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Author Topic: Openreach Extend G.fast Pilot to 1 Million UK Premises  (Read 2114 times)

Chrysalis

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #15 on: September 28, 2017, 12:41:47 AM »

Nice reply wombat, thanks appreciated as always, To address some points its Neil himself in the video who said about pppoe been ditched, and they should probably have done it for FTTC as well.  Just thought I would throw that in as you said was no indication, the indication came from the big man himself.

Doing 500mbit/sec on pppoe would be a painful process, something like an ac66 e.g. cannot even push 60mbit/sec without nat acceleration due to how expensive it is to push pppoe packets.

It is also Neil himself who said the existing capacity to the cabinet is 2.5gbit.  I take his answer to the question not been evasive, it came across to me as, he expects issues when reasonable take up occurs, but its not a problem because things are in place to add capacity as and when it is needed up to a maximum of 40 x 10gbit..
« Last Edit: September 28, 2017, 12:45:42 AM by Chrysalis »
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WWWombat

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #16 on: September 28, 2017, 04:15:05 PM »

Thanks @chrys

I've watched that video on a number of occasions now, as it was one of the first that gave us proper ideas of what BT were up to for both G.Fast and connectorised fibre. Its a shame they haven't kept technical communication quite as open since then.

PPPoE:

Yes, Neil instigated the mention of PPPoE, but only as far as a nice-to-have, "on the list of things to solve". When I said "no indication", I really meant since then; that there was no indication in the current service-defining documents. No matter what Neil said back then, I'd expect reality to be reflected here and now - within STIN 520 on one side, but in a WBC document on the other.

STIN 520 does nothing to indicate any change of focus away from PPPoE. Even when it has a section warning CPs of the long-term possibility of needing battery backup (SOGFAST?)

I did find this tech brief from Cerberus that tells us PPPoE is used in the router still.

Perhaps, in the end, PPPoE is rescued by hardware acceleration. Here's a table of TP-Link router throughput, where there seem to be a few capable devices. I wonder what this will do for the number of MSE bRASs required.

It is also Neil himself who said the existing capacity to the cabinet is 2.5gbit.  I take his answer to the question not been evasive, it came across to me as, he expects issues when reasonable take up occurs, but its not a problem because things are in place to add capacity as and when it is needed up to a maximum of 40 x 10gbit..

I think everything in your second sentence is right, but not the first.

The questioner mostly asks about cabinet backhaul generically, and mentions that it is not a known quantity to LLU CPs (so presumably he's really talking about FTTC backhaul). He does briefly state that he thinks they are serviced in shared PONs, but mostly stays generic with the question. Neil's answer isn't evasive, but just focusses on the generic needs of a G.Fast node. I think.

(Context: The video pre-dates the announcement of the G.Fast pods, so mention of backhaul to the cabinet is probably based on an assumption that G.Fast will be in/next to the FTTC cab)

I do get the impression (but only an impression) that G.Fast backhaul will be PON-based. The impression comes more from wider industry behaviour than from specific BT information, which is otherwise lacking. That Neil's answer only talks about PON is perhaps a tell, though.

My suspicion, then, is that Neil was aware that G.Fast backhaul will be PON-based, and answered the questioner with a focus on G.Fast only, not FTTC. His answer is that GPON speeds will not be enough, but XGPON and NGPON2 will be enough.

My further suspicion relates to why G.Fast and Connectorised FTTPoD both came labelled "NGA2" in this presentation. This suspicion is based on the previous one (that the G.Fast nodes will be fed by PONs), so it will therefore kickstart the deployment of more splitter nodes (ie in FTTC areas). Such deployment of splitter nodes means that FTTPoD no longer needs to go all the way back to the Aggregation Node - instead, being worked only to the Splitter Node ... and hopefully only charged that far.

In which case ... if FTTPoD is going to get cheaper, I bet it does so with the proviso of being in a G.Fast area.

There's a lot of guesswork here, though, and little concrete fact.
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WWWombat

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #17 on: September 28, 2017, 04:18:30 PM »

I've watched that video on a number of occasions now,

It always helps to watch it again though.

Today I realised that Neil twice said that the average loop length is 200-300m.
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smf22

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #18 on: September 28, 2017, 04:46:56 PM »

Not sure if this has been seen before on here, but the Assessment of the theoretical limits of copper in the last mile report from 2008 shows D-side loop lengths in figure 5. The 200-300m length would seem to be the most common, but that's not to say it's the average.
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WWWombat

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #19 on: September 28, 2017, 06:17:57 PM »

Not sure if this has been seen before on here
Yeah - from that Sagentia document, it seems that the median line is about 400m (and median seems like the best kind of "average" to use here). Neil's statement is rather more optimistic.

TBB used to use the Sagentia figures as part of their estimates for FTTC speeds, but they've updated them recently. They reckon that the additional cabinets for infill and EO lines has brought down the average length (and increased the average speed), and have changed their median from around 430m to 300m.
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Ignitionnet

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #20 on: October 04, 2017, 11:14:15 AM »

I got a theory that g.fast areas may get vectoring on vdsl2.

I have three reasons for this.

1 - in this video vdsl optimisation is mentioned https://www.youtube.com/watch?v=LLpk2dz6nBQ

I strongly recommend exercising caution rather than taking this as gospel. Aside from things changing, which they have, Neil McRae is not an Openreach guy, he works for TS&O. He presents everything to UKNOF, his most recent presentation was on EE, and for obvious reasons no-one can be an expert in everything.

My most recent interactions with him involved him claiming that cable and PON 'couldn't be more different', they are extremely similar, and him quoting science fiction movie lines at me in between promising that he/they would change the laws of physics to deal with homes a distance from the node.

I note him saying that FTTP availability would get much better in the next couple of years... well it's a couple of years since that presentation and for all his actions if you aren't in a BDUK area coverage is pretty sparse.

His general philosophy is that whatever BT do is amazing, he is always happy to take credit for it, and if it's not being done by BT it's no good.  ;D
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Black Sheep

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #21 on: October 04, 2017, 12:36:24 PM »

Stop picking on my Uncle Neil !!!  ;D
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Ignitionnet

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #22 on: October 04, 2017, 02:59:39 PM »

You've not had many dealings with him, have you?  ;)

It's an... experience.  :baby:
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WWWombat

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #23 on: October 04, 2017, 03:53:50 PM »

I note him saying that FTTP availability would get much better in the next couple of years... well it's a couple of years since that presentation and for all his actions if you aren't in a BDUK area coverage is pretty sparse.

In one essence, things have improved.... the beancounters approved a rollout of 2m up to 2020.

We all know that's the biggest hurdle. As B4RN would tell us, the rest is just a matter of JFDI.

It's an... experience.  :baby:

hehe
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Ignitionnet

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Re: Openreach Extend G.fast Pilot to 1 Million UK Premises
« Reply #24 on: October 16, 2017, 01:27:25 PM »

Just wanted to add something to this: those are not exchanges mentioned in the pilots, they are NGA headends.

Hunslet is a standalone exchange. It's parent to nothing besides itself. Lofthouse Gate, however, is parent of Lofthouse Gate and Rothwell, and cabinets off the Rothwell exchange are being upgraded.

I am happy to claim some credit for the Hunslet exchange being a part of the pilot, and I've very little doubt that VM having permits in to build FTTP to Rothwell and Robin Hood, both served by the Rothwell exchange, and having a combination of HFC infill in progress with FTTP extension in Lofthouse, served by Lofthouse Gate, helped nudge that guy up the list.
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