson 2008
What is the capital of France?
Chapter 8 DNS: a distributed, hierarchical database client wants IP for www.amazon.com; 1st approx:
client queries root server to find com DNS server client queries .com DNS server to get amazon.com DNS server
client queries amazon.com DNS server to get
Chapter 2 notes
server: always-on host, permanent IP address, data centers for scaling
clients: communicate with server, may be intermittently connected, may have dynamic IP
addresses, do not communicate directly with each other
PTP: Not always on, compri
Chapter 3 notes
Transport services and protocols:
Provide logical communication between app processes running on different hosts.
Transport protocols run in end systems
send side: breaks app messages into segments, passes to network layer
rcv side: reasse
15-441: Computer Networks
Homework 2 Solution
Assigned: September 25, 2002.
Due: October 7, 2002 in class.
In this homework you will test your understanding of the TCP concepts taught in class including ow control,
congestion control, and reliability.
18345 Introduction to Telecommunication Networks
Feb 14, 2011
Due: Feb 21, 2011
(a) Two hosts communicate with each other using Go-Back-N with transmitter window size
equal to 2. Suppose there are three sequence numbers in the system: 0, 1,
Socket Programming Assignment 2: SMTP
Due: Friday, September 28th by midnight
By the end of this lab, you will have acquired a better understanding of SMTP protocol.
Your task is to develop a simple mail client that sends email to any recipient. Your clie
Midterm problem set
Instructions: Submit a separate Python program for each of the following problems.
Write a function to display an integer in reverse order:
For example, reverse(3465) displays 5643. In your program pro
In this lab we will model a matrix storing the expectations of individuals on the economy for 4 quarters.
The matrix represents this information as shown below:
Chapter 6 Spanning tree
first construct a spanning tree
nodes then forward/make copies only along spanning tree Spanning tree: creation center node each node sends unicast join message to center node
message forwarded until it arrives at a node alread