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Network Working Group J. Gargano Request for Comments: 1709 University of California, Davis FYI: 26 D. Wasley Category: Informational University of California, Berkeley

                                                         November 1994
                  K-12 Internetworking Guidelines

Status Of This Memo

 This memo provides information for the Internet community.  This memo
 does not specify an Internet standard of any kind.  Distribution of
 this memo is unlimited.

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.
 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" (also FYI 18)
 1432    "Recent Internet Books"
 1462    "What is the Internet" (also FYI 20)
 1463    "Introducing the Internet - A Short Bibliograpy of
         Introductory Internetworking on Readings for the Network
         Novice" (also FYI 19)

ISN Working Group [Page 1] RFC 1709 K-12 Internetworking Guidelines November 1994

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.
 (Honey, Margaret, Henriquez, Andres, "Telecommunications and K-12
 Educators: Findings from a National Survey," Bank Street College of
 Education, New York, NY, 1993.)  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
      "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
 Database access                 36                      31
 File transfer                   34                      19
 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.

ISN Working Group [Page 2] RFC 1709 K-12 Internetworking Guidelines November 1994

 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
                 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

ISN Working Group [Page 3] RFC 1709 K-12 Internetworking Guidelines November 1994

                 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
 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
 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 Internet School Networking
 (ISN) Working Group 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.

ISN Working Group [Page 4] RFC 1709 K-12 Internetworking Guidelines November 1994

 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 (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.) 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.

ISN Working Group [Page 5] RFC 1709 K-12 Internetworking Guidelines November 1994


 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:
 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 PCs, 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

ISN Working Group [Page 6] RFC 1709 K-12 Internetworking Guidelines November 1994

    programs and community.  This model optimizes use of network
    bandwidth as well;
 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
 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.  ("Connecting to the
 Internet", Susan Estrada, O'Reilly & Associates, Inc. (ISBN 1-56592-
 061-9) lists Internet service providers in California and the
 nation.)  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

ISN Working Group [Page 7] 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 intersite
 topologies, but a hierarchical topology is the simplest to engineer.
 Generally this will mean hierarchical connection of school facilities
 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 (Other protocols, such as AppleTalk or Novells IPX,
 may be supported on a school's local area network (LAN) as needed for
 local function such as printer sharing or local resource servers.),
 and provision of a network router and telecommunications circuit or

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 and
 LocalTalk.  (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.)  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
 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

ISN Working Group [Page 9] RFC 1709 K-12 Internetworking Guidelines November 1994

Equipment Type Network Adapter Communication


Simple terminal "Network Access Server" Built-in to the

                    located centrally.        networkaccess server.

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


Newer IBM PC Ethernet adapter car 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
                    router, for example the   Telnet.  Additional
                    Shiva FastPath.           software for special
                                              applications, e.g.,
                                              "electronic mail

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

   Table 1:  Network Adapters and Software for Typical Computers

ISN Working Group [Page 10] RFC 1709 K-12 Internetworking Guidelines November 1994

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 where they are
 installed, and the cluster connected to the hub site with a single
 cable as shown in Figures 3 & 4.
 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.  (See
 EIA/TIA-568 "Commercial Building Telecommunications Wiring
 Standard.")  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
 (A standard RJ45 jack can be used for ethernet or lower speeds if
 initial cost is amajor factor.  Such jacks can be replaced with
 category 5 versions later as needed.) located near the computer.  The
 other end terminates on a standard "110 distribution block" (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.) 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.
      [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 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
     [Figure 3:  A cluster of computers connected to the network]
      [Figure 4:  A Macintosh cluster connection to the network]

ISN Working Group [Page 11] RFC 1709 K-12 Internetworking Guidelines November 1994

