Fact-checked by Grok 2 weeks ago

SATNET

SATNET, formally known as the Atlantic Packet Satellite Network, was an experimental packet-switched satellite communication network developed and funded by the U.S. in the mid-1970s to enable transatlantic data transmission between the and European research institutions. It utilized commercial to connect ground stations in Etam, (USA), Goonhilly Downs (), and later Tanum (), facilitating the first international extension of packet-switched networking across continents. Operational from 1975 until its decommissioning in 1991, SATNET demonstrated the viability of satellite technology for wide-area computer networking, supporting delay-tolerant protocols essential for long-distance links. The project originated from 's broader efforts to interconnect diverse networks, building on the 1973 connection to via a link to Norway's NORSAR seismic monitoring station. In September 1975, initiated SATNET as a dedicated Atlantic networking program, with the Post Office funding the British earth station to foster U.S.- collaboration. By late 1977, the Norwegian Defense Research Establishment joined via the Tanum station, and in 1979, additional terminals were installed in and , expanding the network's reach. A landmark demonstration on November 22, 1977 successfully transmitted packets across three networks—, the Packet Radio Network (PRNET), and SATNET—spanning radio, cable, and media over a 94,000-mile round trip without loss, proving multi-network . Technically, SATNET employed a Single Channel Per Carrier (SCPC) system on a 64 kbps IV transponder, adapting techniques from earlier projects like to handle satellite propagation delays of around 250 milliseconds. This required evolving beyond the ARPANET's Network Control Protocol (NCP), which was ill-suited for high-latency satellite links, leading directly to the development and adoption of /IP protocols starting in 1977. By May 1979, SATNET had become the primary access route for ARPANET connections, phasing out slower landlines. SATNET's innovations in internetworking heterogeneous media—terrestrial cables, radio, and satellites—laid foundational groundwork for the global , influencing and civilian applications by showing how networks could scale internationally with robust, delay-adaptive protocols. Its experiments also advanced applications like voice conferencing over packet networks, paving the way for future satellite-based systems. Though short-lived relative to modern networks, SATNET exemplified DARPA's role in pioneering resilient communication infrastructures during the era.

Overview

Definition and Objectives

SATNET, formally known as the Atlantic Packet Satellite Network, was an experimental satellite-based packet-switched network funded by the and implemented by Bolt Beranek and Newman Inc. (BBN). It served as a satellite relay system designed to augment terrestrial networks by enabling efficient transmission of packetized data across vast distances via geostationary satellites. The primary objectives of SATNET included facilitating long-distance, high-bandwidth communication between research sites in the United States and , thereby overcoming the limitations of existing cables. It aimed to demonstrate the interconnection of heterogeneous networks, allowing seamless integration with diverse systems like the , the foundational terrestrial packet network it extended. Additionally, SATNET sought to support resource sharing among military and academic communities without the need for dedicated communication lines, promoting efficient use of shared bandwidth for bursty data traffic. SATNET targeted a of 64 kilobits per second for its links, selected to accommodate the intermittent, high-volume nature of packet-switched traffic while maximizing channel utilization.

Relation to

SATNET functioned as a complementary network to the , leveraging technology to enable transatlantic communication hops while the ARPANET handled domestic terrestrial routing through its packet-switched infrastructure. This design allowed SATNET to extend the ARPANET's reach across without requiring fundamental alterations to the existing terrestrial backbone, aligning with broader goals of global network expansion. The interconnection between SATNET and ARPANET relied on specialized gateways that interfaced directly with ARPANET's Interface Message Processors (IMPs) using the BBN 1822 protocol, creating a unified packet-switched system where satellite links appeared as extended network segments. These gateways, often implemented on LSI-11 minicomputers, managed the translation between satellite broadcast channels and ARPANET's point-to-point links, ensuring seamless data flow. An early milestone in this integration occurred in 1973, when the ARPANET connected to (UCL) via a 9.6 kilobits/second routed through NORSAR in , marking the first transatlantic link and paving the way for the full SATNET satellite relay. SATNET received the IPv4 address block 4.x.x.x /8, distinct from 's allocation of 10.x.x.x /8, yet fully routable within the interconnected system to support end-to-end addressing across both networks. This setup demonstrated the of the combined , as it enabled users to access international nodes—such as those in the UK and —without initial modifications to core ARPANET protocols, relying instead on gateway mediation for protocol compatibility.

