Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

On Thu, Apr 28, 2016 at 8:44 AM, Dave Taht wrote: > On Thu, Apr 28, 2016 at 7:59 AM, Juliusz Chroboczek > wrote: >>> Discovery is a special case, that is not quite multicast. [...] So you >>> don't need any facility to "reach all" in one

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

On Thu, Apr 28, 2016 at 7:59 AM, Juliusz Chroboczek wrote: >> Discovery is a special case, that is not quite multicast. [...] So you >> don't need any facility to "reach all" in one message. > > Are we speaking of the IP Internet, or of some other network? Heh.

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

> Discovery is a special case, that is not quite multicast. [...] So you > don't need any facility to "reach all" in one message. Are we speaking of the IP Internet, or of some other network? A number of fundamental Internet protocols, such as ARP and ND, use multicast for discovery (I see

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

Discovery is a special case, that is not quite multicast. Discovery is "noticing". A node wishing to be discovered must be noticed by one (or maybe more) already existent stations in a group (groups are noticed by any member being noticed by a member of another group). So you don't need any

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

Juliusz Chroboczek writes: > For discovery, multicast is unavoidable -- there's simply no way you're > going to send a unicast to a node that you haven't discovered yet. Presumably the access point could transparently turn IP-level multicast into a unicast frame

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

> Multicast is seductive to designers who ignore the realities of > propagation and channel coding issues, because they think it works one > way, but the reality is quite different. Hold on. Mulsticast is used for two distinct purposes: for broadcast-style applications (streaming), and for

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

> Has anyone modeled what the multicast to multiple-unicast efficiency > threshold is? An interesting experiment to perform, without doubt. (Experiment would be more interesting than modelling.) -- Juliusz ___ Babel-users mailing list

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

Interesting stuff. A deeper problem with WiFi-type protocols is that the very idea of "multicast" on the PHY level (air interface) is flawed, based on a model of propagation that assumes that every station can be easily addressed simultaneously, at the same bitrate, etc. Multicast is seductive

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

Has anyone modeled what the multicast to multiple-unicast efficiency threshold is? The point where you go from it being more efficient to send multicast traffic to individual STAs instead of sending a monstrous (in time) multicast-rate packet? 2, 5, 10 STAs? The per-STA-queue work should make

Re: [Babel-users] [Make-wifi-fast] perverse powersave bug with sta/ap mode

On Tue, 26 Apr 2016, Aaron Wood wrote: Has anyone modeled what the multicast to multiple-unicast efficiency threshold is? The point where you go from it being more efficient to send multicast traffic to individual STAs instead of sending a monstrous (in time) multicast-rate packet? is the