                                ==Phrack Inc.==

                     Volume Three, Issue 25, File 4 of 11

              =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
              =-=                                             =-=
              =-=                   S P A N                   =-=
              =-=                                             =-=
              =-=       Space Physics Analysis Network        =-=
              =-=                                             =-=
              =-=     Brought To You by Knight Lightning      =-=
              =-=                                             =-=
              =-=               March 15, 1989                =-=
              =-=                                             =-=
              =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=


Preface
~~~~~~~
In the spirit of the Future Transcendent Saga, I continue to bring forth
information about the wide area networks.  The information presented in this
file is based primarily on research.  I do not have direct access to SPAN other
than through TCP/IP links, but this file should provide you with general
information with which to properly use the Space Physics Analysis Network.


Introduction
~~~~~~~~~~~~
The Space Physics Analysis Network (SPAN) has rapidly evolved into a broadly
based network for cooperative, interdisciplinary and correlative space and
Earth science data analysis that is spaceflight mission independent.  The
disciplines supported by SPAN originally were Solar-Terrestrial and
Interplanetary Physics.  This support has been expanded to include Planetary,
Astrophysics, Atmospherics, Oceans, Climate, and Earth Science.

SPAN utilizes up-to-date hardware and software for computer-to-computer
communications allowing binary file transfer, mail, and remote log-on
capability to over 1200 space and Earth science computer systems in the United
States, Europe, and Canada.  SPAN has been reconfigured to take maximum
advantage of NASA's Program Support Communication Network (PSCN) high speed
backbone highway that has been established between its field centers.  In
addition to the computer-to-computer communications which utilizes DECnet, SPAN
provides gateways to the NASA Packet Switched System (NPSS), GTE/Telenet,
JANET, ARPANET, BITNET and CSNET.  A major extension for SPAN using the TCP/IP
suite of protocols has also been developed.

This file provides basic information on SPAN, it's history, architecture, and
present guidelines for it's use.  It is anticipated that SPAN will continue to
grow very rapidly over the next few years.  Several existing wide-area DECnet
networks have joined with SPAN to provide a uniform internetwork structure and
more will follow.


History Of The SPAN and the Data Systems Users Working Group (DSUWG)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A considerable evolution has occurred in the past two decades in the way
scientific research in all disciplines is done.  This is particularly true of
NASA where early research was centered around exploratory missions in which
measurements from individual scientific instruments could be meaningfully
employed to advance the state of knowledge.  As these scientific disciplines
have progressed, a much more profound and interrelated set of questions is
being posed by researchers.  The result is that present-day investigations are
generally much more complex.  For example, within the space science community
large volumes of data are acquired from multiple sensors on individual
spacecraft or ground-based systems and, quite often, data are needed from many
institutions scattered across the country in order to address particular
physical problems.  It is clear that scientific research during the late 1980s
and beyond will be devoted to intense multi-disciplinary studies aimed at
exploring very complex physical questions.  In general, the need for
researchers to exchange data and technical information in a timely and
interactive way has been increasing.

The problems of data exchange are exacerbated by the lack of standards for
scientific data bases.  The net result is that, at present, most researchers
recognize the value of multi-disciplinary studies, but the cost in time and
effort is devastating to their research efforts.  This trend is antithetical to
the needs of the NASA research community.  SPAN is only one of many research
networks that are just beginning to fill a need for access to remote
capabilities that are not obtainable locally.

In May of 1980 the Space Plasma Physics Branch of the Office of Space Science
of NASA Headquarters funded a project at Marshall Space Flight Center (MSFC) to
investigate ways of performing correlative space plasma research nationwide on
a daily basis.  As a first step, a user group was formed called the Data
Systems Users Working Group (DSUWG) to provide the space science community
interaction and direction in the project.  After the first meeting of the DSUWG
in September 1980, it was decided that the approach would be to design, build,
and operate a spacecraft mission independent science network as a test case.
In addition, the construction of the system would be designed to use existing
data analysis computer systems at space physics institutions and to take full
advantage of "off-the-shelf" software and hardware.

The Space Physics Analysis Network (SPAN) first became operational in December
1981 with three major nodes:

o  University of Texas at Dallas
o  Utah State University
o  MSFC

Since that time it has grown rapidly.  Once operational, SPAN immediately
started to facilitate space-data analysis by providing electronic mail,
document browsing, access to distributed data bases, facilities for numeric and
graphic data transfer, access to Class VI machines, and entry to gateways for
other networks.

The DSUWG continues to provide guidance for SPAN growth and seeks to identify,
promote, and implement appropriate standards for the efficient management and
exchange of data, related information, and graphics.  All SPAN member
organizations are expected to participate in the DSUWG.  The basic composition
of the DSUWG is a representative scientist and computer systems manager (who
has the networking responsibility) at each of the member institutions.  DSUWG
meetings are held regularly at approximately nine month intervals.

