1. Describe how ISDN will
be inserted in the WAN implementation, how data will be sent across
the ISDN link, and the benefits of ISDN for a small site.
For ISDN to be inserted into the WAN implementation, either at the one
remote site or at all of the sites, three things must be done: ISDN
capabilities (router, router configuration, ISDN TA and NT devices)
must be in place at the school site; ISDN connectivity must be provided
by the telephone company or other provider; and the District WAN core
must have ISDN capability (WICs, blades) in its access servers, switches,
and routers (though not necessarily directly into the core routers).
Data will be sent on a "call" basis. Benefits for a small
site include reliability, relatively low cost if it is used intermittently,
and fairly universal service compared to other WAN technologies.
2. Document the use of ISDN
in the WAN design, including providing the following:
· A drawing of the implementation with all major reference points
Combine TI 5.1.3, graphics 2 and 3, with your school site drawings,
your physical topology, and your logical topology from your semester
3 TCS solutions.
· A description of overall bandwidth available to the site and
how data communications will take place
Data communications will take place on a "call" basis. Dial-on-Demand
Routing will be used; when WAN connectivity is required, the DDR configured
router and ISDN devices will place an ISDN "call" and be connected,
via the telephone companies' ISDN equipment, to the school district
WAN. Costs will include installation, monthly access, and a duration-of-call
charge. Bandwidth, for an ISDN BRI line, will be 128 kbps of data over
two B channels, and 16 kbps of signaling data over 1 D channel, with
much flexibility in how these channels are used.
· A description of all data communications equipment needed to
accomplish the implementation
This equipment will depend upon your design. For example, if you use
a Cisco 2621 router, you can order WIC modules that have the ISDN NT1
device built in, and you can connect the router directly to the ISDN
line. On the District WAN end, the same situation occurs -- it depends
on your design. Note that on the District end that if you use DDR to
all 33 sites then you will have to handle, via various means, all of
that incoming ISDN traffic with a combination of access servers and
appropriate routers and/or router modules.
3. Document the router commands
needed to implement ISDN on the router and document the resulting changes
in the local site access router configurations.
See Semester 4, Chapter 5, TI 5.5.5, graphic 1, for a complete BRI configuration
example for the remote site. Of course you will have to change the IP
addresses to match those used in your design, and you should add an
"encapsulation ppp" to the interface configuration. You will
need a similar, but slightly different, configuration for DDR -- see
the Web Link in TI 5.6.1.
Include the COMPLETE router configuration, including these changes.
4. Apply the CCNA Certification
Exam Learning Objectives to your specific design. This will require
a paragraph on how the learning objectives relate to your design. Learning
objectives can be grouped together for the purpose of explanation. In
this way, you will be studying for their CCNA Certification Exam as
you work through the case study.
5. If time permits, try to
add a sample DDR lab to the course. This exercise, ties a lot of the
material that, up to now, students have only read about. The configuration
cookbook at http://www.cisco.com /warp/public /779/ smbiz/ service/configs
/async/ async_ip _static_aux.htm gives detailed instructions on why
and how to setup DDR configurations. There are tutorials covering the
Washington School District Project Task: ISDN
Now that you should have
a firm understanding of the following:
· ISDN provides an integrated voice/data capability that uses
the public switched network.
· ISDN components include terminals, TAs, NT devices, and ISDN
· ISDN reference points define logical interfaces between functional
groupings, such as TAs and NT1s.
· ISDN is addressed by a suite of ITU-T standards, spanning the
physical, data link, and network layers of the OSI reference model.
· The two most common encapsulation choices for ISDN are PPP
· ISDN has many uses, including remote access, remote nodes,
and SOHO connectivity.
· There are two ISDN services: BRI and PRI.
· ISDN BRI delivers a total bandwidth of 144 kbps within three
· BRI configuration involves the configuration of a BRI interface,
an ISDN switch type, and ISDN SPIDs.
· DDR establishes and releases circuit switched connections as