Re: SLIP working group?


Mills@UDEL.EDU
Wed, 30 Mar 88 11:17:16 EST


Rick,

I second your motion. I've been running fuzzballs with raw IP over everything
from noisy leased lines to transcontinental dial-up circuits since 1978 with
no problems. I ran my home fuzzball over a 1200-bps 15-mile dial-up circuit
for five years and then a 4800-bps leased circuit for four years in raw IP.
Those instances when the 24-hour dial-up circuit would drop, maybe once
every month or so, plus the number of packets dropped due congestion, timeout
and similar causes, easily outnumbered the number dropped due checksum
errors. Yes, there is some chance that a few error bits did survive somewhere
in the many megabytes of data transferred over that nine-year period, but I
strongly suspect most of them were due to causes other than checksum errors.

Having said that, I still would not recommend running raw IP between heavy-
hitting nodes like backbone switches or gateways. The NSFNET Backbone fuzzies
use DDCMP links with CRC checking and they do find significant numbers of
errors sometimes on marginal trunks. I would be a little uneasy if the IP
and/or TCP checksums were the only protection. However, I am completely
comfortable without CRC protection on single-user PCs and workstations
and would be even more comfortable if the drat Backfuzz links did NOT use
retransmission (DDCMP interface retransmissions are done in hardware and
cannot be disabled).

Dave
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