605.674.81 - Network Programming

Computer Science
Fall 2023


Emphasis is placed on the theory and practice associated with the implementation and use of the most common processto-process communications associated with UNIX. The interprocess communications comprise both local and distributed architectures. The distributed communications protocols include those most widely implemented and used: the worldwide Internet protocol suite [the Transmission Control Protocol/ Internet Protocol (TCP/IP), and the U.S. government-mandated International Organization for Standardization (ISO) protocol suite]. Practical skills are developed, including the ability to implement and configure protocol servers (daemons) and their clients. Students are expected to have working knowledge of UNIX.


Course Structure

The course content is divided into modules. Course Modules can be accessed from the Course Modules page located on the left navigation. A module will have four main sections: Overview, Learning Guide, Content, and Assignments. Students are encouraged to preview all sections of the module before starting. Modules run for a period of seven (7) days. Module start dates are clearly posted on the Course Calendar. Students should regularly check the Calendar for assignment due dates.

Course Topics

Course Goals

One goal of this course is to design and implement effective and efficient network clients and servers in the TCP/IP protocol family. Another goal is to develop protocol independent solutions. A third goal is to be able to critique current network Application Program Interfaces (APIs) with an eye toward future APIs

Course Learning Outcomes (CLOs)


Stevens, W.R., et. al. (2003) UNIX network programming, The sockets networking API, (3rd ed.)
ISBN-10: 0131411551
ISBN-13: 978-0131411555

Required Software

For this course, you are provided with UNIX accounts on dev4.jhuep.com (a Solaris machine) and absaroka.jhuep.com (a Linux machine). Login access to this server is via the SSH protocol. Thus, in order for you to easily interact with the UNIX system you must get a secure terminal emulation program that uses ssh. There are several good programs available for free; for example PuTTY, a free software program available from http://www.chiark.greenend.org.uk/~sgtatham/putty/ can be used on Windows platforms; if you have a Mac or a Linux system, you can simply use the ssh program there.

SFTP (optional)
You may also want to be able to transfer files between your system and the UNIX systems. Some type of "file transfer protocol" (FTP) client will be required. I recommend that you try "FileZilla", which can be downloaded from: http://sourceforge.net/project/showfiles.php?group_id=21558. Make sure when you install this program, you configure it to use SFTP (Secure FTP). Again, of course, if you have a Mac or a Linux system, you can simply use the sftp program.

Student Coursework Requirements

It is expected that each module will take approximately 7–10 hours per week to complete. Here is an approximate breakdown: reading the assigned sections of the texts (approximately 2–3 hours per week) as well as some outside reading, listening to the audio annotated slide presentations (approximately 1-2 hours per week), and project assignments (approximately 3–5 hours per week).

Note that the projects are spread out over several weeks or modules, so if a student does not put the time into the project during the initial days of the project assignment, a student will need to make up that time as the due date of the project approaches. In other words, course work will be available to allow students to maintain a consistent week by week workload, but procrastination may require a heavier workload as the due date of a project approaches.

This course will consist of three basic student requirements:

1. Module Discussions (30% of Final Grade Calculation)

A minimum of two posts are required for each discussion question: an initial post and a response. These posts are due by midnight of the due date as specified in the Course Calendar. Be concise, but support any assertions using the textbook or other external sources. Keep your posts to a single topic to promote lively discussion. Feel free to agree or disagree with your classmates, but please ensure that your postings are civil and constructive.

Responding to Class Discussion Topics
— Your instructor will monitor class discussions and will respond to some of the discussions as needed. In some instances, your instructor may summarize the overall discussions and post the summary for the class (or may assign a student to do so).

Grading the Class Discussions
— Your instructor will provide a grade (with rationale, if necessary) for your post within 48 hours of your post.

Each discussion is worth 6 points— 3 points for the initial post, and 3 points for a response. If a student receives less than full credit for an initial post, they may post follow-up responses to their own initial post to further clarify and repair shortcomings.

Students are not limited in the number of responses they can provide for a discussion. Each response is graded independently, so regardless of the number of responses, you will receive a grade for your best follow up post.

