On Thursday, February 06, 2014 06:38:23 PM Jean-Francois Mezei wrote:
When an incumbent already has PPPoE deployed for its DSL, putting FTTH on PPPoE makes it simpler.
And that is the practical issue I saw (and still see). A lot of operators just continue with it because it is maturely deployed in their networks, and attempting DHCP may not be as easy. Would I recommend trying DHCP, hell yes!
And PPPoE really simplifies wholesale systems.
You do not want the incumbent/wholesaler to perform DHCP. This is a HUGE headache. We have that in Canada for cable wholesale (TPIA). The incumbent has to micromanage each ISPs IP blocks and carve subnets for each CMTS (for cable).
For as much as everyone hates PPPoE, it makes for managememnt of a wholesale systems much much easier.
In one country I worked, we pressured the incumbent to offer us Layer 2 backhaul instead of Layer 3, for the very same reasons. Co-managing IP address assignments, e.t.c., was problematic, especially because they were not sure how large their network was going to grow, which presented us with planning challenges in how we pre-assign address space for each of their service PoP's. Of course, because the regulator had done their job re: unbundling the fibre, they didn't care how wholesale services were actually provided over said fibre. And yes, the incumbent jumped at the chance not to offer Layer 2 backhaul, because then they knew everything we were up to (to some degree of measure).
Ideally, there would be some protocol where the CPE would setup a layer 2 SVC to the ISP, after which the ISP can provide DHCP services etc.
Some of the vendors I've worked with don't support LNS functionality on their current generation BNG's. Just LAC. In this scenario, for PPPoE-centric operators and wholesalers, VPLS has been used to backhaul customer traffic, as opposed to L2TP, and recently, some vendors are now able to do this over EoMPLS pw's instead. If you have some control over the AN's that go into the incumben's/wholesaler's CO, you can get that Layer 2 connection (VPLS or EoMPLS pw) between your backbone and the CPE, that way. Mark.