RFC - Unknown
(April 1969; Errata)
||RFC Editor Note
RFC 2 (Unknown)
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Network Working Group Bill Duvall
Request for Comments: 2 SRI
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1a Control Links
1a1 Logical link 0 will be a control link between any two HOSTs on
1a1a Only one control link may exist between any two HOSTs on
the network. Thus, if there are n HOSTs on the network, there
are n-1 control links from each HOST.
1a2 It will be primarily used for communication between HOSTs for
the purposes of:
1a2a Establishing user links
1a2b Breaking user links
1a2c Passing interrupts regarding the status of links and/or
programs using the links
1a2d Monitor communication
1a3 Imps in the network may automatically trace all messages sent
on link 0.
1b Primary Links
1b1 A user at a given HOST may have exactly 1 primary link to each
of the other HOSTs on the network.
1b1a The primary link must be the first link established
between a HOST user and another HOST.
1b1b Primary links are global to a user, i.e. a user program
may open a primary link, and that link remains open until it is
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1b1c The primary link is treated like a teletype connected over
a normal data-phone or direct line by the remote HOST, i.e. the
remote HOST considers a primary link to be a normal teletype
1b1d The primary link is used for passing (user) control
information to the remote HOST, e.g. it will be used for
logging in to the remote host (using the remote hosts standard
1c Auxilliary Links
1c1 A user program may establish any number of auxilliary links
between itself and a user program in a connected HOST.
1c1a These links may be used for either binary or character
1c1b Auxilliary links are local to the sub-system which
establishes them, and therefore are closed when that subsystem
2 MANIPULATION OF LINKS
2a Control links
2a1 The control link is established at system load time.
2a2 The status of a control link may be active or inactive
2a2a The status of the control link should reflect the
relationship between the HOSTs.
2b Primary Links
2b1 Primary links are established by a user or executive call to
2b1a The network identification number of the HOST to be linked
to must be included in the call
2b1b An attempt to establish more than one primary link to a
particular HOST will be regarded as an error, and the request
will be defaulted
2b1c Standard Transmission Character Set
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2b1c1 There will be a standard character set for
transmission of data over the primary links and control
2b1c1a This will be full (8 bit) ASCII.
2b1d (get link) The protocol for establishing a link to HOST B
from HOST A is as follows
2b1d1 A selects a currently unused link to HOST B from its
2b1d2 A transmits a link-connect message to B over link 0.
2b1d3 A then waits for:
2b1d3a A communication regarding that link from B
2b1d3b A certain amount of time to elaspse
2b1d4 If a communication regarding the link is received from
B, it is examined to see if it is:
2b1d4a A verification of the link from B.
2b1d4a1 This results in a successful return from the
monitor to the requestor. The link number is returned
to the requestor, and the link is established.
2b1d4b A request from B to establish the link. This
means: that B is trying to establish the same link as A
independently of A.
2b1d4b1 If the network ID number of A(Na) is greater
than that of B(Nb), then A ignores the request, and
continues to await confirmation of the link from B.
2b1d4b2 If, on the other hand, Na<Nb, A:
2b1d4b2a Honors the request from B to establish the
2b1d4b2b Sends verification as required,
2b1d4b2c Aborts its own request, and repeats the
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2b1d4c Some other communication from B regarding the
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