The DSUWG is structured along lines conducive to addressing major outstanding
problems of scientific data exchange and correlation.  There is a chairman for
each subgroup to coordinate and focus the group's activities and a  project
scientist to oversee the implementation of the DSUWG recommendations and
policies.  The working group itself is divided into several subgroups which
address issues of policy, networking and hardware, software and graphics
standards, and data base standards.

The DSUWG is a dynamic, evolving organization.  We expect members to move in
(or out) as appropriate to their active involvement in data related issues.  We
also realize that at present SPAN and the DSUWG are dealing with only a limited
portion of the whole spectrum of problems facing the NASA research community.
As present problems are solved, as the network evolves, and as new issues
arise, we look to the DSUWG to reflect these changes in it's makeup, structure,
and focus.

The SPAN is currently managed by the National Space Science Data Center (NSSDC)
located at Goddard Space Flight Center (GSFC).  All SPAN physical circuits are
funded by the Communication and Data Systems Division at NASA Headquarters.
Personnel at the NSSDC facility, at the NASA SPAN centers, and the remote
institutions work in unison to manage and maintain the network.


Network Configuration and Evolution
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The initial topology for SPAN was a modified star where all communication with
the remote institutions came to a major central switching or message routing
node at MSFC.  This topology served the network well until many new nodes were
added and more scientists became accustomed to using the network.  As data rate
demands on the network increased, it was apparent that a new topology using
lines with higher data rates was needed.  Toward this end, a new communication
architecture for SPAN was constructed and implemented.

The current structure of SPAN in the United States is composed of an
interconnected four-star, mesh topology.  Each star has, as its nucleus, a SPAN
routing center.  The routing centers are located at GSFC, MSFC, Jet Propulsion
Lab (JPL), and Johnson Space Center (JSC).  The routing centers are linked
together by a set of redundant 56 kbps backbone circuits.  Tail circuits, at
speeds of 9.6 kbps (minimum line speed), are connected to each routing center
and and into the SPAN backbone.

Most remote institutions have local area networks that allow a number of
different machines to be connected to SPAN.   Regardless of a machine's
position in the network, all computers on SPAN are treated logically equal.
The main goal of the new SPAN architecture is for a node that is located across
the country through two routing centers to be as transparently accessible as a
SPAN node sharing the same machine room with the originating system.  This ease
of use and network transparency is one of SPAN's greatest assets.

The new configuration allows for rapid expansion of the network via the
addition of new tail circuits, upgrade to existing tail circuits, and dynamic
dialing of higher data-rate backbone circuits Implementation of this new
configuration began in July 1986, and the new topology was completed in
November 1986, although there are new circuits being added on a continuing
basis.  It is expected that a fifth routing center located at Ames Research
Center.

Nearly all of the machines on SPAN are linked together using the commercially
available software package DECnet.  DECnet allows suitably configured computers
(IBM-PCs and mainframes, SUN/UNIX workstations, DEC/PROs, PDPs, VAXs, and
DECSYSTEMs) to communicate across a variety of media (fiber optics, coax,
leased telephone lines, etc.) utilizing a variety of low level protocols
(DDCMP, Ethernet, X.25).  There are also several institutions that are
connected through Janus hosts which run more then one protocol.

SPAN links computers together and touches several other networks in the United
States, Europe, and Canada  that are used for data analysis on NASA spaceflight
missions and other NASA related projects.  At this time, there are well over
1200+ computers that are accessible through SPAN.

DECnet networks has been accomplished by the unprecedented, successful
cooperation of the network management of the previously separate networks.  For
example, the International High Energy Physics Network (HEPNET), the Canadian
Data Analysis Network (DAN) and the Texas University Network (TEXNET) now have
nonconflicting network addresses.  Every node on each of these networks is as
accessible to SPAN users as any other SPAN node.  The mutual cooperation of
these WANs has given enhanced capabilities for all.

There are several capabilities and features that SPAN is developing, making it
unique within the NASA science community.  The SPAN system provides remote
users with access to science data bases and brings scientists throughout the
country together in a common working environment. Unlike past NASA mission
networks, where the remote sites have only remote terminals (supporting one
person at the remote site at a time), SPAN supports many users simultaneously
at each remote node through computer-to-remote computer communications
software.  Users at their institutions can participate in a number of network
functions involving other remote computer facilities.  Scientific papers, data
and graphics files can easily be transferred between network nodes.  This
significantly reduces the time it takes to perform correlative work when
authors are located across the country or ocean.  As an introduction to SPAN's
network wide capabilities.  More advanced users are referred to the DEC DECnet
User's Manual.

SPAN will continue to be used as a test case between NASA science investigators
with the intent of exploring and employing modern computer and communication
technology as a tool for doing NASA science research.  This can be accomplished
because SPAN is not a project dependent system that requires a static hardware
and software configuration for the duration of a mission.  SPAN has provided a
quick reaction capability for several NASA and ESA missions.  Each of these
missions needed to rapidly move near real-time ground and spacecraft
observations to a variety of destinations for analysis and mission planning.
Because of SPAN's great success, new NASA spaceflight missions are seriously
looking into creating networks with similar capabilities that are
internetworked with SPAN.

