COS 460/540 - Computer Networks

Stephen Houser

January 8, 2010

From the USM Course Catalog: "A description of computer networks organized as a layered architecture based on the OSI Reference Model. Protocols and services of each layer are examined in detail. Specific local area networks, metropolitan area networks, and wide area networks will be considered. Prerequisites: COS 285, COS 251. Cr 3."

We no longer explore the OSI network model as much. The focus of the course will be the Internet (TCP/IP) protocol stack, as it has far surpassed the OSI in actual use.

The class is dual-listed as an undergraduate and graduate course; graduate students will have additional reading and must prepare a presentation for the class.

Course Objectives

The lettered items above indicate the USM Computer Science curriculum learning objectives as follows:


Computer Networks: A Systems Approach, Fourth Edition, L.L. Peterson and B.S.Davie, Morgan Kaufman, 2007. lists this textbook as Computer Networks: A Systems Approach, Fourth Edition (The Morgan Kaufmann Series in Networking) (Hardcover) for $75.28.


The class will be graded on the three (3) exams and four (4) assignments (two of which are a multi-part project).

The exams will cover all material covered before the exam. The final exam will primarily cover the last sections of the course but will contain some material from the entire course.

The assignments require you to develop network client and server programs. They will be graded more on how they work (80%) as opposed to how they are constructed and your description of them (20%). Thus, they can be written in any modern programming language. If you intend on using something out of the ordinary (Java, C, C++, python, perl), please work the instructor prior to beginning for approval.

Graduate students will have additional reading and writing assignments as well as a presentation to the class (at the end of the semester) on their research.

Grading Policy

Grades are based on a point system as follows:

Common Assignments
Assignment #1 50 points
Assignment #2 75 points
Assignment #3 100 points
Assignment #4 100 points
Graduate Assignments (COS 540 Only)*
Research Paper 50 points*
Class Presentation 50 points*
Exam #1 100 points
Exam #2 100 points
Exam #3 (final) 125 points
Total 650 points / 750 points*

Letter grades are assigned by the following percentage of the maximum possible score(s):

% Score between Letter Grade
94% (611 points)100% (650 points)A
90% (585 points)93.9% (610 points)A-
87% ...89.9% ...B+
84% ...86.9% ...B


It cannot be stressed enough that attendance is very important. Many topics will be covered in class that may not be covered in the book. You are responsible for acquiring material missed due to absence.

Exam make-ups should be scheduled well ahead of time. If that is not possible, you need to make arrangements to take the exam outside of regular class time. Do not assume you can make up a missed exam.


The following is a preliminary schedule for the semester.

The reading chapters are out of the required textbook. They will cover material discussed in class. Read the material before class, attend class, and then re-read the material after class with your notes to get the best comprehension.

Date Material Covered Reading Due
1/18 Foundation: Architecture, Software, & Performance Ch. 1
1/27 Assignment #1
2/1 Direct Link Networks: Encoding, Framing, & Ethernet
Ch. 2
2/10 Exam #1
2/15 Winter Break
2/22 Packet Switching: Datagrams, Bridges, & Switches
Start discussion of Assignment #3 and #4 protocols
Ch. 3
2/24 Assignment #2
3/1 Finalize protocol for Assignment #3
3/8 Internetworking: IP, Routing, & the Internet Ch. 4
3/17 Exam #2
3/22 Spring Break
3/29 End-to-End Protocols: UDP, RPC, & Transport
Start discussion of Assignment #4 protocol
Ch. 5
4/5 Finalize protocol for Assignment #4 Assignment #3
4/12 End to End Data Ch. 7
4/19 Network Security Ch. 8
4/26 Applications Ch. 9
5/3 Graduate Presentations
5/10 Exam #3 (final) Assignment #4
Graduate Papers

Other Information

Should you need services or accommodations due to a disability to fully participate in the class please speak with me or contact the Office of Academic Support for Students with Disabilities, Luther Bonney 242.

Class cancellations are posted on USM's web site and on the Storm line at 780-4800.