[geeks] ADSL Modem

[Phil Brutsche]

Sridhar Ayengar wrote:
> I'm reasonably certain even my provider does that, but I'm a special
>  case.  Most of my ISP's customers probably don't have a block.

PPPoE is pretty common among those ISPs who deal with the larger telcos,
regardless of dynamic vs static, business vs residential, IP block or no.

Heck, I was surprised to find out my ISP *didn't* require it! Every
other DSL service I had been exposed to required PPP of some kind.

I bet the fact that they own *all* the telco infrastructure in the
county has something to do with it.

>> If the Zyxel is in PPPoA mode the Zyxel gets the IP address.
> 
> There's no way that I can get the Zyxel to bridge ethernet over
> PPPoA? I'd like to be able to use PPPoA just so I don't have to
> shrink my outbound MTU.

I highly doubt it.

I tracked down the manual, and they are pretty standard DSL modems.

> Interesting.  I really wish there were a way to get PPPoA + bridging.

You might want to ask your ISP these questions, they know Zyxel better
than I do.

If it is possible I don't think a Zyxel will do it, that sort of wierd
config is something that might only be possible with Cisco IOS.

I've always been under the impression that routed mode (PPPoA) and
bridged mode (PPPoE) are mutually exclusive.

> According to the manual I've been reading for the Zyxel 645, the two
> setup screens appear not to have much to do with each other.  Will
> it not allow me to configure PPPoA+CHAP if I have bridging
> configured?

PAP/CHAP happens regardless of whether you are doing PPPoA or PPPoE.

Remember, the only real difference between PPPoA and PPPoE is what
speaks PPP to the ISP's equipment.

I bet Zyxel made the screens differ to make things easy for the end user.

Cisco has no qualms about making things unnecessarily difficult. In this
case it made it easy to see the difference between PPPoA and PPPoE.

> I know for a fact that the Zyxel in question can definitely do 
> PPPoE+routing in addition to PPPoA+routing.

PPPoE+routing doesn't make sense to me.

-- 

Phil Brutsche
phil at tux.obix.com