 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.  (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, February,
 1993) for example conduit and utility closet plans.)  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.
 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
 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.
               [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 each
 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 optic
 cable can be used if distance requires it and funding permits.  (If
 fiber optic cable is installed, consideration should be given to
 including both multimode fiber for current and future data
 requirements and single mode fiber for video and future very high
 speed data systems.) Specific design of the "backbone" network
 distribution system will depend on the layout of the buildings to be
 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.  Beyond that size the network must be
 subdivided using "subnetworks".  Design of a such a system is not
 difficult, but is beyond the scope of this document.
 The network distribution system cabling should include unshielded
 multi-pair trunk cabling as well as ethernet trunk cabling.  The
 multi-pair trunk cable will be needed to connect terminals or older
 computers emulating terminals to a central "network access server"
 (NAS).  A typical NAS can serve from 8 to 128 such connections.  It
 is most cost effective to provide one per LAN, if needed.  The NAS
 connects directly to the ethernet LAN.

1.4 Local Network Server

 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 speed
 communication to the users computer.  Since the connection to the
 outside network will be much slower than the school LAN, it will be
 most efficient to access information locally.  In particular,
 software that is to be shared among the schools computers must be
 stored locally since it would be very tedious to transfer it across
 the slower external link.  The network server will be connected
 directly to the ethernet network.
 The location of the server should be chosen carefully to ensure its
 protection from abuse and environmental damage.  Traditionally the
 school library is the focus of information gathering and storage
 activities and many school libraries have clusters of computers or
 terminals already installed.  The library would be a very logical
 place to locate the network server computer.  The Network Router (see
 below) might also be located there if a suitable utility space is not

ISN Working Group [Page 13] RFC 1709 K-12 Internetworking Guidelines November 1994

 The network server will be a small but powerful computer with a large
 amount of disk storage capacity, typically 1-4 gigabytes.  It will
 run software capable of supporting access by a large number of users
 simultaneously.  It could also support dial-in access from teachers
 or students homes using standard inexpensive modems.  (Access control
 with user authentication is essential if dial-in service is to be
 provided.)  If more than a few modems are to be installed, a NAS
 might prove more cost effective.  If dial-in access is to be provided
 to more than a few school sites within a district, a single central
 modem pool maintainted at the district offices will be the most cost

1.5 External Connection

 A single communication circuit will connect the school LAN to the
 local school district offices.  In the school, there will be a
 Network Router attached between the LAN and this circuit.  On the LAN
 side, the connection will be a typical ethernet cable.  On the
 external side, the connection will depend on the type of
 communication circuit used, as discussed in step 2 below.

Step 2: Interconnection of Schools with District Offices

 All schools within a district should be connected individually to the
 network router at the school district offices.  This "star topology"
 will be much easier to manage and the capacity of each schools
 connection can be increased appropriately as needs change.
 Several standard communication circuit services may be used to effect
 this connection.  The least expensive for situations where only
 limited use is needed will be dial-up using high speed modems.
 However, this type of connection is not recommended for serious usage
 due to its very limited capacity.  Also, since most schools receive
 telephone service under business tariffs, usage will be measured and
 the cost will be dependent on how long the connection is maintained.
 This will be true in general for other "switched services" as well
 such as "switched-56" and ISDN.  Dedicated (permanently installed)
 communications circuits are strongly recommended since they will
 allow unattended access to and from the school network at all hours.
 This will be particularly important if information files are to be
 down-loaded during the night to local network servers or teachers and
 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 by
 location and as tariffs are modified.  The exact costs must be
 determined by contacting local communications service providers.
 Total cost must take into account the equipment needed at each

ISN Working Group [Page 14] RFC 1709 K-12 Internetworking Guidelines November 1994

 location as well.

