Telstra ADSL questions (pppoe technical)
eyal at eyal.emu.id.au
Wed Dec 12 23:03:46 EST 2001
Martijn van Oosterhout wrote:
> I think it says somewhere that they consider 1M = 1000K.
To put it clearly, 1M=1,000,000?
> > 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?
> The packets may be compressed, meaning that the traffic on eth0 will be less
> than on ppp0.
How can I tell? I am happy to turn on some debug for a while while
> > 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.
> 20% overhead. Seems high. I would have thought more like 5-10%. Mind you,
> who knows what else went over the link at the time.
Nothing else of course. The whole point of my test was to do nothing
during the 5 minutes of the test. I positively know there was no other
> Well, there is no speed guarentee. And going by the 1K = 1000 byte rules,
> 51K is about right.
How? if one byte is 8 bits (well, call me crazy!) then 512,000 bits/sec
is 64,000 bytes/sec, right? 51000/64000= 20% missing.
Also, I am not saying I sometimes not get more that 51KBps, but I never
anything better. In other words the line is limited to this speed, which
think is lower than the reasonable expectation from the plan.
> There are various types of compression. The actual bodies of packets can be
> compressed and the headers can be compressed. They are independant. On the
> link here it appears that there is VJ header compression but the bodies are
If I can turn anything on to check this then I will. my fw runs kernel
so I have:
# ls /proc/net
dev_mcast wireless dev_stat dev bridge
psched udp tcp sockstat netstat
snmp raw ip_mr_cache ip_mr_vif ip_masq
ip_masquerade ip_fwnames ip_fwchains igmp rt_acct
rt_cache route arp tr_rif unix
Any of these of use?
Eyal Lebedinsky (eyal at eyal.emu.id.au) <http://samba.anu.edu.au/eyal/>
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