Within the next few years, new developments in software and hardware will be
implemented on SPAN that will continue to aid NASA science research.  It is
anticipated that SPAN will greatly improve its access to gateways into Europe
and other locations throughout the world.  As a natural evolution, SPAN will
migrate toward the International Standards Organization's (ISO) Open Systems
Interconnect (OSI) protocol as the software becomes available.  It is expected
that the ISO/OSI protocol will greatly enhance SPAN and increase the number of
heterogeneous computer systems accessible.


Security And Conduct On The Network
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Misconduct is defined as:

     1.  Any unauthorized access or use of computers on the network,
     2.  Attempts to defeat computer security systems (e.g. violating a captive
         account),
     3.  Repeated login failures to computers or privileged accounts to which
         the user is not authorized to use,
     4.  Massive file transfers from a given site without prior consent and
         coordination with the appropriate SPAN routing centers.

The network is monitored very closely, and it is relatively simple to spot an
attempted break-in and then track down the source.  When a violation is found,
the matter will be reported to the DSUWG steering committee and the SPAN line
will be in immediate danger of being disconnected.  If the situation cannot be
resolved to the satisfaction of both the DSUWG steering committee and network
management, the SPAN line to the offending site will be reviewed for the
possibility of permanent disconnection.  In short, NASA pays for the
communications lines and will not tolerate misconduct on the network.


SPAN Network Information Center (SPAN-NIC)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The SPAN-NIC is located at the National Space Science Data Center in Greenbelt,
Maryland.  The purpose of the SPAN-NIC is to provide general user services and
technical support to SPAN users via telephone, electronic mail, and postal
mail.

As SPAN has grown exponentially over recent years, it was realized that a
central organization had to be developed to provide users with technical
assistance to better utilize the resources that the network provides.  This is
accomplished by maintaining and distributing relevant technical documents,
providing user assistance on DECnet related questions, monitoring traffic on
the network, and maintaining an online data base of SPAN node information.
More specific information on becoming a SPAN site, beyond that provided in this
document, can also be obtained through SPAN-NIC.

The SPAN-NIC uses a VAX 8650 running VMS as its host computer.  Users wishing
to use the online information services can use the account with the username
SPAN_NIC.  Remote logins are capable via SET HOST from SPAN, TELENET from
ARPANET and by other procedures detailed later.

        SPAN-NIC DECnet host address: NSSDCA or 6.133

        SPAN-NIC ARPANET host address: NSSDC.ARPA or 128.183.10.4

        SPAN-NIC GTE/TELENET DTE number: 311032107035

An alternative to remote login is to access online text files that are
available.  These text files reside in a directory that is pointed to by the
logical name "SPAN_NIC:". Example commands for listing this directory follow:

        From SPAN: $ DIRECTORY NSSDCA::SPAN__NIC:
        From ARPA: FTP> ls SPAN__NIC:

The available files and a synopsis of their contents can be found in the file
"SPAN_NIC:SPAN_INDEX.TXT".  Once a file is identified, it can be transferred to
the remote host using the VMS COPY command, or the FTP GET command.  It is
important to note that this capability will be growing significantly not only
to catch up to the current SPAN configuration but also keep current with its
growth.