Type of Circuit Data Rate Relative cost

Voice grade leased 20 kilobits per sec modest* telephone line (Kb/s)

ADN-56 56 Kb/s high

ISDN, where 64 or 128 Kb/s modest available Low power radio 64 to 256 Kb/s high startup cost Frame Relay 56 Kb/s to 1.5 Mb/s modest to high DS1 1.5 megabits per sec very high * Measured service charges must be taken into account. At this time, most ISDN tarriffs include message unit charges

 which can make theuse of ISDN prohibitively expensive for
 full-time connectivity.
        Table 2: External Connection Communications Options
 Frame Relay communication services are becoming available in many
 areas.  Frame Relay is a shared, packet based data transport service.
 A school site would contract for Frame Relay service as part of a
 larger service group that includes the school district office and may
 include the Internet service provider.  All members of that group
 would share the communications capacity.  The advantage of this
 service is that only one end of the circuit needs to be ordered (each
 member orders a connection to the common service) and the capacity
 offered to each member can be upgraded independently.  Also, in many
 areas the cost of Frame Relay service is not dependent on distance to
 the service provider which will make service to rural schools much
 less expensive than equivalent services.  Overall system costs will
 be minimized since the central router at the district office will
 need fewer connections.
 If Frame Relay is chosen, the overall service group must be carefully
 engineered.  For example, since all schools would share the
 connection to the district office (and possibly to the Internet
 service provider), that must be a high capacity connection.  For the
 initial design, the aggregate capacity of all school links should not

ISN Working Group [Page 15] RFC 1709 K-12 Internetworking Guidelines November 1994

 exceed the capacity into the district office (or the Internet service
 provider) by more than a factor of 3 or there may be noticeable
 congestion and variability in response times across the system.
 There are many other factors that must be considered as well, such as
 the virtual connection topology and how best to connect to an
 Internet service provider.  Therefore, it is recommended that an
 experienced network engineer be utilized to develop an operational
 plan for Frame Relay if it is chosen as the school interconnection
 Future options for interconnecting schools and district offices will
 o       Community Access Television (CATV) cable systems offering
         either shared or dedicated bi-directional data communication
 o       metropolitan area fiber optic communications service
 o       Switched Multi-megabit Digital Service (SMDS) providing data
         transport service at speeds up to 34 megabits per second.
 o       Asynchronous Transfer Mode (ATM) connection services
         supporting voice, data, and video communications at speeds
         into the gigabit per second range.
 (Many more options will become available as new technologies come to
 The costs for the last three options are unknown at this time, but
 may be generally higher than those indicated in Table 2.  The cost
 for the CATV option may be negotiable as part of the local CATV
 contract with the community.
 As demands for network speed develop due to heavy use of multimedia
 or other bandwidth intensive application, higher speed communications
 circuits can replace the initial circuits with minimal change in the
 equipment or LAN.  This gives great flexibility in tailoring service
 to funding levels and application needs.

Step 3: School District Office LAN and Support Systems

 The School District offices should form the focal point for
 interconnection of all schools in the district.  Within the District
 offices, network operations can be monitored and problem resolution
 managed.  One or more network servers can provide essential network
 support as well as central archiving of common information and

ISN Working Group [Page 16] RFC 1709 K-12 Internetworking Guidelines November 1994

 A critical role of the district office will be to manage Internet
 "Domain Name System" (DNS) (See STD 13, RFCs 1034, 1035 for the full
 explanation of DNS, and also, RFC 1480.) service for the districts
 schools.  DNS is required of all Internet networks.  It defines the
 basic network level identity of each computer, workstation, server,
 and active network component.  This function is described more fully
 below under Network Management and Operational Monitoring.
 The district offices should be wired in a manner similar to a typical
 school, as shown above.  This will allow teachers, superintendents,
 and principals to communicate and share information easily.  In
 addition, an NAS connected to a central pool of modems could provide
 dial-in access to the district network.

