"... and statistics" (Re: [Phil Dykstra: more interesting numbers] )


Mike Brescia (brescia@PARK-STREET.BBN.COM)
Thu, 14 Apr 88 11:27:10 -0400


I think the Internet community would be better served if you could compare
these gateways in some way. I want to point out that the LSI11 gateways on
the arpanet/milnet border will drop packets and count them for reasons other
than congestion, such as '1822 host dead' or 'net unreachable'. Also the
"average" throughput is a measure of packets actually offered over the course
of the day or week reporting period, so that 10 packets per second really
means 864,000 packets in one day, not that the machine is somehow limited to
10 packets per second. While I can cite higher numbers over the 15 minute
periods the statistics are sampled, both for arpanet-milnet gateways, and more
so for ethernet-ethernet gateways, that still is a measure of handling offered
load rather than limitation. There is also no indication whether the packets
are long and saturate the communication lines, or short and saturate the
gateway processor.

Specifically on the msg from Specifically on the msg from phil@brl...

     Some recently obtained per node averages for gateways:

     The seven BBN ARPA/MILNET Core gateways:
        10.04 packets/sec 5.78 % drop rate

(These gateways connect 2 wide area packet switch nets which have 56 kb and
9.6 kb lines.)

(As a comparison, here are 2 lsi11 gateways' statistics from yesterday)
( tot sent avr/sec(day) peak/sec(15min) drop(day) )
(MILBBN 1.5e6 19.61 34.30 2.01% )
(CORPE(lan-lan) 1.4e6 18.16 50.01 0 )

     The NSFNET Backbone "Fuzzball" gateways:
        15.55 packets/sec 0.18 % drop rate

(These 5(?) gateways connect to each other with 56 kb lines.)

     The Bld 394 BRL gateway:
        ~20 packets/sec ~0.8 % drop rate

I would also look for more pleasing statistics from the arpa/mil gateways now
that the processors have all been upgraded from dec lsi 11/23 to 11/73.

Mike Brescia
BBNCC Gateway Development Group



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