Subject: Internet Draft - K-12 Internetworking Guidelines

ISN Working Group                                       Joan Gargano
Internet Draft                       University of California, Davis
December 28, 1993                                       David Wasley
                                  University of California, Berkeley

                 K-12 Internetworking Guidelines

Status Of This Memo

This Internet Draft provides technical guidance to the K-12
educational community on school networking and connections to
the Internet.  Distribution of this memo is unlimited.

This document is an Internet Draft.  Internet Drafts are working
documents of the Internet Engineering Task Force (IETF), its
Areas, and its Working Groups.  Note that other groups may also
distribute working documents as Internet Drafts.

Internet Drafts are draft documents valid for a maximum of six
months.  Internet Drafts may be updated, replaced, or obsoleted by
other documents at any time.  It is not appropriate to use Internet
Drafts as reference material or to cite them other than as a
"working draft" or "work in progress."  Please check the 1id-
abstracts.txt listing contained in the internet-drafts Shadow
Directories on nic.ddn.mil, nnsc.nsf.net, nic.nordu.net,
ftp.nisc.sri.com, or munnari.oz.au to learn the current status of any
Internet Draft.

This Internet Draft expires June 4, 1994.

I.      Introduction

Many organizations concerned with K-12 educational issues and
the planning for the use of technology recognize the value of data
communications throughout the educational system.  State
sponsored documents such as the California Department of
Education's "Strategic Plan for Information Technology"
recommend the planning of voice, video and data networks to
support learning and educational administration, but they do not
provide specific technical direction.

The institutions that built the Internet and connected early in its
development are early adopters of technology, with technical staff
dedicated to the planning for and implementation of leading edge
technology.  The K-12 community traditionally has not had this
level of staffing available for telecommunications planning.  This
document is intended to bridge that gap and provides a
recommended technical direction, an introduction to the role the
Internet now plays in K-12 education and technical guidelines for
building a campus data communications infrastructure that
provides internetworking services and connections to the Internet.

Gargano, Wasley                [Page 1]

Internet Draft          K-12 Internetworking Guidelines         December 1993

For a more general introduction to the Internet and its
applications and uses, the reader is referred to any of the
references listed in the following RFCs:

1392    "Internet Users' Glossary"
1432    "Recent Internet Books"
1462    "What is the Internet"
1463    "Introducing the Internet - A Short Bibliograpy of
              Introductory Internetworking Readings for the Network
              Novice"

II.     Rationale for the Use of Internet Protocols

In 1993, the Bank Street College of Education conducted a survey
of 550 educators who are actively involved in using
telecommunications.  The survey looked at a wide variety 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 access
        to the Internet, which is supplied most frequently by a
        university computer or educational service.

        "Internet services are used almost twice as often for
        professional activities as for student learning
        activities."

        "Sending e-mail is the most common use of the
        Internet, followed by accessing news and bulletin
        boards and gaining access to remote computers."

The following chart shows the percentage of respondents that use
each network application to support professional and student
activities.

Applications                    Professional                     Student
                                Activities                      Activities

Electronic mail                 91                              79

News or bulletin board          63                              50

Remote access to other          48                              32
computers

Database access                 36                              31

File transfer                   34                              19

______________________________________________________________________________
1  Honey, Margaret, Henriquez, Andres, "Telecommunications and K-12 Educators:
   Findings from a National Survey," Bank Street College of Education,
   New York, NY, 1993.

Gargano, Wasley                [Page 2]

Internet Draft          K-12 Internetworking Guidelines         December 1993

The value of the Internet and its explosive growth are a direct
result of the computer communications technology used on the
network.  The same network design principals and computer
communications protocols (TCP/IP) used on the Internet can be
used within a school district to build campuswide networks.  This
is standard practice within higher education, and increasingly in
K-12 schools as well.  The benefits of the TCP/IP protocols are
listed below.

Ubiquity        TCP/IP is available on most, if not all, of the
                computing platforms likely to be important for
                instructional or administrative purposes.  TCP/IP is
                available for the IBM compatible personal
                computers (PCs) running DOS or Windows and all
                versions of the Apple Macintosh.  TCP/IP is
                standard on all UNIX-based systems and
                workstations and most mainframe computers.

Applications    TCP/IP supports many applications including, but
                not limited to, electronic mail, file transfer,
                interactive remote host access, database access, file
                sharing and access to networked information
                resources.  Programming and development expertise
                is available from a wide variety of sources.

Flexibility     TCP/IP is flexible, and new data transport
                requirements can be incorporated easily.  It can
                accommodate educational and administrative
                applications equally well so that one set of network
                cabling and one communications system may be
                used in both the classroom and the office.

