CS70 Network Fundamentals & Architecture

David Morgan
Santa Monica College
see syllabus for email address



Grade information

Reading list, per chapter:
 6th edition
 5th edition

Course outline

SMC dates/deadlines

DETER net testbed
  get/use an account
  news report (pbs)


Textbook's website

RFC lookup

Remote Unix access with ssh

Fundamental Unix Commands

Protocols: non-cyber examples

MAC address assignments
 - listing
 - search

TCP/IP - Intro to the IP Protocols

TCP/IP Pocket
Reference Guide
 - IPv4 version
 - IPv6 version

IP addresses

IP packet delivery

Network calculators:
  here's one
  and another
  and a third

Real world DSL
  - a DSL order

commercial routers

Windows networking
 Practically networked

Linux Network Administrator's Guide

Playing client
with telnet and netcat

Sockets: socket programming

Client/server sample:
 general architecture
 source code:
 - echoserver.c
 - echoclient.c
 executables (fedora15):

Sockets: sample programs
 - letter-upgrader server
 - letter-upgrader's client

 - upper-echoback server
 - client for echo-back server

 - web (file-send) server
 - client for file-send server

nmap: Ethical Hacker article

VPN article







echo (port 7)

discard (port 9)

chargen (port 19)

Slide presentations
(miscellaneous - see
course outline for
mainstream slides)





Access technologies (Chs. 12+16 abridged)

Wires, hubs, switches


dhcpd (address server)

DHCP protocol

Samba (MS fileshare client) 

SMB (MS fileshare) protocol


Networks: miscellaneous essentials

Networks: modems & Point-to-Point Protocol

Networks: firewalls

Narrated slide presentations

internetworks  (33MB)

ping  (16MB)


Section 1791  9:00a - 12:05p Sat Bus 263

This Website (http://homepage.smc.edu/morgan_david/)  will be used extensively to communicate with you. Announcements, grade reports, and assignments will be posted here. Please access the website from any SMC computer lab. Alternatively, it can be viewed from an internet-connected browser anywhere. You are responsible for awareness of the information posted here.

Installing fiber - there's a Certificate for that! Amateurs need not apply. I received this publisher promotion by email.


Where is optical data fiber found? - along rail, utility, and road rights-of-way, and underwater. (9/24)

Who owns the fiber? Companies like Level 3. They rent rights-of-way from the right-of-way owners. Level 3 has built an elaborate world wide network. A downtown L.A. datacenter allows you to co-locate your equipment where it can tap directly into their channels for faster and greater capacity data traffic than could be achieved at other endpoint locations in the city. (9/24)

Undersea cabling - former student Philip Postovoit did the service of researching cabling quite thoroughly. Of the many links about it he sent me, I found particularly interesting:
submarine cable map (click individual cables)
manufacture, shipboard loading, seabed laying youtube video
Haut débit en eau profonde (French)
"Contrary to conventional wisdom, satellites play a minimal role in the operation of the internet. Nearly 99% of international phone and data traffic goes through [submarine cables] like ours." Patricia Boulanger, Alcatel Submarine Networks  (9/24)

New transatlantic data cable by Microsoft/Facebook/Telexius completed. (9/24)

Homework - see "Homework" posting below dated 9/9. It's now current. (9/21)

Jet Propulsion Lab internship information. (9/20)

Wireshark, protocols, and people
--how many protocols does it support? - Apparently the number of protocols supported has reached about 2000.
--who pays these open-source people, anyway? - in most cases nobody. Open source is a labor of love and mostly programmers don't get paid. As for who they are in the case of Wireshark, a list of "contributors" appears at the bottom of the Wireshark man page (that means "manual" page, the traditional form of unix/linux documentation-- give the command "man wireshark" on a linux computer to see it). To my surprise it lists about 850 people. (9/16)

Packet capture files for you from the "wireshark" in-class exercise
I performed the exercise while running Wireshark and saved the traffic into capture files. You can open my files in Wireshark, to replay and analyze what I did.

The IP addresses of the machines I used were and Those are reflected in the captures. Get the files (unzip) then open them in Wireshark. You can then ponder the questions the exercise asks and use the captures to help you understand. The files are:
 for section 4:  echo-udp.cap  echo-tcp.cap
 for section 7:  login-telnet.cap  login-ssh.cap
 for section 8:  http.cap 

Satisfy yourself you have a pretty good idea what you are looking at. In particular, compare the header structures you see in the captured frames with the ones mapped out in the TCP/IP Pocket Reference Guide. And, practice using Wireshark's "Follow TCP stream" feature, found by right-clicking on packets in the packet list pane. It will starkly and unmistakably extract the password used in the telnet login session. And it will reveal the content of the web page obtained in the http browse session. There is nothing to turn in.  (9/16)

do the reading shown in the "Homework" columns of the course outline's topic 1 through 5, at your own pace as we cover these topics in class. All of this material is now current so please read it. Listen to the Bob Metcalfe youtube video, course outline section 4. (9/15).