History

Conception and Proposals

Following the successful launch of the in , the recognized the need for robust long-haul communication capabilities to support distributed research amid Cold War-era demands for resilient, international collaboration among U.S. and allied scientists. The 's terrestrial infrastructure, while effective for domestic connections, faced limitations in extending reach across oceans, prompting to explore satellite-based extensions for global . In the mid-1970s, at ARPA's Information Processing Techniques Office (IPTO) proposed leveraging technology to interconnect U.S. research sites with European partners, envisioning a shared 64 kbps channel via global beams to enable efficient, multi-site packet transmission at reduced costs. This concept built on earlier ideas for network interlinking, including 1970 discussions with UK researchers on connecting to the National Physical Laboratory (NPL) network. Kahn's vision emphasized bouncing packets between ground stations and to overcome transatlantic distance constraints. Funding and approvals advanced in 1974 when the UK Post Office (BPO) agreed to cover costs for the UK-side satellite connection to the U.S., facilitating international participation. initiated the SATNET project in September 1975 by contracting BBN Technologies to develop the necessary ground stations, marking the formal commitment to implementation. Early planning centered on utilizing commercial satellites for packet-switched communications, with initial experiments conducted via leased 9.6 kbps lines to (UCL) starting in 1973 to test transatlantic connectivity. These efforts included BBN-supplied Terminal Interface Processors (TIPs) shipped to UCL in July 1973, valued at approximately £50,000, to interface with ARPANET hosts. Peter Kirstein at UCL led the project, which facilitated early transatlantic links and later SATNET integration. A key figure in conceptualizing SATNET's broader role, , who joined in 1972, envisioned it as an integral component of multi-network "internetting," alongside and the Packet Radio Network (PRNET), to demonstrate seamless protocol interoperability across diverse media. Kahn's gateway concepts were essential for managing instabilities between satellite and terrestrial links, laying groundwork for unified .

Development and Implementation

The SATNET project was initiated by the in September 1975 as an extension of capabilities, aiming to incorporate satellite technology for transatlantic connectivity. This marked the beginning of engineering efforts to design and deploy a packet-switched satellite network, with BBN Technologies contracted to lead the hardware and software development. In 1976, construction of key ground stations commenced to support the network's infrastructure, including facilities at Goonhilly Downs in the UK and Etam in , , which served as primary transatlantic endpoints. BBN developed the Single-Channel Per Carrier (SCPC) modulation technique to enable efficient use of satellite bandwidth, allowing multiple low-rate carriers to share a without interference. These stations were integrated with through custom gateways, facilitating seamless packet routing between terrestrial and satellite segments. International collaboration was integral, with the () establishing a terminal connected via landlines to the Goonhilly station for European access. Planning also incorporated Norwegian sites, such as NORSAR, and German facilities at Raisting, expanding the network's scope during the implementation phase. Pre-operational trials began in 1977 using the IV F-3 satellite operating at 6/4 GHz frequencies in the C-band, testing packet transmission and protocol performance across the Atlantic. By late 1977, these efforts culminated in the achievement of 64 kilobits per second full-duplex capacity, demonstrating reliable transoceanic data transfer for the experimental network.

