[LINK] FTTP soon normal

[Frank O'Connor]

Sorry, 

I meant CDMA ... collision detection. Error correction, as Hamish said ... is a level 3 Feature.

Again ... just my 2 cents worth ...
---
On 28 Apr 2014, at 6:39 pm, Hamish Moffatt <hamish at cloud.net.au> wrote:

> On 28/04/14 18:22, Frank O'Connor wrote:
>> Well, yeah ... but:
>> 
>> 1. ANY form of networking causes 'slow-downs' simply by its very nature, irrespective of what the data interface is capable of.
>> 
>> 1Gbs hard wired Ethernet? Sure ... if you only have 2 devices connected, are running a single networked application ... and even then all you'll get is 300-500Mbs max due to error correction (huge overhead in Ethernet which increases logarithmically as nodes activate), data scheduling problems and lots of negotiations (e.g.ACK/NACKS, non-data packets ... ICMP for example, and other high level protocols inherent in TCP/IP) between the devices.
>> 
>> It doesn't much matter what network architecture you use ... the overheads persist (as they were designed to do by the network protocol inventors) and slow traffic way below the optimum. With networks its important that little numbers like error detection and recovery work ... especially in non-tolerant applications and devices.
> 
> I think you're getting your layers pretty mixed up here. 
> 1000base-T/802.3ab (Gigabit Ethernet) has no error correction (it has 
> error detection), and given that's it's almost always switched won't 
> have problems scaling as you add more devices and applications unless 
> your switch is completely hopeless. Of course it has overheads that mean 
> you won't actually get 1000Mbit/sec of user data (HTTP or whatever) but 
> the performance is pretty predictable and quite close to the theoretical 
> with modern computers.
> 
> TCP/IP adds overheads to get its work done but there's no interference 
> between nodes and applications there either.
> 
>> 
>> 2. Bottom line: WiFi is no more or less efficient than hard wired network protocols. Indeed, low level WiFi protocols are typically Ethernet protocols ... and hence subject to the SAME efficiency and effectiveness limitations as the wired protocols they emulate. The difference is that with WiFi you can overlay channels more easily than you can on an Ethernet connection ... which doesn't handle packet crowding very well at all.
> 
> WiFi of course is working on a shared channel, while switched ethernet 
> effectively has a separate channel for each connection.
> 
> 
> 
> Hamish
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