[Ecn-sane] [Bloat] [iccrg] Fwd: [tcpPrague] Implementation and experimentation of TCP Prague/L4S hackaton at IETF104
Jonathan Foulkes
jf at jonathanfoulkes.com
Fri Mar 15 16:28:41 EDT 2019
All this discussion of DSCP marking brings to mind what happened on the Windows platform, where the OS had to suppress ALL DSCP marks, as app authors were trying to game the system.
And even if not trying to ‘game’ it, they have non-obvious reasons why they don’t mark traffic how one would expect. Example:
I know an engineer who works at a cloud-storage solution company, and I asked why a long-standing customer request for DSCP marking (as bulk) was not implemented. His answer was they’d never do that, as that would impact benchmarks against their competitors for which service syncs faster. <sigh>
Which brings me to a question: Is anyone aware of an easy to use Windows app that will allow the user to select an application and tell the OS to mark the traffic (all or by port) with a user selected DSCP level?
There are many guides on using regedit and other error-prone (and geek-only) means of doing this, but is there a simple Windows 10 home app?
Now that Cake is out there with simple DiffServ3 support, it would be nice to lower the priority of cloud-storage services and other bulk traffic by correctly marking it at the origin.
Cheers,
Jonathan Foulkes
> On Mar 15, 2019, at 3:32 PM, Jonathan Morton <chromatix99 at gmail.com> wrote:
>
>> On 15 Mar, 2019, at 8:36 pm, Mikael Abrahamsson <swmike at swm.pp.se> wrote:
>>
>> Having a "lower-than-best-effort" diffserve codepoint might work, because it means worse treatment, not preferential treatment.
>>
>> The problem with having DSCP CPs that indicate preferential treatment is typically a ddos magnet.
>
> This is true, and also why I feel that just 2 bits should be sufficient for Diffserv (rather than 6). They are sufficient to express four different optimisation targets:
>
> 0: Maximum Throughput (aka Best Effort)
> 1: Minimum Cost (aka Least Effort)
> 2: Minimum Latency (aka Maximum Responsiveness)
> 3: Minimum Loss (aka Maximum Reliability)
>
> It is legitimate for traffic to request any of these four optimisations, with the explicit tradeoff of *not* necessarily getting optimisation in the other three dimensions.
>
> The old TOS spec erred in specifying 4 non-exclusive bits to express this, in addition to 3 bits for a telegram-office style "priority level" (which was very much ripe for abuse if not strictly admission-controlled). TOS was rightly considered a mess, but was replaced with Diffserv which was far too loose a spec to be useful in practice.
>
> But that's a separate topic from ECN per se.
>
> - Jonathan Morton
>
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