[clug] DSL connection: modem or router?

Alex Satrapa grail at goldweb.com.au
Tue Sep 28 23:38:10 GMT 2004

On 28 Sep 2004, at 18:53, Dave wrote:

> I agree that it makes you *feel* better when you can see a few more
> details about the error. In practice though, at least for me, it is
> ALWAYS the ISP at fault when I have problems connecting to my ADSL
> account.

Other people (especially ISPs) have differing experiences.

For example, say you're running Linux 2.4.26 amongst others on your 
heterogenous network. You can get to websites fine. When you try the 
same web site from your Windows XP box, everything works fine. You 
can't ssh anywhere from the Linux box. Your older Linux 2.2.20 box 
works fine.

If you didn't have the ability to see packets transiting the router, 
you'd have to look at things like the fact that HTTPS transfers don't 
work from the Linux box either, to suddenly realise that what's 
happened is that you've got ECN enabled in the kernel, and the router 
is silently dropping ECN enabled packets. So you cat 0 > 
/proc/sys/net/ipv4/tcp_ecn, and suddenly everything works.

>  I know this, yet I still pull the modem out of the router and
> into my PC to see whats up :) doesnt get me online any faster...

This is only because the level 1 help desk people are running from 
scripts. If you can't help them run through the script by using the O/S 
that they're "trained" (in the behavioural psychology sense of the 
term) for, they can't help you at all. In fact, I sometimes suspect 
that level 1 help desk could be replaced with a VRU and fax-back 

> You can still use it as a quasi 'all-in-one' solution (no pc required) 
> if you want to because the AP/router should still support pppoe

Oh... there's one more advantage of an ADSL modem/router or a USB modem 
- it can do PPPoA. That gives you an extra few bytes per packet. I'm 
not sure of other advantages, since my only experience with PPPoE/PPPoA 
was over a wholesale ADSL product that delivered L2TP tunnels to the 
ISPs servers.

"If knowledge can create problems, it is not through ignorance that we 
can solve them."  --Isaac Asimov

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