I have to push back gently on this...
XG(S)-PON is gross 10Gbps (after FEC you are left with around 8,6 Gbps), Noki's
proprietary (aka not ITU) @% Gbps PON seems to be abbreviated 25GS-PON.
Now XGS-PON allows maximally 128 end-nodes in the tree, so:
8600/128 = 67.18 Mbps/subscriber
unless the ISPs royally screwed up the configuration there should be a CIR per
subscriber of around 60 Mbps. So setting your cake shaper to 50 Mbps shpuld
give you:
a) 10 times the throughput of the 5/1 Mbps DSL (ignoring overhead compensation
for a change, which likely will be in favor of PON)
b) decent low latency, round robin delay for full MTU packets between 128
active nodes would be:
packet/sec: ((8.6 * 1000^3)/(1500*8)) = 716666.666667
millisec/packet: 1000 / ((8.6 * 1000^3)/(1500*8)) = 0.00139534883721
round-robin delay 128: 128 * 1000 / ((8.6 * 1000^3)/(1500*8)) =
0.178604651163 milliseconds...
DSL uses a 4KHz clock so 1000/4000 = 0.25 millisecond quantization
So XGS-PON has at least theoretical potential to deliver lower latency than
DSL, but the details depend on if/how packets are aggregated. HOWEVER the
125µsec GPON frames can be shared between different ONUs in upstream and
downstream direction... so these are not a hard quantisation but more the
interval between control information required for the access grant cycle...
c) robustness against RF noise sources and electricity/lightning
So I am not su sure I would prefer the 5/1 (A)DSL over a PON...
That however is orthogonal to me preferring a competent ISP that takes care of
keeping latency under load at bay.
> On Mar 21, 2023, at 12:26, Rich Brown via Starlink
> <starl...@lists.bufferbloat.net> wrote:
>
>
>
>> On Mar 21, 2023, at 1:21 AM, Frantisek Borsik via Rpm
>> <r...@lists.bufferbloat.net> wrote:
>>
>> Now, I hope to really piss You off with the following statement :-P but:
>>
>> even sub 5/1 Mbps “broadband” in Africa with bufferbloat fixed on as many
>> hops along the internet journey from a data center to the customers mobile
>> device (or with just LibreQoS middle box in the ISP’s network) is feeling
>> way better than 25Gbps XG-PON. The only time the XG-PON guy could really
>> feel like a king of the world would be during his speedtest.
>
> Nope. Sorry - this doesn't piss me off :-) It's just true.
>
> - 7mbps/768kbps DSL with an IQrouter works fine for two simultaneous Zoom
> conferences. (Even though no one would think that it's fast.)
> - I recommend people on a budget drop their ISP speed so they can afford a
> router that does SQM
> https://forum.openwrt.org/t/so-you-have-500mbps-1gbps-fiber-and-need-a-router-read-this-first/90305/40
Even simpler, even on a 100Gbps link nobody stops you from setting your
shaper to 50/10 if that is all your router can deliver (and I agree if there
are cheaper plans closer to the 50/10 it makes economic sense to scale down the
plan)...
>
> The people that get annoyed are those who just upgraded to 1Gbps service and
> still are getting fragged in their games.
>
> Rich
> _______________________________________________
> Starlink mailing list
> starl...@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink
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