RE: Upstream bandwidth usage

[Vasilenko Eduard via NANOG <nanog () nanog org>]

I did believe that it is about the cost of SFP on the CPE/ONT side: 5$ against 7$ makes a big difference if you 
multiply by 1000000.

By the way, there are many deployments of 10G symmetric PON. It was promoted for "Enterprise clients".
CPE cost hurts in this case.
But some CPE could be 10GE and another 1GE upstream (10G downstream) on the same tree.

Ed/
-----Original Message-----
From: NANOG [mailto:nanog-bounces+vasilenko.eduard=huawei.com () nanog org] On Behalf Of Mel Beckman
Sent: Friday, June 10, 2022 4:11 AM
To: Raymond Burkholder <ray () oneunified net>
Cc: nanog () nanog org
Subject: Re: Upstream bandwidth usage

I’m not mistaken, it also depends on the optics in the splitter, given that GPON is bidirectional single strand fiber. 

-mel via cell

> On Jun 9, 2022, at 5:01 PM, Raymond Burkholder <ray () oneunified net> wrote:
>
> 
>
> > On 2022-06-09 17:35, Michael Thomas wrote:
> >
> > > On 6/9/22 4:31 PM, Mel Beckman wrote:
> > > Adam,
> > >
> > > Your point on asymmetrical technologies is excellent. But you may not be aware that residential optical fiber is 
> > > also asymmetrical. For example, GPON, the latest ITU specified PON standard, and the most widely deployed, calls 
> > > for a 2.4 Gbps downstream and a 1.25 Gbps upstream optical line rate.
> >
> > Why would they mandate such a thing? That seems like purely an operator decision.
>
> There are also vendor issues involved.  I am glad that Mel mentioned 'optical line' rate.  Which becomes a 
> theoretical thing.  If the line cards aren't set up with buffering properly, then line rate won't be seen.  And I 
> think the line cards can also be easily over-subscribed.  Oh, and due to the two or three step fan-out of 8/16/32, 
> upstream becomes even more limited.
>
> So, if you have FTTH with 1::1 house::port, then you are cooking with fire.  Else, it is the luck of the draw in 
> terms of how conservative the ISP is provisioning a GPON infrastructure.  Which, I suppose, depends if it is 1G or 
> 10G GPON.