A COMPUTER SCIENCE UNDERGRADUATE SPECIALIZATION IN ...

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computer science context. UAB'S undergraduate specialization in Telecommu- nications and Computer. Networking includes a four- course sequence: CS 433.
A COMPUTER SCIENCE UNDERGRADUATE SPECIALIZATION IN TELECOMMUNICATIONS AND COMPUTER NETWORKING *

Anthony C. L. Barnard Barrett R. Bryant Warren T. Jones Kevin D. Reilly Department of Computer and Information Sciences University of Alabama at Birmingham 1300 University Blvd. Birmingham, {barnard,

AL 35294-1170,

bryant,

jones,

that university curricula appropriIt k important ately reflect the rapid advances taking place in computer science ([ Fole88], [Hart92]). The area of telecommunications and computer networks is undergoing particularchange.

A conference

sponsored

(UAB)

by BellSouth

expressed an urgent need for educational programs keep up with the rapid advances that have occurred this area. paper

we use the phrase

offers

an undergraduate

program

based upon

ACM Curriculum ’91 [~ck91], leading to the Bachecore courses provide lor of Science degree. Traditional students with the fundamental design principles of the software and hardware of computer systems, the use of modern programming languages, and operating systems and equipment. Additionally, students have been able to specialize in one of two tracks: Information Systems, or Scientific Computing. In 1993 we instituted a third

Foundation [Jone90] called attention to the importance of telecommunications to the computer field and the need to emphasize this area in coursework and laborate ries at both the undergraduate and graduate levels (see also [Jone91]). Similarly, an NSF report [N CR192] on research priorities in networking and communications

In this

edu

The Department of Computer and Information Sciences at the University of Alabama at Birmingham

INTRODUCTION

ly rapid

U. S. A.

reilly}@cis.uab.

track

to complement

the activities

for Telecommunications

to in

is largely

a graduate

graduate

program

Education study

center)

embedded

of the UAB

Center

and Research (which with

a strong

in a traditional

under-

computer

science context.

“telecommunica-

UAB’S undergraduate nications and Computer course sequence:

tions and computer networking” in a broad sense, to include information networking and distributed computing, especially heterogeneous client-server applications.

specialization in TelecommuNetworking includes a four-

CS 433. Telecommunications

and Computer

Net-

works * This work was supported in part by National Science Foundation Instrumentation and Laboratory Improvement Grant Inc.

DUE-9351476

and a donation

from FTP

CS 434. Internetworking

Software, CS 435. gramming

Network

CS 436. Advanced

Permission to copy witbout fee all or part of this material is grantad provided that the copies are not made or distributed for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Mscbinery. To copy otherwise or to republish, rerfuires a fee andlor specific permission. SIGCSE ‘SS 2/9S Philadelphia, PA USA e199S ACM 0-09791 -757-X9WO002.... SO.SO

and

Distributed

Information

System

Pro-

Networking

In the sections which follow, we will describe curriculum and conclude with a discussion of experiences with the curriculum. More details about the specialization may be found at

the our

324

http://www.cis. spirit

of ACM

uab.edu/info/dept/courses/. Curriculum

for the “knowledge

In the a proposal

‘91, we begin with

units”

which

comprise

through

TN22.

CS 435 covers TN23

436 fills in the wireless

this special-

and high-

through

TN25.

performance

CS

aspects

of TN 13, and covers TN26.

ization. LABORATORIES KNOWLEDGE CATIONS

UNITS AND

IN

COMPUTER

At

NETWORKING

UAB

ratories, We propose that this field be composed lowing knowledge units: TN: Telecommunications and Computer (approximately 144 lecture hours)

of the fol-

History and Overview of Telecommunications and Computer Networking (4 hours)

TN2:

Protocol

TN3: TN4:

Model (3 hours) Services and Primitives Protocol Specification,

TN5:

Theoretical

TN6: TN7:

(2 hours) Transmission Media and Modes (4 hours) Switching Systms, including standard Telephone and Narrowband ISDN (5 hours)

TN8:

Cellular

Performance

(2 hours) Verification,

client;

and

[Tane96]).

