[Cake] flow isolation for ISPs

Jonathan Morton chromatix99 at gmail.com
Thu Apr 6 04:57:42 EDT 2017

> On 6 Apr, 2017, at 11:27, Pete Heist <peteheist at gmail.com> wrote:
> Suppose there is a cooperative ISP that has some members who access the network through a single device (like a router with NAT), while others use multiple devices and leave routing to the ISPs routers. (No need to suppose, actually.)
> There’s fairness at the IP address level (currently with esfq, maybe soon with Cake), but it's not fair that members with multiple devices effectively get one hash bucket per device, so if you have more devices connected at once, you win. There is a table of member ID to a list of MAC addresses for the member, so if there could somehow be fairness based on that table and by MAC address, that could solve it, but I don’t see how it could be implemented.
> Is it possible to customize the hashing algorithm used for flow isolation, either with Cake or some other way?

That is an important use-case, and one that Cake is not presently designed to explicitly accommodate.  Currently, the design assumes a single Cake instance per subscriber or household, and fairness between hosts within a household is assumed to be a relatively simple problem.

Also, Cake’s general philosophy of simplifying configuration means that it’s unlikely to ever support “lists” or “tables” of explicit parameters.  This is a conscious design decision to enable its use by relative non-experts.  Arguably, even some of the existing options could reasonably be streamlined away.

With that said, a related qdisc *with* such support is eminently feasible, and could easily be the focus of a project.  I think it would be worth gathering requirements for such a thing and considering potential funding sources.

 - Jonathan Morton

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