DECnet Primer
~~~~~~~~~~~~~
The purpose of the SPAN is to support communications between users on network
nodes.  This includes data access and exchange, electronic mail communication,
and sharing of resources among members of the space science community.

Communication between nodes on the SPAN is accomplished by means of DECnet
software.  DECnet software creates and maintains logical links between network
nodes with different or similar operating systems. The operating systems
currently in use on SPAN are VAX/VMS, RSX, and IAS. DECnet provides network
control, automatic routing of messages, and a user interface to the network.
The DECnet user interface provides commonly needed functions for both terminal
users and programs.  The purpose of this section of the file is to provide a
guide on the specific implementation of DECnet on SPAN and is not intended to
supercede the extensive manuals on DECnet already produced by DEC.

DECnet supports the following functions for network users:

1. TASK-TO-TASK COMMUNICATIONS:  User tasks can exchange data over a network
   logical link.  The communicating tasks can be on the same or different
   nodes.  Task-to- task communication can be used to initiate and control
   tasks on remote nodes.

2. REMOTE FILE ACCESS:  Users can access files on remote nodes at a terminal or
   within a program.  At a terminal, users can transfer files between nodes,
   display files and directories from remote nodes, and submit files containing
   commands for execution at a remote node. Inside a program, users can read
   and write files residing at a remote node.

3. TERMINAL COMMUNICATIONS:  RSX and IAS users can send messages to terminals
   on remote RSX or IAS nodes.  This capability is available on VMS nodes by
   using the PHONE utility.

4. MAIL FACILITY:  VMS users can send mail messages to accounts on remote VMS
   nodes.  This capability is currently available for RSX and IAS nodes but is
   not supported by DEC.  There are slight variations for RSX and IAS network
   mail compared to VMS mail.

5. REMOTE HOST:  VMS, RSX, and IAS users can log-on to a remote host as if
   their terminals were local.


Network Implementations For DECnet
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The SPAN includes implementations for RSX, IAS and VAX/VMS operating systems.
DECnet software exists at all the SPAN nodes and it allows for the
communication of data and messages between any of the nodes.  Each of the
network nodes has a version of DECnet that is compatible with the operating
system of that node.  These versions of DECnet have been presently developed to
different extents causing some nodes to have more or less capabilities than
other nodes.  The version or "phase" of the DECnet, as it is called, indicates
the capability of of that node to perform certain levels of communication.
Since RSX and IAS implementations are almost identical, they are described
together.

Users need not have any special privileges (VAX/VMS users will need the NETMBX
privilege on their account) to run network tasks or create programs which
access the network.  However users must supply valid access control information
to be able to use resources.  The term "access control" refers to the user name
and password of an account (local or on a remote node).

Online system documentation is a particularly important and valuable component
of DEC systems.  At the present, SPAN is comprised almost completely of DEC
systems.  An extensive set of system help files and libraries exists on all the
SPAN DEC nodes.  The HELP command invokes the HELP Utility to display
information about a particular topic.  The HELP utility retrieves help
available in the system help files or in any help library that you specify. You
can also specify a set of default help libraries for HELP to search in addition
to these libraries.

   Format:   HELP [keyword [...]]

On many systems, new users can display a tutorial explanation of HELP by typing
TUTORIAL in response to the "HELP Subtopic?" prompt and pressing the RETURN
key.


Utilities for DECnet-VAX
~~~~~~~~~~~~~~~~~~~~~~~~
VAX terminal users have several utility programs for network communications
available from the VMS operating system.  Documentation for most of these
utilities can be found in the Utility Reference Manual of the VAX/VMS manual
set, and each utility has extensive online help available.  The following
descriptions offer a brief introduction to these utilities:

MAIL:  The VAX/VMS mail utility allows you to send a message to any account or
       to a series of accounts on the network.  To send a message, you must
       know the account name of the person you wish to contact and his node
       name or node number. (This will be covered more extensively later in
       this file).

FINGER:  The DECUS VAX/VMS Finger utility has been installed on a number of
         SPAN VAX/VMS systems.  Finger allows a user to see who is doing what,
         both on his machine and on other machines on the network that support
         Finger.  Finger also allows a user to find information about the
         location and accounts used by other users, both locally and on the
         network. The following is an example session using the FINGER utility.

$ FINGER


          NSSDCA VAX 8600, VMS V4.3. Sunday, 28-Sep-1986 19:55,4 Users,0 Batch.
          Up since Sunday, 28-Sep-1986 14:28

 Process         Personal name        Program  Login Idle Location

 HILLS           H.Kent Hills         Tm       19:02      NSSDC.DECnet
 _RTA4:          Dr. Ken Klenk        Tm       17:55      NSSDC.DECnet
 _NVA1:          Michael L. Gough     Mail     15:13
 SPAN Man        Joe Hacker           Finger   17:33      bldg26/111


 $ FINGER SWAFFORD@NSSDCA

 [NSSDCA.DECnet]

 NSSDCA VAX/VMS, Sunday, 28-Sep-1986 19:55

 Process         Personal name        Program   Login  Idle Location

 SPAN Man                             Finger    17:33

  Logged in since: Sunday, 28-Sep-1986 17:33

  Mail: (no new mail)

  Plan:

     Joe Hacker, SPAN Hackers Guild

     Telephone: (800)555-6000

If your VAX supports VMS Finger, further information can be found by typing
HELP FINGER.  If your system does not currently have the FINGER utility, a copy
of it is available in the form of a BACKUP save set in the file:
NSSDCA::SPAN_NIC:FINGER.BCK

PHONE:  The VAX/VMS PHONE utility allows you to have an interactive
        conversation with any current user on the network.  This utility can
        only be used on video terminals which support direct cursor
        positioning.  The local system manager should know if your terminal can
        support this utility.  To initiate a phone call, enter the DCL command
        PHONE.  This should clear the screen and set up the phone screen
        format.  The following commands can be executed:

DIAL nodename::username

         Places a call to another user.  You must wait for a response from that
         user to continue.  DIAL is the default command if just
         nodename::username is entered.


ANSWER Answers the phone when you receive a call.

HANGUP Ends the conversation (you could also enter a CTRL/Z).

REJECT Rejects the phone call that has been received.

DIR nodename::

         Displays a list of all current users on the specified node.  This
         command is extremely useful to list current users on other nodes of
         the network.

FACSIMILE filename

         Will send the specified file to your listener as part of your
         conversation.

