As per Relevance of the word communication, we have this rfc below:
Network Working Group J.
Request for Comments: 1709 University of California,
FYI: 26 D.
Category: Informational University of California,
November 1994
K-12 Internetworking
Status Of This
This memo provides information for the Internet community. This
does not specify an Internet standard of any kind. Distribution
this memo is unlimited
I.
Many organizations concerned with K-12 educational issues and
planning for the use of technology recognize the value of
communications throughout the educational system. State
documents such as the California Department of Education's "
Plan for Information Technology" recommend the planning of voice
video and data networks to support learning and
administration, but they do not provide specific technical direction
The institutions that built the Internet and connected early in
development are early adopters of technology, with technical
dedicated to the planning for and implementation of leading
technology. The K-12 community traditionally has not had this
of staffing available for telecommunications planning. This
is intended to bridge that gap and provides a recommended
direction, an introduction to the role the Internet now plays in K-12
education and technical guidelines for building a campus
communications infrastructure that provides internetworking
and connections to the Internet
For a more general introduction to the Internet and its
and uses, the reader is referred to any of the references listed
the following RFCs
1392 "Internet Users' Glossary" (also FYI 18)
1432 "Recent Internet Books
1462 "What is the Internet" (also FYI 20)
1463 "Introducing the Internet - A Short Bibliograpy
Introductory Internetworking on Readings for the
Novice" (also FYI 19)
ISN Working Group [Page 1]
RFC 1709 K-12 Internetworking Guidelines November 1994
II. Rationale for the Use of Internet
In 1993, the Bank Street College of Education conducted a survey
550 educators who are actively involved in using telecommunications
(Honey, Margaret, Henriquez, Andres, "Telecommunications and K-12
Educators: Findings from a National Survey," Bank Street College
Education, New York, NY, 1993.) The survey looked at a wide
of ways telecommunications technology is used in K-12 education
Their findings on Internet usage are summarized below
"Slightly less than half of these educators have
to the Internet, which is supplied most frequently by
university computer or educational service."
"Internet services are used almost twice as often
professional activities as for student
activities."
"Sending e-mail is the most common use of the Internet
followed by accessing news and bulletin boards and
access to remote computers."
The following chart shows the percentage of respondents that use
network application to support professional and student activities
Applications Professional
Activities
Electronic mail 91 79
News or bulletin board 63 50
Remote access to other 48 32
Database access 36 31
File transfer 34 19
The value of the Internet and its explosive growth are a
result of the computer communications technology used on the network
The same network design principals and computer
protocols (TCP/IP) used on the Internet can be used within a
district to build campuswide networks. This is standard
within higher education, and increasingly in K-12 schools as well
The benefits of the TCP/IP protocols are listed below
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RFC 1709 K-12 Internetworking Guidelines November 1994
Ubiquity TCP/IP is available on most, if not all, of
computing platforms likely to be important
instructional or administrative purposes. TCP/
is available for the IBM compatible
computers (PCs) running DOS or Windows and
versions of the Apple Macintosh. TCP/IP
standard on all UNIX-based systems
workstations and most mainframe computers
Applications TCP/IP supports many applications including,
not limited to, electronic mail, file transfer
interactive remote host access, database access,
sharing and access to networked
resources. Programming and development
is available from a wide variety of sources
Flexibility TCP/IP is flexible, and new data
requirements can be incorporated easily. It
accommodate educational and
applications equally well so that one set of
cabling and one communications system may
used in both the classroom and the office
Simplicity TCP/IP is simple enough to run on low-
computing platforms such as the Apple
and PCs while still providing efficient support
large minicomputer and mainframe
platforms. TCP/IP benefits from over twenty
of refinement that has resulted in a large
technically sophisticated environment
Capacity TCP/IP supports local area network and wide
network services within the entire range of
data rates available today, from dial-up
speeds to gigabit speed experimental networks
Communications can occur reliably among
across this entire range of speeds
Coexistence TCP/IP can coexist successfully with
networking architectures. It is likely that
and classrooms that already have networks may
using something other than TCP/IP. Networks
Apple Macintosh computers will probably be
Appletalk; networks of PCs may be using any of
common network operating systems such as
Netware or LANManager. Mainframe
may be using IBM's System Network
(SNA). None of these proprietary protocols
ISN Working Group [Page 3]
RFC 1709 K-12 Internetworking Guidelines November 1994
broad connectivity on a global scale.
