We are looking at several larger WIFI projects. One key aspect is that devices will need to smoothly had off from one AP to the next. There will be roaming laptops and Wifi phones. I’m looking for any info from people who have done this either using the Hot spot software or a standard AP config.
Thanks
Erik
maybe this helps?
http://wiki.mikrotik.com/wiki/Mesh_wds
MT doesn’t have the best solution available, but they’re getting closer. With WDS you have a huge loss of bandwidth. With RTSP, you lose the first frame as you move from AP to AP (so they say).
How is WDS a huge performance loss unless you use 1 radio for both AP and transport? RTSP = RSTP ? RSTP is not necessary unless the topolegy can change automatically. Dynamic WDS is best used to get surprises. If you love surprises you love dynamic stuff.
If I have 60 APs in a WDS, that’s 5.5 megs (well, using B) throughput max on that whole network. I’m sure there’s going to be mroe demand than that across a whole town.
That would be many 5.5 mbit half duplex links as WDS does not automatically reduce an 802.11d compliant bridge to a HUB under all conditions.
And I don’t think it’s WDS that is the problem as much as it’s the way you have chosen to use it in your implementation.
You are implying that enabling WDS between two units reduce the bandwidth dramatically between those two.
I know that just between 2 units in a, n-strme, blah, blah it goes down 3 mbit (according to someone who posted their results on this forum). However, I am wanting to setup an 802.11 hotzone that covers a whole town. I want someone to be able to be on a VoIP call and traverse the whole network without suffering any audio quality. There are other vendors that can do what I want without a technical problem. However, they cost about $3k/AP. MT is the swiss army knife of the wireless and routing world, so I figured it would be the way to go. However, using WDS that whole town is limited to 5.5 max throughput in 802.11b… not very effective at all. I’m actually looking at using G throughout the whole network for client access. The guys at MT have told me that what I am describing is what would happen. The VoIP call would work how I want it to, but at the sacrafice of system capacity.
2.4GHz or 802.11b for that matter was never intended for wide scale (MAN) roaming users. 2.4GHz has its limitations being that you need good line of sight or have a good number of APs to cover a few square miles, and of course the bandwidth limitations as stated above. A combination of 5GHz and 2.4, using 2.4 as the client access and 5GHz as the network distribution and interconnection would be a better way to go to alleviate those bottlenecks and bandwidth constraints. 5GHz has a more narrow freznel zone, less interference, and in my experience has faired better with near-LOS situations than 2.4. So for distribution it’d be more suited than 2.4b/g.
It’s all in how you design the network, and what your goals are.
Well, all of the backhauls would be 5 gig N-Streme, fiber, or some other non-802.11, non-2.4 GHz method. However, it is my understanding that no matter how many of these backhauls I have or their capacity, I would still be limited to 5.5 megabits total throughput on that system using WDS. Therefore, it looks like RTSP would be the way to go in the Mikrotik world. The other vendor’s solutions may or may not be better as I don’t know if they drop that first frame or not.
I would assume that I could do the same SSID, but different frequencies if I used RTSP? Also, I don’t know if dropping that first frame would be noticable to a roaming VoIP client. I believe just the amount of time it takes for standard 802.11 to associate would cause a problem, however. These other solutions don’t have that problem.
Our idea is similar, as we wish to cover small rural towns. In most cases well under 1sqr mile. So If I get 5.5mb (over the air) that should be fine as I don’t see any ap handeling more then dozen or 2 customers at at time… but more badwith would be good.
Our thought was to go 5.3 on the back haul or mesh part of the net work. So why would there be any impact on 2.4 bandwidth ?
Any comments on if it is best to use the same or different cannnels when moving about. Any one know what the hand off time is between APs ? is this effected by the client, Is there any control of the hand off like setting it to a certain signal strength etc to make sure the client is not dropped ?