Simplicity      TCP/IP is simple enough to run on low-end
                computing platforms such as the Apple MacIntosh
                and PCs while still providing efficient support for
                large minicomputer and mainframe computing
                platforms.  TCP/IP benefits from over twenty years
                of refinement that has resulted in a large and
                technically sophisticated environment.

Capacity        TCP/IP supports local area network and wide area
                network services within the entire range of network
                data rates available today, from dial-up modem
                speeds to gigabit speed experimental networks.
                Communications can occur reliably among machines
                across this entire range of speeds.

Coexistence     TCP/IP can coexist successfully with other
                networking architectures.  It is likely that offices
                and classrooms that already have networks may be
                using something other than TCP/IP.  Networks of
                Apple Macintosh computers will probably be using
                Appletalk; networks of PCs may be using any of the

Gargano, Wasley                [Page 3]

Internet Draft          K-12 Internetworking Guidelines         December 1993

                common network operating systems such as Novell
                Netware or LANManager.  Mainframe computers
                may be using IBM's System Network Architecture
                (SNA).  None of these proprietary protocols provides
                broad connectivity on a global scale.  Recognizing
                this, network technology vendors now provide many
                means for building networks in which all of these
                protocols can co-exist.

Multimedia      TCP/IP networks can support voice, graphics and
                video as part of teleconferencing and multimedia
                applications.

Compatibility   All of the major Universities, as well as
                thousands of commercial and governmental
                organizations use TCP/IP for their primary
                communications services.  Commercial networks
                such as Compuserve and America Online are also
                connected to the Internet.  Many State Departments
                of Education have sponsored statewide initiatives to
                connect schools to the Internet and many K-12
                school districts have connected based upon local
                needs.

NREN            The High Performance Computing Act of 1991 and
                the Information Infrastructure and Technology Act
                of 1992 provide the foundation for building the
                national telecommunications infrastructure in
                support of education and research.  The National
                Research and Education Network (NREN) will be
                based upon Internet technology.

The benefits of internetworking technology have been
demonstrated through twenty years of use by thousands of
organizations.  This same experience also provides tested technical
models for network design that can be adapted to K-12
campuswide networking in schools of all sizes and technical
development.

III.    A Technical Model for School Networks

The vision of a modern communications network serving all
primary and secondary schools has been articulated and discussed
in many forums.  Many schools and a few school districts have
implemented ad hoc network systems in response to their own
perception of the importance of this resource.  This section of the
ISN RFC presents a standard network implementation model to
assist county offices of education and school districts in their
planning so that all such implementations will be compatible with
each other and with national networking plans intended to enrich
K-12 education.

Gargano, Wasley                [Page 4]

Internet Draft          K-12 Internetworking Guidelines         December 1993

The future goal of "an integrated voice, data, and video network
extending to every classroom" is exciting, but so far from what
exists today that the investment in time and dollars required to
realize such a goal will be greater than most districts can muster
in the near term.  We suggest that a great deal can be done
immediately, with relatively few dollars, to provide modern
communications systems in and between all schools around the
nation.

Our present goal is to define a highly functional, homogeneous,
and well supported network system that could interconnect all K-
12 schools and district, county, and statewide offices and that will
enable teachers and administrators to begin to use new
communications tools and network-based information resources.  It
takes considerable time to adapt curricula and other programs to
take full advantage of new technology.  Through the use of
standard models for implementation of current network
technologies, schools can begin this process now.

Many states have already developed communications services for
their schools.  A notable example is Texas which provides terminal
access to central information resources from every classroom over a
statewide network.  Modem-accessible systems are available in
many states that serve to encourage teachers to become familiar
with network resources and capabilities.  Although modem-access
may be the only practical option today in some areas, it always will
be limited in functionality and/or capacity.  In anticipation of
emerging and future bandwidth intensive information resource
applications and the functionality that they will require, we
believe it is essential to provide direct network access to the
National Research and Education Network (NREN) Internet[2] from
computers in every classroom.

The Internet communication protocols, commonly known as
"TCP/IP," are the "glue" that will allow all computers to
communicate.  As noted above, software that implements Internet
protocols is available for all modern computers.  These protocols
support a very wide variety of applications, from electronic
messaging to client/server data access.  The use of Internet
protocols will ensure that all networked computers will have direct
access to the vast range of existing information and education
resources on the Internet, as well as to the emerging National
Information Infrastructure.