this, network technology vendors now provide
means for building networks in which all of
protocols can co-exist
Multimedia TCP/IP networks can support voice, graphics
video as part of teleconferencing and
applications
Compatibility All of the major Universities, as well
thousands of commercial and
organizations use TCP/IP for their
communications services. Commercial
such as Compuserve and America Online are
connected to the Internet. Many State
of Education have sponsored statewide initiatives
connect schools to the Internet and many K-12
school districts have connected based upon
needs
NREN The High Performance Computing Act of 1991
the Information Infrastructure and Technology
of 1992 provide the foundation for building
national telecommunications infrastructure
support of education and research. The
Research and Education Network (NREN) will
based upon Internet technology
The benefits of internetworking technology have been
through twenty years of use by thousands of organizations. This
experience also provides tested technical models for network
that can be adapted to K-12 campuswide networking in schools of
sizes and technical development
III. A Technical Model for School
The vision of a modern communications network serving all primary
secondary schools has been articulated and discussed in many forums
Many schools and a few school districts have implemented ad
network systems in response to their own perception of the
of this resource. This section of the Internet School
(ISN) Working Group RFC presents a standard network
model to assist county offices of education and school districts
their planning so that all such implementations will be
with each other and with national networking plans intended to
K-12 education
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RFC 1709 K-12 Internetworking Guidelines November 1994
The future goal of "an integrated voice, data, and video
extending to every classroom" is exciting, but so far from
exists today that the investment in time and dollars required
realize such a goal will be greater than most districts can muster
the near term. We suggest that a great deal can be done immediately
with relatively few dollars, to provide modern communications
in and between all schools around the nation
Our present goal is to define a highly functional, homogeneous,
well supported network system that could interconnect all K-12
schools and district, county, and statewide offices and that
enable teachers and administrators to begin to use new
tools and network-based information resources. It takes
time to adapt curricula and other programs to take full advantage
new technology. Through the use of standard models
implementation of current network technologies, schools can
this process now
Many states have already developed communications services for
schools. A notable example is Texas which provides terminal
to central information resources from every classroom over
statewide network. Modem-accessible systems are available in
states that serve to encourage teachers to become familiar
network resources and capabilities. Although modem-access may be
only practical option today in some areas, it always will be
in functionality and/or capacity. In anticipation of emerging
future bandwidth intensive information resource applications and
functionality that they will require, we believe it is essential
provide direct network access to the National Research and
Network (NREN) Internet (The Internet is a "network of networks"
interconnects institutions of higher education, research labs
government agencies, and a rapidly growing number of technology
information vendors.) from computers in every classroom
The Internet communication protocols, commonly known as "TCP/IP,"
the "glue" that will allow all computers to communicate. As
above, software that implements Internet protocols is available
all modern computers. These protocols support a very wide variety
applications, from electronic messaging to client/server data access
The use of Internet protocols will ensure that all
computers will have direct access to the vast range of
information and education resources on the Internet, as well as
the emerging National Information Infrastructure
ISN Working Group [Page 5]
RFC 1709 K-12 Internetworking Guidelines November 1994
The implementation we suggest would use current proven and
effective technology and would be expandable and upgradable to
technology with minimum additional investment. This
requires careful, modular design to meet the following criteria
1) Any physical infrastructure development should be general
flexible enough to be reused as technology improves.
example, a school office might have a simple terminal
which could be wired to a network adapter serving the
building. Later a Macintosh, DOS, or Windows-based PC
replace the terminal, and the type of connection to the
would change accordingly. However, the wiring between
office and the network "hub" site could remain the same if
is designed properly to begin with. This is an
consideration since wiring typically represents 20 to 40%
the cost of individual network hookups
2) Existing computers and terminals in schools and
offices should be integrated as much as possible into
communication system. This installed base represents a
investment, albeit in many cases a somewhat dated set
equipment. Wholesale replacement of that base would be
large additional burden on funding resources
A consequence of the above is that the user interface and
services available will vary depending on the type of
used to access the network. For example, DOS PCs,
computers, or Unix workstations would be connected directly
Local Area Networks (LANs) and would be provided
communications software to support a broad set of functions
many of which will have graphical user interfaces and will
use of client/server technology. Apple-II computers, "dumb
terminals, or other such devices could be connected
intelligent network hubs that would allow access to
server computers or information resources, but almost
will not support the full range of functionality provided by
direct network connection. In the short term, this is
limitation that we must accept
3) Network servers will be located where they can be managed
supported, and also provide access paths with
bandwidth. A system of hierarchical servers should be
in larger school districts, with automatic transfer of
information from a central system to the secondary systems
