Re: Internet Uselessness


Andy Malis (malis@CC5.BBN.COM)
Mon, 20 Jul 87 09:44:49 -0400


Mike,

As a whole, I think the internet community has been doing "clever
engineering" for quite a number of years now. However, there
comes a time when offered load just overwhelms the resources
devoted to the task. We are very close to that point on the
ARPANET, even though we just made the routing algorithm more
"clever" and added another transcontinental trunk.

We are currently in the process of implementing congestion
control in the PSNs. This should optimize the total available
throughput of the network (at the expense of backing flows into
source hosts if necessary).

Finally, the X.25 spec really says nothing about what goes on in
the subnet, it is just an interface spec between a DTE and its
DCE. Internally, the PSNs use virtual circuits to support both
AHIP (1822) and X.25 traffic while using good old dynamic
adaptive routing to get the packets between the endpoint PSNs.
Internally, neither AHIP nor X.25 data packets contain full
addressing information, just the destination PSN number and a
connection identifier at that PSN. So I guess you might say that
we "do it right".

Cheers,
Andy



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