Telstra ADSL questions (pppoe technical)

Eyal Lebedinsky eyal at
Wed Dec 12 21:40:11 EST 2001

I wrote a simple script that looks at the traffic at my firewall
(pppstats) and tracks my usage.

I use pppoe as in LEAF (Linux Router 3.1.0).

I encountered a few uncertainties. If anyone has an idea... Some
Qs may be stupid, but I will still appreciate your comments.

1) The AUP says the "free" limit is 3G. Elsewhere (on the usage page)
   it says 3000M. And what is M anyway then?

2) I see ADSL traffic on eth0 and on ppp0. I expected to see the raw
   volume on eth0, with the net on ppp0 but this is not what I see.
   While the number of packets on both is identical, the volume on
   ppp0 os higher. Can anyone explain?

3) What traffic is chargeable then? The ppp0 has extra headers
   that only exist between me and the Telstra connection, but it
   does not go into the external network. So I assume the net
   volume is measured? How do I get at it?

   Also, an idle line has constant traffic showing on eth0 but not
   on ppp0 (as I expected) which comes up to an hourly rate of:
	rcv bytes	34560
	rcv packets	  540
	xmt bytes	32400
	xmt packets	  540

   BTW, I xfered a large file (15,751,285) and eth0 had a rcv of
   16,644,696 while ppp0 shows 19,001,215. Reasonable? The xfer
   rcvd 11,358 packets and sent 5,758.

4) I am on a 512/128K plan. I find that the best rcv rate I get is
   51KB/s (looking at 'curl' running). How does this match the 512Kb
   rate? 512Kb/8 -> 64KB, right? how does it go down all the way so
   badly? Maybe I need better settings? Is the slower upstream slowing
   it that much? I do appreciate there is some headers overhead but
   this is more than that.

5) On the same subject, pppstats shows zero compressed packets. Is it
   my setup or telstra that prevents header compression? My ifconfig
	ppp0:  mtu 1492 qdisc pfifo_fast qlen 10

What I keep is the above for both eth0 and ppp0 once an hour. This
should give enough accuracy.

Eyal Lebedinsky (eyal at <>

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