night, or at appropriate intervals. Local servers will
each school to provide on-line information particular to
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RFC 1709 K-12 Internetworking Guidelines November 1994
programs and community. This model optimizes use of
bandwidth as well
4) School interconnect topologies (links) must be both
effective and manageable. Communication between schools
district offices, county offices of education, and the
Department of Education must be reliable and of
capacity to support the primary applications as well as
development of new applications
Capacity is measured both by total data traffic volume and
response time when information is requested over the network
Reliability is measured by the percentage of time that
network is able to transport data. Reliability should be
over 99.7%. Capacity should be such that no more than 10%
the communications bandwidth is used during a typical work day
This is intended to leave adequate capacity for good
time to short term communication demands
Many schools already have some form of
infrastructure in place. In some cases this infrastructure
be adapted to newer technologies; in other cases it may have
be replaced over time. These issues are explored
following presentation of the basic model that serves as
guideline for future communications system development
Implementation
There is no one "blueprint" for a network that will drop into
school. Each school will have particular physical constraints
functional needs, an existing technology base, funding constraints
and opportunities for collaboration with vendors and support
in its area. What is presented here is a set of general
that can be followed in the planning of a school
implementation
The strategic decision to use Internet protocols in developing
networks provides the opportunity to avoid the major expense
building new statewide backbone infrastructures in the near term
Interconnection of schools, districts, county offices of
and the State Department of Education can be accomplished
acquiring Internet connection service from any of the
Internet service providers in the state. ("Connecting to
Internet", Susan Estrada, O'Reilly & Associates, Inc. (ISBN 1-56592-
061-9) lists Internet service providers in California and
nation.) It is critical that Internet connection service
criteria for reliability and capacity but connection to any
service provider will provide communication capability to all
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RFC 1709 K-12 Internetworking Guidelines November 1994
Internet subscribers within the state, the nation, and the world
Internet technology is designed to allow very flexible
topologies, but a hierarchical topology is the simplest to engineer
Generally this will mean hierarchical connection of school
to district offices, in many cases further aggregated at
offices, and finally a link to an Internet service provider
Coordination of circuit services and a single point of connection
an Internet service provider serves both to minimize overall
and increase opportunities to make use of newer technologies
The basic school network implementation model is quite simple:
a local area network (LAN) within each school building or cluster
buildings, provide at least one network server for that LAN
interconnect that LAN with the local school district offices where
similar LAN should be installed and where centrally
information resources should exist, and connect the district
to the nearest Internet service provider, possibly through the
office of education
Primary technical support for network monitoring and
resolution, and for managing network resource servers should
from the district or county offices initially to avoid
duplication at the local level. As expertise is developed at
local level, more of the responsibility for daily operation
problem resolution can be assumed by individual schools
It is impossible to cover all conceivable scenarios
implementation of this model in specific schools. However, it
possible to state general principles that should be followed
designing school network implementations. The discussion below
organized into sections corresponding to the basic model
in the previous paragraph. It includes a description of the
principles that are important to each level of the implementation
Step 1: School Local Area Network
A "school" is used here to mean a building or cluster of
that are managed as a unit and typically are on contiguous,
owned property. Implementation of a LAN in this setting will
installation of a cabling system to distribute the network
the structure(s), installation of premise wiring to
connections of computers and terminals to the network
system, installation of one or more network server machines in
central location (Other protocols, such as AppleTalk or Novells IPX
may be supported on a school's local area network (LAN) as needed
local function such as printer sharing or local resource servers.),
and provision of a network router and telecommunications circuit
ISN Working Group [Page 8]
RFC 1709 K-12 Internetworking Guidelines November 1994
radio link to connect that school to the district offices
The most common LAN technologies in use today are ethernet
LocalTalk. (IEEE 802.5 Token Ring is not recommended for
installations. It is more expensive and it is not available for
wide a range of computers.) Both are quite inexpensive and easy
install and maintain. Ethernet is adaptable to most modern
and is built-in to high performance workstations such as Sun
Hewlett-Packard, SGI, or Digital Equipment Corporation computers
LocalTalk is built-in to all Macintosh computers and is adaptable
DOS PC computers as well. Ethernet is roughly 20 to 40 times
than LocalTalk. Therefore ethernet is recommended for all
connections, when possible, and for the school LAN "backbone"
network distribution system
1.1 Network Adapters and
Individual computers will require network or communications
and appropriate software. Table 1 gives basic recommendations
the computers most commonly found in schools. Basic
software is available in the public domain for many
computers at no cost. More sophisticated software is being
by a number of vendors for applications such as electronic mail
distance learning, and multimedia database access. For example,
California Technology Project is developing very easy to use
for Macintosh and DOS or Windows PC computers that will enable
to a wide variety of information resources and services.