Approach

The implementation we suggest would use current proven and cost
effective technology and would be expandable and upgradable to
newer technology with minimum additional investment.  This
approach requires careful, modular design to meet the following
criteria:

Gargano, Wasley                [Page 5]

Internet Draft          K-12 Internetworking Guidelines         December 1993

1)      Any physical infrastructure development should be general and
        flexible enough to be reused as technology improves.  For
        example, a school office might have a simple terminal today
        which could be wired to a network adapter serving the school
        building.  Later a Macintosh, DOS, or Windows-based PC might
        replace the terminal, and the type of connection to the network
        would change accordingly.  However, the wiring between the
        office and the network "hub" site could remain the same if it is
        designed properly to begin with.  This is an important
        consideration since wiring typically represents 20 to 40% of the
        cost of individual network hookups;

2)      Existing computers and terminals in schools and district offices
        should be integrated as much as possible into the
        communication system.  This installed base represents a large
        investment, albeit in many cases a somewhat dated set of
        equipment.  Wholesale replacement of that base would be a
        large additional burden on funding resources.

        A consequence of the above is that the user interface and the
        services available will vary depending on the type of equipment
        used to access the network.  For example, DOS PC s, Macintosh
        computers, or Unix workstations would be connected directly to
        Local Area Networks (LANs) and would be provided with

        communications software to support a broad set of functions,
        many of which will have graphical user interfaces and will
        make use of client/server technology.  Apple-II computers,
        "dumb" terminals, or other such devices could be connected to
        intelligent network hubs that would allow access to network
        server computers or information resources, but almost certainly
        will not support the full range of functionality provided by a
        direct network connection.  In the short term, this is a
        limitation that we must accept;

3)      Network servers will be located where they can be managed
        and supported, and also provide access paths with adequate
        bandwidth.  A system of hierarchical servers should be created
        in larger school districts, with automatic transfer of common
        information from a central system to the secondary systems
        each night, or at appropriate intervals.  Local servers will allow
        each school to provide on-line information particular to its
        programs and community.  This model optimizes use of network
        bandwidth as well;

_____________________________________________________________________________
[2] The Internet is a "network of networks" that interconnects
    institutions of higher education, research labs, government
    agencies, and a rapidly growing number of technology and
    information vendors.

Gargano, Wasley                [Page 6]

Internet Draft          K-12 Internetworking Guidelines         December 1993

4)      School interconnect topologies (links) must be both cost effective
        and manageable.  Communication between schools, district
        offices, county offices of education, and the State Department of
        Education must be reliable and of sufficient capacity to support
        the primary applications as well as allow development of new
        applications.

        Capacity is measured both by total data traffic volume and by
        response time when information is requested over the network.
        Reliability is measured by the percentage of time that the
        network is able to transport data.  Reliability should be well
        over 99.7%.  Capacity should be such that no more than 10% of
        the communications bandwidth is used during a typical work
        day.  This is intended to leave adequate capacity for good
        response time to short term communication demands.

        Many schools already have some form of communications
        infrastructure in place.  In some cases this infrastructure can be
        adapted to newer technologies; in other cases it may have to be
        replaced over time.  These issues are explored further following
        presentation of the basic model that serves as a guideline for
        future communications system development.

Implementation Model

There is no one "blueprint" for a network that will drop into every
school.  Each school will have particular physical constraints,
functional needs, an existing technology base, funding constraints,
and opportunities for collaboration with vendors and support
groups in its area.  What is presented here is a set of general
guidelines that can be followed in the planning of a school network
implementation.

The strategic decision to use Internet protocols in developing
school networks provides the opportunity to avoid the major
expense of building new statewide backbone infrastructures in the
near term.  Interconnection of schools, districts, county offices of
education and the State Department of Education can be
accomplished by acquiring Internet connection service from any of
the existing Internet service providers in the state[3] .  It is critical
that Internet connection service meet criteria for reliability and
capacity but connection to any Internet service provider will
provide communication capability to all other Internet subscribers
within the state, the nation, and the world.

Internet technology is designed to allow very flexible intersite
topologies, but a hierarchical topology is the simplest to engineer.
Generally this will mean hierarchical connection of school facilities

_____________________________________________________________________________
[3] "Connecting to the Internet", Susan Estrada, O Reilly & Associates,
    Inc. (ISBN 1-56592-061-9) lists Internet service providers in
    California and the nation.

Gargano, Wasley                [Page 7]

Internet Draft          K-12 Internetworking Guidelines         December 1993

to district offices, in many cases further aggregated at county
offices, and finally a link to an Internet service provider.
Coordination of circuit services and a single point of connection to
an Internet service provider serves both to minimize overall costs
and increase opportunities to make use of newer technologies.

