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**INTERFACE CONTROL DOCUMENT**

**FOR**

**ISCS WORKSTATION**

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Prepared by the ISCS Program Office

[**1)** **Scope** 3](#__RefHeading___Toc190483981)

[**2)** **Background** 3](#__RefHeading___Toc190483982)

[**3)** **Reference: Documents** 4](#__RefHeading___Toc190483983)

[**4)** **Standards Precedence** 5](#__RefHeading___Toc190483984)

[**5)** **Interface Characteristics** 5](#__RefHeading___Toc190483985)

[Diagram 1 3](#__RefHeading___Toc190484385)

1)  []{#__RefHeading___Toc190483981 .anchor}**Scope**

> This document defines the interface for the International Satellite
> Communications System (ISCS) workstation. The purpose of the interface
> is to transmit data from the ISCS satellite network to the ISCS
> workstation / computer for a receive-only site, and for the two-way
> sites the interface will also transmit data.

2)  []{#__RefHeading___Toc190483982 .anchor}**Background**

> The purpose of the ISCS is to provide timely delivery of critical
>
> aviation-related weather information to support air traffic management
> and flight operations in more than 80 countries, and regional
> meteorological telecommunications between the United States and
> nations in the Caribbean and Central America (WMO Region IV).
>
> The Atlantic Ocean Region (AOR) has two broadcasts \-- a one-way
> broadcast service (downlink only) and a two-way service (uplink and
> downlink). Two-way sites in the AOR make use of an FTP session via the
> broadcast to send weather products to the telecommunications gateway.
>
> The Pacific Ocean Region (POR) has a single, one-way broadcast
> service.
>
> The ISCS network connection to a workstation/ computer is shown below:

![](media/image4.jpeg){width="5.571527777777778in"
height="4.175694444444445in"}

[]{#__RefHeading___Toc190484385 .anchor}Diagram 1

> This document will address the interconnectivity from the satellite
> ground station receiver equipment to the workstation/ computer.

3)  []{#__RefHeading___Toc190483983 .anchor}**Reference: Documents**

> INTERNATIONAL STANDARDS

a.  International Standard ISO 8802-2: 1989

> \[ANSI/ IEEE Standard 802.2: 1989\]
>
> (Revision of ANSI/ IEEE Std. 802.2-1985)
>
> Part 2: Logical Link Control

INDUSTRY STANDRDS

b.  Digital Equipment Corp, Intel Corp, Xerox Corp (DIX).

> Ethernet Local Area Network Specification Version 2.0
>
> MILITARY STANDARDS

c.  MIL-STD-1777 Internet Protocol (IP)

d.  MIL-STD-1778 Transmission Control Protocol (TCP)

e.  MIL-STD-1780 File Transfer Protocol (FTP)

> INTERNET REQUEST FOR COMMENTS (RFC) STANDARDS
>
> [RFC No. NAME STATUS]{.underline}

f.  RFC 791 Internet Protocol Required

g.  RFC 950 IP Subnet Extension Required

h.  RFC 919 IP Broadcast Datagrams Required

i.  RFC 922 IP Broadcast Datagrams with Subnets Required

j.  RFC 792 Internet Control Message Protocol Required

k.  RFC 826 Address Resolution Protocol Elective

l.  RFC 894 Internet Protocol on Ethernets Elective

m.  RFC 891 Internet Protocol on 802 Elective

n.  RFC 793 Transmission Control Protocol Required

o.  RFC 959 File Transfer Protocol Required

p.  RFC 1122 Requirements for Internet Hosts Required

> Communication Layers

q.  RFC 913 Simple File Transfer Protocol Elective

r.  RFC 2660 Secure Hypertext Transfer Protocol Required

s.  RFC 4346 The Transport Layer Security Protocol Required

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4)  []{#__RefHeading___Toc190483984 .anchor}**Standards Precedence**

> There are variances in the Digital Equipment Corporation, Intel
> Corporation, Xerox Corporation (DIX) Ethernet Standard, version 2.0,
> and the American National Standards Institute/ Institute of Electrical
> and Electronics Engineers (ANSI/ IEEE) LAN standards 802.2/ 802.3.
> These differences are relatively minor and are to be dismissed in
> regards to this interface. Physical layer and data link layer
> protocols for the ISCS workstation/ computer interface are completely
> defined by the ANSI/ IEEE 802.3 and ANSI/ IEEE 802.2 standards. The
> ANSI/ IEEE 802.2 and the ANSI/ IEEE 802.3 Standards take precedence
> over the DIX Ethernet version 2.0 specifications.
>
> Likewise, the Internet Community specifications for the File Transfer
> Protocol (FTP) (RFC-959, as modified by RFC-1123) and DoD MIL-STD
> specification describe exactly the same protocol. For the purpose of
> the ISCS Workstation/ Computer interface, RFC-959 and RFC-1123 take
> precedence over the MIL-STD for FTP.

5)  []{#__RefHeading___Toc190483985 .anchor}**Interface
    Characteristics**

> The ISCS workstation/ computer interface will adhere to all to
> standards for TCP/IP 10BaseT Ethernet connections. Furthermore, the
> interface will adhere to the following:

1.  Interface to the LAN/ workstation/ minicomputer is TCP/IP Ethernet
    LAN (10BaseT) connection from the satellite ground station receiver
    equipment. *(Refer to diagram 1 to view the connections.)\
    *

2.  ISCS-G3 data products for each end-user site will be presented\
    over the interface via a single IP address with port assignments\
    by type of data. The data types are: GRIB 1, BUFR, T4, Text, and
    GRIB2.

3.  The contractor will assign a logical port for each product type as
    described in the following list. The ports assigned will not
    conflict with the well known ports 0 through 1023.

  -----------------------------------------------------------------------
  **ISCS-G3** **Product Type**

  WAFS ALPHA TEXT

  WAFS GRIB I

  WAFS GRIB II

  WAFS BUFR / T4 - FAX

  WAFS Test

  RMTN-AOR ALPHA TEXT

  RMTN-AOR GRIB I 

  RMTN-AOR GRIB II

  RMTN-AOR BUFR

  RMTN-AOR RADAR

   RMTN-AOR Test

   RMTN-POR ALPHA TEXT

   RMTN-POR GRIB I 

   RMTN-POR GRIB II

  RMTN-POR BUFR  

  RMTN-POR Test

  Tsunami TEXT 
  -----------------------------------------------------------------------

4.  There will be no ISCS G3 contractor provided interface software on
    the workstation in order to accept the ISCS G3 data. The data
    product ingest will be handled by the workstation / computer
    application software.

5.  The interface will support both IPV4 and IPV6.

6.  The interface will support WAFS and Regional (RMTN) data products.

7.  Two way sites will use an outbound FTP session.