Protocols

TN23-TN25. AND

NETWORKS

The

course

generally

pursues

a bottom-up

After

mid-term

the course

includes

a “hands-on”

Local Area Network (LAN) laboratory, nominally of Transmission Control Prototwo hours per week. col/Internet Protocol (TCP/IP) is emphasized, which involves bringing in material from [Come95], since the

Connection

material

(6 hours)

TN15: Network-Layer

by an

study, following the 1S0 Open Systems Interconnect (0S1) model. Layers 1, 2 (MAC sublayer), 3, and 4 are emphasized.

for Shared Channels

Service;

by two laboin part

CS 433 is the first course in the sequence and includes portions of knowledge units TN1-TN16, concentrating on local-area networks and using (Tane89] as a textbook (shortly to be replaced by the 1996 edition

and Communications

and Unreliable

funded

TELECOMMUNICATIONS

COMPUTER

(3 hours) TN13: IEEE 802 Standards and High-Speed Extensions (10 hours) Management

is supported

equipment

this lab supports

CS 433 Communication

Satellites (2 hours) TN9: Framing and Error Control (3 hours) TN 10: Flow Control, including Sliding Window (3 hours) TN1l: Data-Link Layer Protocols (3 hours)

TN 14: Reliable

specialty

datagrams). Lab B contains two networked Sun workstations, one configured as a server and the other as a

(4 hours)

TN12: Access Protocols

this

containing

Software’s LANWatch monitor; students normally work in pairs at these machines. The other two PCs normally run aa server/routers, using Novell NetWare 4.01 (which includes the capability to route Internet Protocol (1P)

and the 0S1 Reference

Basis of Data

Radio

EQUIPMENT

NSF ILI grant. Lab A, which supports knowledge units TN2-TN22, contains ten networked Gateway 2000 PCs. Eight of these normally”run as workstations or run FTP

Networking

TN1:

Layering

AND

TELECOMMUNI-

port

(10 hours)

extends

TN16: Transport-Layer Protocols (10 hours) TN17: Bridging between Networks (2 hours) TN18: Internet Control and Management, including MIB/SNMP (8 hours)

on TCP/IP

the lab.

The

in [Tane89]

is not adequate

laboratory

into the final

component

to sup-

of the class

examination.

Although TCP/IP was developed as an internetworking protocol suite, wide-area networks and internetworking

are de-emphasized

in CS 433.

TN19: Static and Dynamic Routing (10 hours) TN20: Directory (Name) Service (4 hours) TN21: File Systems and Transfer, Remote Login,

1ne specmc laD sessions are:

and E-Mail (8 hours) TN22: Security, Cryptography, (4 hours)

Students get their first “hands-on” experience with an Ethernet LAN, connecting 10baseT cables and

TN23: Protocol

Compiling

and Firewalls

loading

(6 hours)

TN24: Distributed Systems (10 hours) TN25: Programming Client-Server Systems TN26: Broadband

ISDN

Ethernet/Address

and ATM

(10 hours)

(8 hours)

These knowledge units are distributed across the four courses. CS 433 focusses on TN1 through TN16. CS 434, which specializes in TCP/IP, fills in the relevant details

in TN1O,

TN15,

and TN16,

325

TCP/IP

Protocol

software

(ARP).

layers.

Ac-

tivities include: testing connectivity using “ping”; examining structure of frames using LANWatch monitor (including decoding hexadecimal representations of frames); examining the ARP cache. This experience emphasizes the multi-level encapsulation of messages within an 1P datagram and of the 1P datagram within an Ethernet frame.

2. Internet

and covers TN17

the various

Resolution

Protocol

(IP)/Internet

Control

Mes-

sage

Protocol

(ICMP)/User

(UDP)/’Ikivial

Datagram

File Transfer

Protocol

Although

Protocol

Students set up a PC as a TFTP-server and copy a 1.6 MByte file from the server to a client workstation. Activities include: measuring time taken for transfer; examining internal details of the frames using LANWatch. This shows encapsulation of the TFTP

message within

a UDP

datagram,

datagram within an 1P datagram, gram within an Ethernet frame.

