Re: Dialup over Ethernet

On 13 September 2017 at 19:03, Ewen McNeill <nznog-g+LI5CTLdeyVez4R2NBCHqU/[email protected]>
wrote:

>
> Part of what prompted my surprise is that this Mikrotik very much did have
> a username and password on the PPPoE configuration, apparently given to my
> client (setting it up for their customer) by the ISP in question -- and the
> password looks "password like" rather than just a placeholder.  It's good
> to hear from you (and Nathan) that at least that part is less common.


My ISP at home uses the same username/password as the customer portal for
PPPoE authentication (we might be talking about the same one, though).



> Unless I'm missing something, wouldn't the PVLAN sort of approach work out
> here?  Put each customer into a isolated PVLAN, and put the ISP-end gateway
> into a community PVLAN, then the customer VLANs can talk to the ISP but not
> to each other -- and you can use a larger subnet for efficiency (/24, /22,
> etc).  Possibly this would require some fibre provider/ONT assistance...
> but the whole UFB thing was built from scratch so doing it didn't have to
> be layers upon layers of abstraction to make it look like the past.


The problem with that approach is that you break P2P connectivity between
customers. If I have a public IP address, I would expect it to be
accessible from any other public IP address unless explicitly filtered.

I guess proxy-arping is the best solution here, unfortunately. You will
still need to allocate a gateway IP address per subnet (although you can
increase the subnet size to mitigate this, assuming you have enough
contiguous address space available).



> This particular one seems to have the Mikrotik defaulting the PPPoE
> interface MTU to 1480.  I didn't investigate exactly why, but it didn't
> seem to be specified in the PPPoE client config on the Mikrotik.  (VLAN 10
> MTU was 1500.)
>
> 1492 MTU seems to be the best case for PPPoE if the parent ethernet
> interface MTU is 1500; and configuring for mini-jumbo frames on the ONT/UFB
> side would seem to be an obvious work around, but it's not clear if that's
> commonly done either.  I'd be a little less bitter about forcing PPPoE on
> end users if it didn't force their user-data-MTU down below the
> assumed-in-end-user-equipment 1500 byte MTU....


I believe most Chorus products support at least a 2000 byte MTU, the
problem is that you need to set it up manually on every CPE.



Kind regards,
Andre

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