High local ping when two people try to game at the same time (local or online)

Question

Okay, I apologise in advance if this isn't the sort of question intended for here. It looked like it was because https://networkengineering.stackexchange.com/ looks like it's intended for people who are professional network engineers. I am not.

I'm asking here because my research options have been exhausted. I did try posting about this on reddit, without success. I've since done even further research since then.

I've linked to the reddit thread for reference purposes, but I'll try to summarise everything I know here (and will gladly answer any questions in the comments that may help), in the hopes of finally finding out what on Earth is going on. I'm afraid this is going to be somewhat lengthy.

The scenario and the problem

Me and my brother attempt to play a game such as CounterStrike: Global Offensive at the same time. It could be online or he could locally host it (which we tried for testing purposes).

When we both play, the local ping (to the router) will rapidly become high and fluctuate, for everyone wirelessly connected to the router (even those not trying to play online). By extension, this obviously causes high latency to internet servers and so on, causing web-page timeouts, etc.

One of us disconnecting from the game (not the network) will resolve the problem almost immediately.

The problem will occur whether it's just me and my brother connected to the router, or if there are others connected; it appears to make no difference.

The problem is rarely experienced if we both try and download something at the same time, and if it is experienced, it's less severe than with gaming.

Initially I suspected it was the wireless hardware for the TP-Link WD-W8970 V1 router we use. However, today I tried out a different device (a Belkin F7D4302 v1), running DD-WRT (v24-sp2 (03/25/13) mega (SVN revision 21061)). I connected it via an ethernet cable to the TP-Link router, and then switched off the TP-Link's wireless and me and my brother then tested it again, wirelessly connected to the second router, and experienced the same problem.

One possible reason for this that I've read could be packet-retransmission due to packet-loss, but I'm unsure how to identify this if it is the problem. After leaving it on for a bit, and trying out a few tests with my brother, under Status >> Sys-Info, it had the following statistics:

Received (RX)401552 OK, 1 errors 
Transmitted (TX)534051 OK, 591 errors 

I'm guessing that having any errors is probably bad, but 591 doesn't seem like that many compared with the number that were OK, and examples I've seen online of this statistic with things going wrong seemed to have a lot more errors.

The router running DD-WRT gives me a lot of extra information which I'm hoping might shed some light on the problem, if I could actually understand it.

I've also tried raising and lowering TX power/transmission power, on both routers. It had no impact on the issue.

Additional information

• We live in the middle of nowhere. There's no other wireless networks anywhere around us.
• We do not own a microwave (research suggests they can cause interference).
• Me and my brother's rooms are pretty close, but are on the opposite side of the house to the router. We do seem to get solid connections to the router though (aside from this issue).
• Our internet connection is slow, but shouldn't have any bearing on what the local ping is. Indeed, the bandwidth usage of the game we play doesn't come anywhere near to what our max-bandwidth is (160KB/s download, 50KB/s upload).
• I work as a software developer, so I'd like to think I'm reasonably competent when it comes to technical things such as this, but I'm not deluded enough to think that writing software gives me a solid understanding of networking concepts and hardware. It's possible I've overlooked something really obvious, but if I have, I don't know what it is.

I don't know what I'm missing. Googling this has turned up nothing of use, and I do not even know if my search terms are going along the right lines.

Apologies again if this is the wrong section (or if my tags are wrong - I tried to select ones that seemed to fit, but if there's better ones then please let me know), but if it is, PLEASE direct me to where this question should go so that I can perhaps have a chance of getting some answers to this problem.

Thanks.

Answer 1

It sounds like you're just pushing the limits of what WiFi is capable of under the conditions you have. WiFi link performance drops with distance and drops with the number of users.

There are a lot of things that can help. Probably the biggest help is to set up more than one access point, ideally connected by wire and as far from the existing access point as practical. Use only 20MHz bandwidth on 2.4 GHz.

Another possibility it to use powerline Ethernet to place the other router in another room. Only user powerline Ethernet adapters that are labelled "AV2" or have advertised peak speeds of 600Gbps or more. The earlier adapters work poorly.

To use a DD-WRT router as an access point:

1. Disable its DHCP server.
2. Give it a LAN IP address inside the block served by the other router but outside its DCHP range. (So, for example, if the other router is 192.168.1.1 and the DCHP range is .100 to .200, 192.168.1.2 is a good IP address.)
3. Connect one of the LAN ports on that router to one of the other router's LAN ports, through the powerline Ethernet if desired.
4. You can configure the SSID and wireless key the same if you like. Just make sure to configure different channels.

I do not recommend using wireless repeaters or range extenders.