Thursday, 16 June 2011

High speed internet - fixed at high speed

Slight surprise from our favourite telco yesterday, and worth a mention I feel.

A customer with FTTC (Fibre to the Cabinet) service.

His line started going wrong at 9am and packed up completely by 10am. He called us up at 2pm, and by just after 4pm an engineer had visited him and replaced his VDSL modem and got him back on line. Even the diagnostics tools were sensible, for a change, and confirmed there was a fault. We did not even have to argue about SFI visits.

I suspect that is a record for an engineer fixed fault. Lets hope we see more of this type of excellent service.

Well done BT!

Why did this happen? The main reason is that for FTTC there is a BT owned and managed VDSL router on the end of the line. It means there is active equipment that BT can communicate with (or not) as part of the service. BT can tell when there is a fault or not right up to the hand over point in the customer premises. They cannot do that with ADSL hence all the SFI arguments.

Now if only BT had done this for ADSL - provided a PPPoE DSL router as part of the broadband service. That way they can tell if the line is OK or not by end to end tests. It would have to be the dumbest simplest router from a user point of view, hence saying PPPoE (with jumbo frames) so that customers have a proper choice of router/firewall. Ideally it would also have Ethernet testing built in and available to the ISP. It would be nice if the VDSL routers did this. It is a standard part of many Ethernet chips sets, and would allow testing beyond the hand-over point (Ethernet port). We'd be able to confirm no Ethernet cable, or things like a broken pair in an Ethernet cable so eliminating most of the testing. Such a system would rule out almost all of the grey areas in faults and remove the need for SFI engineers even. It could even have a pair of Ethernet ports and a loop back test option. It could constantly test the line at an ATM level and identify faults before customers see them.

We have suggested the VDSL routers for FTTC and the active NTE for FTTP should have Ethernet tests, and all tests should be available to the ISP. No idea if they will take this up.

Maybe one day we'll make a DSL modem, and build all this in. Problem is that we can't get the chip sets as cheaply as you can buy DSL routers!

But anyway, yes, on this occasion, well done BT.
And well done Terry, our latest tech support engineer to join the team.


  1. Of course, they did try having a provided modem from the start, the hideous green frog. But yes, a PPPoE model would have made a lot of sense now - but if I recall correctly back when ADSL started, Ethernet on home computers was very rare, so it wouldn't have been such a great option.

  2. Indeed, but the routers and modems they offered also did not have the line testing, so did not really help a lot. I think they should consider it - get someone to make them a suitable router and offer it as a service to ISPs. Heck they could sell the modems to ISPs even, but it would have the necessary "back doors" to remove the grey areas of SFI engineers. Would be really cool if they could so a line powered one, or maybe we need a main powered PPPoE router with PoE and PoE powered IP routers :-) Just thinking plug-top count here that is all. Of course they could just make a standard for the testing side, so that, for example, BT Retail could make that aspect part of their home-hub or something.

    Given the grief and cost most ISPs have with SFI it may fly.

  3. There's good hysterical raisins for not doing a PPPoE router back in the day. For starters, PPPoE with jumbo frames wasn't standardised until 2006; AAISP were offering wires-only ADSL 5 years before then.

    Also, telcos still thought ATM was going to replace Ethernet back when ADSL was new in the UK; USB and Ethernet modems were stopgaps until everyone got with the program. Once PCs all had ATM interface cards in, and ATM switches were common at home, you would just do PPPoA from your PC, not PPPoE.

    Having said that, you miss the other benefit for BT; if they have a family of Ethernet presented services, from cheap ADSL up to expensive FTTP, all doing babyjumbo PPPoE (indeed, I assume you could do babyjumbo PPPoE on the metro Ethernet fibre products), they have services that "grow with your business". A customer buys a cheap ADSL service and a nice router, then upgrades to FTTC/FTTP, then metro Ethernet as their needs grow, without changing CPE on each upgrade.

  4. Early ADSL installations in the UK were a two-box setup with a Fujitsu modem which presented ATM or PPPoA (I forget) to an Efficient Networks/Speedstream router, each box about the size of a Sky box. The customer was then presented with an Ethernet cable bearing a single RFC1918 address and if their computer didn't have Ethernet BT would supply a D-Link card and even book PC World to come and install it.

    This was soon replaced by the frog for residential contracts and a one-box Speedstream (with an MTBF of less than 18 months) for business until wires-only became the norm.

    Are we going full circle?

  5. We were there right at the beginning you know :-)

    Yes, the routers or USB modems BT offered were not quite what I am saying and were not good either.

  6. The standards are certainly there to allow this to happen. TR-101 allows a kind of ethernet level ping, and
    I think a TR-069 compliant cpe could by queried for the state of the LAN-side ports.

  7. What does all this give you that a half decent SNMP-manageable modem with the right MIBs (which have been around, but not often seen, since e.g. the DSL-604+) combined with decent access to DSLAM line info (for the times when there is a line/CPE fault) couldn't already give you?

    If there's no sync, then there's no comms, whether it's ADSL or VDSL. If you've got sync, and ISP->CPE comms, you're half way there, surely?

  8. What it gives you is an SEP field. I.e. if the link does not work it is someone else's problem. If the modem is part of the service from BT (as it is with FTTC) and the ISP has means to run tests up to (and ideally beyond) that modem, then it is clear from the start when it is a BT problem or an end user problem (or an ISP problem even). You don't have the crazy scenario of engineers going out, not finding any problem and concluding it must be end user kit and so charging a huge amount of money.

    We are already very good at diagnosing issues. Simple things like where a customer has two lines side by side - swap the plugs at the master socket - does fault stay with line or move with router/wiring/etc? When a line has a fault that stays with the line when switched at the handover point (master socket) it is absolute deductive proof it is a BT issue. Yet, when a BT engineer cannot find the fault they charge.

    If a BT test on a BT box says there is a fault then they could not charge and have to fix the problem.

    It is all about where you draw the line, not about the technical aspects, sadly.

  9. "It is all about where you draw the line, not about the technical aspects, sadly."

    OK, that I understand only too well (as will many long-suffering BT customers).