To execute any of these commands during a conversation, the switch hook
character must be entered first.  By default, that character is the percent
key.

REMOTE FILE ACCESS:  DCL commands that access files will act transparently over
                     the network.  For example, to copy a file from a remote
                     node:

$copy

From: node"username password"::disk:[directory]file.lis
To: newfile.lis

This will copy "file.lis" in "directory" on "node" to the account the command
was issued in and name it "newfile.lis".  The access information (user name and
password of the remote account) is enclosed in quotes.  Note that you can also
copy that same file to any other node and account you desire.  For another
example, to obtain a directory listing from a remote node, use the following
command:

$dir node::[directory] (if on the default disk)


Utilities for DECnet-11M/DECnet-IAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There are certain DECnet functions that can only be done on nodes that have the
same type of operating systems, such as the MPB, TRW, SPRL, LASR, and UTD nodes
all with an RSX-11M operating system.  The capabilities offered to the RSX
DECnet user can be broken down into two major categories: those functions for
terminal users and those functions for FORTRAN programmers.

DECnet-11M terminal users have several utility programs available to them which
allows logging onto other machines in the network, file transfers, message
communication, and network status information.

REMOTE-LOGON:  The REMOTE-LOGON procedure allows a user at a node to log-on to
               another node in the network.  This capability is also called
               virtual terminal.  The "SET /HOST=nodename" command allows the
               user to log-on to adjacent nodes in the network from a
               DECnet-11M node.  This command is initiated by simply typing
               "SET /HOST=nodename".  The "SET HOST" command on the SPAN-VAX
               also allows you to log-on to adjacent nodes.

NETWORK FILE TRANSFER:  NFT is the Network File Transfer program and is part of
                        the DECnet software.  It is invoked by typing NFT <CR>
                        to file = from file or by typing NFT to file = from
                        file.  Embedded in the file names must be the node
                        name, access information, and directory if it is
                        different than the default conventions.  Also note that
                        file names can only be 9 (nine) characters long on RSX
                        systems.

                        Therefore, VAX/VMS files with more than 9 characters
                        will not copy with default-file naming.  In such a case
                        you must explicitly name the file being copied to an
                        RSX system.  The following structure for the file names
                        must be used when talking to the SPAN nodes with NFT.

                        NODE/username/password::Dev:[dir.sub-dir]file.type

                        The following NFT switches are very useful:

                        /LI   Directory listing switch.
                        /AP   Appends/adds files to end of existing file.
                        /DE   Deletes one or more files.
                        /EX   Executes command file stored on remote/local
                              node.
                        /SB   Submits command file for execution
                              (remote/local).
                        /SP   Spools files to the line printer (works only with
                              "like" nodes).

                        A particular use for NFT is for the display of graphics
                        files on the network.  It is important to note,
                        however, that some device-dependent graphics files are
                        not all displayable, such as those generated by IGL
                        software.  The graphic files generated by graphic
                        packages that are displayable when residing at other
                        nodes may be displayed by using the following input:

                        NFT> TI:=SPAN/NET/NET::[NETNET.RIMS]D1364.COL

                        Graphics files generated by IGL can be displayed by
                        running either REPLAY or NETREP programs (see the
                        net-library documentation).

TERMINAL COMMUNICATIONS:  TLK is the Terminal Communications Utility which
                          allows users to exchange messages through their
                          terminals.  TLK somewhat resembles the RSX broadcast
                          command but with more capabilities.  TLK currently
                          works only between RSX-11 nodes and within a RSX-11
                          node.  There are two basic modes of operation for
                          TLK:  The single message mode and the dialogue mode.

                          The single message mode conveys short messages to any
                          terminal in the same node or remote node.  The syntax
                          for this operation is:

                          >TLK TARGETNODE::TTn:--Message--

                          To initiate the the dialogue mode type:

                          >TLK TARGETNODE::TTn<cr>

                          When you receive the TLK> prompt, you can enter a new
                          message line.


Graphics Display Utilities
~~~~~~~~~~~~~~~~~~~~~~~~~~
One of the main objectives of the SPAN system project is to accommodate
coordinated data analysis without leaving one's institution.  Therefore, there
is a strong need to develop the ability to have graphic images of data from any
node to be displayed by any other node.  The current inability to display data
on an arbitrary graphics device at any node has been quickly recognized. As
general network utilities are developed to support the display of device
dependent and independent graphic images, the handbook SPAN Graphics Display
Utilities Handbook will serve to document their use and limitations.  The
graphics handbook is a practical guide to those common network facilities which
will be used to support network correlative studies from the one-to-one to the
workshop levels.  For each graphics software utility the handbook contains
information necessary to obtain, use, and implement the utility.


Network Control Program
~~~~~~~~~~~~~~~~~~~~~~~
NCP is the Network Control Program and is designed primarily to help the
network manager.  However, there are some NCP commands which are useful for the
general user.  With these commands, the user can quickly determine node names
and whether nodes are reachable or not.  Help can be obtained by entering
NCP>HELP and continuing from there.  For a complete listing of all the NCP
commands that are available to nonpriviledged users, refer to the NCP Utility
manual on VAXs, and the NCP appendix of the DECnet-11M manual for PDPs.  The
following two commands are probably the most beneficial to users:

$ RUN SYS$SYSTEM:NCP       !on VAXs

       -or-

> RUN $NCP                 !on PDPs

NCP> SHOW KNOWN NODES      !show a list of all nodes
                           !   defined in the volatile data base
NCP> SHOW ACTIVE NODES     !show a list of only currently reachable

Please note that the second command cannot be used on "end nodes", that is,
nodes that do not perform at least DECnet Level I routing.  In addition, only
nodes in the user's area will be displayed on either Level I or Level II
routers.  In the case of end nodes, users should find out the name of the
nearest Level I or II routing node and issue the following command:

NCP> TELL GEORGE SHOW ACTIVE NODES


Mail
~~~~
As briefly discussed earlier all SPAN DEC nodes have a network mail utility.
Before sending a mail message, the node name and user name must be known.  To
send a message to the project manager, you would enter the following commands:

$ MAIL

MAIL> SEND

To: NSSDCA::THOMAS
Subj: MAIL UTILITY TEST
Enter your message below. Press ctrl/z when complete
ctrl/c to quit:

VALERIE,
   OUR NETWORK CONNECTION IS NOW AVAILABLE AT ALL TIMES.  WE ARE LOOKING
FORWARD TO WORKING FULL TIME ON SPAN.  THANKS FOR ALL YOUR HELP.

                            FRED
<CTRL/Z>

MAIL>EXIT

In order to send mail to more than one user, list the desired network users on
the same line as the TO: command, separating each with a comma.  Another way to
accomplish this is to use a file of names.  For example, in the file SEPAC.DIS,
all SEPAC investigators on SPAN are listed:

        SSL::ROBERTS
        SSL::REASONER
        SSL::CHAPPELL
        SWRI::JIM
        TRW::TAYLOR
        STAR::WILLIAMSON

The network mail utility will send duplicate messages to all those named in the
above file by putting the file name on the TO: command line (TO: @SEPAC).  A
second option for the SEND command is to include a file name that contains the
text to be sent.  You will still be prompted for the To: and Subject:
information.  The following statements give a brief description of other
functions of the MAIL utility:

 READ n     Will list, on the terminal, the mail message corresponding to
            number n.  If n is not entered, new mail messages will be listed.

 EXTRACT    Saves a copy of the current message to a designated file.

 FORWARD    Sends a copy of the current message to other users.

 REPLY      Allows you to send a message to the sender of the current message.

 DIR        Lists all messages in the current folder that you have selected.
            The sequence numbers can then be used with the READ command.

 DEL        Delete the message just read.  The message is actually moved to the
            WASTEBASKET folder until you exit the utility, when it is actually
            deleted.  Therefore, you can retrieve a message that you have
            "deleted", up until you enter "exit" or ^Z to the MAIL> prompt.

 HELP       Always useful if you're lost.


Remote Node Information Files
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
All nodes on the SPAN are required to maintain two node specific information
files in their DECnet default directories.

The first file is a network user list file that contains specific information
on each network user who has an account on the machine.  At a minimum, the user
list file should contain the name of the user, his electronic mail address, his
account/project identifier, and his default directory.  All of this information
is easily obtained on VAX/VMS systems from the SYS$SYSTEM:SYSUAF.DAT file.
(Note that the SYSUAF.DAT file is (and should be) only readable by the system
manager.)  The file is called USERLIST.LIS and resides in the node's DECnet
default directory. A command procedure for creating this file is available in
NSSDCA::SPAN_NIC:USERLIST.COM.  This procedure should be executed from the
SYSTEM account on the remote node for which it is to be compiled.  Following is
an example of displaying the USERLIST.LIS file on NSSDCA from a VAX/VMS system.

 $ TYPE NSSDCA::USERLIST

      Userlist file created at : 28-SEP-1986 22:06:01.71

        Owner          Mail Address     Project   Default Directory
  ----------------  -----------------  ---------  -----------------
  ROBERT HOLZER     NSSDCA::HOLZER     CD8UCLGU  CDAW_C8USER:[HOLZER]
  RICHARD HOROWITZ  NSSDCA::HOROWITZ   ACQ633GU  ACQ_USER:[HOROWITZ]
  CHERYL HUANG      NSSDCA::HUANG      CD8IOWGU  CDAW_C8USER:[HUANG]
  DOMINIK P. IASCO  NSSDCA::IASCONE    PCDCDWPG  CDAW_DEV:[IASCONE]
  ISADARE BRADSKY   NSSDCA::IZZY       DVDSARPG  DAVID_DEV:[IZZY]
  WENDELL JOHNSON   NSSDCA::JOHNSON    DCSSARPG  CODD_DEV:[JOHNSON]
  DAVID JOSLIN      NSSDCA::JOSLIN     SYSNYMOP  OPERS_OPER:[JOSLIN]
  JENNIFER HYESONG  NSSDCA::JPARK      CAS130GU  CAS_USER:[JPARK]
  HSIAOFANG HU      NSSDCA::JUDY       DVDSARPG  DAVID_DEV:[JUDY]
  YOUNG-WOON KANG   NSSDCA::KANG       ADCSARGU  ADC_USER:[KANG]
  SUSAN E. KAYSER   NSSDCA::KAYSER     ACQSARGU  ACQ_USER:[KAYSER]
  DR. JOSEPH KING   NSSDCA::KING       ADM633MG  ADM_USER:[KING]
  BERNDT KLECKER    NSSDCA::KLECKER    CD8MAXGU  CDAW_C8USER:[KLECKER]
  KENNETH KLENK     NSSDCA::KLENK      PCDSARPG  ADM_USER:[KLENK]

Much like the user list, a node information listing is available for all nodes
in their DECnet default account.  This file is named NODEINFO.LIS.  The
following example is for the SSL node and should be taken as a template for the
generic NODEINFO.LIS file that should be on each node in SPAN.

 $ TYPE SSL::NODEINFO


Telenet Access To SPAN
~~~~~~~~~~~~~~~~~~~~~~
As SPAN grows, the number of users wishing to make use of its capabilities
increases dramatically.  Now it is possible for any user with a terminal and a
0.3 or 1.2 kbps modem to access SPAN from anywhere in the U.S. simply by making
a local telephone call.  There exists an interconnection between SPAN and the
NASA Packet Switched Service (NPSS).  The NPSS in turn has a gateway to the
public GTE Telenet network which provides the local call access facilities.
The user dials into one of Telenet's local access facilities and dials the NASA
DAF (Data Access Facility) security computer. The user is then able to access
SPAN transparently through the NSSDC or SSL machines.