Grades - have been posted at link entitled "Grade information" at left. (9/15)

What other data link protocols besides ethernet are out there? You might instead have
  point-to-point protocol ("dial up")
  frame relay
  asynchronous transfer mode (ATM)
  802.11 ("wi-fi") in part (9/15)

What's the difference?
ARPANet, Leonard Kleinrock's network (now, the Internet), used dedicated connections between computer nodes. He made a phone call to Stanford from UCLA. The wire employed belonged to the phone company. The wire was not used by any other nodes, during the phone call. It was not shared. It was dedicated. Nodes that used it owned it and did not have to compete for it with any other nodes.
ALOHAnet, Norm Abrahamson's satellite based network among islands in Hawaii, used a satellite that could service only one connection at a time, and that all participating computer nodes had to use. So necessarily, nodes had to share it. It was non-dedicated. Nodes that used it did not own it and had to compete for it with all other nodes.
Ethernet was derived from ALOHAnet, and relied on a shared medium too. But while the ALOHAnet medium was radio to the satellite, the ethernet medium was a copper wire. (3/4)

Cassini space mission - symbolizes the enterprise of human science of which we are small parts, and ends today. I knew a couple people on Jet Propulsion Laboratory's Cassini team where I learned that rocket scientists are just people, applied people first then rocket scientists a consequential second. People like you. Anything's possible.


Homework - 
see/do - the homework column of course outline, section 4 ("ethernet frames"). due on sputnik in the "assignments" subdirectory of your home directory end-of-day Wednesday 9/27
read - readings shown in the course outline through section 4; also read forward to succeeding sections as you have time, to prepare for upcoming topics.
listen - to Bob Metcalfe talk about inventing ethernet.

RFC process - how protocols get created. Here is a current example, HTTP 2 which was published as an RFC in May, 2015. See in particular the development timeline that has led it to this point. (9/8)

Screenshot of Microsoft Network Monitor courtesy of a former student. Compare the interface with Wireshark's.


Course outline - with approximate weekly topic coverage corresponded to related readings, homework assignments, and in-class slides I will use.

Homework - 
do the reading and homework shown in the "Reading" and "Homework" columns of the course outline's topic #1.

Cover art on Tannenbaum textbook:

What is it??

"Number please?" asks the switchboard operator. The switchboard is a board. It's for switching. Switching changes a circuit between you and somebody. It can complete a circuit to your Aunt Bheulah in Iowa City so you can thank her for the knit socks. After you hang up if you want to call your uncle in Waco you'll need to switch circuits, to get a circuit to him instead of her. That's what the operator does for you. The "switch"ing in "switch"board is circuit switching. Nowadays in computer networks it's not circuit switching anymore, it's packet switching.


Functional layering - the famous "Open Systems Interconnect" model is depicted below. Somebody once had the idea that maybe there could be a way to get independent computer systems of different types to be able to exchange information with one another. The diagram blueprints the idea for "how in the world are we going to make that work??" That idea is the subject of this course.

First-day administrative information you will need to know:

Procedures for using class laptops

A Remote Unix system account will be created for you.

Distributing files from sputnik to the class as a whole,  publicly - the above file transfer discussion describes file movement to and from your own home directory, exclusive to you. Sometimes I will want to have someplace to put a file so everybody can get to it and download it. When I do that, here's how to download them.

Using ssh (secure shell). ssh is an important tool you will use for interacting with remote computers. For that you will need an ssh client. There are a number of ssh client alternatives.

Running linux at home.

Slides available online - for most if not all slides I will show in class. Links to them can be found in the "Slides" column of the course outline.

Course-long textbook reading - a chapter-by-chapter list ( 6th edition, 5th edition ). The textbook is divided into chapters and they in turn into numbered sections. The list tells you which sections to read for this course when chapters are assigned. For example if I assigned chapter 10 and it had 17 sections, if this list specifies "10.1-100.5, 10.7, 10.12-17" it means I didn't feel sections 10.6 nor 10.8-11 were relevant enough so I only list the balance of the chapter. Read unlisted portions for your own interest if you wish, but the listed sections are what's officially assigned to you.

Textbook - Computer Networks and Internets, sixth edition, Douglas Comer, Pearson Prentice Hall , 2015.

Wireshark - is an excellent free packet capture utility. What is a packet, and why caputre it? We'll talk about that later. I will ask you to install and use Wireshark later in the semester, assuming you have a linux or windows computer available on which to do so. Please visit Wireshark's home page.

Opportunity - I'm happy to tell you that as a class we have the fortunate invitation to use a network testbed facility operated by USC/ISI called DETER. I will request individual DETER accounts for you; when they are created you will get an email message with info and credentials. In class I will describe DETER and how we will use it. This will come some weeks into the semester. In the meantime, you can explore the links under the heading "DETER net testbed" at left if you like.


"What hath God wrought?"
May 24, 1844

"Mr. Watson come here, I want to see you."
March 10, 1876

October 29, 1969