Kitz Forum

Broadband Related => Broadband Technology => Topic started by: Weaver on March 30, 2017, 06:38:24 AM

Title: Modern backhaul - how does it work - confused dinosaur here
Post by: Weaver on March 30, 2017, 06:38:24 AM
How does backhaul work _physically_ and in terms of _who owns / provides what_ nowadays in the case of LLU and FTTC when services are being resold by wholesalers such as TTB? A bit vague and incoherent I know, as I am very out-of-date and confused about how things work in the modern world, being so very much in the dark ages here still. (Despite having now got 21CN.)

I'd better try and make it a bit more concrete:

* If I buy an ADSL2+ service from a small ISP who is getting errm something from TTB, who supplies what bits of the chain, who owns what bits of kit, who charges whom for what?

* Ditto if I buy FTTC from a small ISP?
Title: Re: Modern backhaul - how does it work - confused dinosaur here
Post by: Chrysalis on March 30, 2017, 01:45:17 PM
Dont know all the answers as a certian degree of it of course is commercially sensitive to the providers.

I expect something like this tho.

Sky probably lease openreach link's to carry traffic from the LLU exchanges to their core network, once it hits their core network which they own and dont lease, it is on their owned infrastructure.
Entanet use BT wholesale (WBC) to reach the interconnects, then transfer traffic to backhaul they lease of another provider (I forgot the name).
BT retail and plusnet use WBMC dedicated which is wholely through BT wholesale until it reaches their handover point (typically in london), but the MSIL's are dedicated not shared with other isp's.
Other BTw isp's like aaisp use WBMC shared, which is also routed through BT wholesale before handed over to aaisp, but the MSIL's are shared with other CPs and managed by BT wholesale.
Talktalk I expect is similar to sky, likewise vodafone.
Talktalk resellers seem to have 2 options open to them.  They can either use talktalk backhaul all the way to their handover point which is what I think aaisp does.  Or they can hand it over at a node to another backhaul which is what I think uno does who uses daisy backhaul similar to WBC.

Of course I stand to be corrected if I have made a mistake here.

http://www.kitz.co.uk/adsl/wbc_wbmc.htm
Title: Re: Modern backhaul - how does it work - confused dinosaur here
Post by: Weaver on March 30, 2017, 04:26:51 PM
Brilliant and generous answer from Chrysalis. I understand LLU in the sense that the exchange provides a physical location where you can park an interlink to make a handover to possible third-party kit to carry backhaul, assuming that you are not just using BT's backhaul anyway. But does that mean that a non-BT backhaul user eg TT has literally physically plumbed in their own fibre to an exchange? Or would eg TT rent dark fibre and light it themselves or rent lit fibre?

Does anyone know what the story is regarding FTTC? I have no idea how that works as I don't understand where physically one would park interlinks to make changes of ownership / responsibility in backhaul possible. Is the only difference that fibre from a cab goes to some exchange somewhere although not necessarily the local one and from there on the backhaul story is the same as for LLU ADSL2+ ? I don't know where I got that from?

I read that the new deals that are available from AA with much higher bulk data usages only became possible because of cheap bulk purchases of TTB backhaul, and iirc these deals were contingent on you being on a TT-POP exchange. But given that the AA deals apply to FTTx, that leaves me not understanding how FTTx backhaul works.
Title: Re: Modern backhaul - how does it work - confused dinosaur here
Post by: Chrysalis on March 30, 2017, 04:34:49 PM
With FTTC there is a GEA link at the exchange from openreach to the CPs LLU equipment, so then ADSL and FTTC traffic would share the same backhaul out the exchange.

https://www.openreach.co.uk/orpg/home/products/super-fastfibreaccess/cablelink/cablelink.do
Title: Re: Modern backhaul - how does it work - confused dinosaur here
Post by: gt94sss2 on March 30, 2017, 04:48:52 PM
But does that mean that a non-BT backhaul user eg TT has literally physically plumbed in their own fibre to an exchange? Or would eg TT rent dark fibre and light it themselves or rent lit fibre?

Yes, could be any of the 3 depending on the economics.