PPP throughput

PPP throughput

Post by Bill Whitin » Thu, 07 Nov 1996 04:00:00



I have been getting poor throughput on my PPP link.  I would like to be
sure that the problem is not on my end before I accuse the ISP of poor
service.  

I have a USR Courier V.32 modem connected to a builtin serial port on a
Zeos PC (I think that this is better than an 8250 equivalent).

The symptom that I see is that the data comes through link in bursts,
often there are long periods of inactivity.  The throughput in Netscape
is often less than 200 bytes per second.  When I first subscribed to
this ISP, I would regularly get peaks over 1000 bytes per sec. and the
average throughput was normally 700-800.

I ran ifconfig and found that I am getting RX errors

ppp0      Link encap:Point-Point Protocol  
          inet addr:204.177.103.94  P-t-P:204.176.24.48
Mask:255.255.255.0
          UP POINTOPOINT RUNNING  MTU:1524  Metric:1
          RX packets:307 errors:52 dropped:0 overruns:0
          TX packets:389 errors:0 dropped:0 overruns:0

Is this indicative of the kernel not being able to service the serial
port quickly enough?  I only have 8Mb of ram and the system does quite a
bit of swapping.  The processor is a 486/33

Thanks in advance for any help.

Bill Whiting

 
 
 

PPP throughput

Post by Tomas Pospise » Mon, 11 Nov 1996 04:00:00



> I have been getting poor throughput on my PPP link.  I would like to be
> sure that the problem is not on my end before I accuse the ISP of poor
> service.
> ...

have you set the portspeed correctly with s.th. like:

/bin/setserial /dev/cua0 spd_vhi
/bin/setserial /dev/ttyS0 spd_vhi

T

--------------------------------------------------------------------------------
                            Tomas Pospisek  


             for more info have a look at "http://www.spin.ch/"
--------------------------------------------------------------------------------

 
 
 

PPP throughput

Post by bill davids » Wed, 13 Nov 1996 04:00:00




| I have been getting poor throughput on my PPP link.  I would like to be
| sure that the problem is not on my end before I accuse the ISP of poor
| service.  
|
| I have a USR Courier V.32 modem connected to a builtin serial port on a
| Zeos PC (I think that this is better than an 8250 equivalent).
|
| The symptom that I see is that the data comes through link in bursts,
| often there are long periods of inactivity.  The throughput in Netscape
| is often less than 200 bytes per second.  When I first subscribed to
| this ISP, I would regularly get peaks over 1000 bytes per sec. and the
| average throughput was normally 700-800.

One thing to check is that you are setting up the modem in hardware
flow control mode. You must have the modem doing flow control, and
the rtscts (from memory) option to pppd at startup.

Since you say it used to work, chances are that it is the modem
setup. I ran four 56k serial ports for several years on a 486-16, so
I am dubious that you are losing ints, at least on a regular basis.
--

  What do you mean I shouldn't do thing like that at my age?
  At my age if you don't do things like that you might die of natural causes!

 
 
 

1. 1.2.8 patch causes bad ppp throughput

Last night I patched my 1.2.7 kernel to 1.2.8 and my PPP connections
REALLY slowed down.  In many cases telnet wasn't even able to make
connections with other machines.  I didn't see anything abnormal in
the syslog files.  I did some NON PPP downloads via. minicom and rzsz
and the throughput seemed OK there.  Needless to say I moved back to
1.2.7 which wasn't causing me problems anyway :-)

-Jeffrey E. Hundstad
(Thanks MUCH in advance for people who actually CONTRIBUTE to this
 project)

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