Thanks Carl .

I should have added, as I did in earlier posts, about referring to consumer (and many SOHO) levels. Let's call them retail ADSL/ADSL2+/VDSL2.

This until very recently when the higher speeds and presumed reliability of consumer/SOHO FTTP started making many leased lines redundant. As is being discussed in the thread. The upstream speeds of these FTTP products often being adequate for businesses.

Basically I think a lot of the asymmetry is down originally to historical user needs and provider bandwidth costs. Technological advances and the resulting associated usage patterns having changed everything.

Underlying provider marketing is only just waking up.

The point was trying to make was that consumer level services have been asymmetric since before the internet existed. Though I have a sneaky deep memory that the old 100 baud and 300 baud teletypes may have been symmetric . The clattering of them connected through an acoustic coupler is still easily and chucklingly remembered.

No worries.

The upstream speeds aren't really a big deal for operators. Even symmetrical networks have a bias towards inbound traffic as far as usage goes. Operators will usually be paying their own providers for whichever of the usages is higher of the two directions.

It's a sales thing now. Just as downstream speeds became Internet-[censored] size measurement it seems as though upstream speeds are the next one.

In reply to a post by RobertoS:

Though I have a sneaky deep memory that the old 100 baud and 300 baud teletypes may have been symmetric . The clattering of them connected through an acoustic coupler is still easily and chucklingly remembered.

You don't have to quite as far back as acoustic couplers. Dialup modems were mostly symmetric, unless it was the viewdata 1200bps 75bps that Prestel (Micronet 800) used on my Prism VTX5000 modem in the 1980s. After that it was 1200/1200, 2400/2400 all the way to 33600/33600.

The first difference was the 56k dialup, which relied on the ISP having a digital connection (e.g. ISDN30 or similar) and so the downstream link was faster than uplink. In MANY cases the uplink was really slow, and forcing a 33600/33600 symmetric was much better for TCP/IP due to the ACK packets.

Hi there. We install a true fibre-to-the-building (FTTB) network. Within your building, we use CAT5e cabling or fibre, depending on its characteristics. Both offer the same throughput at this usage. If you need any further info, feel free to PM us.

In reply to a post by CarlTSpeak:

B4RN use BiDi / 1000Base-BX and always have...

Not according to their early documentation on the their website they didn't. Might have changed very quickly but they started out (or at least planned) to start out with standard fibre optics. There was a whole section about possibly changing to BiDi and using the second core for RFoG TV/Satellite or other options at a later stage.

In reply to a post by jabuzzard:

Not according to their early documentation on the their website they didn't. Might have changed very quickly but they started out (or at least planned) to start out with standard fibre optics. There was a whole section about possibly changing to BiDi and using the second core for RFoG TV/Satellite or other options at a later stage.

https://indico.uknof.org.uk/event/29/contributions/3...

FTTH
� PtP delivery not GPON - (want symmetrical)
� 2 fibres per property � 1000BaseBX on one, other spare

Nope you need a more expensive laser for the higher speeds for the upload where the photodiode for the download is basically the same regardless of the speed. This bumps the cost up, multiply by millions of ONT's and add in that most people download more than upload (especially with streaming) you can save a lot of $$$ by making the system asymmetric. Remember a single OLT laser is serving lots of ONT's so a more expensive transmit laser in the OLT is not such a large financial burden. Basically the faster you can turn the laser on/off the more expensive it gets and to transmit information you basically turn the laser on/off very quickly.

As regards xDSL the asymmetric nature is just down to the best way to split the limited spectrum up to achieve the best experience for the majority of users. For example most people would rather get 80/20 than 50/50 on FTTC, but there is no technical or even cost reason for this, the VDSL modem would be the same in both cases.

With a PON network you use a different wavelength for transmit and receive and even through they are passing down the same fibre there is no interference between the two (well strictly speaking there is but it is not relevant here), so you are not carving up the same limited spectrum between upload and download so the reasons for the asymmetry are different.

I have my doubts that long term PON networks make sense. CWDM-PON might save it's bacon but you end up with more expensive equipment in the customers premises and more expensive equipment in the exchange over a BiDi point to point system. Probably looked a good idea a decade ago, but today given the prices of SFP's not so much. It is also a lot easier to mix and match between vendors than with PON based solutions because it's just plain ethernet. There is no that media convertor does not work with my switch, unlike the that ONT does not work with my OLT in PON land. The cheaper equipment either end also make speed upgrades much cheaper in the long run.

Not saying they are not BiDi now or even before they actually started deployment just that was not their original intention. I have very clear memories of reading some of their early pre rollout documentation when they talked about how it was going to be done and thinking well that's stupid use BiDi and half some of your costs.

In reply to a post by jabuzzard:

I thought that Hyperoptic had made a big fuss about FTTC being called fibre. In which case using some Cat6a (assuming they are future proofing themselves for 10Gb and are not cheaping out on Cat5e) is rank hypocrisy.

On an Openreach FTTP service, your ISP will give you a CAT5e cable to go between your ONT and your router - but that doesn't make it a "non fibre" service.

1000base-T gives you a guaranteed 1Gbps, bidirectional link (up to 100m). There is no "up to" speed, and there is no retraining or dynamic line management - it's fixed rate, and it's the same technology as you use for your LAN.

It's "fibre to the building" that counts.

In reply to a post by jabuzzard:

Not saying they are not BiDi now or even before they actually started deployment just that was not their original intention. I have very clear memories of reading some of their early pre rollout documentation when they talked about how it was going to be done and thinking well that's stupid use BiDi and half some of your costs.

They evidently agreed with you!