Question

An ISP is marketing Fiber speeds on Wimax / wireless how true is that?

Answer 1

Not true at all, just selling lies!!

Regardless of what you hear, wimax wireless does not transmit data at advertised speed because:

-- wireless technology is all half duplex which means it transmit data at half the actual speed. For example, if you have 54mb wireless router, it will transfer at 27 excluding other factors.

-- even at half duplex, you will need clear line of site otherwise they will be more troubles. Things like trees, buildings, lorries or water bodies, even raining days can affect speed.

-- if there are other wireless transmitters or high voltage power lines they can introduce noise and speed suffers.

On the other hand, fibre is full duplex and transit at exactly said speed, there is no interference since its light.

Fibre have high capacity bandwidth than any technology at the moment.2

Answer 2

I'm not sure that Duplex has anything to do with it ultimately - http://en.wikipedia.org/wiki/Duplex_%28telecommunications%29 explains that Full Duplex can transmit data in both directions simultaneously while half duplex only allows transmission in one direction at a time

what it comes down to is that Wimax uses radio frequencies to transmit data which means the signal is more "lossy" which means data packets have to be resent and thus take longer to get there and slows the connection speed experienced down - the problem gets worse as Macdonald describes if there is poor line of sight and over greater distances

It is theoretically possible to get near fibre speeds with wimax technologies (300mbps) however i am not aware of the technology making it to zim yet due to its extremely high cost.

I know that Utande (Umax's Sister Company) offers a package that they call "Virtual Fibre" its possible this is what you are referring to, they are specific to say that its a Wimax product setup in such a way that you get bandwidth allocated to you in the same way fibre (the full fibre not GPON) does, that is that it is 100% dedicated to you and no one else can slow it down on the last mile, your not getting fibre speeds as they only advertise for speeds up to 1mbps however you can get a fibre connection in zim that only runs at 1mbps, ask Zol or YoAfrica for example - the flexibility of physical Fibre is that you can scale up your speed (at increased cost) much much further than wimax.

Fibre can go to speeds of 10gbps and above (not neccesarily in Zimbabwe yet though) even 100gbps on a single fibre cable (although the tech isnt available yet to physically do it with existing routers, but the fibre can take it) where as wimax in most cases in zim (at this time) stops at about 1.5-2mbps.

Comments

It has, taking the example from that link, imagine having conversation over the walkie talkie radio(chiovha-ovha). You both cannt speak at the same time. One have to talk whilst the other listen. This means the conversation take twice as long than if you were talking on the phone which is full duplex.

Coming to wireless, it is half duplex by design because it csma/ca. This means that whilst the otherside is sending data, the otherone keeps listen until the channels are clear.

Unlike csma/cd which hav method of detecting collision and backoff, then try again at random timers.

Wireless have no way of detecting collisions.