Step 4: Interconnection of the School District with the Internet

 Connection of the entire school district to the Internet will take
 place through the district office interconnect site, as shown in
 Figure 6.  This hierarchical model can be extended another level to
 interconnection of the school district offices through the county
 office of education facilities.  Many administrative information
 resources could be located at the county level, and there might be
 cost savings if the entire county connects to an Internet service
 provider through a single point.  The bandwidth required for this
 single connection, however, will be much greater than that required
 for each school district since traffic will be aggregated.
 This hierarchical topology also provides a logical model for network
 support and information resource management.  The school district or
 county offices can provide continuous monitoring of the network and
 provide high level technical expertise for problem resolution,
 relieving the individual schools of this burden.  Interactions with
 communications circuit providers and Internet service providers will
 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 similar
 to those shown in Table 2 above.  The higher speed services should be
 considered if traffic demands increase and funding permits.  Circuit
 costs usually will be lowest when connecting to the provider with the
 nearest "point of presence" (POP), but newer technologies such as
 Frame Relay and SMDS (At this time, SMDS services are not widely
 available.) make circuit costs less dependent on distance.  The
 Internet connection will require a high quality router that can be

ISN Working Group [Page 17] RFC 1709 K-12 Internetworking Guidelines November 1994

 configured to interact correctly with the service providers routers.
 In most cases, this can be the same router used to support the local
 school connections.
 [Figure 6:  Interconnection of schools to the Internet through local
                       School District Offices]

Integration of Existing School Networks

 Many schools have developed LAN systems in support of particular
 classroom activities or administrative functions.  In some cases the
 technologies used are not those recommended for new installations. If
 these older LAN systems are capable of transporting Internet
 protocols they may be integrated into a new LAN system and replaced
 later as funding permits.
 For example, IEEE 802.5 Token Ring is often used to interconnect DOS
 PC-type computers and IBM minicomputer servers.  Token Ring networks
 can transport Internet protocols and software is available for DOS
 computers to support basic Internet functions.  Many Internet routers
 support optional Token Ring adapters.  This is the recommended way
 that existing Token Ring LANs can be integrated into a wider school
 LAN system in order to extend Internet information resources to those
 PC users.
 Another example is a Novell Network system using ethernet as a LAN.
 The ethernet LAN, if implemented well, is perfectly capable of
 transporting Internet protocols as well as Novell protocols,
 simultaneously.  Each PC or Macintosh can be given software that will
 allow both Novell and Internet services to be used as needed. This
 coexistence is important so that, for example, a person using a PC
 that depends on the Novell server for disk file space can transfer a
 large file from a remote Internet server to the PCs pseudo-disk.  It
 also permits each user to run client software such as Eudora
 (electronic mail), Gopher (information services), and Mosaic (World
 Wide Web information services) which require direct Internet access.
 To integrate the Novell ethernet LAN into the wider school LAN system
 a simple ethernet repeater can be used in a manner similar to Figure
 3 above.
 An alternative to supporting both protocols that is sometimes
 suggested in cases such as the one cited above in which a network
 server already exists is to use the server as a "network application
 gateway".  This approach is strongly discouraged.  It is essential
 that each computer and workstation support Internet protocol data
 communication directly so that modern client/server applications can
 be supported where the server or servers may be located anywhere on
 the Internet.  The "gateway" approach severely restricts the

ISN Working Group [Page 18] RFC 1709 K-12 Internetworking Guidelines November 1994

 workstations potential ability to access multimedia and other
 important information resources.
 Some technologies, such as "arcnet," may not be capable of supporting
 Internet protocols but may offer "terminal emulation" shared access
 to something like a "modem pool".  The modem adapter might be rewired
 to connect to ports on a network access server instead.  This would
 provide simple access to information resources for the arcnet users.
 In any case, older LAN technologies should not be expanded and should
 be phased out as funding permits.  It is critical that there be a
 relatively homogeneous installed base of technology in order that new
 applications of information resources can be provided to the entire
 school community.

Network Management and Operational Monitoring

 All networks require some level of network management in order to
 ensure reliable service.  Monitoring of the health of the network can
 help identify problems before they become detrimental to network
 users.  It also can help predict trends in traffic patterns and
 Internet technology network management consists primarily of
 determining the proper routing parameters for optimal and reliable
 network operation, assignment of network Internet Protocol (IP)
 addresses and maintenance of a network-accessible database of node
 names corresponding to each address (See RFC 1480 for a discussion of
 Internet naming conventions for school networks.), and monitoring the
 daily operation of the network.  These functions typically are
 performed by the staff of a Network Operations Center (NOC).