To find the phone number of a PAD local to the area you are calling from, you
can call the Telenet customer service office, toll free, at 1-800-TELENET. They
will be able to provide you with the number of the nearest Telenet PAD.

The following outlines the steps that one must go through to gain access to
SPAN through Telenet.

     1.  First dial into the local Telenet PAD.
     2.  When the PAD answers, hit carriage return several times until the '@'
         prompt appears.

                            <CR><CR><CR>

                            @

     3.  Next enter the host identification address of the NASA DAF (security
         computer).  This identification was not yet available at publication
         time, but will be made available to all users requesting this type of
         access.

                            @ID ;32100104/NASA

     4.  You will then be prompted for a password (which will be made available
         with the identification above).

                            PASSWORD = 021075

                (Note: Tthe password will not be echoed)

     5.  Then type <CR>.  You will be connected to the NASA DAF computer.  The
         DAF will tell you which facility and port you succeeded in reaching,
         along with a "ready" and then an asterisk prompt:

                NASA PACKET NETWORK - PSCN

                 TROUBLE 205/544(FTS 824)-1771

                  PAD 311032115056

                *1

                ready

                *

         All entries to the DAF must be in capital letters, and the USERID and
         PASSWORD will undoubtedly be echoed on the screen.

                 *LOGON
                 ENTER USERID>                   LPORTER
                 ENTER PASSWORD>                 XXXXXXX
                 ENTER SERVICE>                  SPANSSL
                 NETWORK CONNECTION IN PROGRESS
                 connected

         Alternatively, you may enter NSSDC for the "Service>" request.

     6.  You should now get the VMS "Username" prompt:

         Username: SPAN

     7.  You will then be prompted for the name of the SPAN host destination.
         For instance, if you are a Pilot Land Data System user on the NSSDC
         VAX 11/780, you would enter NSSDC and hit the carriage return in
         response to the prompt for host name.

         SPAN host name? NSSDC

     8. Finally, continue with normal logon procedure for the destination host.


The SPAN X.25 gateways have also been used extensively for internetwork
communications to developing networks in Europe and Canada.

The traffic from the United States to Europe was so extensive that a dedicated
link between the GSFC and ESOC routing centers.  This link became operational
in January 1987.

                     Configuration Of SPAN/TELENET Gateway

                                  ----------
                                  | dial-up|
                                  |  user  |
                                  ----------
                                       |
                           -------------------------
                           |       TELENET         |
                           -------------------------
                                   | gateway
                           -------------------------
                           |         NPSS          |
                           -------------------------
                             |                   |
                        -----------        -----------
                        |  SSL    |        |  NSSDC  |
                        | VAX 780 |        | VAX 8650|
                        -----------        -----------
                             |                   |
                           -------------------------
                           |         SPAN          |
                           -------------------------
                           |       |       |       |
                        ------   ------  ------  ------
                        |SPAN|   |SPAN|  |SPAN|  |SPAN|
                        |node|   |node|  |node|  |node|
                        ------   ------  ------  ------


SPAN/ARPANET/BITNET/Public Packet Mail Gateways
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SPAN supports several gateways both to and from several major networks.  The
following gives the current syntax for forming an address to another user on
another network.  There are several similar gateways at other SPAN nodes that
are not included in this list.  Stanford is used here only as a typical
example.  If it is necessary for you to use the Stanford mail gateway on an
occasional basis, you should obtain permission from the system manager on the
STAR node (or any other non-NASA gateway node).  Currently, there is no
restriction on the NSSDCA gateway usage.