should look at all the available software and base choices
required functionality and support costs as well as
costs
In locations where computers will be purchased, the choice
computer type should be driven by the availability of software
the particular application(s) to be supported. Almost all
computers can be attached to the type of network described in
document
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RFC 1709 K-12 Internetworking Guidelines November 1994
Equipment Type Network Adapter
________________________________________________________________________
Simple terminal "Network Access Server" Built-in to
located centrally. networkaccess server
Apple II, Amiga, Serial asynchronous Serial
Tandy, Commodore, port that will allow software that
older IBM PCs, etc. connection to the a simple terminal
above
Newer IBM PC Ethernet adapter car TCP/IP "TSR" software
with "10-base-T" port. for example "
"Thin-net" port may be Software" package
used in lab clusters. Additional software
special appl
Older Apple PhoneNet adapter MacTCP or
Macintosh computers (external) and shared plus "telnet" and "ftp".
LocalTalk to ethernet For example,
router, for example the Telnet.
Shiva FastPath. software for
applications, e.g.,
"electronic
client."
Newer Apple May use same as the Same as the above
Macintosh computers above. For
performance, use
ethernet adapter
with "10-base-T port
"Thin-net" port may
used in lab clusters
Unix workstations Ethernet adapter card, Typically comes
if not already built in. the basic system
Additional
may be
for
applications
________________________________________________________________________
Table 1: Network Adapters and Software for Typical
ISN Working Group [Page 10]
RFC 1709 K-12 Internetworking Guidelines November 1994
1.2 Premise
A major component of the implementation will be installation
cabling to connect individual computers or clusters of computers
the LAN. The recommended topology is a "star" where each computer
wired directly to a "hub site" within the building as shown
Figures 1 & 2. A cluster of computers, typically found in a
lab or library, may be interconnected within the room where they
installed, and the cluster connected to the hub site with a
cable as shown in Figures 3 & 4.
The recommended premise wiring is "unshielded twisted pair" (UTP
wire that meets the Electronic Industries Association (EIA)
5 standards for high speed data communication service. (
EIA/TIA-568 "Commercial Building Telecommunications
Standard.") While 2 pair cable may be adequate for most purposes
industry standards recommend installation of 4 pair cable.
difference in cost is minimal so we recommend installation of
latter. One end of each cable terminates in a category 5 RJ-45
(A standard RJ45 jack can be used for ethernet or lower speeds
initial cost is amajor factor. Such jacks can be replaced
category 5 versions later as needed.) located near the computer.
other end terminates on a standard "110 distribution block" (In
sites, M66 distribution blocks may already be installed. These
be used for the time being but will not support newer higher
technologies.) at the hub site utility closet. A labeling
must be chosen and strictly adhered to so that cables can
identified at both ends later, as needed
[Figure 1: Individual ethernet connection to the network
[Figure 2: LocalTalk connection to the network
In most cases, the hub site utility closet will be shared
telephone services. It is essential that a separate wall area be
aside within the closet for data service interconnections.
there will be a "field" of interconnect blocks for termination of
premise wires, another field for termination of trunk cables (
for low speed data terminals), and a third field for hub
ports. Interconnections between premise wiring blocks and hub
trunk blocks are installed as needed in order to provide
appropriate service to each location where communication service
required
[Figure 3: A cluster of computers connected to the network
[Figure 4: A Macintosh cluster connection to the network
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RFC 1709 K-12 Internetworking Guidelines November 1994
Installation of wiring in a building typically is performed by
qualified data wiring contractor. This is a critical aspect of
program and must be planned and installed professionally with
current and future requirements in mind. (See "Virtual Schoolhouse -
A Report to the Legislature on Distribution Infrastructures
Advanced Technologies in the Construction of New Schools, K
12" (Department of General Services, State of California, February
1993) for example conduit and utility closet plans.) To be
for future distribution of video signals, school network
should consider installation of RG-59 coaxial cable to
locations where video may be required at the same time that the
premise wiring is being installed. The coaxial cable would
on a wall plate mounted "F" connector in the classroom, and would
left unterminated in the utility closet. Future technologies
support video signals over other media so the installation of RG-59
cable should be limited to near term potential requirements
It will be cost effective to install premise wiring to as
locations as might ever serve a computer. This will
administrative offices as well as classrooms, laboratories as well
libraries. In high density locations such as offices,
should be given to installation of two UTP cables to each
location in order to provide the potential for several computers
workstations. Terminating both cables on the same wall plate
add little to the overall wiring project costs and will add
to the flexibility of the system. Premise wiring that is not to
used initially will not be connected to any electronics in the
site
Hub sites should be utility closets or other protected, non-
areas. Hub sites can be created by construction of small closets
cabinets in low use areas. A hub site must be located within 300
feet of any connection. Typically, multiple hub sites are
in large or multi-story buildings
1.3 Network Distribution
All hub sites within a school must be interconnected to complete
school LAN. The design of this network distribution system
depend greatly on the physical layout of the school buildings.
