Running the server with the noccp flag does not change the error count
reported by the ifconfig.
Now, here is the ifconfig from the server:
ppp0 Link encap:Point-to-Point Protocol
inet addr:192.168.1.201 P-t-P:192.168.1.202
Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:3319 errors:0 dropped:0 overruns:0 frame:0
TX packets:3994 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:191000 (186.5 KiB) TX bytes:5948354 (5.6 MiB)
and the matching from the client:
ppp0 Link encap:Point-to-Point Protocol
inet addr:192.168.1.202 P-t-P:192.168.1.201
Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:3664 errors:322 dropped:0 overruns:0 frame:0
TX packets:3319 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:5454546 (5.2 MiB) TX bytes:191000 (186.5 KiB)
The data is transfered from the server to the client, and the client shows
322 errors, which is the delta between the server TX and client RX packet
count.
The tcpdump run on the server and client shows that the client does not
receive some tcp packets that the server shows to have sent and the client
requests them to be resent. However, the tcp does not get these
packets and it is not clear what happened to them and what errors they
had.
Can you suggest anything to shed more light onto what could be causing
these errors?
Thanks,
Swavek
On Tue, 11 Jan 2011, James Carlson wrote:
Slawomir Skret wrote:
I tried to use the "debug" and "kdebug" flags when starting pppd but get
only the configuration related info but nothing during the runtime that
would tell me why the errors occurred or what do they mean. From what I
read, the ifconfig reports the contents of the /proc/net/dev file which
is updated by the kernel modules but again it is a statistics reporter
only without describing the nature of the errors.
How can I get more information about these errors?
How did you use "kdebug?" It doesn't work quite the same way as "debug"
-- it takes an argument, and on most platforms, the argument is an
integer interpreted as a set of flags representing the debug information
to enable. "kdebug 7" usually turns everything on.
The "debug" option is unlikely to help when you're talking about basic
I/O errors. The "debug" option causes the system to log the details of
the PPP negotiation between the peers, but this usually has little to do
with I/O problems.
And where did you look for the messages generated by those options?
/etc/syslog.conf directs these things to files depending on the origin
of the message, and the severity. You may need to modify
/etc/syslog.conf (and SIGHUP syslogd) to see everything.
Did you try using the "pppstats" command? If the errors are related to
data compression or the like, then pppstats may well give you more
details than kdebug. At least, I'd use pppstats to rule out other problems.
What options are you using? Have you tried disabling data compression
with "noccp"?
How fast does your "serial bus" run? Is it likely to drop data when
there are bursts -- as you might see with packet-oriented networking
protocols, such as PPP?
--
James Carlson 42.703N 71.076W <carlsonj@xxxxxxxxxxxxxxx>
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