The grading rubric for the discussions is as follows:

3 points— a full credit posting will thoughtfully consider and respond to the question (or classmate's message), demonstrating critical thought with support from course resources. Not only will such a post engage with the ongoing conversation in a rhetorically suitable fashion, it will foster further discussion on the topic, perhaps exploring new lines of discussion or different perspectives. The three-pointer isn't just a response; it's proof that you are facilitating learning both for yourself and your fellow students. Usually, you should cite a reference to support your claims in the post.

2 points— this posting is a competent response to the subject. It addresses the question, without demonstrating sufficient critical thought, and perhaps missing support for your assertions from your course or other on-line resources. This post contributes to the overall conversation as another voice on the subject.

1 point— reflects a less-than-adequate engagement with the subject, perhaps repeating a thought from another student in the discussion without adding much to it. It does little to advance the discussion underway, and does not demonstrate critical thought. Provided information is thin and commonplace. External support for your assertions are missing.

0 points— No post, only a brief nod toward the discussion, a post that is completely unrelated to the discussion or module content, or a post which detracts from the discussion (e.g. is a "flame").

Timeliness: A post missing the deadlines as laid out in the Course Calendar by a few days will lose a point; posts made more than a few days after the deadline will not be graded.

2. Projects (50% of Final Grade Calculation)

There are four projects throughout the course. These projects shall be completed on the UNIX servers: dev4.jhuep.com and absaroka.jhuep.com. Each project is designed to build on the previous; it is important to correct the errors in each assignment (after the grades are posted) so you don't make the same mistakes twice! Mistakes that are not fixed in the subsequent assignment shall receive a higher deduction than in the previous assignment.

When you complete the project on the UNIX system, you will submit your notification that the assignment is complete in Blackboard. Each project assignment will have explicit instructions on how you are to submit the assignment.

Project grades are reported to you via the Grade Center in Blackboard. Details on each deduction shall be provided. If that error applies to the next assignment, you should make sure to fix that error before the next assignment is submitted. If you aren’t sure what the issue is, or are not sure how to fix it, be sure to ask.

The assignments should be compiled and run on the (UNIX) systems (dev4 and absaroka) at the Computer Center. The executable programs must be installed in the structure mandated in the project assignment.

Problems or Questions - There will be a discussion topic for each project where you can post problems and questions that you have regarding each of these projects. Sharing these with classmates will be helpful to everyone, and I will be visiting this area regularly. Of course, you may also email me privately with questions as well.

Project Rules

1. The programs must be written in the 'C' or the 'C++' programming language.

2. A comment block at the beginning of each program, library source file, and Makefile shall include the following information: the student, the course, the name of the file, and a short description of the file's purpose.

3. Programs must exhibit reasonable style and readability. Your source code will be examined; it is not enough to get the programs to execute satisfactorily.

4. No copying or plagiarism. If copying or plagiarism occurs, the person or persons involved will receive no credit. They will be treated as not having submitted the assignment. This includes copying assignments which you may find on the Internet that are similar to your assigned work. (See the section on Academic Misconduct Policy below for more details.)

5. Collaboration by students on the assignment is limited to the blackboard discussion boards, or by explicit permission of the instructor. You are not permitted to provide your code to another student, nor are you permitted to receive code from another student.

6. Assignments are due by midnight of the due date stated in the course calendar. Your submission to Blackboard must be made before that time to avoid a late penalty. If the assignment is submitted late without prior arrangements (see #7 below) an automatic late penalty of 5% will be assessed with the additional 5% of the original possible grade for each day or part of day late until submission.

7. Extensions are only granted if arrangements are made with the instructor well in advance of the due date of the assignment. No last-minute extensions will be given; if a student has not completed the assignment by the due date, the student has the choice of receiving a grade based on the work completed to that point, or receiving the initial 5% penalty plus the 5% penalty for each additional day (or part of a day) it takes to complete the assignment. In these cases, the assignment is not considered complete until the assignment is submitted via the Blackboard Course Module and the instructor is notified by the student of the completion of the assignment via e-mail. The extension time will be considered complete at the time of the submission.

3. Quizzes (20% of Final Grade Calculation)

There shall be several short on-line quizzes throughout the course, at most one per module. These quizzes shall be true/false, multiple choice, and short answer, and are usually taken directly from the module content. These assessments are generally timed at about an hour each. The quizzes are "open-book", however, when taking the quiz, you must limit yourself to the module content, your notes, your text, and one other external reference. No "google" please!

Each quiz will be worth 100 percentage points. The quizzes shall be averaged together to provide a score which will make up 20% of your final grade.