Domain Name System

 The Internet Domain Name System (DNS) is the mechanism for
 documenting and distributing information about the name and address
 of each computer attached to the network (network nodes).  The DNS
 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 it
 must be unique among all nodes associated with the network.
 Furthermore, if the network is to be part of the global Internet, all
 addresses must be legitimate within the worldwide Internet system.
 Associated with each numerical address can be one or more "node
 names".  Although computers have no difficulty using numerical
 addresses, it is often easier for computer users to remember and use

ISN Working Group [Page 19] RFC 1709 K-12 Internetworking Guidelines November 1994

 the node names rather than the numerical addresses.  In particular,
 electronic mail addresses use node names.  DNS node names are
 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 the
 context of the whole organization.
 A plan for the assignment of IP network addresses and node names
 should be developed early in the planning for the network
 installation.  Initially, the database serving the DNS should reside
 on the "district server" so that there is one site at which all
 assignments are officially registered.  As the network grows and
 expertise is developed, secondary DNS service can be run on the
 servers at larger school sites.
 The main DNS server for the district should be located as close to
 the Internet connection (topologically) as possible.  This proximity
 is to help ensure that network problems within the district network
 will have minimal impact on access to the server.  This design is
 illustrated in Figure 1 where the district server is on an ethernet
 connected directly to the main distribution router.
 Associated with the assignment of node names and addresses should be
 a database of specific information about the computers connected to
 the network.  When trying to resolve problems or answer user
 questions, it is very important to know where the computers and other
 nodes are located, what type of computer and software are in use, and
 what type of network connection is installed.  With proper software
 this database can be used to extract the DNS database discussed

Network Monitoring

 Internet network monitoring serves three primary purposes:
 1) Constant observation of the "health" of the network, network
    components, and external network connectivity.  Standard Simple
    Network Management Protocol (SNMP) support is built-in to most
    active components today.  Even network servers and workstations
    can be monitored in this way.  Operations staff can be provided
    with network monitoring stations that will display alerts
    immediately upon detecting a wide variety of problems or
 2) Collection of statistics on the performance of the network and
    patterns of traffic in order to identify needed enhancements or
    re-engineering.  Using the same SNMP capabilities mentioned
    above, data on packet forwarding and total traffic volume can

ISN Working Group [Page 20] RFC 1709 K-12 Internetworking Guidelines November 1994

    be collected and used to generate periodic reports on network
 3) More rapid problem resolution.  When problems do occur, SNMP
    tools can help to pinpoint the source of the problem(s).  Such
    problems include transient routing anomalies, DNS query
    failures, or even attempts at breaking into network accessible
    host computers.
    Since network management and monitoring is a technically
    demanding task and requires special equipment and software, it
    should be a centralized function in the initial design of school
    network systems, as discussed above.

IV. Network Support


 The model for school network implementation described above is based
 on broad experience with this technology in higher education and
 administrative environments.  Many schools have already installed
 networks very similar to this model.  We believe that it is a
 practical first step towards bringing a powerful resource to bear for
 enriching all of the nations school programs.
 None of the suggestions above preclude or postpone in any way future
 development of an integrated voice, data, and video network for the
 nations schools.  Use of existing Internet carriers does not in any
 way preclude future development of a separate "backbone" for the K-12
 community if such a "backbone" is determined to be cost effective or
 required for enhanced functionality.  Rather, the infrastructure
 recommended above can be the foundation at the local level in
 preparation for future high capacity networks.
 The installation of a campuswide network or Internet connectivity
 will also require a commitment to ongoing network support and its
 related resource requirements.  There are two major areas of network
 support, network operations and user services.  These support
 functions are usually performed through the establishment of a
 Network Operations Center (NOC) and Network Information Center (NIC),
 however both functions can be performed by the same individual or
 groups of individuals.

