[Cerowrt-devel] cerowrt-3.10.24-5 dev build released

Rich Brown richb.hanover at gmail.com
Wed Dec 18 08:58:05 EST 2013

I like David Lang’s questions:

1) If we had “full knowledge” of the customer’s link, how many different cases would we have to take into account?

2) What happens if we get it wrong?

And I think I understand Sebastian Moeller’s answers:

1) People using ATM-based carriers need the ATM link layer adaptation calculation; others (PTM, Cable, Fiber, etc.) don’t need that calculation.

2) Getting it wrong hurts in each case, but it seems worse where people are using PTM or Ethernet-based links since they lose 10% of their bandwidth due to the 48 in 53 bytes encapsulation. Failure to use the ATM calculation over an ATM-based link makes VoIP etc. less good and fails to make CeroWrt stand out as a great solution, but it’s the status quo for the entire world.

If the choices are as “simple” as this (and please correct me if I’m wrong :-) we really want to find a way to encourage people to use the ATM calculation when it’s warranted. We could hope that they find their way to the AQM tab (before their eyes glaze over), but that seems too big a hurdle.

Perhaps we could extend the Interface configuration page to add a “Link uses DSL/ADSL:” checkbox right below the Protocol dropdown. Default would be off, but when customers go to the GE00 interface to enter their PPPoE/PPPoATM/ISP credentials, they’d see this additional checkbox. Checking it would feed that info to the AQM tab. (And perhaps there could be a link there either to the AQM tab, or to the wiki for more information.)



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