The Adopt-A-Mailbridge foster parent program.

29 Nov 87 16:13:00 EST


CONTEL Federal Systems became the first foster parent in the Adopt-A-
Mailbridge campaign. This campaign is an outgrowth of the suggestion to
upgrade the EGP core gateways which was made at the recent IETF meeting. The
EGP upgrade appears to have been very successful, reducing delays and packet
loss by up to two orders of magnitude while the network load increased.

The Adopt-A-Mailbridge program, as I've coined it, encourages members of the
Internet community to improve service for all by making a temporary loan of
equipment to upgrade a mailbridge gateway. Contel loaned an 11/73 processor

This note lists the results of some informal ping testing of the upgraded
DCEC-MILNET-GW.ARPA (, in comparison to concurrent tests of some of
the other mailbridge gateways, and against a few tests of taken
before the upgrade. I do not have access to a net-26 host with which I could
have performed throughput testing, so ping echo results are all I can provide.

When comparing the performance of the upgraded DCEC to the other mailbridges
keep in mind that more PSN hops must be traversed on net-10 to get to the
other mailbridges. The host that I performed the testing from is connected to
PSN DCEC20, as is

The "testing" consisted of pinging the net-10 interface address of the various
mailbridge gateways and recording the average echo delay. Most measurements
are based on receiving approximately 100 replies. One measurement of the
original DCEC mailbridge received only 47 replies. For the purpose of
removing the net-10 delay involved in opening a connection to the distant end,
each test was preceded by a separate ping session of sufficient duration to
see a few responses come back.

Comparing the longest average delay measured from DCEC mailbridge (347ms) to
the shortest average from any of the others (682ms), the improvement is a
factor of 2.

Comparing the average of all the upgraded DCEC measurements (279), to the
average of the average measurements from all the others (1034), the
improvement is a factor of 3.7.

It would be useful if the effects of the extra net-10 PSN hops could be
removed. Perhaps a conservative way to take a swag at this is to subtract off
the afternoon net-10 average end to end delay (422ms) from the average delay
figure for the remote mailbridges. This yields a corrected (??) delay figure
for the remote mailbridges of 612ms, and an improvement factor of 2.2.

My only data for the old DCEC was taken on the weekday test of the new PSN end
to end software. Four measurements were taken. The longest of these received
129 packets, and lost 31%. It had an average delay of 14479ms. I am not
considering this measurement. The average of the remaining three average
delay measurements is 803ms. Based on this, the upgraded DCEC running on the
old end to end is 2.88 times quicker.

While the improvement is not as dramatic as that seen on the Arpanet EGP core
gateways, it is still significant. I think we should try to locate Foster
Parents for the rest of the mailbridges. Steve Atlas also reminds me that the
EGP core gateways on the Milnet are still "un-sponsored". Finally, I wonder
if the EGP core gateways would benefit from an even faster processor? Does
anyone know if we can drop in an 11/83 cpu as easily as we dropped in the
11/73s? Has anyone got one to loan out?

I hope all of you had a nice Thanksgiving Day,

Bob Enger
Contel Federal Systems

This archive was generated by hypermail 2.0b3 on Thu Mar 09 2000 - 14:39:57 GMT