Operational Milestones

SATNET achieved initial operational status in 1975, with its transatlantic satellite channel enabling packet-switched communication across the ocean in a fully integrated experimental setup. This activation built on earlier satellite experiments but marked the network's readiness for routine inter-network operations, with ground stations including Goonhilly in the UK facilitating the connection to UCL's system. The link supported early tests of protocol interoperability, demonstrating reliable data transfer over the 64 kbps IV channel despite the challenges of satellite-based transmission. A pivotal milestone occurred in July 1977, when Vint Cerf and Bob Kahn conducted the first multi-network demonstration using the Transmission Control Program (TCP), successfully interconnecting SATNET, ARPANET, and the Packet Radio Network (PRNET). This test involved transmitting data across a 94,000-mile round-trip path—from the SRI van in Menlo Park via PRNET, ARPANET, and SATNET to London and back—without any packet loss, validating TCP's ability to handle heterogeneous networks with varying delays and error rates. The demonstration, coordinated by teams at Stanford, DARPA, and international partners, represented a foundational proof-of-concept for internetworking and highlighted SATNET's role in bridging continental distances. By 1979, SATNET expanded to include additional European connections, linking sites in (Kjeller), (Raisting), and (Fucino), alongside existing stations in the UK and , reaching a peak of seven international nodes. These additions enhanced the network's capacity for collaborative research, interconnecting local area networks at these locations with hosts and supporting experiments in protocol testing across diverse geographies. The expansion utilized Satellite Interface Message Processors (SIMPs) at each to manage broadcast-mode , allowing up to five nodes initially with software upgrades enabling further growth. SATNET's operations contended with significant packet delays of up to 500 ms, primarily due to the 250 ms one-way propagation time inherent in geostationary links, which required adaptations in protocol design for efficient throughput. To address and optimization, the network employed specialized tools such as , which collected status reports and statistics from SIMPs and gateways, and Ltbox, a real-time display program for analyzing and error patterns at the Network Operations Center. These tools enabled operators to fine-tune parameters remotely, ensuring high reliability during peak usage for data exchange. As TCP/IP protocols matured in the early and cost-effective terrestrial fiber optic alternatives proliferated, SATNET underwent a gradual phase-out between 1984 and 1985, with sites transitioning to direct connections and the infrastructure being decommissioned for research purposes. This shift reflected the network's success in proving viability for while paving the way for more scalable global connectivity solutions.

Technical Architecture

Network Components and Hardware

SATNET's satellite infrastructure relied on transponders from the , positioned in over the Atlantic Ocean, specifically the Atlantic Primary slot off the west coast of . These transponders operated within the C-band frequency spectrum, utilizing 6 GHz for uplink transmissions and 4 GHz for downlink, with specific channels centered at 6320.2275 MHz for uplink and 4095.2275 MHz for downlink. Each transponder provided a 40 MHz , supporting demand-assignment multiple access via the SPADE (Single Channel Per Carrier Demand Assignment Equipment) system, which enabled efficient allocation of bandwidth for packet-switched communications across the network. The primary ground stations formed the core of SATNET's terrestrial infrastructure, with the U.S. terminal located at Etam, , and the UK terminal at the Goonhilly Earth Station in . These were Standard-A earth stations equipped with 30-meter parabolic antennas designed for high-gain C-band operations, achieving a (G/T) of +40.7 dB/K to ensure reliable signal reception amid atmospheric noise. A third station at Tanum, , extended connectivity to sites, while a smaller receive-only station at , supported testing with reduced capabilities. These facilities incorporated low-noise amplifiers and high-power amplifiers to maintain link budgets, with carrier-to-noise ratios balanced at approximately 17.5 dB across stations. Terminal equipment at these ground stations included modems and packet switches developed primarily by , Beranek and Newman (BBN) in collaboration with other contractors. BBN's Satellite Interface Message Processors (SIMPs), initially based on H-316 minicomputers with 32K memory and later upgraded to C/30 processors, handled and queuing at rates up to 128 kbit/s. Modems, such as Linkabit QPSK units integrated with BBN interfaces, supported burst-mode acquisition for single-channel-per-carrier (SCPC) operations, enabling multiple virtual channels over the shared satellite link through . Error correction was implemented via (FEC) codes, reducing the effective information rate to 32 kbit/s on a 64 kbit/s channel to combat bit errors from propagation delays and noise. Network capacity was structured around a nominal 64 kbit/s per , scalable through aggregation to support up to 1 Mbps in aggregate for the wideband packet satellite experiments, though operational SATNET primarily utilized the 64 kbit/s shared . Uplink power levels ranged from 10-20 watts per MHz, ensuring effective isotropic radiated power (EIRP) of +22 dBW from the , adjustable to +23 dBW for optimized performance. Auxiliary components enhanced reliability, including redundant Satellite Modem Interfaces (SMIs) and power supplies at key sites like Etam and Goonhilly, along with RF links for test and monitoring data transfer between packet switches and gateways. These redundancies, combined with command and monitoring modules in the Packet Switch Processor () terminals, allowed for fault-tolerant operations in remote locations.

