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