As per Relevance of the word mechanism, we have this rfc below:
Network Working Group D. Walden (BBN-NET
Request for Comments: 660 Oct 1974
NIC #31202
SOME CHANGES TO THE IMP AND THE IMP/HOST
In the next few weeks several changes will be made to the
software including changes to the IMP/Host software
as specified in BBN Report No. 1822, Specifications for
Interconnection of a Host and an IMP. These changes come
four areas: a) decoupling of the message number sequences
Hosts; b) Host/Host access control; c) expansion of
message number window from four to eight; and d) provision
messages outside the normal message number mechanism. All
are backward compatible with possible minor exceptions in timing
a. Decoupling of the Host/Host message number sequences
Since 1972 the IMP system has provided for exactly
messages to be outstanding at a time between any pair
IMPs, and thus, a total of only four messages
all the possible pairs of Hosts on the two IMPs.
all the pairs of Hosts on the two IMPs have had to
the four outstanding messages, it has been quite
for the various Hosts to interfere with each other.
remove this possibility of interference, the IMP'
message number logic will soon be changed to allow
separate message number sequence between each pair of Hosts
To keep manageable the space required to maintain
Host/Host message sequences above that presently are
for the IMP/IMP message sequences, the Host/Host
will be taken dynamically from a limited pool of
sequences. The pool will be sufficiently large to
interfere with a pair of Hosts wishing to communicate.
no case will Hosts be prevented from communicating.
the event that the Hosts on an IMP desire to
communicate with so many other Hosts that the pool
be exhausted, the space in the pool is quickly
in time among all the desired Host/Host
so that none is stopped although all are possibly slowed
b. Host/Host access control
Upon instructions from ARPA, we will soon add a Host/
access control mechanism to the IMPs. Any pair of
wishing to communicate is checked (via bits in the IMP
to verify that they have administrative permission
communicate. This check normally is made whenever a
of Hosts attempts to communicate after not
communicated for two minutes. If the pair of Hosts
not allowed to communicate, a special type of
Dead Message (sub-code 3) is returned to the
Host. The default case initially will be to allow
Hosts to communicate with each other
-1-
c. Message number window.:
Once the message number sequences are on a Host/
rather than IMP/IMP basis, the number of messages
will be permitted to be outstanding at a time
a pair of Hosts will be expanded from four to eight
permitting increased Host/Host throughput in some cases
d. Message outside the normal mechanism:.
For certain limited experiments which are being carried
using the network, it is thought to be
for specified Hosts to be able to communicate outside
normal ordered, error controlled message sequences
Thus, the following expansion to the IMP/Host protocol is
provided
i. a single packet message coming from the source
to the source IMP with a (new) special message type
3, will be put directly into the IMP store-and-
logic with a mark saying the packet is this
kind of message. A multi-packet message of type 3
will be discarded
ii. such messages (packets) are routed normally to
destination IMP, possibly arriving out of order
iii. at the destination IMP, messages of the
type will be put directly on the destination
output queue skipping the reassembly logic and
with a special (new) IMP to Host message type, also 3.
iv. there is no source-to-destination
logic, no reassembly, no RFNMs, no
transmissions, etc
v. if at any time there are insufficient resources in
network to handle one of these special
(e.g., the destination Host won't take it),
message will be discarded
vi. by using the special message type between the
and the IMP, the normal message number mechanism
preserved for all the Host/Host transmissions
presently depend on it
Because the uncontrolled use of this mechanism will degrade
performance of the network for all users, the set of Hosts
to use this mechanism will be regulated by the Network
Center
Please file this note with your copy of BBN Report 1822
that document is updated
-2-
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
RFC documents can be found at I.E.T.F.
Relevance System Copyright © 2002 Spectrum WorldResearch
other technical nosh by ServerMasters Corporation
collaboration of BobX