assume that ethernet technology will be used since higher
technology is still quite expensive
[Figure 5: A complete small school LAN
If all hub sites are within 300 cable feet of a central location
then 10-base-T wiring can be used from a central hub to connect
hub site, as shown in Figure 5. If longer distances are required
ISN Working Group [Page 12]
RFC 1709 K-12 Internetworking Guidelines November 1994
either thin-net or standard thick ethernet can be used. Fiber
cable can be used if distance requires it and funding permits. (
fiber optic cable is installed, consideration should be given
including both multimode fiber for current and future
requirements and single mode fiber for video and future very
speed data systems.) Specific design of the "backbone"
distribution system will depend on the layout of the buildings to
served
With proper design as many as 250 computers can be connected to
single ethernet segment. Most often the practical maximum
will be much lower than this due to the amount of data sent onto
network by each computer. For planning purposes, one can
100-125 computers per segment. Beyond that size the network must
subdivided using "subnetworks". Design of a such a system is
difficult, but is beyond the scope of this document
The network distribution system cabling should include
multi-pair trunk cabling as well as ethernet trunk cabling.
multi-pair trunk cable will be needed to connect terminals or
computers emulating terminals to a central "network access server
(NAS). A typical NAS can serve from 8 to 128 such connections.
is most cost effective to provide one per LAN, if needed. The
connects directly to the ethernet LAN
1.4 Local Network
It is highly recommended that each school install a "network server
to support local storage of commonly used information, software
electronic mail, and other functions that may require high
communication to the users computer. Since the connection to
outside network will be much slower than the school LAN, it will
most efficient to access information locally. In particular
software that is to be shared among the schools computers must
stored locally since it would be very tedious to transfer it
the slower external link. The network server will be
directly to the ethernet network
The location of the server should be chosen carefully to ensure
protection from abuse and environmental damage. Traditionally
school library is the focus of information gathering and
activities and many school libraries have clusters of computers
terminals already installed. The library would be a very
place to locate the network server computer. The Network Router (
below) might also be located there if a suitable utility space is
available
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The network server will be a small but powerful computer with a
amount of disk storage capacity, typically 1-4 gigabytes. It
run software capable of supporting access by a large number of
simultaneously. It could also support dial-in access from
or students homes using standard inexpensive modems. (Access
with user authentication is essential if dial-in service is to
provided.) If more than a few modems are to be installed, a
might prove more cost effective. If dial-in access is to be
to more than a few school sites within a district, a single
modem pool maintainted at the district offices will be the most
effective
1.5 External
A single communication circuit will connect the school LAN to
local school district offices. In the school, there will be
Network Router attached between the LAN and this circuit. On the
side, the connection will be a typical ethernet cable. On
external side, the connection will depend on the type
communication circuit used, as discussed in step 2 below
Step 2: Interconnection of Schools with District
All schools within a district should be connected individually to
network router at the school district offices. This "star topology
will be much easier to manage and the capacity of each
connection can be increased appropriately as needs change
Several standard communication circuit services may be used to
this connection. The least expensive for situations where
limited use is needed will be dial-up using high speed modems
However, this type of connection is not recommended for serious
due to its very limited capacity. Also, since most schools
telephone service under business tariffs, usage will be measured
the cost will be dependent on how long the connection is maintained
This will be true in general for other "switched services" as
such as "switched-56" and ISDN. Dedicated (permanently installed
communications circuits are strongly recommended since they
allow unattended access to and from the school network at all hours
This will be particularly important if information files are to
down-loaded during the night to local network servers or teachers
students are to access the schools information resources from home
Table 2 shows the most common options for dedicated circuit services
Costs are indicated in relative terms since they vary greatly
location and as tariffs are modified. The exact costs must
determined by contacting local communications service providers
Total cost must take into account the equipment needed at
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RFC 1709 K-12 Internetworking Guidelines November 1994
location as well
Type of Circuit Data Rate Relative
________________________________________________________________________
Voice grade leased 20 kilobits per sec modest
telephone line (Kb/s
ADN-56 56 Kb/s
ISDN, where 64 or 128 Kb/s modest**
Low power radio 64 to 256 Kb/s high
Frame Relay 56 Kb/s to 1.5 Mb/s modest to
DS1 1.5 megabits per sec very
________________________________________________________________________
* Measured service charges must be taken into account
