Messages in this thread | | | Subject | Re: _Very_ strange network delay over dialup-ISDN in 2.2.11. | Date | Thu, 19 Aug 1999 23:36:05 +0100 | From | David Woodhouse <> |
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Marc@Mutz.com said: > I just experienced a very wierd network delay: I use a ISDN dialup > line to my university. Normally I do not run ping, so this is - apart > from a similar occurence with up to 20 sec lags in 2.2.10 - the first > time I noticed this behaviour. But this time I wanted to keep the > connection established. So I fired up ping, and saw that it reported a > round-trip time of 1 second (1000 ms)!
Marc@Mutz.com said: > it could only be resolved by shutting down the ISDN system (/sbin/ > init.d/i4l stop) and starting it again.
Marc@Mutz.com said: > Anyone got a clue?
This sounds familiar. I had a similar problem a few months ago. There were always a constant number of packets in the outgoing queue. If I ran tcpdump on the ISDN interface, I could see them being sent out. TCP connections would stall, unless I ran ping across the link to keep the queue moving. ping -f would make packets go out almost immediately (chronologically speaking).
I didn't ever manage to find out the cause of the problem. It used to take some days of connectivity before it would happen, so I couldn't easily debug it. Eventually we installed a leased line to replace the ISDN, so I have no clue if it's still happening.
I was using the CVS ISDN code at the time - the standard code wouldn't work with the Teles 16.3c IIRC.
---- ---- ---- David Woodhouse David.Woodhouse@mvhi.com Office: (+44) 1223 810302 Project Leader, Process Information Systems Mobile: (+44) 976 658355 Axiom (Cambridge) Ltd., Swaffham Bulbeck, Cambridge, CB5 0NA, UK. finger dwmw2@ferret.lmh.ox.ac.uk for PGP key.
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