Netware

the UDP

and the 1P data-

Protocol (IP)/Transmission (TCP)/TelNet.

ing, etc. ) (option

with

establishment, attention

negotiation,

44 File Transfer

Control

Pro-

of TFTP and FTP, required for transfer

Cs

434

sequence

also to TelNet

number-

ered up.

activities

comparing

2. Static

emphasize

Exams

include

a

Bridges

Between

characteristics

Students

units

Routing

use TFTP

to transfer

a 1.6 M-

Between

of the same file within a in CS 433 lab session 2. Two Networks.

1P router.

This

es, subnet

masks and default

stations.

involves

The router

assignment

has static

of 1P address-

routers

in the work-

routing

enabled

and

Routing Information Protocol (RIP) disabled. Only the direct connections are needed in the routing tables (no indirect connections exist with only two segments). Students ping the target on the “other” network, and use LANWatch to observe the sequence and internal details of frames exchanged, noting that the hardware destination addresses and 1P destination addresses are different for the first time (the difference between the immediate destination and the ultimate destination). Students a-

covered. In this second course the weekly lab sessions are again central, this time lasting the entire course. knowledge

Networks.

Again we begin with two disconnected Ethernet segments, which are then connected using a single

including comparison of times of the 1.6 MByte file.

from

and the Final

time required for transfer single network, measured

The title of CS 434, “Internetworking,” signals that the emphasis is on a connected system of at least two net works. Connection by means of bridges or routers is

mainly

434

Byte file across the bridge, measuring elapsed time for transfer. This can then be compared with the

INTERNETWORKING

The course draws

CS

This lab begins with two disconnected Ethernet segments, which are then connected using a transparent bridge. Using the LANWatch monitor, students observe functioning of the bridge, including the “learning” process when the bridge is first pow-

(FTP).

frames;

and

lab sessions are:

1, Transparent

Students set up a PC as an FTP server, and copy the same file as in Lab Session 2 to a client workstation. Activities include: measuring time taken for transfer; using LANWatch to study sequence of frames exchanged and the internal composition of representative

the Mid-Term

The specific

etc.)

Protocol

433

4.01.

Both

Students set up a PC as a TelNet server, and establish cent act from a client workstation, using LANWatch to observe sequence of frames exchanged; detailed internal composition of representative frames with emphasis on TCP activities (connection

CS

lab component.

3 Internet tocol

both

TCP/IP, they are not exclusively TCP/IP courses. In the middle of CS 434 there are lectures on the Xerox system, XNS, which formed the basis for the Novell systems that dominate the LAN world. In the lab the students have the opportunity to work with an IPX internet constructed with two server/routers running Novell

(TFTP).

TN17-

TN22, and fills in TCP/IP details from TN1O, TN15 and TN 16. Again a bottom-up inside-out approach

gain use TFTP

is used. In the lectures, [Come95] is used, although the order of the material is varied considerably to mesh with the lab semions.

taken for transfer across the router with the time obtained in lab session 1 for file transfer across the bridge.

this time

3. Static

In the labs, internetworking is introduced first as the connection of Ethernet segments entirely within the

The

physical lab (this allows us to take liberties such as deliberately introducing routing loops). In later lab ses-

campus

network,

and finally

a 1.6 MByte they compare

and Dynamic lab internet

file,

but

the time

Routing. is now expanded

to three

Eth-

ernet segments, connected by two routers. Additional entries are made in the static routing tables for the indirect connections (via a second router).

sions the students “escape” from the physical confines of the lab, first to the CIS Department network, then to the UAB

to transfer

across the router;

Students

out to the Inter-

changed

net. In the last lab sessions the students use Netscape to obtain multimedia information over the Internet.

use LANWatch when

pinging

to study targets

the frames

ex-

across two routers.

At first, a deliberate mistake is made, omitting necessary routes from the tables; this results in

326

“network unreachable” ICMP messages, which are studied by the students. Addition of the necessary routes establishes connectivity. routing is disabled and RIP enabled. LANWatch router,

to observe

RIP

more distant

routes

serve dynamic

from each other.

addition

4. “Host

Redirect”

Complex

Network Management Protocol (SNMP) and the Management Information Base (MIB).

when physi-

Students examine the management information base in their workstations, and see how this can be remotely monitored using SNMP.