** At this time, most ISDN tarriffs include message unit
which can make theuse of ISDN prohibitively expensive
full-time connectivity
Table 2: External Connection Communications
Frame Relay communication services are becoming available in
areas. Frame Relay is a shared, packet based data transport service
A school site would contract for Frame Relay service as part of
larger service group that includes the school district office and
include the Internet service provider. All members of that
would share the communications capacity. The advantage of
service is that only one end of the circuit needs to be ordered (
member orders a connection to the common service) and the
offered to each member can be upgraded independently. Also, in
areas the cost of Frame Relay service is not dependent on distance
the service provider which will make service to rural schools
less expensive than equivalent services. Overall system costs
be minimized since the central router at the district office
need fewer connections
If Frame Relay is chosen, the overall service group must be
engineered. For example, since all schools would share
connection to the district office (and possibly to the
service provider), that must be a high capacity connection. For
initial design, the aggregate capacity of all school links should
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RFC 1709 K-12 Internetworking Guidelines November 1994
exceed the capacity into the district office (or the Internet
provider) by more than a factor of 3 or there may be
congestion and variability in response times across the system
There are many other factors that must be considered as well, such
the virtual connection topology and how best to connect to
Internet service provider. Therefore, it is recommended that
experienced network engineer be utilized to develop an
plan for Frame Relay if it is chosen as the school
service
Future options for interconnecting schools and district offices
include
o Community Access Television (CATV) cable systems
either shared or dedicated bi-directional data
services
o metropolitan area fiber optic communications
providers
o Switched Multi-megabit Digital Service (SMDS) providing
transport service at speeds up to 34 megabits per second
o Asynchronous Transfer Mode (ATM) connection
supporting voice, data, and video communications at
into the gigabit per second range
(Many more options will become available as new technologies come
market.)
The costs for the last three options are unknown at this time,
may be generally higher than those indicated in Table 2. The
for the CATV option may be negotiable as part of the local
contract with the community
As demands for network speed develop due to heavy use of
or other bandwidth intensive application, higher speed
circuits can replace the initial circuits with minimal change in
equipment or LAN. This gives great flexibility in tailoring
to funding levels and application needs
Step 3: School District Office LAN and Support
The School District offices should form the focal point
interconnection of all schools in the district. Within the
offices, network operations can be monitored and problem
managed. One or more network servers can provide essential
support as well as central archiving of common information
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RFC 1709 K-12 Internetworking Guidelines November 1994
software
A critical role of the district office will be to manage
"Domain Name System" (DNS) (See STD 13, RFCs 1034, 1035 for the
explanation of DNS, and also, RFC 1480.) service for the
schools. DNS is required of all Internet networks. It defines
basic network level identity of each computer, workstation, server
and active network component. This function is described more
below under Network Management and Operational Monitoring
The district offices should be wired in a manner similar to a
school, as shown above. This will allow teachers, superintendents
and principals to communicate and share information easily.
addition, an NAS connected to a central pool of modems could
dial-in access to the district network
Step 4: Interconnection of the School District with the
Connection of the entire school district to the Internet will
place through the district office interconnect site, as shown
Figure 6. This hierarchical model can be extended another level
interconnection of the school district offices through the
office of education facilities. Many administrative
resources could be located at the county level, and there might
cost savings if the entire county connects to an Internet
provider through a single point. The bandwidth required for
single connection, however, will be much greater than that
for each school district since traffic will be aggregated
This hierarchical topology also provides a logical model for
support and information resource management. The school district
county offices can provide continuous monitoring of the network
provide high level technical expertise for problem resolution
relieving the individual schools of this burden. Interactions
communications circuit providers and Internet service providers
be more effective if handled through a central "trouble desk".
Similarly, it is highly desirable that network users have a single
well known point of contact in case of problems or questions
Internet service should be acquired from the most cost effective
reliable Internet service provider. Circuit services can be
to those shown in Table 2 above. The higher speed services should
considered if traffic demands increase and funding permits.
costs usually will be lowest when connecting to the provider with
nearest "point of presence" (POP), but newer technologies such
Frame Relay and SMDS (At this time, SMDS services are not
available.) make circuit costs less dependent on distance.
