Re: Muni fiber: L1 or L2?

[Owen DeLong <owen () delong com>]

On Feb 4, 2013, at 13:17 , Jean-Francois Mezei <jfmezei_nanog () vaxination ca> wrote:

> On 13-02-04 16:04, Scott Helms wrote:
>
> > Subscribers don't care if the hand off is at layer 1 or layer 2 so this is
> > moot as well.
>
> This is where one has to be carefull.  The wholesale scenario in Canada
> leaves indepdendant ISPs having to explain to their customers that they
> can't fix certain problems and that they must call the telco/cableco to
> get it fixed. (in the case of a certain cable company, they can't even
> call them, it has to be done by email with response of at least 48 hours).
>
> So splitting responsabilities can be an annoyance if it becomes very
> visible to the end users.
>
> Another aspect: customers espect to be able to switch seamlessly from
> one ISP to the next. But ISP-2 can't take over from ISP-1 until ISP-1
> has relinquised control over the line to the end user. In a layer 1
> scenario, it means ISP-1 has to physically go and deinstall their CPE
> and disconnect strand from their OLT, and then ISP-2 can do the reverse
> and reconnect evrything to provide services.

Only if you insist on re-using the same strand.  More likely in the proposed
scenario, the customer is only using 1 of the 3 pairs of fiber to their prem.
In such a case, just light the second strand with ISP-2 and ISP-1 can
do their de-install at their leisure (or not).

> What happens when ISP-1 isn't interested in a quick disconnect and ISP-2
> has to wait days/weeks with end use without service ?

Nope. See above.

> In a layer2 service, it is a matter of reconfiguring the OLT to pass
> ethernet packets to a different VLAN to a different ISP.  No physical
> changes required and it can be almost tranparent to the end user who
> just has to make a new DHCP request and be provisioned by ISP-2.

I agree this can be an advantage in some scenarios. That's one of the
reasons I think allowing the muni to provide optional L2 aggregation
services is worth while.

Owen