The basic school network implementation model is quite simple:
create a local area network (LAN) within each school building or
cluster of buildings, provide at least one network server for that
LAN, interconnect that LAN with the local school district offices
where a similar LAN should be installed and where centrally
managed information resources should exist, and connect the
district offices to the nearest Internet service provider, possibly
through the county office of education.

Primary technical support for network monitoring and problem
resolution, and for managing network resource servers should
come from the district or county offices initially to avoid
unnecessary duplication at the local level.  As expertise is
developed at the local level, more of the responsibility for daily
operation and problem resolution can be assumed by individual
schools.

It is impossible to cover all conceivable scenarios for
implementation of this model in specific schools.  However, it is
possible to state general principles that should be followed in
designing school network implementations.  The discussion below
is organized into sections corresponding to the basic model
summarized in the previous paragraph.  It includes a description of
the general principles that are important to each level of the
implementation.

Step 1: School Local Area Network Implementation

A "school" is used here to mean a building or cluster of buildings
that are managed as a unit and typically are on contiguous,
district owned property.  Implementation of a LAN in this setting
will involve installation of a cabling system to distribute the
network throughout the structure(s), installation of premise wiring
to support connections of computers and terminals to the network
distribution system, installation of one or more network server
machines in a central location[4] , and provision of a network router
and telecommunications circuit or radio link to connect that school
to the district offices.

__________________________________________________________________________
[4]  Other protocols, such as AppleTalk or Novell s IPX, may be supported
       on a school s local area network (LAN) as needed for local functions
       such as printer sharing or local resource servers.

Gargano, Wasley                [Page 8]

Internet Draft          K-12 Internetworking Guidelines         December 1993

The most common LAN technologies in use today are ethernet and
LocalTalk[5] .  Both are quite inexpensive and easy to install and
maintain.  Ethernet is adaptable to most modern computers 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
to DOS PC computers as well.  Ethernet is roughly 20 to 40 times
faster than LocalTalk.  Therefore ethernet is recommended for all
computer connections, when possible, and for the school LAN
"backbone" or network distribution system.

1.1  Network Adapters and Software

Individual computers will require network or communications
adapters and appropriate software.  Table 1 gives basic
recommendations for the computers most commonly found in
schools.  Basic communications software is available in the public
domain for many personal computers at no cost.  More
sophisticated software is being developed by a number of vendors

for applications such as electronic mail, distance learning, and
multimedia database access.  For example, the California
Technology Project is developing very easy to use software for
Macintosh and DOS or Windows PC computers that will enable
access to a wide variety of information resources and services.
Schools should look at all the available software and base choices
on required functionality and support costs as well as acquisition
costs.

In locations where computers will be purchased, the choice of
computer type should be driven by the availability of software for
the particular application(s) to be supported.  Almost all modern
computers can be attached to the type of network described in this
document.

1.2  Premise wiring

A major component of the implementation will be installation of
cabling to connect individual computers or clusters of computers to
the LAN.  The recommended topology is a "star" where each
computer is wired directly to a "hub site" within the building as
shown in Figures 1 & 2.  A cluster of computers, typically found in
a teaching lab or library, may be interconnected within the room

______________________________________________________________________________
[5]  IEEE 802.5 Token Ring is not recommended for new installations.  It is
      more expensive and it is not available for as wide a range of computers.

Gargano, Wasley                [Page 9]

Internet Draft          K-12 Internetworking Guidelines         December 1993

where they are installed, and the cluster connected to the hub site
with a single cable as shown in Figures 3 & 4.

Equipment Type          Network Adapter                 Communication
                                                        Software
-----------------------------------------------------------------------------
Simple terminal         "Network Access Server"         Built-in to the network
                        located centrally.              access server.

Apple II, Amiga,        Serial asynchronous             Serial communications
Tandy, Commodore,       port that will allow            software that emulates a
older IBM PC s, etc     connection to the above.        simple terminal.

Newer IBM PC            Ethernet adapter card           TCP/IP "TSR" software,
                        with "10-base-T" port.          for example "FTP
                        "Thin-net" port may be          Software" package.
                        used in lab clusters.           Additional software for
                                                        special appl.

Older Apple             PhoneNet adapter                MacTCP or equivalent
Macintosh computers     (external) and shared           plus "telnet" and "ftp".
                        LocalTalk to ethernet           For example, NCSA
                                                        Telnet.  Additional
                        router, for example the         software for special
                        Shiva FastPath.                 applications, eg.
                                                        "electronic mail
                                                        client."

