Net device- can't feed fast enough

Robert O'Kane (
Sun, 08 Sep 1996 20:55:04 +0200


I am using the ISDN-4-Linux package and have a general question,

Linux 2.0.18
Isdn-4-linux 2.0 (i4lutils 2.0)
Teles 16.3 cards
Net-utils 1.32alpha
Libc 5.3.12
(both host configurations identical)

The I4L package has the ability to bind together multiple channels
over 1 "kernel" net device. The slave device is triggered when the
master device is "loaded". For I4L, it kicks the slave device in at
7000 cps.

This works fine except I can't get 7000cps through (to?) the device.
Using RAW-IP encapsulation and starting an FTP process, I4L tells me
it is doing arround 6040 - 6146 cps so the slave doesn't kick in.

I re-compiled the I4L so the slave starts at 6000 cps. This works
fine except that I get again, arround 6040 cps TOTAL across the
interface. (with ftp "put" and "get" if that makes a difference).
I get the same results when starting the transfer from either host.

Is there a way to see where the bottleneck is?

I'm not sure what to describe so....

tcpdump runs but wasn't interesting except it looks like a "bursting"
problem (lots of packets with matching ACKs,, then 5-10 bursts of data,
then 5 sequential ACKS).
Also, all the FTP data packets were signed DF (don't fragment) and P
(push), but I think that is normal though (compared to the ethernet ftp
The same ethernet ftp transfers were in the 400K/sec range.

Any help or thoughts would be appriciated.

Bob O'Kane

Unfortunatly, I find language (like politics) necessary for humans.
Leider finde Ich Sprache (wie Politik) fuer die Menschen notwendig.
Robert O'Kane
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