Wireless Router Issues

[zim2411]

At Philadelphia we had our scouting system up and running for everyone to use. We constantly ran into issues with our router crashing however. We used a Linksys WRT54G with dd-wrt firmware. Stock settings are to hand out 50 dhcp addresses, which we hit midday Thursday I think. I upped it to 250 maximum users, but we started running into issues with the Wi-Fi just dropping out of existence (no one's device could find it). We had a few things hardwired into the router, and they continued to function normally. We had about 70-80 DHCP entries around this time.

Is the issue with the router handling too many DHCP users? Would running the DHCP server on a computer behind the router, thus making the router function only as a access point/switch? Or can a WRT54G absolutely not handle this traffic load?

Is there any wi-fi system that is more powerful?

[yongkimleng]

hmm.. dd-wrt, means you are using a v5 router which has only 8mb ram and 2mb flash?
You'd be better off with an older one which has more flash ..
But if you are thinking of serving a whole arena of users (probably > 250) I think you will be better off with a linux box giving out serving DHCP on class A or B subnets, with the router merely bridging your wireless and wired interfaces (i.e. disable internal dhcp).
The number of requests / flows may also be maxing out its ram.

[writchie]

Originally Posted by zim2411

At Philadelphia we had our scouting system up and running for everyone to use. We constantly ran into issues with our router crashing however. We used a Linksys WRT54G with dd-wrt firmware. Stock settings are to hand out 50 dhcp addresses, which we hit midday Thursday I think. I upped it to 250 maximum users, but we started running into issues with the Wi-Fi just dropping out of existence (no one's device could find it). We had a few things hardwired into the router, and they continued to function normally. We had about 70-80 DHCP entries around this time.

Is the issue with the router handling too many DHCP users? Would running the DHCP server on a computer behind the router, thus making the router function only as a access point/switch? Or can a WRT54G absolutely not handle this traffic load?

Is there any wi-fi system that is more powerful?

Generally, more than about 25 associated clients on a single access point will start to lead to problems. This is true for higher-end AP's as well. The number of DHCP entires or MAC entries are unlikely to be limiting factors.

You might see a somewhat greater number of simultaneous users if you run in G only mode.

If you want to increase the number of connected clients, you could run 3 access points on the non-overlapping channels 1, 6, and 11, and route them on the WAN side of the 3 WRT54G's.

[zim2411]

Originally Posted by writchie

Generally, more than about 25 associated clients on a single access point will start to lead to problems. This is true for higher-end AP's as well. The number of DHCP entires or MAC entries are unlikely to be limiting factors.

You might see a somewhat greater number of simultaneous users if you run in G only mode.

Yeah.. but running in G only mode limits the range. If you are far away enough that it drops to even 36mbps, the router won't serve you anymore. (Or that's what my testing in the past proved)

I have a v2 WRT54G, so it is with 16mb of RAM. I just upgraded to dd-wrt v24 RC 6.2, and I'm going to try and disable as many functions as possible. It's impossible to test until we get to an event though

[Joe Ross]

While I was reading the Championship Essential Information I noticed that it asks people not to set up wireless networks at the Championship.

[sanddrag]

I <3 the DD-WRT firmware. It does wonderful things traditional router firmware cannot. I've used it on a WRT54G v7 and it would use up about 94% of the memory just idling. So, perhaps you are hitting the upper limits of your memory?

[yongkimleng]

Tomato firmware rocks too

[mtaman02]

You can try wiring a second router behind the first router to ease the load instead of having a computer.

[zim2411]

Originally Posted by Joe Ross

While I was reading the Championship Essential Information I noticed that it asks people not to set up wireless networks at the Championship.

Bad link. In the past I know teams have setup their own access points at Championship. The manual explicitly says not to arrange for Internet access while at an event... could you find where it says no wireless networks?

I'm going to try using a gigabit switch with two wireless access points connected, and either a computer or a wired router giving out DHCP addresses. This way, all wireless connections are split between the access points, and all traffic goes through the switch - which should be more than capable of the load.

[Chris Marra]

Originally Posted by zim2411

Bad link. In the past I know teams have setup their own access points at Championship. The manual explicitly says not to arrange for Internet access while at an event... could you find where it says no wireless networks?

I'm going to try using a gigabit switch with two wireless access points connected, and either a computer or a wired router giving out DHCP addresses. This way, all wireless connections are split between the access points, and all traffic goes through the switch - which should be more than capable of the load.

Wireless Networks
Teams will not be allowed to set up their own wireless networks at the Championship. While we certainly
appreciate the positive potential team-created wireless networks could represent, there is a chance such
wireless networks could interfere with planned activities during the event.

I am similarly disappointed by this, as The Blue Alliance was going to have TBATV installs set up in each of the divisions to provide hopefully seamless coverage in the pits.

[zim2411]

Originally Posted by Chris Marra

I am similarly disappointed by this, as The Blue Alliance was going to have TBATV installs set up in each of the divisions to provide hopefully seamless coverage in the pits.

Do you know if this is for the stands, the pits or the entire event? This really kills our scouting system then...

[Chris Marra]

Although I believe this 'rule' covers the entire event (Stands + Pits), I don't see where you would get power to run one in the stands anyways, as I am pretty sure there is no AC easily accessible.

That being said, I don't think they would mind an ad hoc wireless network being run in the stands, which ought to work for a scouting system.

[zim2411]

Originally Posted by Chris Marra

That being said, I don't think they would mind an ad hoc wireless network being run in the stands, which ought to work for a scouting system.

Yeah that should work in the stands for match scouting, but for team scouting we rely on a server in our pit with clients connecting + entering info.

[EricVanWyk]

Originally Posted by Chris Marra

That being said, I don't think they would mind an ad hoc wireless network being run in the stands, which ought to work for a scouting system.

Yes they would! An ad hoc system is equally "disruptive" as one based around a router. Also, the stands are probably worse than the pits for such activities, as they are closer to the fields.

I'm not sure why they are showing negative love for the WiFi, but please respect their decision.

[Covey41]

This could be because maybe FIRST is doing a frequency study for the new control system.

If FIRST decides to go with 2.4 Ghz for the new control system, it could spell the end for all team owned WI-FI networks at events.