[AusNOG] Looks like the NBN will be a PON variant for sure...

[Rob Wise]

On Wed, Apr 29, 2009 at 10:12 AM, Mark Smith <marksmith at adam.com.au> wrote:

> Nick Brown wrote:
>
> > Because from an ISP operational perspective thats a horrible thought?
> > You lose the ability to shape / count / monitor traffic, in addition to
> > the increased support because Joe next door has been browsing someone
> > else's $c share.
>
> Look up "IPoE" in Google (as silly as the acronym is), all those
> problems have or are being solved (e.g. cable networks use DHCP, and all
> the Ericsson DSLAMs that a lot of ISPs have are (and have been for a
> long time) "IPoE" capable)). Cisco's ISG product can apparently turn
> DHCP leases into RADIUS accounting records for example.


The extensive use of PPPoE/A and LAC/LNS in Australia is largely due to the
monopoly carrier situation and the requirement for wholesale access (IMHO).
In many other countries DHCP-based access is far more common than PPP and
all the usual features like Radius, shaping, ACLs, etc are still available.
I'd be surprised if you found a router vendor which did not support DHCP
based subscribers these days.

In a "native", not wholesale ADSL environment, the 8 byte per-packet
> overhead and BRAS processing load, MTU issues and hair-pinning of PPPoE
> encapsulated traffic are very expensive, when you consider that the only
> real purpose of converting a multi-access medium like Ethernet into a
> point-to-point virtual link is to be able to authenticate the user. If
> you already know where they live (and DSLAMS can insert that circuit-id
> in DHCP requests), why do you care what username / password they use?


Another model that is common is for each access port on the DSLAM / ONT to
be assigned a different VLAN on the trunk to the BRAS.  This can also allow
for wholesale access by carrying the VLAN all the way through to the retail
provider at layer 2.  With a PON it would be quite easy to have multiple
retailers access the same household and break out on different ethernet
ports on the back the ONT.  Eg, internet on port 1, IPTV on port 2, voice on
port 3, etc.  The household could potentially take all these services from
different retail providers.

Cheers,

Rob
(who was setting up a PON in the lab last week)
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