©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for
advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists,
or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Remote Laboratory Access for Students with Vision Impairment
Iain Murray
Department of Electrical & Computer Engineering
Curtin University of Technology
Perth Australia
i.murray@curtin.edu.au
Helen Armstrong
School of Information Systems
Curtin University of Technology
Perth Australia
h.armstrong@curtin.edu.au
Abstract— The delivery of laboratory exercises to
students that are unable to attend in person due to physical
disabilities is a significant issue. Both Netlab and Packet
Tracer are inaccessible to many students who use assistive
technology, particularly those with vision impairment. This
paper presents the development of an accessible, cost
effective, remote laboratory and describes the modification
to laboratory sessions necessary for the blind to undertake
CCNA laboratory sessions remotely and with full
accessibility. Also discussed is the development of an
accessible network simulator, iNetSim, illustrating possible
methodologies that may be applied to make existing
simulation packages accessible to those with severe vision
impairment.
Keywords-component; Networking laboratories, vision
impaired, accessible eLearning
I. INTRODUCTION
Curtin University of Technology commenced offering
the Cisco Network Academy Program to mainstream
(sighted) students as part of the Bachelor of Technology
(Computer Systems & Networking) degree program in
2002. Shortly after, four vision impaired students expressed
an interest in entering the Bachelor of Technology program.
These students faced significant problems with accessibility
to the Cisco course on-line materials as much of these
materials were not accessible to non-sighted users.
Extending the Cisco courses to vision impaired students
posed numerous teaching and learning challenges.
The Cisco Academy for the Vision Impaired (CAVI) has
been delivering the Cisco Academy Programs to blind and
vision impaired students since 2003, with up to 9 students
per year from the local area. In 2007 the program was
expanded to include students located in other parts of
Australia and the U.S.A, with 25 vision impaired students
enrolled in that year. In 2008 the enrolments of legally blind
students exceeded 120, from countries including India, Sri
Lanka, Canada, Egypt, Australia and the U.S.A. During the
intervening period, a number of vision impaired students
entered the Bachelor of Technology (Computer Systems &
Networking) course at Curtin University with the total
number of vision impaired students (in the CAVI program)
increasing to 146 in the year 2008. In order to achieve the
practical components of the CCNA courses, remote access
to router and switch bundles was required. This paper
describes the remote laboratory established for these
students together with a network simulation application
developed.
A. The Mechanics of Delivering the Curricula
The Cisco curriculum is “media rich”, with much of the
content delivered as Flash and interactive web pages. This
style of delivery is often unsuitable for vision impaired
persons. The arrangement of frames is inaccessible to
screen review applications (speech output), but more
importantly the curriculum relies heavily on visual keys to
illustrate learning objectives. Several problems, not
apparent to most sighted users, are also inherent in the
curriculum design. The first problem is that the diagrams
are extremely difficult to access or even explain to a person
who has been blind since birth. The second problem is that
the arrangement of frames and the lack of correct ALT
labels (text equivalent buttons) add to the complexity of the
presented material. The vision impaired students also
advise they have no way of accessing the content of
interactive sessions and find the supporting text confusing
and misleading. To overcome these issues many supporting
applications and documents were created but are beyond the
scope of this document.
The CAVI program utilizes blind instructors to deliver
the Cisco course materials with the support of a sighted
teaching assistant. Blind instructors have first hand
experience of the difficulties encountered by the vision
impaired students and understand the most effective ways of
presenting the materials. The classroom environment
consists of a laboratory containing a network of PCs fitted
with assistive technologies, routers and associated network
equipment. Classes run two full days per week over the
academic year. Local students physically attend classes and
2009 Fifth International Conference on Networking and Services
978-0-7695-3586-9/09 $25.00 © 2009 Crown Copyright
DOI 10.1109/ICNS.2009.107
571
2009 Fifth International Conference on Networking and Services
978-0-7695-3586-9/09 $25.00 © 2009 Crown Copyright
DOI 10.1109/ICNS.2009.107
566
Authorized licensed use limited to: CURTIN UNIVERSITY OF TECHNOLOGY. Downloaded on July 14,2010 at 06:22:31 UTC from IEEE Xplore. Restrictions apply.
remote students log in (via the Internet) to a virtual
classroom to listen to the lectures and participate in the
tutorial exercises. The virtual classroom provides the
facilities for students to talk to one another as well as
communicate with the instructors, similar to a normal
classroom environment. The lectures are recorded and made
available as audio files on the project website along with
other teaching materials for access by the students at any
time.
