Saturday, 1 October 2011

PPPoA DSL users will only want legacy internet

We are still trying to get usable entry level DSL routers with IPv6.

The latest complication here, which really is baffling us, is that Comtrend have decided that they will deliberately disable IPv6 when using the router in PPPoA mode.

The chipset does IPv6, and is the same Broadcom chipset as used by billion. It is not an issue with memory size of anything like that as it will happily do IPv6 if using it in PPPoEoA mode. It looks very much like a deliberate and arbitrary policy decision by Comtrend.

We are trying to get an answer, and all they seem to be saying that there is no demand. That alone makes no sense. There is either no demand for IPv6 in which case why have it in the product at all, or no demand for PPPoA in which case don't have it in the product at all. Saying no demand for some specific combination of unrelated functions makes no sense.

This seems to be totally a marketing thing - and I know my view of marketing departments is a bit DIlbertesque, but this is total madness. As far as I can tell it is not even as if they are going to sell a higher priced product that does do both (which would be an admission that there is demand). So they are taking a no cost choice to disable a combination of unrelated functions for no logical reason just so they can make fewer sales.

Why would PPPoA users only want legacy Internet when PPPoEoA users want IPv6?

Someone please just sell us an entry level DSL router that does IPv6. How hard can it be?!?!?!


  1. Someone should make an ipv6 tunnel device. Just a simple device that has one ethernet port and a power connector and all it does is act as a gateway that tunnels ipv6 packets over an ipv4 connection in the same way we can already do now using a computer connection.

    They wouldn't require any configuration at all and would do nothing other than this tunnel to make them simple, they would just be a device you plugged into your network and your computers would automatically pick up an ipv6 address and gateway from it, and ipv6 would "just work".

    Surely such a simple device could be manufactured at low cost

  2. The problem with a simple plug-in device comes with where in the network the device fits - if it's on the WAN-side of the modem, then it has to replace the modem (and therefore have all the modem functionality) and if it plugs into the LAN-side of the modem, features operating on the modem/router (e.g. WiFi etc.) wouldn't be available on IPv6.

  3. "I demand you make a product which does X"

    "Sorry, but there's no demand for feature X"


  4. Indeed, there are many multi box solutions. We want something cheap, simple and standard.

  5. John: somebody already has, sortof:


  6. Nice box, but again, an extra box. I just want the freebie entry level routers we supply to have the current Internet protocol. I am just staggered that the router manufacturers cannot appreciate that.

    I know we are ahead of the game demanding the IPv6 now, but they have to see that in the lifetime of any product range they make now, this will be a requirement over a much larger group of their customers.

    They should also realise that this is such a simple PR exercise now to just get it right!

  7. I wonder if they ran into a bug/problem that occurs when IPv6 is used in combination with PPPoA and rather than fix it they decided to just disable IPv6 for PPPoA

    Only logical reason I could think of

  8. Have you tried PPPoA and IPv6 with the Technicolor router?

  9. Have you thought of trying to create some sort of consortium of others in the industry looking for the same thing? Would allow you to send a coherent and forceful message to the manufacturers that there's demand. Having said that, are you so ahead of the game that there would there be no demand amongst ISPs for such a thing? ;)

  10. Have you tried PPPoA and IPv6 with the AVM Fritz!box range recently? I know they have cut deals with an Australian ISP and the recent update was in response to some of their issues

  11. My guess would be that they have only tested one mode with ipv6, so they have only enabled one.

  12. One other thought for ipv6 - you can set up windows and linux to use your ipv6 tunnel, but it's fairly complicated to do so. Why not get someone to write a small program that sets it all up for you (and uninstalls it with a single click too in case it goes wrong)...

    I guess you wouldnt welcome the extra support calls it might bring...

  13. I thought you'd ditched Comtrend after the £50 almost-IPv6 router debacle?

    I can't imagine they know there's no demand for something they haven't made yet, so my bet is that they have a bug which occurs when they have IPv6 and PPPOA together, so they made it a limitation rather than spend money finding and fixing it. Isn't that the attitude they had with the aforementioned £50 problem router?

    Cheers, Howard

  14. Yes, indeed, but as they use the same chipset as the "Now working" Billions, worth a second try.

  15. The postbox in our village will only accept up to C5 envelopes. If we need to post anything larger we have to drive 6 miles to town.

    I asked the Post Office to put in a bigger slot but they said "There is no demand, people only post small letters in that box"

    Nuff said?

  16. There is no demand because some major DSLAM vendors don't support PPPv6oA on massively deployed legacy hardware. PPPoE works because the BRAS terminates the PPP session and the DSLAM is just bridging. So when ISP's want to deploy IPv6 on ADSL, they do PPPoE, despite the advantages of PPPoA (less overhead, higher MTU).

    There you go, conspiracy theory busted. Now leave us poor CPE vendors alone. :-P

  17. Zombie, do you have a reference for that claim. A DSLAM should be transparrent to the PPP level, and all or the DSLAMs we have encountered in BT and Be are. In order for a DSLAM to not handle it, it would have to interfere at the PPP layer, fr which there is no logic reason to do so. Do you know which makes of DSLAM interfer with PPP? Out of interest, why don't these DALAM also interfere with PPP on PPPoE traffic?

  18. I'm not an expert on the CO side; I don't even know how to configure a DSLAM.
    Well, assuming the upstream interface of the DSLAM is Ethernet here, like it is in the DSLAM in our lab. If it isn't (fibre probably), then the frames are normally Ethernet style in any case.
    PPPoE frames can be copied literally to Ethernet after the ATM AAL5 frames are reassembled. They're just bridged at layer 2.
    PPPoA frames are converted to PPPoE. I'm assuming that the PPP session must be tracked and state must be maintained to tie it to a MAC address of the corresponding PPPoE server. Something has to happen in the discovery phase for that too; not sure what.
    One would indeed think that, because PPP encapsulates IP entirely, all this happens in the PPP layer, so whether the PPP payload is IPv6 vs. IPv4 should be irrelevant. I suspect IPV6CP, which is a different protocol than IPCP, to be the problem.
    These things are typically full of layering violations due to historical mistakes, not only in the implementation but also in the Broadband Forum standards and recommendations.
    What I can tell you is that, if the requirement is made by the service provider, then the business case is made to the chipset vendor (in this case Broadcom) and the software + packet accelerator firmware is fixed. If you're looking at off the shelf entry level modems, you don't have a lot of control. Perhaps you should talk to a high end CPE vendor like us instead. ;-)

  19. We have not encountered any DSLAM that is not transparent to PPP. We did encounter a BRAS that had a bug affecting ipv6 which we could work around, but that affected pppoe and pppoa the same as you would expect. It seems unlikely a DSLAM would have this issue.

    As for requirement, obviousl┼Ě there is no reason an end user would not want ipv6 depending on how they configure pppoe or pppoa, and all BT and Be circuits in the UK are PPPoA by preference and that is the norm in the UK.

    At the end of the day, if pppoa is a requiment a all, which it is, and if ipv6 is a requirement at all, which it is, then obviously there is no requirement to blocking both together.

    As for Broadcom, we can see from the billions that they do this no problem, so we can only assume that two router makers now have chosen to restrict this for no apparent reason or cost saving.

  20. I missed the part about the Billions being able to do it. Depends on the chip and the version of the Broadcom software though. Maybe Comtrend is on an older version. Maybe they have the same problem as us and can't actually test it with their DSLAMs. Maybe none of their customers have indicated that it's important to them. Ask them?

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