binary1000
Premium
join:2005-10-04
White Lake, MI
| Users per AP and bandwidth
1. How may concurrent users can one expect to adequately support on an 2.4Ghz AP with 64mb RAM and a 256Mhz CPU that is connected to a full T1 line if all the users are throttled to 512kbps, have good signals and none are doing VOIP? I'm calculating that the user base would be happy with around 20 concurrent users and a subscription base of 200 (unless everyone is hitting a key to d/l a file at exactly the same time, there should be no issues). Is that something you all are seeing or are these numbers too high?
2. What is the ratio most of you are using:
a) input bandwith to # of CONCURRENT users
b) # of concurrent users to subscribers (15 to 1 .. more?)
3. How does the ratio change when VOIP is added?
4. How many of you are going to support VOIP? Those that already have QoS monitoring can, but the others will not be able to reliably?
This is a great forum!!!
Thanks. |
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funkyfelty
Armament For Peace
join:2002-10-01
Lebanon, PA | What type of equipment?
What Bandwidth shaping/throttling software
What type of AP, etc....
Need more details
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PA Army National Guard - I turn the wrenches that keep the forces moving |
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binary1000
Premium
join:2005-10-04
White Lake, MI | I'm looking for average figures .. a general rule of thumb .. a starting point that everyone uses. If you can expect a better ratio with some gear and not others, that would be very useful to know. There is an unlimited combination of equipment. |
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superdog
I Need A Drink
Premium,MVM
join:2001-07-13
Lebanon, PA
| said by binary1000  :I'm looking for average figures .. a general rule of thumb .. a starting point that everyone uses. Sorry, but without more info., You will probably get no or limited answers. I guess the first thing to remember is that whatever the manufacturer says You can have as active users?, divide that by2 and You will have a more realistic # to work with.
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pdg2
join:2005-10-19
Waterford, MI | So if the mfr says 50 users per AP, only 25 can be supported? But that's CONCURRENT users. So if we use a 10 to 1 ratio, then an AP that can support 25 users can support a SUSCRIPTION BASE of 200 or more. |
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John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
 ·CenturyLink
| said by pdg2 :So if the mfr says 50 users per AP, only 25 can be supported? But that's CONCURRENT users. So if we use a 10 to 1 ratio, then an AP that can support 25 users can support a SUBSCRIPTION BASE of 200 or more. That is the "rule-of-thumb" that people use for concurrent connected users. The problem arises when you get more than that (25) on an AP...contention becomes a problem for 802.11b systems.
So the next plan is to install 3 APs (for 2.4 GHz) and spread your sub base out over the three APs.
The other issue is that it is necessary to do shaping and protocol control to limit the negative effects of BT and other similar programs.
There are many factors to consider...
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A is A |
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jasonepowell
join:2002-08-01
Charles Town, WV
| reply to binary1000
Using an 8 to 1 oversubscription rate tends to work for us, but we have ap's where this doesn't work because 1 or 2 customers are constantly using their bandwidth. In any case, with a maximum of 1.5 meg down available to each customer, we generally feel comfortable supporting 25-30 users. In some cases, we have AP's that are supporting 45 or more users, but those are AP's where there just isn't a lot of constant usage. Monitoring will tell the story here. Plan on taking John Galt's advice and sectorizing.
Also, you can not provide adequate QOS such that you can guarantee VOIP using 802.11b. It's just not possible. If you keep the number of users down and avoid contention issues, your latency should remain good, and most people will have no problems, but you are always at risk for one customer with a virus to take your AP out. Don't guarantee anything.
One more thing - "concurrent users" is a phrase bandied about quite often that is poorly defined. In every fixed wireless situation I have ever been in, every client antenna was connected to the AP at all times. I believe that even though those antenna's aren't doing much (maybe a K or 2), they still take resources at the AP. Be sure to account for this in your guesses. |
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PersComp
Premium
join:2005-08-17
Cayce, SC | As subs go up, is the main limiting factor the AP's ability to organize the clients or is it bandwidth? In other words, can it support more clients if a 1M or 512K service is sold vs a 1.5M? |
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superdog
I Need A Drink
Premium,MVM
join:2001-07-13
Lebanon, PA
| said by PersComp :As subs go up, is the main limiting factor the AP's ability to organize the clients or is it bandwidth? In other words, can it support more clients if a 1M or 512K service is sold vs a 1.5M? No, it really has to do with the amount of users that are on at any given time, and not how much bandwidth they have available.