It may be argued that the most difficult issue in
delivering eLearning to blind students is that of explaining
the meaning of graphical information. To overcome this
issue, textual descriptions were created for all graphics used
in the courses, including the curriculum, laboratory manuals
and on-line exams. An example textual description is given
in the excerpt below and refers to the diagram in Figure 1,
graphic 2 of 4 in the text description.
Page has 4 graphics
Graphic 1 shows the segmentation with routers. There
are four hubs and one router in the picture. Router is in the
middle connected to hubs in four corners, three stations
(PC) are connected to each hub.
Segmentation with routers provides:
More manageable, greater functionality, multiple activate
paths
Smaller broadcast domain
Operates at layer 3
Graphic 2 show routers connected by WAN technologies.
There are 10 routers in the graphic. Four of them are
connected to each other in a square shape (each one corner
of a square). If we name these routers from 1 to 4 clockwise
starting from the left top, router number 1 is connected to
router number 2 with ATM (Asynchronous Transfer Mode).
Router number 2 is connected to router number 3 with
T1/E1 and T3/E3. Router number 3 is connected to router
number 4 with ATM. Router number 4 is connected to
router number 1 with T1/E1 and T3/E3.Each of these four
routers are connected to other routers.
Router number 1 is connected to two other networks one
a cable modem via a router and other one X.25 via other
router.
Router number 2 is connected to a dial-up modem via a
router.
Router number 3 is connected to SDMS via a router and
to xDSL via another router.
Router number 4 is connected to ISDN network via a
router.
There are antenna signal to router number 3 and
satellite signal to ISDN router connected to router number
4.
Figure 1: Example diagram from CCNA2 version 3.1 section 1.1.3
Further details of the teaching aids used in the project
can be found in Murray and Armstrong [3] and on the
project website http://www.cucat.org
.
II. T
HE REMOTE LABORATORY USER EXPERIENCE
Laboratory exercises form a significant portion of the
curriculum. In order for students situated remotely to access
and participate in the laboratory sessions, a functional,
remotely accessible network topology was developed. The
configuration illustrated was developed for the CCNA
version 3.1 curriculum, with work currently underway to
reconfigure for Discovery and Exploration curricula to be
delivered in 2009. Laboratory equipment generally consists
of three routers and two switches. The configuration may be
described as two branch offices, say Perth and Sydney,
connected together via the ISP or Internet cloud [1]. The
edge routers are configured by the students to allow
connectivity via the middle router (cloud or ISP). Local
students interact directly with the routers’ configuration via
serial (console) interfaces. A problem exists when
attempting to allow remote students access to “real” routing
hardware. The routers may not be placed on production
networks for obvious reasons and initial configurations must
be entered via the console connection. Therefore
requirements for a remote lab must allow students to
perform:
• Initial configuration via the console cable
• Remote power cycling of network equipment and
workstations
• Connectivity tests
• Advanced router and switch configuration.
One such system does exist, Netlab, developed and
distributed by NDG (http://www.netdevgroup.com/
),
however the cost of this system is a major factor hindering
its adoption. Additionally, the java based applications in
Netlab, including the booking system, telnet client to interact
with the network hardware and server system are not
572567
Authorized licensed use limited to: CURTIN UNIVERSITY OF TECHNOLOGY. Downloaded on July 14,2010 at 06:22:31 UTC from IEEE Xplore. Restrictions apply.
accessible by screen readers (software utilized by blind
computer users to convert on-screen information to audio or
Braille output). The CAVI system developed costs
significantly less than the Academy Edition of Netlab.
Whilst it does not offer advanced features such as equipment
booking it performs all the required functions for the vision
impaired class applications. In its most simple form, it
consists of the standard CCNA laboratory bundle: 3 routers
and 2 switches, with several virtualized Linux PC servers
running FTP, HTTP, Telnet and other associated services; all
may be accessed by their serial ports (see Figure 2).
