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I'm having WLAN trouble on my dualbooting win/linux laptop - the connection on linux side has occasional trouble, and seems somewhat slow and chunky. I would try to fix this issue by fiddling with all sorts of router settings, or WLAN kernel modules backports, or whatever - but problem is, it's hard to know if the settings have had any effect, since the problem appears in only subjective feeling about connection speed. So I'd like to have some way of executing a measurement that would tell me if the problem was affected or not.

So far I've just used iwconfig which returns normal data, and ping -c 100 -i 0.2 on the router and some stabile website ip addresses, but the summary doesn't give me all that good data, only the occasional packet loss. One information that's missing from the summary is the count of packets with clearly deviating roundtrip time, since that's one of the symptoms I've noticed - most packets come back with a regular time, but some of them take a lot longer.

So what tools can I use to get some actual, numerical data on the quality of my internet connection?

(And just in case someone's wondering, yes, the problem is real and not just confirmation bias, as it sometimes appears bad enough to throw me off the WLAN connection. It's probably somehow related to this Ubuntu bug and/or this Redhat bug)

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up vote 8 down vote accepted

Maybe setup smokeping on the Linux side, and point it at your AP?

Smokeping will periodically (configurable) send -20 pings at the same time, and then graph how how many returned and the range of times that they returned in. If you have a lot of dropped packets, or the really wide range, then you should be concerned.

Smokeping Graph

If you want to run smokeping you could use fping, which is what Smokeping is calling to collect the data. It is a lot easier to interpret with the graph though.

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Use tcpdump to capture packets that are leaving your local LAN subnet. Then use tools like Wireshark or tshark to do some analysis on how much loss you're experiencing, as well as what the variance in round trip time is, and how TCP is behaving. (Windowing, retransmits, etc).

The reason I suggest this rather than running some sort of ping/traceroute based monitoring software is that many network operators treat ICMP traffic (and generation of ICMP unreachables, which traceroute relies on) differently to actual UDP/TCP traffic. Using an ICMP based tool may therefore give you spurious results.

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