Internets.

8. Gopher

In the TCP/IP implementation that we use (Novell’s LAN Workplace for DOS), workstations do not participate is a mechanism namically:

may send an ICMP

“host redi-

this activity with LANWatch and LWPCON. As a final exercise in building internets, we assemble an internet consisting of five Ethernet segments and two routers. At the hardware level, “null-modem” cables are used for two of the networks, so that students see this possibility y. At the network level,

Cs 435 NETWORK AND SYSTEM PROGRAMMING

routing

tables

sizes the upper layers of the 0S1 reference model, and gives students their first opportunity to program appli-

of the

cations to run in a distributed computing environment. The knowledge units covered by this course include por-

routers.

5. Exploration

of Novell

Netware

tions of TN2, TN4, TN1l, TN12, TN15 and TN16, and the entirety of TN23-25. Since the material covered in CS 435 is heavily influenced by programming and operating systems considerations, the subject matter also coordinates nicely with other courses within the UAB

4.01.

An internet is established with two Novell LAN’s, each with a NetWare 4.01 server and four workstations; these two LAN’s are connected using the IPX

routing

capability

of the servers.

eral exploration of Novell on a carefully-structured vell file system

After

a gen-

undergraduate

LAN’s, students embark investigation of the No-

and its security,

controlled

6. Domain

(DNS).

and use LANWatch

to observe

course.

the process Sun Solaris systems form the core of the laboratory environment. Student exercises are mainly rooted in illustrations in [B1oo92]. For a DCE context there

of querying the domain name server to determine the corresponding 1P address. With connection to the outside world established, students can ping a machine anywhere in the world, and use LANWatch to measure the time taken for the round trip. The students use TRACEROUTE utility to determine ty, using

path

taken

LANWatch

by ping to Purdue to study

in-

Directory Service (a naming service), time service mechanics and security, are all covered using [Rose93]. ONC analogs from [B1oo92], are also covered. Distributed file systems are cited as premier examples of clientserver and remote procedure calling. Demonstrations form an important part of the classroom portion of the

This network lab reverts to a single Ethernet segment, but now is connected by a bridge “through the wall” to the CIS department network. Students ping one of the CIS department computers by name,

a survey of the complex

teracting software that makes up a distributed programming environment. The Open Software Foundation’s Distributed Computing Environment (OSF DCE), Cell

of FTP).

Name Service

curriculum.

The course begins with

by the

lab instructor’s adding “rights” incrementally (this provides a comparison to the relatively unsophisticated security

DISTRIBUTED

Completing the bottom-up development of networking outlined in the previous two courses, CS 435 empha-

students must assign suitable 1P addresses, subnet masks, and default routers in the workstations, as in the static

Gopher and wide variety in the world World-Wide

Web ( WWW), including instruction on Hyper-Text Markup Language (HTML); students use HTML to construct their own WWW home pages.

rect” message to a workstation, which will note this information in its routing table. Students observe

well as entries

and Netscape.

Students are instructed in the use of Netscape, and are able to obtain a of information from sources anywhere using the Internet, Emphasis is on the

in the RIP activity. However, there for workstations to learn routes dy-

Routers

Stu-

7. Simple

ob-

made, and deletion of old are deliberately broken.

and More

works.

each

“learn”

Stduents

of new routes

cal connections are first routes when connections

from

automatically

how TRACEROUTE

dents also use the FINGER utility, and use FTP to obtain a sample Request For Comments (RFC) from the InterNet Information Center.

Then static Students use

broadcasts

and see how routers

and understand

the frames

is similar material in [Shir94]; this contains examples, such as vector addition, that when slightly modified can be run under Solaris or Linux. OSF and ONC flavors thus dominate, but side commentary is provided on 0S1

Universi-

and the Windows-NT

involved

327

variant.