ISN Working Group [Page 21] RFC 1709 K-12 Internetworking Guidelines November 1994

Network Operations Center (NOC)

 The Network Operations Center (NOC) oversees the performance of the
 physical network and some of its software support systems.  The staff
 may install networks, configure network devices and provide
 configurations for computers attached to an organization-wide
 network.  Real-time monitoring of the network can be performed using
 the Simple Network Management Protocol and many vendors produce
 monitoring systems that graphically display network performance, log
 events and usage, and produce trouble tickets.  The use of this type
 of network monitoring allows NOC staff to quickly detect problems and
 greatly reduces the personnel required to perform this function.
 Routine monitoring of the network can help to anticipate problems
 before they develop and lead to reconfigurations and upgrades as
 indicated.  If problems do arise, NOC personnel may go on-site to
 troubleshoot a problem and repair it.  If the problem is not local,
 NOC personnel will work with school district, County or regional
 network technical staff to resolve the problem.
 NOC personnel also assign addresses to network computers and devices
 and maintain the Domain Nameservice (DNS) for their organization.
 Domain Nameservice is a machine registry service that runs on a
 network server and enables access to machines by easy to remember
 names, rather than a network number.  DNS is required for any
 organization connected to the Internet and critical to the
 establishment of an electronic mail system.
 It is most cost effective to have the Network Operation Center serve
 an entire organization or region.  In order to ensure timely service
 all the way out to the most remote LAN, it is recommended that an
 organization assign local area network administration duties to on-
 site personnel to interact with NOC staff and assist with the
 maintenance of the network.  In the case of a school district,
 administrative support staff, teachers, librarians or school based
 technical staff can each take responsibility for a LAN or group of
 LANs.  If a problem arises, it can be reported to the LAN
 administrator.  The LAN administrator can determine if the problem is
 local or remote and if NOC staff need to be notified.  If so, the LAN
 administrator acts as the single point of contact for the NOC to
 provide a good communications channel for information and ensure
 efficient coordination of problem resolution.  This method of
 delegating responsibility provides for a high level of service for
 each LAN and optimally uses the time of NOC staff to provide
 economies of scale.

ISN Working Group [Page 22] RFC 1709 K-12 Internetworking Guidelines November 1994

Network Information Center (NIC)

 The Network Information Center (NIC) provides information and support
 services to facilitate the use of the network.  The NIC often
 provides a help-desk service to answer questions about use of the
 network, references to useful resources and training in new tools or
 applications.  The NIC may also provide services such as an on-line
 directory of network users and their electronic mail addresses,
 bulletin board services of information and notices about the network
 and on-line training materials.  These NIC services could be provided
 on a school district or County level.  Most of the information would
 not be site specific and can be delivered electronically using
 electronic mail, electronic conferencing, on-line bulletin boards or
 other document delivery mechanisms.  These types of services may be
 well suited for a school or school district librarian.
 Other types of support services may be performed by NIC personnel
 such as maintenance of the electronic mail system or Postmaster
 duties, coordination of an on-line bulletin board or campuswide
 information system (CWIS) and management of an on-line conferencing
 system.  These duties are more technical in nature and will require
 technical staff to maintain them.


 Every organization which uses electronic mail should have an
 Electronic Mail Postmaster and a mailbox, postmaster, for the receipt
 of messages regarding use of the electronic mail system, mail
 problems and general inquiries about reaching people within the
 organization.  The Postmaster is responsible for reading postmaster
 mail and responding to inquiries.  These duties can be performed by
 non-technical staff with forwarding of messages to the appropriate
 technical support person as required.