Grading Policy

Student assignments are due according to the dates in the Calendar and assignment item within the corresponding module. Grades will be posted one week after assignment due dates.

We generally do not directly grade spelling and grammar. However, egregious violations of the rules of the English language will be noted without comment. Consistently poor performance in either spelling or grammar is taken as an indication of poor written communication ability that may detract from your grade.

A grade of A indicates achievement of consistent excellence and distinction throughout the course—that is, conspicuous excellence in all aspects of assignments and discussion in every week. A grade of B indicates work that meets all course requirements on a level appropriate for graduate academic work.

These criteria apply to both undergraduates and graduate students taking the course.

100–90 = A
89–80 = B
79–70 = C ​

Final grades will be determined by the following weighting:

Item% of Grade
Module Discussions                   30%

Academic Policies

Deadlines for Adding, Dropping and Withdrawing from Courses

Students may add a course up to one week after the start of the term for that particular course. Students may drop courses according to the drop deadlines outlined in the EP academic calendar (https://ep.jhu.edu/student-services/academic-calendar/). Between the 6th week of the class and prior to the final withdrawal deadline, a student may withdraw from a course with a W on their academic record. A record of the course will remain on the academic record with a W appearing in the grade column to indicate that the student registered and withdrew from the course.

Academic Misconduct Policy

All students are required to read, know, and comply with the Johns Hopkins University Krieger School of Arts and Sciences (KSAS) / Whiting School of Engineering (WSE) Procedures for Handling Allegations of Misconduct by Full-Time and Part-Time Graduate Students.

This policy prohibits academic misconduct, including but not limited to the following: cheating or facilitating cheating; plagiarism; reuse of assignments; unauthorized collaboration; alteration of graded assignments; and unfair competition. Course materials (old assignments, texts, or examinations, etc.) should not be shared unless authorized by the course instructor. Any questions related to this policy should be directed to EP’s academic integrity officer at ep-academic-integrity@jhu.edu.

Students with Disabilities - Accommodations and Accessibility

Johns Hopkins University values diversity and inclusion. We are committed to providing welcoming, equitable, and accessible educational experiences for all students. Students with disabilities (including those with psychological conditions, medical conditions and temporary disabilities) can request accommodations for this course by providing an Accommodation Letter issued by Student Disability Services (SDS). Please request accommodations for this course as early as possible to provide time for effective communication and arrangements.

For further information or to start the process of requesting accommodations, please contact Student Disability Services at Engineering for Professionals, ep-disability-svcs@jhu.edu.

Student Conduct Code

The fundamental purpose of the JHU regulation of student conduct is to promote and to protect the health, safety, welfare, property, and rights of all members of the University community as well as to promote the orderly operation of the University and to safeguard its property and facilities. As members of the University community, students accept certain responsibilities which support the educational mission and create an environment in which all students are afforded the same opportunity to succeed academically. 

For a full description of the code please visit the following website: https://studentaffairs.jhu.edu/policies-guidelines/student-code/

Classroom Climate

JHU is committed to creating a classroom environment that values the diversity of experiences and perspectives that all students bring. Everyone has the right to be treated with dignity and respect. Fostering an inclusive climate is important. Research and experience show that students who interact with peers who are different from themselves learn new things and experience tangible educational outcomes. At no time in this learning process should someone be singled out or treated unequally on the basis of any seen or unseen part of their identity. 
If you have concerns in this course about harassment, discrimination, or any unequal treatment, or if you seek accommodations or resources, please reach out to the course instructor directly. Reporting will never impact your course grade. You may also share concerns with your program chair, the Assistant Dean for Diversity and Inclusion, or the Office of Institutional Equity. In handling reports, people will protect your privacy as much as possible, but faculty and staff are required to officially report information for some cases (e.g. sexual harassment).

Course Auditing

When a student enrolls in an EP course with “audit” status, the student must reach an understanding with the instructor as to what is required to earn the “audit.” If the student does not meet those expectations, the instructor must notify the EP Registration Team [EP-Registration@exchange.johnshopkins.edu] in order for the student to be retroactively dropped or withdrawn from the course (depending on when the "audit" was requested and in accordance with EP registration deadlines). All lecture content will remain accessible to auditing students, but access to all other course material is left to the discretion of the instructor.