Both

the IDL

and ONC

rpcgen-based protocol ers are discussed.

definition

languages

The ONC system for student projects.

is used for class assignments

tions and the electrical power utility. We have made several presentations about our curriculum to local groups,

and compil-

which and

Some students select ambitious projects, e.g. running an example from [Rose93] on a Linux port of DCE. Other students prefer the safer ground close to examples demonstrated in the classroom,

e.g.

remote

and directory

database

listing,

query/update,

or distributed

remote

image

all welcomed

file

[B1oo92]

J. Bloomer,

INFORMATION

networks

-

wireless

LANs

switches Ethernet;

[Fole88]

J. Foley, ed., “Report of the Computer Science Workshop: Undergraduate Computer Science Education”, Report on the National Science

(IEEE

Using RPC,

1992.

Intern etworking with TCP/IP. D. Comer, Protocols and ArchiVolume I: Principles, tecture, 3rd cd., Prentice-Hall, 1995.

on

802. 11), non-blocking Ethernet peting standards for 100 Mbps

it was

(Come95]

not covered thoroughly in the earlier courses, such as the following topics from knowledge units TN13 and TN26: Local-area

Programming

Power

& Associates,

O’Reilly

A preliminary version was taught in Spring 1995 as a “special topics” course, but CS 436 will not be formally offered until Spring 1996, so that its content is still somewhat fluid. Clearly, it should include areas



and thought

REFERENCES

processing

(based on [B1oo92]). CS 436 ADVANCED NETWORKING

the information

a significant contribution to the local and regional needs for networking expertise. Therefore, we believe that the specialization has been successful in meeting its objectives.

[Hart92]

and com-

Foundation

Disciplinary

Undergraduate

J. Hartmanis The

and

Future:

H. Lin,

A Broader

er Science

Workshops

Education,

1988.

eds.,

Agenda

Computing for

Comput-

National

and Engineering,

Acade-

my Press, 1992. ●



Metropolitan-area networks - IEEE 802.6 (Dual Bus Distributed Queue) and Switched Multimegabit Data Service (SMDS)

[Jone90]

lenges and Opportunities,” (Invited PreBelLSouth Foundation Conference sentation)

Wide-area networks - frame relay as an out.mowth Optical Network (S~NET) of X.25, Synchronous and cell relay (Asynchronous

‘llansfer

on Telecommunications:

Mode)

Students

Equipment is on order to support a lab experience wireless Ethernet LANs. However, it is far from

with clear

four

respectively.

times,

Thirteen

enrolling students

Networking

[Rose93]

[Shir94]

importance

J. Shirley, Writing

W. DCE

sociates, [Tane89]

[Tane96]

the growing

Rosenberry,

& Associates,

CONCLUSIONS specialization

W.

Kenney

DCE

of computer

in response networks

[Tuck91]

to

in our

328

G. Fisher, O’Reilly

Guide to D. Magid, O’Reilly & As-

Applications,

1994. Computer

A. S. Tanenbaum,

A. B. Tucker, et. the ACM/IEEE-CS Report

Commun.

and

Applications,

Hu and

A. S. Tanenbaum, ed., Prentice-Hall,

Force

geographic area, as communicated to us by local financial institutions, hospitals, BellSouth Telecommunica-

Research

1993.

cd., Prentice-Hall, was established

1990.

1992. D.

Understanding

435, and seven took the preliminary version of CS 436. The complete sequence has been completed by 6 students, all of whom will be graduating in the next academic year. We expect to be able to rotate 32 students per year through the entire sequence, out of a senior student body of approximately 50 students. That is, most students in our B. S. program will be graduating with this specialization.

The

and Communications

and Infrastructure,

CS

College

Age,

Research Priorities in Networking and Communications, Report to the NSF Division of

109 and 66 stuhave taken

Connecting

Information

[NCR192]

Over the past two years, CS 433 and CS 434 have dents,

The

W. T. Jones and F. M. McGuirt, Telecommunications and Computer Science: Two MergACM SIGCSE Bulletin .23 ing Paradigms, (Dec. 1991), 13-22.

ENROLLMENT

each been offered

To

[Jone91]

how to offer students a significant laboratory experience relevant to metropolitanand wide-area networks. STUDENT

W. T. Jones and F. M. McGuirt, “Computer Science and Telecommunications: Chal-

ACM

Networks,

2nd

Networks,

3rd

1989. Computer

1996. al. “A Summary of Joint Curriculum Task

Computing Curricula 1991,” 34, 6 (Jun. 1991), 69-84.