Protocols and Transmission Methods

SATNET initially employed the ARPANET's 1822 protocol for host-to-interface message processor communications, leveraging extensions of ARPANET's Interface Message Processors (IMPs) known as Satellite IMPs (SIMPs) to interface ground stations with the satellite channel. This protocol facilitated basic packet exchange between hosts and the network but required adaptations for the satellite's unique constraints. In 1977, SATNET transitioned to the , a precursor to the modern TCP/IP suite, enabling end-to-end reliable data transfer across heterogeneous networks including and the Packet Radio Network (PRNET). To address the satellite environment's high propagation delays—approximately 250 ms round-trip time due to the geostationary Atlantic —SATNET implemented windowing mechanisms in the precursor. These adjustments increased the initial congestion window size to accommodate the longer delays, allowing more unacknowledged packets in flight and improving throughput without excessive retransmissions. Such adaptations were critical for maintaining performance in a system where terrestrial links had much lower latencies, preventing the protocol from stalling during satellite hops. Packet switching in SATNET utilized multi-access methods tailored to the shared channel, including variants of the protocol for random access. Specifically, Slotted (S-ALOHA) synchronized transmissions into discrete time slots to reduce collisions, achieving higher channel utilization compared to pure while supporting bursty traffic from multiple ground stations. For efficient bandwidth allocation, SATNET incorporated Demand Assignment Multiple Access () through the Contention-based Priority-Oriented Demand Assignment (C-PODA) protocol, which dynamically assigned transmission slots based on station requests and priorities, minimizing idle time on the expensive resource. Error management at the integrated (HDLC) framing to ensure reliable packet delivery over the noisy satellite channel, providing bit-oriented synchronization, error detection via cyclic redundancy checks, and retransmission capabilities. SATNET targeted bit error rates below 10^{-5} through and modulation techniques, as specified in host access protocols for SIMPs, to maintain without overburdening higher-layer retransmissions. Network monitoring relied on custom software tools to track performance metrics in . The Mon program collected and displayed statistics on packet delays, throughput, and error rates from SIMPs and gateways, enabling operators to identify bottlenecks. Complementing this, Ltbox logged detailed transmission events and measurements, supporting post-hoc for and fault . These tools were essential for managing the distributed satellite topology and ensuring operational stability.

International Aspects

Collaborating Institutions and Sites

The development of SATNET involved key U.S. institutions that provided foundational funding, technical implementation, and satellite coordination. The , later known as , served as the primary funding body, initiating and supporting the project as an extension of to enable transatlantic . BBN Technologies played a central role in implementation, developing the Satellite IMP (SIMP) hardware and software based on ARPANET's Interface Message Processors to handle packet broadcasting over satellite links. On the UK side, (UCL), led by Professor Peter T. Kirstein, acted as the primary international gateway, hosting the first non-U.S. node in 1973 and integrating SATNET connections to interface with local research networks. The UK Post Office (later British Telecom) managed operations at the Goonhilly Downs earth station in , providing essential ground station infrastructure and financing for transatlantic links, including a free 9.6 Kbps connection to . Other European participants included the Norwegian Defence Research Establishment (FFI) at Kjeller, which hosted the NORSAR seismic array and connected via the Tanum earth station in to support early international data exchange. The (, formerly DFVLR) contributed to network expansion in the late 1970s through the Raisting earth station. The Italian National Research Council (CNR) operated the Fucino earth station, enabling packet transmission from and facilitating southern European connectivity. By the early 1980s, SATNET had expanded to include five nodes, with serving as the main gateway to ; each node featured packet switches that interfaced with local networks for distributed experimentation. Coordination among these entities occurred through international collaboration involving U.S. and European participants, including .

