MikroTik

Hi there! we have the oportunity and want to try and offer a 20mbps service using all mikrotik hardware. We hope to use 5ghz bands and would be starting from scratch so we can use any hardware radio combination possible.

Does anybody think this is possible or is it asking too much for this current wireless tech?

Undedicated no problem.
To keep your clients per AP down, use 30 degree sectors.

Thanks for your reply, when you say 'undedicated no problem', I assume you mean a little contention? Do you already offer this? If so how many users do you find can be attached per AP and what minimum signal level is needed to ensure 20mbps is possible most of the time? Also what about hardware? Are MT boards good enough? Ideally we would use 532A for AP's and possibly 133c for clients? Would that be up to the job do you think?

you wont get 20mbit though a 133...and you wont get multipul 20mbit users through a 532 AP....

we see around 13mbit tcp max on a 133 @ 900mhz...and are VERY happy with that.

Thanks for your reply, when you say 'undedicated no problem', I assume you mean a little contention? Do you already offer this? If so how many users do you find can be attached per AP and what minimum signal level is needed to ensure 20mbps is possible most of the time? Also what about hardware? Are MT boards good enough? Ideally we would use 532A for AP's and possibly 133c for clients? Would that be up to the job do you think?

20 mbps is possible. Use RB/333 for AP and client.

i can confrim this, dont know why it slipped my mind in earler post.

but for the AP side you will need multipul cards and mulipul large sector antennas, as some one suggested, 30 degree.

but do some benchtests with some MT equipment and cards- to get to know it first.

you will def. need to use 5ghz for that level of BW, you need to make sure those frequencies are clear in ur area too

I think its to risky offering 20Mbit.

I really wouldn't do it, perhaps 10Mbit if you had -65 for every one of you clients and only 10 - 20 users per AP.

Again, I'd put a "up to X-Mbits" on the contract

Thanks for all your infos.

I guess it's up to us to come up with a way to see if it's possible with some testing. We would really like to beat the crappy and wildly variable speeds of ADSL 8mbps services here in our location. We think it's possible and will give us a real selling point! We were thinking of using Turbo mode in 5.8ghz which is light licenced here and only supporting the top rates on the AP wireless settings to prevent a lower signal client droping the rate for all. We have a superb tower with LOS to almost every rooftop and rules allow up to 4watts EIRP here for all 5.8ghz

PS-: I checked the specs on the RB 333 and it looks lower spec than the RB 532a but somebody said we would not get 20mbps using RB 532a as AP?

RB333 is faster, its a diffrent kind of CPU

http://forum.mikrotik.com/viewtopic.php ... 263&hilit=

I missed the fact that the question was posted 2 times...

Yeah sorry. nobody really replied quickly to that one so I made another post with a better heading!!

Also were not planning on making dedicated speed. It's a contented service we plan like ADSL is here. To give you an idea ADSL providers here only go up to 8mbps @50:1 contention and thats even a lie as they can really only do about 6.5mbps/300k max with overhead if your next door to the exchange. Also this is very variable depending on line distance etc and most ADSL users only get around 4mbps/300kbps with a hell of a lot on 1mbps - 512kbps etc and this is variable at peak times also we have found.

I guess we just want to have a product which will let people see up to 20mbps on a http download enough of the time that they know it's capable but it's no way guarenteed. We are already very good with MT and bandwidth shaping and we already use a mixed mode b/g service over many sites which seems capable of 3-4mbps which I think is about the max rate you can expect from a mixed b/g network.

if you use high enough power AP's and CPE's (referring to processing power, not radio dBm), and you keep all your client signal strengths between -45 and -67 on both sides of the link (those numbers are based on using SR5 radio's, the strongest signal I would feel comfortable without risking blowing out the receive side of the radio, and taking the 48Mbps receive sensitivity plus 10dB as a fade margin), and you are in an area that has very low noise, using NStream + Polling, and keep your numbers very low per AP, you should be able to acheive 20mbps bursts (we see 8mbps burst over the wireless the way we set our systems up, and limit the pppoe to 3mbps)

one thing that I've found helps stabilize the connection alot is to define the default ap and client tx rates at the ap, and set them slightly higher then the pppoe connection allows. this stops the client from bursting and pushing the wireless to it's limit, which causes it to step down the data rate usually. since implementing this we've seen speed improvments as well as latency decreases.

does this happened in real life ? a signal with -47 ?
RB333+R52H+17db sector ----- RB333+R52H+17db flat
5.8GHz and distance less than 1000m
and the signal is -67 !!!

does this happened in real life ? a signal with -47 ?
RB333+R52H+17db sector ----- RB333+R52H+17db flat
5.8GHz and distance less than 1000m
and the signal is -67 !!!

maybe

does this happened in real life ? a signal with -47 ?
RB333+R52H+17db sector ----- RB333+R52H+17db flat
5.8GHz and distance less than 1000m
and the signal is -67 !!!

if you changed the 17dbi cpe for a 29dbi grid, you would see a significant increase in signal strength, maybe as much as into the -55 range... we've got customers 2-3 miles out that have signals in the -67 range, using rootennas

does this happened in real life ? a signal with -47 ?
RB333+R52H+17db sector ----- RB333+R52H+17db flat
5.8GHz and distance less than 1000m
and the signal is -67 !!!

RB532 + R52H + 29dBi solid dish and 6km over a harbour, signal varies between -45 and -65 throughout the day, directly related to the tides.

but i'm talking about less than 1000 m !!!!! both antenna are 17db 25 degree and 120 degree .

Perhaps I am missing somethng?

Where did you get the (17db 25deg and 120 deg) from?
And Yes it is possible, with multpath loss and other influences.

they are every where , 25 degree 17db echo , 120 degree 17db sector ..

they are every where , 25 degree 17db echo , 120 degree 17db sector ..

then it sounds like that antenna / radio combination would not work to acheive the necessary signals to get 20mbps bust speeds on ptmp

Clear line of sight, you should be able to get mid -50's at 1 km according to my distance calc. Upgrade the client side to a 23 db grid dish and that goes up to around -48. 16dbi client antenna puts you at -45ish.