Figure 2: Standard router bundle (top) & Switch Bundle (bottom)
A standard serial port or console switch is used to access
the devices in the laboratory bundle. Remote students may
telnet into the console server (a device that allows Ethernet
to multiple serial port connections), accessing the routers,
switches and Linux servers from any locality worldwide.
The use of Linux on the host and server machines is
necessary as the command line may be accessed through the
serial ports allowing the students to connect directly to the
server hosting the multiple virtual machines. Users may then
telnet to the virtual machines and access the command line
via the screen reader. Virtualized GUI based operating
systems are not easily accessible to the assistive technology
when installed behind the console switch.
The physical layout of the remote laboratory equipment is
depicted in Figure 3.
Figure 3: Teaching environment (top) and physical remote laboratory
equipment layout (bottom)
Figure 4 illustrates an active telnet session logged into
the remote bundle. As the routers are on their own network,
with remote access attaching only to the serial ports, this
system does not offer any security risk to the institution
utilising it. Once the student has authenticated with the
console switch (simple plain text password) a list of
available equipment is displayed, as shown in Figure 5.
573568
Authorized licensed use limited to: CURTIN UNIVERSITY OF TECHNOLOGY. Downloaded on July 14,2010 at 06:22:31 UTC from IEEE Xplore. Restrictions apply.
Figure 4: Active console session
[Murray-2:~] iainmurray% telnet 134.7.43.171
Trying 134.7.43.171...
Connected to 134.7.43.171.
Escape character is '^]'.
Enter Password: ********
PORT STATUS: Version 3.0, Site ID: Curtin -o o- --oo o- -o oo -
o
PORT | NAME | PASSWORD | STATUS | MODE |
BUFFER COUNT
-----+------------------+------------------+--------+--------+--------------
09 | Router1 | (defined) | Free | Any | 0
10 | Router2 | (defined) | Free | Any | 0
11 | Router3 | (defined) | Free | Any | 0
12 | WKS1 | (defined) | Free | Any | 0
13 | WKS2 | (defined) | Free | Any | 0
14 | WKS3 | (defined) | Free | Any | 0
Figure 5: Remote bundle equipment list
Several commands are available and are listed in Table 1.
Connection to equipment is made via the /C n command,
where n = required equipment port number.
TABLE I. TABLE 1: CONSOLE SWITCH COMMAND MENU
Display Options
/S /SD Port Status
/W Port Parameters (who)
/J Site ID
/H Command Menu (Help)
Control
<Enter> Enter Command Mode
/x Exit Command Mode
/C n Connect to Port (n: Port# or name)
As the booking system was incomplete at the time of
writing, a virtual classroom was utilised as a method of
ensuring students knew if the equipment was in use. When
undertaking a laboratory, students logged into the Ventrilo
server (a voice communication application designed for on-
line gamers) and entered the appropriate channel, as shown
in Figure 6. In this way students not only can tell if a
particular bundle is in use but may also conduct laboratory
sessions collaboratively with other students.
Power cycling of equipment is undertaken by
authenticating first to the console switch and connecting to
the remote power switch. The power switch may then be
used to power down individual devices within the bundle.
This is usually done with a secondary telnet session,
allowing access to the router/switch to be power cycled and
therefore the boot process to be interrupted (as in the case of
password recovery laboratories). Each device may be
powered on, off or rebooted. Figure 7 illustrates the process
of remotely rebooting a router.
Figure 6: Ventrilo session (note users in the “Pod 1” channel)
Figure 7: Remotely rebooting the router
Once connected via telnet, students may configure
routers, switches and workstations in the same manner as if
physically present. One such session is shown in Figure 7.
Although this system allows laboratories to be completed,
including e-Labs it has several shortcomings. These include
the lack of a formal booking system, leading to students
attempting to access the limited resources while others are
574569
Authorized licensed use limited to: CURTIN UNIVERSITY OF TECHNOLOGY. Downloaded on July 14,2010 at 06:22:31 UTC from IEEE Xplore. Restrictions apply.