Cross-Atlantic Integration Challenges

One of the primary technical hurdles in SATNET's cross-Atlantic integration was the significant propagation delay inherent to geostationary links, with round-trip times ranging from 520 milliseconds minimum due to the 260-millisecond one-way , leading to total end-to-end delays of approximately 600 milliseconds including processing overhead and up to 800 milliseconds on average. This delay caused substantial throughput reductions, achieving peak performance of around 71 kilobits per second for large (256-byte) packets and steady-state throughput of about 59 kilobits per second, exacerbated by rates of 0.1% to 1% and bit error rates of 10^{-6} under load. While protocol adjustments, such as optimizing implementations in 4.3 BSD with improved maximum segment sizes, window sizing, and round-trip time estimation, boosted throughput from 3-4 kilobits per second to over 12 kilobits per second by minimizing retransmissions, these tweaks provided only partial mitigation without fully resolving the latency-induced bottlenecks. Standardization discrepancies between U.S. and European networks posed another major barrier, as the U.S.-led ARPANET and SATNET emphasized TCP/IP protocols, while European systems, particularly in the UK, heavily relied on X.25-based standards promoted by postal, telegraph, and telephone authorities for public packet networks. This gap stemmed from Europe's preference for international OSI protocols and X.25's virtual circuit approach, which conflicted with TCP/IP's connectionless datagram model, leading to interoperability issues and resistance to U.S. standards amid concerns over technological dependency and brain drain to American institutions. Integration was achieved through custom gateways, such as the University College London (UCL) gateway established in 1982 to bridge SATNET with UK X.25 networks like JANET and EPSS, enabling protocol translation but introducing additional complexity and overhead in multi-protocol environments. Logistical challenges included securing regulatory approvals for satellite frequency allocations across international borders, as SATNET utilized the IV-A satellite's in the C-band spectrum, requiring coordination with bodies like the to avoid interference in shared orbital slots. Additionally, the ground station at Goonhilly faced operational disruptions from adverse weather, where extreme conditions could cause antenna misalignment and signal degradation in satellite dishes, compounding the network's vulnerability to environmental factors in operations. Security considerations arose from the need to protect sensitive data transmissions, particularly for military-related research. Bandwidth contention intensified during peak academic usage periods, as the shared 64-kilobit-per-second channel on the led to scheduling conflicts under protocols like PODA (Packet Oriented Data Access), further strained by variable loads from multiple European sites. Cost overruns plagued the project, with the fabrication and installation of terminals exceeding initial estimates by more than a factor of two due to unanticipated technical complexities in the hardware. Shared leasing expenses for the IV-A , which allocated just 0.125% of its bandwidth and 0.3% of power to SATNET, were managed through ARPA's contract with (F04701-76-C-0240), where ARPA bore the primary funding responsibility for development and operations, covering the bulk of satellite capacity costs estimated at $0.5 million to $4 million annually for comparable segments.

