[comp.protocols.tcp-ip] sparta.com

sparta@SAIC.COM (Sparta guest account) (12/19/89)

Columbus,

The Internet has been prone to forming repeated routing loops for the
last few days.  Below is an interesting traceroute run from
narnia.saic.com (192.5.8.2) to cj3.centcom.com (131.240.95.31), at
10:00 EST on 19 Dec:

 1  MCLEAN-MB.DDN.MIL (10.3.0.111)  180 ms  120 ms  120 ms
 2  MCLEAN-MB.DDN.MIL (10.3.0.111)  180 ms  100 ms  120 ms
 3  MOFFETT-FLD-MB.DDN.MIL (26.20.0.16)  1180 ms  2220 ms  1540 ms
 4  CAMBRIDGE-MB.DDN.MIL (10.3.0.5)  1340 ms  1360 ms *
 5  MCLEAN-MB.DDN.MIL (10.3.0.111)  2400 ms  1380 ms  1820 ms
 6  * MOFFETT-FLD-MB.DDN.MIL (26.20.0.16)  2060 ms  2860 ms
 7  CAMBRIDGE-MB.DDN.MIL (10.3.0.5)  2100 ms  3360 ms  3720 ms
 8  MCLEAN-MB.DDN.MIL (10.3.0.111)  4240 ms  3520 ms *
 9  131.240.95.31 (131.240.95.31)  2160 ms !  1560 ms !  2280 ms !

There seems to be quite a bit of route thrashing; we have frequently
seen evidence that the routes are changing during a traceroute run
(witness the miraculous discovery of cfm.centcom.com, above!).

This is not an isolated occurrence.  We've been seeing quite a few
loops, especiaslly in traffic to the West coast.  I guess that
includes the West coast of South Florida :-).

- Bob

Mills@UDEL.EDU (12/20/89)

Bob,

This problem has been going on for several months, as reported some
time ago in my Internet Monthly report. At the time, it appeared the
WIDEBAND (aka FATNET) gateways appeared the most involved and even
involved traffic fluttering between ARPANET and MILNET between the
same two sites. However, things may be changing so fast that the
apparent traceroute loops aren't really that, just rickety routes
flopping all over the place. Try a record-route option, assuming
you don't have far to go.

Dave