[sdnog] P2P link

[Patrick Okui]

On 20 Jul 2020, at 7:39 EAT, الفاتح محمد حامد wrote:

> greeting
> I want to deliver an internet service to a College that is 4 km away 
> from the data center via wireless and I currently have two options, 
> which is installation via
>  nanostation m5
> or
>  tp link cpe510
> Note that the college is very large and the number of users can reach 
> 1000 Do these devices meet the purpose or not?
> And if not, what are the alternative solutions?
> Thank you


Firstly the number of users does not really matter for these devices 
because you are going to use them to create a point-to-point link. 
Similar to how an ISP would deliver a link to the data centre. The 1000 
users will not connect directly to either of these devices. To serve the 
individual students you’ll need more access points in the college or 
cabled network drops they can plug in. What is important for this link 
is how much bandwidth you expect the college to use. i.e when those 
1,000 users are online, what are their requirements?

It is hard for an ajnabi to give an estimate on this because our 
perception of what is needed is likely different from what is expected 
locally.

However, the nsm5 can transmit at max 150Mbps and for max 15km 
https://www.ui.com/airmax/nanostationm/ and the TP Link claims it will 
do 300 Mbps at max the same distance: 
https://www.tp-link.com/us/business-networking/outdoor-radio/cpe510/. 
Note that the quoted TP link speed is 1/2 duplex so in real life expect 
a max of about 100 Mbps full duplex from both. In some scenarios you may 
be able to squeeze close to 200 Mbps full duplex. Note that the max rate 
is when the radios are just meters apart so for the 4km link you won’t 
get the max speeds.

I am not sure if Ubiquity still blocks access to Sudan (if they do now 
would be a good time to tell the reseller) but you can put in the 
physical properties of both radios into https://link.ui.com/ plus the 
GPS locations and estimated tower heights to get a better estimate of 
how they should perform for your distance. It’s a radio physics 
calculator and I doubt they have data on what buildings are at the 
locations you’re looking at (which could degrade the signal) but it 
should give you the very max performance you can hope to achieve.

Of course the next question will be how fast of an Internet link you 
will be able to provide on the data centre.


--
patrick