SPAN-to-ARPANET: NSSDC Gateway . . To: NSSDCA::ARPA%"arpauser@arpahost"
                 JPL Gateway . . . To: JPLLSI::"arpauser@arpahost"
                 Stanford Gateway. To: STAR::"arpauser@arpahost"

ARPANET-to-SPAN: NSSDC Gateway . . To: spanuser%spanhost.SPAN@128.183.10.4
                 JPL Gateway . . . To: spanuser%spanhost.SPAN@JPL-VLSI.ARPA
                 Stanford Gateway. To: spanuser%spanhost.SPAN@STAR.STANFORD.EDU
                 [Note:  128.183.10.4 is MILNET/ARPANET address for the NSSDC]

SPAN-to-BITNET:
    NSSDC Gateway. . .To: NSSDCA::ARPA%"bituser%bithost.BITNET@CUNY.CUNYVM.EDU"
    JPL Gateway. . . .To: JPLLSI::"bituser%bithost.BITNET@CUNY.CUNYVM.EDU"
    Stanford Gateway .To: STAR::"bituser%bithost.BITNET@CUNY.CUNYVM.EDU"

BITNET-to-SPAN: Stanford Gateway. . . . To: spanuser%spanhost.SPAN@SU-STAR.ARPA


The following gateways allow users on a VAX that supports a connection to a
public packet switch system (virtually anywhere in the world) to reach SPAN
nodes and vice-versa.  Note that this will transmit mail only to and from VAXs
that support DEC PSI and PSI incoming and outgoing mail.

SPAN-to-Public Packet VAX
        NSSDC Gateway. To: NSSDCA::PSI%dte_number::username
        SSL Gateway. . To: SSL::PSI%dte_number::username

Public Packet VAX-to-SPAN node
        NSSDC Gateway. To: PSI%311032107035::span_node_name::username
        SSL Gateway. . To: PSI%311032100160::span_node_name::username


It is possible for remote terminal access and mail between users on England's
Joint Academic Network (JANET) and SPAN.  JANET is a private X.25 network used
by the UK academic community and is accessible through the two SPAN public
packet switched gateways at MSFC and at the NSSDC.


List Of Acronyms
~~~~~~~~~~~~~~~~
ARC     - Ames Research Center
ARPANET - Advanced Research Projects Agency network
BITNET  - Because It's Time Network
CDAW    - Coordinated Data Analysis Workshop
CSNET   - Computer Science Network
DDCMP   - DEC "level II" network protocol
DEC     - Digital Equipment Corporation
DECnet  - DEC networking products generic family name
DSUWG   - Data System Users Working Group
ESOC    - European Space Operations Center
ESTEC   - European Space Research and Technology Center
GSFC    - Goddard Space Flight Center
GTE     - General Telephone and Electic
HEPNET  - High Energy Physics Network
INFNET  - Instituto Nazional Fisica Nucleare Network
ISAS    - Institute of Space and Astronautical Science
ISO/OSI - International Standards Organization/Open Systems Interconnection
          (network protocol)
ISTP    - International Solar Terrestrial Physics
JANET   - Joint Academic Network (in United Kingdom)
JPL     - Jet Propulsion Laboratory
JSC     - Johnson Space Center
kbps    - Kilobit per second
LAN     - Local area network
LANL    - Los Alamos National Laboratory
MFENET  - Magnetic Fussion Energy Network
MILNET  - Defence data network (originally part of ARPANET)
MSFC    - Marshall Space Flight Center
NCAR    - National Center for Atmospheric Research
NFT     - Network File Transfer (program on RSX/IAS systems)
NIC     - Network Information Center
NPSS    - NASA Packet Switched System (using X.25 protocol)
NSSDC   - National Space Science Data Center (at GSFC)
PDS     - Planetary Data System
PSCN    - Program Support Communications Network
SESNET  - Space and Earth Science Network (at GSFC)
SPAN    - Space Physics Analysis Network
SSL     - Space Science Laboratory (at MSFC)
RVT     - Remote virtual terminal program for RSX or IAS systems
TCP/IP  - Transmission Control Protocol/Internet Protocol
Telenet - A public packed switched network owned by GTE
TEXNET  - Texas Network (Academic network)
WAN     - Wide area network
X.25    - A "level II" communication protocol for packet switched networks
_______________________________________________________________________________