Newer Apple             May use same as the             Same as the above.
Macintosh computers     above.  For higher
                        performance, use an
                        ethernet adapter card
                        with "10-base-T port.
                        "Thin-net" port may be
                        used in lab clusters.

Unix workstations       Ethernet adapter card,          Typically comes with
                        if not already built in.        the basic system.
                                                        Additional software
                                                        may be needed
                                                        for special
                                                        applications.

______________________________________________________________________________
Table 1:  Network Adapters and Software for Typical Computers

Gargano, Wasley                [Page 10]

Internet Draft          K-12 Internetworking Guidelines         December 1993

The recommended premise wiring is "unshielded twisted pair"
(UTP) wire that meets the Electronic Industries Association (EIA)
category 5 standards for high speed data communication service .[6]
While 2 pair cable may be adequate for most purposes, industry
standards recommend installation of 4 pair cable.  The difference
in cost is minimal so we recommend installation of the latter.  One
end of each cable terminates in a category 5 RJ-45 jack [7]  located
near the computer.  The other end terminates on a standard "110
distribution block "[8] at the hub site utility closet.  A labeling
scheme must be chosen and strictly adhered to so that cables can
be identified at both ends later, as needed.

In most cases, the hub site utility closet will be shared with
telephone services.  It is essential that a separate wall area be set
aside within the closet for data service interconnections.  Typically
there will be a "field" of interconnect blocks for termination of all
premise wires, another field for termination of trunk cables (used
for low speed data terminals), and a third field for hub equipment
ports.  Interconnections between premise wiring blocks and hub or
trunk blocks are installed as needed in order to provide the
appropriate service to each location where communication service
is required.

Installation of wiring in a building typically is performed by a
qualified data wiring contractor.  This is a critical aspect of the
program and must be planned and installed professionally with
both current and future requirements in mind .[9]  To be prepared for
future distribution of video signals, school network planners
should consider installation of RG-59 coaxial cable to those
locations where video may be required at the same time that the
UTP premise wiring is being installed.  The coaxial cable would
terminate on a wall plate mounted "F" connector in the classroom,
and would be left unterminated in the utility closet.  Future
technologies may support video signals over other media so the
installation of RG-59 cable should be limited to near term potential
requirements.

_____________________________________________________________________
[6]  See EIA/TIA-568 "Commercial Building Telecommunications Wiring Standard."

[7]  A standard RJ45 jack can be used for ethernet or lower speeds if
     initial cost is a major factor.  Such jacks can be replaced with
     category 5 versions later as needed.

[8] In older sites, M66 distribution blocks may already be installed.
    These can be used for the time being but will not support newer
    higher speed technologies.

[9]  See "Virtual Schoolhouse - A Report to the Legislature on Distribution
      Infrastructures for Advanced Technologies in the Construction of New
      Schools, K through 12" (Department of General Services, State of
      California, Feb 1993) for example conduit and utility closet plans.

Gargano, Wasley                [Page 11]

Internet Draft          K-12 Internetworking Guidelines         December 1993

It will be cost effective to install premise wiring to as many
locations as might ever serve a computer.  This will include
administrative offices as well as classrooms, laboratories as well as
libraries.  In high density locations such as offices, consideration
should be given to installation of two UTP cables to each outlet
location in order to provide the potential for several computers or
workstations.  Terminating both cables on the same wall plate will
add little to the overall wiring project costs and will add greatly to
the flexibility of the system.  Premise wiring that is not to be used
initially will not be connected to any electronics in the hub site.

Hub sites should be utility closets or other protected, non-occupied
areas.  Hub sites can be created by construction of small closets or
cabinets in low use areas.  A hub site must be located within 300
feet of any connection.  Typically, multiple hub sites are required
in large or multi-story buildings.

1.3  Network Distribution System

All hub sites within a school must be interconnected to complete
the school LAN.  The design of this network distribution system
will depend greatly on the physical layout of the school buildings.
We assume that ethernet technology will be used since higher
speed technology is still quite expensive.

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 each
hub site, as shown in Figure 5.  If longer distances are required,
either thin-net or standard thick ethernet can be used.  Fiber optic
cable can be used if distance requires it and funding permits. [10]
Specific design of the "backbone" network distribution system will
depend on the layout of the buildings to be served.

With proper design as many as 250 computers can be connected to
a single ethernet segment.  Most often the practical maximum
number will be much lower than this due to the amount of data
sent onto the network by each computer.  For planning purposes,
one can assume 100-125 computers per segment.