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pdg2
join:2005-10-19
Waterford, MI
| So 3 sectors and 3 APs would support at most about 75 users from a sub-base of about 300 maybe? And that would be just data.
Is there a way to have multiple APs on one sector or is the only other alternative to add more sectors and more APs?
We're at the end of a valley of about 10,000 people sitting up on a hill looking down across all of them. We can just continue to add more sectors and APs to this tower I guess, but man that's a lot of antennas and APs to support 400 users (1000 subs?). That would be at least 13 sectors and APs. Since the users are all in a 180deg arc, that would be 4 or 5 stacks of 3 90deg sectors.
Has anyone put that many on one tower? I guess the other alternative is to use the tower for Bhaul to multiple smaller towers, but this tower is clear LOS to almost everyone in the valley. If we BH to smaller locations, those locations will have LOS issues that we won't have by staying on this tower. Suggestions? |
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uscomputing
join:2005-01-26
Buffalo, NY | Since there are only 3 non overlapping channels of 2.4ghz available, you would need a FHSS system to support that many APs on one tower. |
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superdog
I Need A Drink
Premium,MVM
join:2001-07-13
Lebanon, PA
| said by uscomputing :Since there are only 3 non overlapping channels of 2.4ghz available, you would need a FHSS system to support that many APs on one tower. Correct. 802.11b systems can only have 3 AP's on one tower/location because of the channel issue. FHSS(802.11-Raylink and Alvarion radios) allow You to put close to 15(I would NEVER do more than 9) separate AP's and antennas at one location. The only downside to this is thruput, as the best they will do is 1.3Mb per user on a good day, but You can put an average of 40 users per AP without a problem(Raylink uses 75Mhz 486 processors and Alvarion uses another type of processor, but equally as fast). The down side to this besides thruput is the price per AP and CPE, as they are much more expensive than any DSSS radio out there. That's why the majority of WISP's are using 802.11b(DSSS) solutions, because the ROI is much faster.:)
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jasonepowell
join:2002-08-01
Charles Town, WV
| reply to pdg2
Most people in your situation use proprietary gear like Trango, Motorola, or Axxcelera (my favorite) for this reason. More bandwidth, more users.
Welcome to the world of WISP's, where there ain't nothin' coming easy, and you get to pick two: fast, cheap, or reliable. Good luck! |
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John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
·CenturyLink
| reply to pdg2
said by pdg2 :We're at the end of a valley of about 10,000 people sitting up on a hill looking down across all of them. Tower coordinates?
It makes it easier to visualize...
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A is A |
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John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp | Bump...
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A is A |
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pdg2
join:2005-10-19
Waterford, MI | My guess is that not too many people that know of a location in a valley of 10,000 with no competition will want to share that, John. Not at least until he gets set up and skims the top. |
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John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
·CenturyLink
| said by pdg2 :My guess is that not too many people that know of a location in a valley of 10,000 with no competition will want to share that, John. Not at least until he gets set up and skims the top. If you want a list of un-served areas that have huge populations with no HSI...just let me know. I get requests all the time to provide service to un-served areas.
It is not an uncommon occurrence, believe me. This is why I continue to advocate for people to get out into the "un-served" areas...there are a lot of them.
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A is A |
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chiefbmr
join:2003-04-08
College Station, TX
| reply to jasonepowell
said by jasonepowell :Most people in your situation use proprietary gear like Trango, Motorola, or Axxcelera (my favorite) for this reason. More bandwidth, more users. Yeah if you are wanting 1 location with this many subs go proprietary. |
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cmaenginsb
Premium,MVM
join:2001-03-19
Palmdale, CA
| reply to binary1000
I think you are extremely confused binary1000. Oversubscription ratios do not come into play with 802.11b or any AP for that matter. Do not think in terms of "active" vs "allocated" clients.
The bottomline is that even with a 2.8ghz p-4 with 1 gb ram you won't see more than about 45 customers installed off of that AP.
As mentioned, for the subscriber densisities mentioned, do not attempt using 802.11b use a proprietary system which handles these things better.
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CCNA, Comtrain Certified Tower Climber |
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