Legacy and Impact

Contributions to Internet Protocols

SATNET served as a critical testing ground for the Transmission Control Protocol (), particularly through a landmark demonstration in November 1977 that interconnected the , SATNET, and Packet Radio Network () using /. This experiment successfully transmitted data across heterogeneous networks with differing characteristics, including satellite links, validating 's ability to handle diverse transmission media and paving the way for its adoption as the standard protocol suite. The demonstration's success was instrumental in the U.S. Department of Defense's decision to mandate / for all military networks, culminating in 's full transition to / on January 1, 1983. SATNET also played a key role in the early design and implementation of IPv4 addressing and mechanisms. It was assigned the entire 4.0.0.0/8 address block, one of the original Class A allocations, which supported its operations as a dedicated within the broader internetwork. This allocation highlighted the need for scalable addressing schemes capable of accommodating specialized networks, while experiences with SATNET informed protocols that could operate across varied media types, such as terrestrial cables and satellite transponders, ensuring seamless in multi-hop environments. The network provided a practical proof-of-concept for the "catenet" concept—coined by Robert Kahn and Vinton Cerf to describe interconnected packet networks—demonstrating reliable inter-networking before the term "" became standard. SATNET's integration with and PRNET in the 1977 demonstration directly influenced foundational RFCs. These efforts underscored the feasibility of a unified protocol layer for linking disparate systems, shaping the architectural principles of the modern . Insights gained from SATNET's operational challenges, particularly the high propagation delays of approximately 500 milliseconds round-trip over Atlantic satellite links, contributed to early understandings of protocol behavior in environments and informed subsequent developments in s for communications. These experiences highlighted limitations of end-to-end acknowledgments in delayed networks, providing precursors to (DTN) architectures designed for intermittent and long-latency links, such as those in deep missions. Key publications documenting SATNET's contributions include RFC 829 (1982), which compiles reference sources on packet technology and details the network's implementation experiences, offering invaluable data on protocol adaptations for environments.

Shutdown and Technological Succession

SATNET's operations began to wind down in the early , with significant reductions by as key European sites, including and , transitioned away from integration and adopted TCP/ directly over the link. Full decommissioning occurred in the early , as the specialized infrastructure was no longer essential for intercontinental connectivity. The primary reasons for SATNET's shutdown included the maturation of TCP/ protocols, which had been successfully demonstrated on in 1977 and became the Department of Defense standard by 1983, eliminating the need for dedicated satellite-specific adaptations. Additionally, rising operational costs of satellite maintenance, coupled with rapid advancements in fiber optic technology—such as the deployment of the transatlantic cable in 1988—shifted priorities toward more efficient terrestrial backbones like NSFNET for civilian and research networking. Following decommissioning, SATNET's physical assets were repurposed into successor systems; for instance, the Etam in was integrated into broader communications infrastructure and later acquired by in 2021 for use in the Deep Space Network. The network's protocols and packet-switching techniques were absorbed into emerging standards, contributing to the foundational interoperability of TCP/IP across diverse media. SATNET's legacy influenced subsequent satellite communication projects, including NASA's Advanced Communications Technology Satellite (ACTS) launched in 1993, which advanced high-speed packet-based transmission concepts originally tested on SATNET. Modern (VSAT) networks, widely used for backhaul in remote areas, build on SATNET's pioneering work in efficient packet . Archival data and operational experiences from SATNET informed IETF working groups on satellite IP extensions, providing historical context for protocols like those in RFC 2488, which outlines enhancements for performance over satellite channels with high latency.