Internet connection will require a high quality router that can
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configured to interact correctly with the service providers routers
In most cases, this can be the same router used to support the
school connections
[Figure 6: Interconnection of schools to the Internet through
School District Offices
Integration of Existing School
Many schools have developed LAN systems in support of
classroom activities or administrative functions. In some cases
technologies used are not those recommended for new installations.
these older LAN systems are capable of transporting
protocols they may be integrated into a new LAN system and
later as funding permits
For example, IEEE 802.5 Token Ring is often used to interconnect
PC-type computers and IBM minicomputer servers. Token Ring
can transport Internet protocols and software is available for
computers to support basic Internet functions. Many Internet
support optional Token Ring adapters. This is the recommended
that existing Token Ring LANs can be integrated into a wider
LAN system in order to extend Internet information resources to
PC users
Another example is a Novell Network system using ethernet as a LAN
The ethernet LAN, if implemented well, is perfectly capable
transporting Internet protocols as well as Novell protocols
simultaneously. Each PC or Macintosh can be given software that
allow both Novell and Internet services to be used as needed.
coexistence is important so that, for example, a person using a
that depends on the Novell server for disk file space can transfer
large file from a remote Internet server to the PCs pseudo-disk.
also permits each user to run client software such as
(electronic mail), Gopher (information services), and Mosaic (
Wide Web information services) which require direct Internet access
To integrate the Novell ethernet LAN into the wider school LAN
a simple ethernet repeater can be used in a manner similar to
3 above
An alternative to supporting both protocols that is
suggested in cases such as the one cited above in which a
server already exists is to use the server as a "network
gateway". This approach is strongly discouraged. It is
that each computer and workstation support Internet protocol
communication directly so that modern client/server applications
be supported where the server or servers may be located anywhere
the Internet. The "gateway" approach severely restricts
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workstations potential ability to access multimedia and
important information resources
Some technologies, such as "arcnet," may not be capable of
Internet protocols but may offer "terminal emulation" shared
to something like a "modem pool". The modem adapter might be
to connect to ports on a network access server instead. This
provide simple access to information resources for the arcnet users
In any case, older LAN technologies should not be expanded and
be phased out as funding permits. It is critical that there be
relatively homogeneous installed base of technology in order that
applications of information resources can be provided to the
school community
Network Management and Operational
All networks require some level of network management in order
ensure reliable service. Monitoring of the health of the network
help identify problems before they become detrimental to
users. It also can help predict trends in traffic patterns
volume
Internet technology network management consists primarily
determining the proper routing parameters for optimal and
network operation, assignment of network Internet Protocol (IP
addresses and maintenance of a network-accessible database of
names corresponding to each address (See RFC 1480 for a discussion
Internet naming conventions for school networks.), and monitoring
daily operation of the network. These functions typically
performed by the staff of a Network Operations Center (NOC).
Domain Name
The Internet Domain Name System (DNS) is the mechanism
documenting and distributing information about the name and
of each computer attached to the network (network nodes). The
service is provided by software that runs on the main network server
It uses a database that is created and maintained by the NOC staff
An Internet address is the numerical identifier for a node and
must be unique among all nodes associated with the network
Furthermore, if the network is to be part of the global Internet,
addresses must be legitimate within the worldwide Internet system
Associated with each numerical address can be one or more "
names". Although computers have no difficulty using
addresses, it is often easier for computer users to remember and
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the node names rather than the numerical addresses. In particular
electronic mail addresses use node names. DNS node names
hierarchical and by appropriately using this hierarchy "subdomains
can be assigned to each school site or district office. In this way
naming can be structured to be flexible as well as meaningful in
context of the whole organization
A plan for the assignment of IP network addresses and node
should be developed early in the planning for the
installation. Initially, the database serving the DNS should
on the "district server" so that there is one site at which
assignments are officially registered. As the network grows
expertise is developed, secondary DNS service can be run on
servers at larger school sites
The main DNS server for the district should be located as close
the Internet connection (topologically) as possible. This
is to help ensure that network problems within the district
will have minimal impact on access to the server. This design
illustrated in Figure 1 where the district server is on an
connected directly to the main distribution router
Associated with the assignment of node names and addresses should
a database of specific information about the computers connected
the network. When trying to resolve problems or answer
questions, it is very important to know where the computers and
nodes are located, what type of computer and software are in use,
what type of network connection is installed. With proper
this database can be used to extract the DNS database
above
Network
Internet network monitoring serves three primary purposes
1) Constant observation of the "health" of the network,
components, and external network connectivity. Standard
Network Management Protocol (SNMP) support is built-in to
active components today. Even network servers and
can be monitored in this way. Operations staff can be
with network monitoring stations that will display
immediately upon detecting a wide variety of problems
anomalies
2) Collection of statistics on the performance of the network
patterns of traffic in order to identify needed enhancements
re-engineering. Using the same SNMP capabilities
above, data on packet forwarding and total traffic volume
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be collected and used to generate periodic reports on
utilization
3) More rapid problem resolution. When problems do occur,
tools can help to pinpoint the source of the problem(s).
