Hi -
HP-UX (and MPE before it IIRC) has a utility called "linkloop" which will send an 802.2 test frame to a specified MAC and check for a response:
# tcpdump -i lan0 -v -x ether src 0:15:60:ae:a9:fb or ether dst 0:15:60:ae:a9:fb tcpdump: listening on lan0
11:28:42.718957 0:10:83:cf:55:2 sap 80 > 0:15:60:ae:a9:fb null test/P len=1497 0080 f300 0102 0304 0506 0708 090a 0b0c 0d0e 0f10 1112 1314 1516 1718 191a 1b1c 1d1e 1f20 2122 2324 2526 2728 292a 2b2c 2d2e 2f30 3132
11:28:42.720777 0:15:60:ae:a9:fb null > 0:10:83:cf:55:2 sap 80 test/R len=1497 8001 e300 0102 0304 0506 0708 090a 0b0c 0d0e 0f10 1112 1314 1516 1718 191a 1b1c 1d1e 1f20 2122 2324 2526 2728 292a 2b2c 2d2e 2f30 3132
There is a linux port of linkloop at
formatting link
What I'm wondering is how many other platforms/switches/whatnot would respond to the test frames produced by linkloop or something like it.
rick jones