References

  1. [1]
    The essence of the 'Net: a history of the protocols that ... - Ars Technica
    Mar 7, 2011 · In 1974 the UK Post Office agreed to cover the UK's costs for a satellite connection to the US, and in September 1975 ARPA initiated the SATNET ...
  2. [2]
    How the Internet Came to Be - Vint Cerf - Packetizer
    ... Atlantic Packet Satellite network (SATNET) through a Single Channel Per Carrier (SCPC) system, which had ground stations in Etam, West Virginia, Goonhilly ...
  3. [3]
    [PDF] Untitled
    ARPANET ..the Atlantic Packet Satellite Network. The current program has two major thrusts: i.e., the development and refinement of practical low-cost ...
  4. [4]
    RFC 829: Packet satellite technology reference sources
    ### Summary of SATNET and Its Relation to ARPANET (RFC 829)
  5. [5]
    SATNET and the Provision of Transnet Service - » RFC Editor
    ABSTRACT: This note discusses the problem of providing service to ARPANET from the UK via SATNET after the existing direct ARPANET link disappears. ... We expect ...
  6. [6]
    RFC 790 - Assigned numbers - IETF Datatracker
    This Network Working Group Request for Comments documents the currently assigned values from several series of numbers used in network protocol implementations.
  7. [7]
    2017 CHM Fellow Lawrence G. Roberts - Computer History Museum
    Apr 27, 2017 · Roberts and Taylor chose three centers to be responsible for critical parts of the new network, which they had prosaically named “ARPAnet.” ...Missing: proposal | Show results with:proposal
  8. [8]
    Early Experiences with the ARPANET and INTERNET in the UK
    In late 1970, Larry Roberts proposed to Donald Davies that it would be very interesting to link their two networks together. The existence of the Washington ...Missing: objectives | Show results with:objectives
  9. [9]
    TCP Design Published | IEEE Communications Society
    Kahn's vision of linking ARPANET, PRNet, and SATNET took place in November, 1977, greatly increasing the visibility of internetworks and the viability of TCP ...
  10. [10]
    SATNET Development and Operation. Pluribus Satellite IMP ... - DTIC
    This Quarterly Technical Report is the current edition in a series of reports which describe the work being performed at BBN in fulfillment of several ARPA work ...
  11. [11]
    Vinton Cerf : How the Internet Came to Be - Netvalley
    Atlantic Packet Satellite network (SATNET) through a Single Channel Per Carrier (SCPC) system, which had ground stations in. Etam, West Virginia, Goonhilly ...
  12. [12]
    None
    ### Summary of SATNET Development (1975-1977)
  13. [13]
    [PDF] Early Experiences with the ARPANET and INTERNET in the UK
    The communications went through some of the UCL networks of Fig. 4, SATNET across the Atlantic, ARPANET to Palo Alto, and then. Packet Radio to the car. As the ...
  14. [14]
    [PDF] Untitled - Leonard Kleinrock
    SATNET is an experimental satellite network sponsored by the Ad- vanced ... The development of SATNET was initiated in mid 1975. The net- work consists ...
  15. [15]
    [PDF] University College London ARPANET Project - DTIC
    Nov 2, 2024 · This report describes the work of he UCL INDRA group during 1977. The bulk of the report:0consists of papers which) have been published or ...
  16. [16]
    Major Internet Milestones: A 30th Anniversary Celebration of the ...
    From abstract: " A major internet milestone occured on November 22, 1977. On this date the first known three-network transmission took place among SRI ...Missing: TCP | Show results with:TCP
  17. [17]
    [PDF] Netizen Empowerment and the 30th Anniversary of TCP/IP
    Network Intercommunication” was written by Robert. E. Kahn and Vinton Cerf.2. The article sets out the design and philosophy for the creation of a protocol.<|control11|><|separator|>
  18. [18]
    [PDF] Amateur Computerist newsletter - Columbia University
    TCP/IP protocols were matured sufficiently, SATNET was used as a means to interconnect local area networks in Norway, England, Germany, and Italy with.
  19. [19]
    [PDF] Bolt Beranek and Newman Inc. - DTIC
    should be mentioned that the same NU programs are used to monitor the Atlantic Packet Satellite Network (SATNET). The NU system's flexibility and ...Missing: objectives | Show results with:objectives
  20. [20]
    The SATNET Monitoring System - IEEE Xplore
    This paper describes the two SATNET monitoring programs: Mon and Ltbox, and the ways in which information from these programs is used to perform troubleshooting ...Missing: tools | Show results with:tools
  21. [21]
