Network Working Group Alex McKenzie
RFC#374 BBN
NIC 11099 19 July 1972
There are two significant developments in the operation of the network
which should be of interest to all sites:
NEW IMP SYSTEM IS RELEASED !
On Tuesday July 18, the new IMP software described in previous RFC's
(#331,#343,#359) was apparently sUCcessfully released. We ran from
10:00am on that day until Wednesday afternoon with very few network
problems attributable to the new system. We are quite pleased with
this performance, and eXPect to leave the new system up permanently!!
We are, of course, aware that in any system of this size, bugs may
crop up at any time, and we solicit the help of the network community
in finding them. We also believe that the new system may have a
different "feel" to users, both terminal users and Hosts. We urge
everyone to have a bit of patience while getting used to any change in
the "feel" of the network. On the other hand, PLEASE REPORT ANY
SUSPECTED NETWORK MALFUNCTION TO THE NCC AS SOON AS POSSIBLE.
Evidence of bugs, guesses as to what went wrong, etc., are always
useful in hunting bugs, but don't let the lack of positive proof delay
the reporting of suspected system malfunction. The NCC telephone
number is (617) 661-0100. Feel free to call collect!
The one known shortcoming of the new software is the exacerbation of a
long-standing TIP software problem. The TIP now often appears to
neglect sending an Allocate control message for some active
connection, with the effect that the Server-to-User path becomes
blocked. We are giving the solution of this problem the highest
priority! (Our current data seems to indicate that this problem is
most likely to occur when there are several users and when the Server
Host is a TENEX system. If you know of other situations where this
problem has occurred, please let us know!)
Now that the new system is up, all sites with Model 516 IMPs will be
contacted by telephone and asked to reset the switches on their IMPs
as follows:
HALT INH - on
W.D.T. - on
AUTO RSTRT - on
MEMORY PRTCT - on
[Page 1]
SITE POWER PROBLEMS
The network has recently been experiencing serious difficulties
related to the annual problem of more demand for electricity than is
available during the summer months. For example:
During the month of June, between 1/4 and 1/2 of the
IMP down time was due to site power failure.
During the weekend of July 15-16, two sites were down
all weekend due to air-conditioning failure which was
apparently related to power failures or brownouts.
This left several sites connected to the rest of the
net through only one path which, according to Murphy's
law, eventually failed - leaving nine sites partitioned
from the remainder.
On July 18, an underground power transformer supplying
power to the entire computer room at site 27 failed,
putting IMP 27 out of action for several hours (anddit
could easily have been several weeks.)
Obviously in these cases there is little that either the NCC or the
site can do to restore service. We expect these situations to
continue or even get worse as the summer continues. Please try to
restrain your annoyance when these situations arise; we don't like
them either!
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