[Cerowrt-devel] a smart SFP

[Joel Wirāmu Pauling]

Those are really high split rates. We (as in UFB in NZ) looked at 32:1
splits but it's rare - in practice it's often half that. Splits end up
based on contention of regulated L2 plans which are sold to RSP's to
on-sell to customers. Based on available backhaul bandwidth rather than any
factor. i.e on a 2.5Gbit Duplex GPON port which carries a L2 service to
RSP(L3 providers) it's a simple matter of dividing up the Active Optical
backhaul to the GPON unit (minimally 2x10Gbit Active Paths to the CO for an
old style GPON only node) so that gives you around 66 customers on a
300/300 service without resorting to Teletraffic engineering in the access
equipment. Splits per line card port are then distributed based on that
metric rather than anything else. There are of course some exceptions to
this rule for some nodes in the network but it's uncommon.

RSP's are responsible once the L2 is handed to them, so experience varies
once it's off the access network. But the entire PON network is engineered
without contention at any points, including in the last-mile, it actually
works out cheaper than introducing engineering required for massive
contention ratios and results in better experience for everyone.

The active GPON nodes used in the network mostly have been moved to 2 or 4
* 40gbit or 100Gbit uplinks at the this point to support XPON.


On Sat, Jan 15, 2022 at 8:22 AM Michael Richardson <mcr at sandelman.ca> wrote:

>
> Jonas Mårtensson <martensson.jonas at gmail.com> wrote:
>     >> getting gpon more right has increasingly been on my mind
>
>     > I think more right is to not turn the fiber into a shared medium in
> the
>     > first place but since gpon is so popular, improving it seems like a
>     > nice goal.
>
>     >> Nobody in their right mind is going to hook up 128 terminalt to one
>     >> OLT
>     > port, I hope...
>
>     > Well, sharing one OLT port between many terminals is kind of the
> (only)
>     > advantage of PON, although split ratios of 32 or 64 are more
>     > typical. But often it's the loss budget that limits the ratio.
>
> And, there are also situations, many of them industrial, where the fiber
> allows one to avoid ground loops, and where the bandwidth/latency
> requirements are very modest.
> it's not all youtube downloads and zoom meetings :-)
>
> I was involved in a GPON build back in 2010 into a very poorly served
> industrial park.  (That was for email/web browsing by the industries).
> A reason they were so poorly served is that there were two expressways (one
> of them the TransCanada) and a river that bordered the area.
> There were only eight strands in a single conduit available....
> We considered moving (an) OLT into that area actually... DWDM to the rescue
> in the end, but that was a bit bleeding edge at the time.
>
> --
> ]               Never tell me the odds!                 | ipv6 mesh
> networks [
> ]   Michael Richardson, Sandelman Software Works        |    IoT
> architect   [
> ]     mcr at sandelman.ca  http://www.sandelman.ca/        |   ruby on
> rails    [
>
> _______________________________________________
> Cerowrt-devel mailing list
> Cerowrt-devel at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/cerowrt-devel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.bufferbloat.net/pipermail/cerowrt-devel/attachments/20220115/1068a1e1/attachment.html>