problems include transient routing anomalies, DNS
failures, or even attempts at breaking into network
host computers
Since network management and monitoring is a
demanding task and requires special equipment and software,
should be a centralized function in the initial design of
network systems, as discussed above
IV. Network
The model for school network implementation described above is
on broad experience with this technology in higher education
administrative environments. Many schools have already
networks very similar to this model. We believe that it is
practical first step towards bringing a powerful resource to bear
enriching all of the nations school programs
None of the suggestions above preclude or postpone in any way
development of an integrated voice, data, and video network for
nations schools. Use of existing Internet carriers does not in
way preclude future development of a separate "backbone" for the K-12
community if such a "backbone" is determined to be cost effective
required for enhanced functionality. Rather, the
recommended above can be the foundation at the local level
preparation for future high capacity networks
The installation of a campuswide network or Internet
will also require a commitment to ongoing network support and
related resource requirements. There are two major areas of
support, network operations and user services. These
functions are usually performed through the establishment of
Network Operations Center (NOC) and Network Information Center (NIC),
however both functions can be performed by the same individual
groups of individuals
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Network Operations Center (NOC
The Network Operations Center (NOC) oversees the performance of
physical network and some of its software support systems. The
may install networks, configure network devices and
configurations for computers attached to an organization-
network. Real-time monitoring of the network can be performed
the Simple Network Management Protocol and many vendors
monitoring systems that graphically display network performance,
events and usage, and produce trouble tickets. The use of this
of network monitoring allows NOC staff to quickly detect problems
greatly reduces the personnel required to perform this function
Routine monitoring of the network can help to anticipate
before they develop and lead to reconfigurations and upgrades
indicated. If problems do arise, NOC personnel may go on-site
troubleshoot a problem and repair it. If the problem is not local
NOC personnel will work with school district, County or
network technical staff to resolve the problem
NOC personnel also assign addresses to network computers and
and maintain the Domain Nameservice (DNS) for their organization
Domain Nameservice is a machine registry service that runs on
network server and enables access to machines by easy to
names, rather than a network number. DNS is required for
organization connected to the Internet and critical to
establishment of an electronic mail system
It is most cost effective to have the Network Operation Center
an entire organization or region. In order to ensure timely
all the way out to the most remote LAN, it is recommended that
organization assign local area network administration duties to on
site personnel to interact with NOC staff and assist with
maintenance of the network. In the case of a school district
administrative support staff, teachers, librarians or school
technical staff can each take responsibility for a LAN or group
LANs. If a problem arises, it can be reported to the
administrator. The LAN administrator can determine if the problem
local or remote and if NOC staff need to be notified. If so, the
administrator acts as the single point of contact for the NOC
provide a good communications channel for information and
efficient coordination of problem resolution. This method
delegating responsibility provides for a high level of service
each LAN and optimally uses the time of NOC staff to
economies of scale
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Network Information Center (NIC
The Network Information Center (NIC) provides information and
services to facilitate the use of the network. The NIC
provides a help-desk service to answer questions about use of
network, references to useful resources and training in new tools
applications. The NIC may also provide services such as an on-
directory of network users and their electronic mail addresses
bulletin board services of information and notices about the
and on-line training materials. These NIC services could be
on a school district or County level. Most of the information
not be site specific and can be delivered electronically
electronic mail, electronic conferencing, on-line bulletin boards
other document delivery mechanisms. These types of services may
well suited for a school or school district librarian
Other types of support services may be performed by NIC
such as maintenance of the electronic mail system or
duties, coordination of an on-line bulletin board or
information system (CWIS) and management of an on-line
system. These duties are more technical in nature and will
technical staff to maintain them
Every organization which uses electronic mail should have
Electronic Mail Postmaster and a mailbox, postmaster, for the
of messages regarding use of the electronic mail system,
problems and general inquiries about reaching people within
organization. The Postmaster is responsible for reading
mail and responding to inquiries. These duties can be performed
non-technical staff with forwarding of messages to the
technical support person as required
CWIS
Campuswide information systems or bulletin boards are one of the
useful applications on the network. These systems allow people
share timely notices, documents and other resources with large
of people. These systems typically provide a hierarchical or
like structure of menus that lead to on-line documents or
services. Common types of information include deadline notices
grant announcements, training schedules, lists of available
such as videos in a library or reference materials
[Figure 7: Distributed Network Information Servers
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Information need not be stored all in one location. Figure 7 shows
set of distributed servers. These servers can receive
information automatically from a central server and can also
information generated locally that may pertain only to the
school. Users of the information need not know where the
is stored: the information access software will present choices on
integrated menu
