Upstream bandwidth usage

Raymond Burkholder ray at oneunified.net
Thu Jun 9 23:58:28 UTC 2022



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.


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