CWIS Administrator

 Campuswide information systems or bulletin boards are one of the most
 useful applications on the network.  These systems allow people to
 share timely notices, documents and other resources with large groups
 of people.  These systems typically provide a hierarchical or tree
 like structure of menus that lead to on-line documents or other
 services.  Common types of information include deadline notices,
 grant announcements, training schedules, lists of available resources
 such as videos in a library or reference materials.
         [Figure 7:  Distributed Network Information Servers]

ISN Working Group [Page 23] RFC 1709 K-12 Internetworking Guidelines November 1994

 Information need not be stored all in one location.  Figure 7 shows a
 set of distributed servers.  These servers can receive new
 information automatically from a central server and can also contain
 information generated locally that may pertain only to the local
 school.  Users of the information need not know where the information
 is stored: the information access software will present choices on an
 integrated menu.
 A CWIS or bulletin board must have an administrator or sponsor to
 oversee the design and maintenance of the system so that it is easy
 to navigate and find information, provides a professional
 presentation of information and ensures that information remains
 timely and relevant.  This function can be performed by NIC staff, or
 trained librarians or administrative staff as appropriate.

Management of On-line Conferences

 On-line conferences provide a way for groups of people to share
 information, discuss ideas and pose questions.  Conferences usually
 are set up to serve the needs of a group of people sharing a common
 interest.  For example, an on-line conference might be established
 for teachers to discuss a new science teaching framework or a teacher
 may establish a conference for the discussion of the Civil War as
 part of an American History class.  Some conferences are on-going and
 may exist for years.  Others are short term and may exist for only
 one semester.  Conferences may be created using the electronic mail
 system or a facility called Usenet News.
 On-line conferencing systems require a server computer on the network
 that collects messages posted to a conference and distributes them
 when requested.  Usually these systems are managed by a systems
 administrator and someone must configure the system to establish and
 delete groups upon request.  Other management duties include
 scheduling the deletion of old messages and archiving especially
 valuable conversations.  Typically these duties are performed by a
 systems administrator or technical staff.

Staffing Considerations

 The duties described above do not necessarily require hiring new
 staff and they may be shared by people already within an
 organization.   Small schools or districts may rely on County Office
 of Education Information Systems staff to perform all functions.
 Larger schools or districts may have staff to take on any combination
 of duties and rely on the County Office of Education for others.
 Access to the network and the use of electronic communications allows
 people throughout the organization to perform these functions
 remotely.  The assignment of responsibility for any of these duties

ISN Working Group [Page 24] RFC 1709 K-12 Internetworking Guidelines November 1994

 is flexible and should be approached with the goal of providing the
 highest quality of service in the most cost effective and workable

V. References

 Honey, Margaret, Henriquez, Andres, "Telecommunications and K-12
 Educators: Findings from a National Survey", Bank Street College of
 Education, New York, NY, 1993.
 Susan Estrada, "Connecting to the Internet", OReilly & Associates,
 Inc. (ISBN 1-56592-061-9)
 Carole Teach, Editor, "Building the Future: K-12 Network Technology
 Planning Guide", California Department of Education, Research,
 Evaluation & Technology Division, 1994.

VI. Special Thanks

 Special thanks to Brian Lloyd of Lloyd Internetworking, Inc.  for his
 contributions to this document.  Brian was one of the contributors to
 the California Department of Education "K-12 Network Technology
 Planning Guide" which served as the motivation for writing most of
 this document.  Brian contributed significantly to Section II,
 "Rationale for the Use of Internet Protocols" and thoroughly reviewed
 Section III, "A Technical Model for School Networks", providing
 valuable feedback.

ISN Working Group [Page 25] RFC 1709 K-12 Internetworking Guidelines November 1994

VII. Security Considerations

 Security issues are not discussed in this memo.

VIII. Authors' Addresses

 Joan C. Gargano
 Information Technology
 Distributed Computing Analysis and Support
 University of California
 Davis, CA   95616
 David L. Wasley
 Data Communication & Network Services
 Information Systems and Technology
 University of California
 Berkeley, CA   94720

ISN Working Group [Page 26]

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