    The SATNET Monitoring System - Semantic Scholar
    The SATNET monitoring system uses programs like Mon and Ltbox for troubleshooting and system fine-tuning to keep SATNET working efficiently.
  22. [22]
    Hobbes' Internet Timeline - the definitive ARPAnet & Internet history
    An Internet timeline highlighting the key events and technologies that helped shape the Internet as we know it today.Missing: objectives | Show results with:objectives
  23. [23]
    [PDF] Untitled - DTIC
    This earth terminal is small relative to the Standard A INTELSAT earth terminals (e.g., Etam, Goonhilly, and Tanum) in that its figure of merit, G/T, is 11 dB ...
  24. [24]
    [PDF] Internetting and Packet Satellite Program. - DTIC
    SATNET: A problem with the transfer of Test and Monitor (T&M) data from the PSP Terminal to the. Satellite IMP was detailed.
  25. [25]
    RFC 889 - Internet Delay Experiments - IETF Datatracker
    ... 1822 Error Control Units operating over a 56-Kbps line. The NTA Fuzzball is connected to the NTARE Gateway by an 1822 interface and then via VDH/HAP ...
  26. [26]
    [PDF] packet satellite multiple access: - models and measurements
    This paper reports on a series of channel access measurements recently carried out on SATNET, an experi- mental packet satellite network, to evaluate and com-.
  27. [27]
    https://ieeexplore.ieee.org/document/4795070
  28. [28]
    How Britain got its first internet connection – by the late pioneer who ...
    Jan 8, 2025 · And so, once connected to the wider network through our gateway at UCL, the IBM computer at RAL became one of the most powerful on the Arpanet.
  29. [29]
    From the US to FFI: Kjeller was first online
    Jul 29, 2021 · On 15 June 1973, Kjeller became the first place outside the United States to go online. Pål Spilling at FFI pressed the necessary keys.
  30. [30]
    [PDF] 2 Objectives of the Measurements 235
    ABSTRACT. - The analysis of the test and measurement of. TCP/IP performance over the Atlantic Packet Satellite Network. (SATNET) is described.
  31. [31]
    [PDF] The "hidden" prehistory of European Research Networking
    Oct 1, 2012 · PRNET [73] and SATNET [74] [75]. UCL that was part of SATNET ... the healthy European X.25 industry wanted to continue to reap the ...
  32. [32]
    [PDF] COMSAT Participation in ARPA Packet Satellite Program (PSP) - DTIC
    the SATNET program dates back to the Fall of 1976, the work during that earlier period is summarized adequately in Refer- ences (lJ-[4]. This report will ...
  33. [33]
    [PDF] Combined Quarterly Technical Report Number 22. SATNET ... - DTIC
    This QTR covers work on several ARPA-sponsored projects including (1) development and operation of the SATNET satellite network; (2) development of the.
  34. [34]
    TCP/IP Internet Protocol | LivingInternet
    In November, 1977, a three-network TCP/IP test was conducted, successfully simulating complex, military-grade communications and verifying the inter-networking ...
  35. [35]
    RFC 675 - Specification of Internet Transmission Control Program
    This document describes the functions to be performed by the internetwork Transmission Control Program [TCP] and its interface to programs or users that ...Missing: SATNET | Show results with:SATNET
  36. [36]
    Distributed testing and measurement across the Atlantic packet ...
    The analysis of the test and measurement of TCP/IP performance over the Atlantic Packet Satellite Network (SATNET) is described. Both the methodology and ...<|control11|><|separator|>
  37. [37]
    Delay/Disruption Tolerant Networking - NASA
    Sep 23, 2025 · Utilizing DTN has improved efficiency of operations by automatically initiating transfer of bundles when a communication contact occurs, ...
  38. [38]
    RFC 829: Packet satellite technology reference sources
    This paper describes briefly the packet satellite technology developed by the Defense Advanced Research Projects Agency and several other participating ...
  39. [39]
    NASA acquires Earth Station property at Etam - WV News
    Mar 17, 2021 · The International Earth Station at Etam, once owned by AT&T, is now owned by Deep Space Network LLC, which is part of NASA.
  40. [40]
    Advanced Communications Technology Satellite (ACTS)
    Jun 1, 1989 · This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small ...Missing: SATNET influence
  41. [41]
    RFC 2488 - Enhancing TCP Over Satellite Channels using Standard ...
    This document focuses on improving TCP in the satellite environment and non-TCP considerations are left for another document.Missing: SATNET | Show results with:SATNET