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tion of the network. A Network Control Center

• NCC – at BBN supervised the traffic and state
  of every node in the net. It was important for
  efficiency of the operation and the experiments
  that each node (IMP, Interface Message Proces-
  sor or TIP, Terminal Interface Message Proces-
  sor) in the entire net could be reprogrammed
  remotely from NCC. New ideas and variations
  of protocols were tried all the time. Data from
  the experiments were recorded and sent via the
  net to the responsible experimenters at their
  home locations and to other interested groups.
  Programs could be tested and errors corrected
  from the NCC. As the network grew and traffic
  from connected universities became significant
  “natural traffic” could be used for experiments
  in addition to synthetically generated traffic.

Most of the researchers, typically 20 to 30 per-
sons met every third month approximately. The
meetings rotated among the sites mentioned
above and consisted of detailed discussions fol-
lowing in-depth presentations of results and
ideas. The tone was open and could be heated
although always friendly. A certain amount of
social occasions usually took place and stimu-
lated the smooth co-operative spirit. From day
to day the researchers exchanged e-mail. It com-
prised discussions, experimental results, com-
ments and programs. The assembled group con-
stituted a strong and inspiring research team.
From mid 1977 the usual two-day PSPWG
(Packet Switching Protocol Working Group)
was supplemented by a third – “Internet” meet-
ing dedicated to techniques for internetworking
of different nets.

Norwegian Participation

In 1972 ARPA invited the Norwegian Defence
Research Establishment – NDRE – to a co-oper-
ative effort about so-called resource-sharing net-
working. Before that ARPA had been in contact
with the Norwegian Telecommunications Ad-
ministration – NTA – with a similar invitation.
NDRE then already had long traditions for
research co-operation with ARPA. A few re-
searchers at NDRE soon became convinced of
the promising prospects of this form of computer
networking, and NDRE joined in with ARPA’s
efforts.

NDRE’s work was mainly directed towards
packet switched satellite channels. However
these channels were integrated with Arpanet at
the time and were treated similarly to the leased
land-lines. Measurements were made using “Sat-
net”. It consisted of a free channel in a satellite
(a digital, 64,000 bits per second channel of type
“Spade” in the Intelsat IV satellite) and three
ground stations located in Maryland, England
and Sweden. The ground station at Tanum, Swe-
den was owned collectively by Nordic telecom

administrations. Some Swedish researchers

showed interest in Arpanet, but did not partici-

pate in the development. UCLA contributed

strongly in the satellite work in addition to the

groups at Comsat, UCL and NDRE. It resulted

in the satellite channel access protocol called

CPODA (Contention Priority Oriented Demand

Access). This form of satellite communication

has had limited use up to now.

In the early 1970s the Arpanet consisted of both

leased lines, mostly of 56,000 bits per second

capacity, and of packet radio nets, mainly one in

Hawaii and one in the San Francisco Bay area.

ARPA now suggested developing packet

switched satellite channels as a new information-

carrying medium especially for use in resource

10 – 11 Aug 74 On the ferry between Stockholm, Sweden and

Åbo, Finland

4 – 5 Sep 75 Linkabit Co, San Diego, California.

Host: Irwin Jacobs

12 – 13 Nov 75 UCL, London, England.

Host: Peter Kirstein

12 – 14 Feb 76 DCA and ARPA, Washington, DC.

Host: Bob Kahn

29 – 30 Apr 76 BBN, Cambridge, Massachusetts.

Host: David Walden

29 – 30 Jun 76 NDRE, Kjeller, Norway.

Host: Yngvar Lundh

23 – 24 Sep 76 UCLA, Los Angeles, California.

Host: Leonard Kleinrock

9 – 10 Dec 76 UCL, London, England.

Host: Peter Kirstein

10 – 11 Mar 77 Comsat, Washington, DC.

Host: Estil Hoversten

8 – 10 Jun 77 NDRE, Kjeller, Norway.

Host: Yngvar Lundh

17 – 19 Aug 77 Linkabit, San Diego, California.

Host: Irwin Jacobs

31 Oct – 2 Nov 77 BBN, Cambridge, Massachusetts.

Host: Bob Bressler

1 – 3 Feb 78 UCLA, Los Angeles, California.

Host: Wesley Chu

3 – 5 May 78 UCL, London, England.

Host: Peter Kirstein

31 Jul – 2 Aug 78 MIT Lincoln Lab, Lexington, Massachusetts.

Host: James Forgie

1 – 3 Nov 78 Linkabit, San Diego, Caliornia.

Host: Estil Hoversten

8 – 11 May 79 BBN, Cambridge, Massachusetts

4 – 7 Feb 80 SRI, Menlo Park, California

14 – 15 May 80 MIT, Cambridge, Massachusetts

7 – 9 Oct 80 UCL, Royal Signals and Radar Establishment,

Malvern, England

28 – 30 Jan 81 ISI, Marina del Rey, California

PSPWG meetings 1974 – 81.

The Packet Switching Protocol

Working Group meetings

during the most active period

of development