Hi,

on my NetBSD_1.5ALPHA/i386 running i4b-00.90.0/sppp, I see
some strange traffic on the isp0 interface: after dial-out,
there is some small traffic going in and out (16 bytes in
each direction) every ten seconds even if the interface
is unused by any application. See the following tcpdump
log (this is _all_ output -- nothing is printed after the
timestamp).

00:00:04.301539 
00:00:04.301630 
00:00:14.300850 
00:00:14.300941 
00:00:24.300533 
00:00:24.300625 
00:00:34.300222 
00:00:34.300312 
(and so on)

This could be some keep-alive mechanism -- I have no idea.
I am quite sure that I did not see this on 1.4M or so, but
I have changed ISPs meanwhile, so this could be the reason.

Although this traffic does not keep the isdn connection up
endlessly, it disturbs isdnd's idle time calculation (the
connection is terminated at a time totally different from
end_of_unit-early_hangup.

What is the explanation for this behaviour, and what can I
do to stop this traffic?

(I have sent this to both the netbsd-help and the freebsd-isdn
lists as I am not sure which party is the right addressee
in this case.)

Regards
    Ingolf
-- 

Ingolf Koch     ICQ#60829470     Beste Kneipe in Jena-Ost
PGP: 0x7B3B5661  213C 828E 0C92 16B5  05D0 4D5B A324 EC04