High Ping Time on Local Network

Since my other articles on figuring out problems that you can’t Google are popular I thought I would write about my latest mood killer. I began to get a very high ping time on my local network, even higher out to the Internet. This caused problems with ssh sessions and NVIDIA game streaming, but was not noticeable when watching Netflix.

It started simply enough, one night I left my wife to watch Netflix downstairs while I went up stairs to get some work done. My job involves using ssh to login to remote servers, any latency (high ping) is very noticeable. That was the case this night. I could type much faster than the text would display, using the arrow keys to navigate was jerky at best. I figured my ISP was being lame. I finished up as quickly as possible. The next day there was no problem.

Jump cut to a few days later. Same situation. I head upstairs to work and my ssh session is just crap. The next day its fine.

The next morning is a Saturday. I take a seat on the couch and try to play Grim Dawn over NVIDIA game streaming and it doesn’t work. The bad connection icon appears in the top right, the graphics are pixelated and jerky, not good. Having no clue what could be wrong, I give my PC and Shield TV a restart. No luck, same problem. I tried the test connection option on the Shield TV, it reported back that I have a 9mb/s connection and 200ms ping. Considering I was on a wired gigabit network with only a switch between the Shield TV and my PC this was very bad.

My wife and children, bored of me, starting watching Netflix as I furiously Googled for a hint at a solution. Immediately my phone’s connection started having problems. Sites wouldn’t load or would load slowly. I tried a speed test and while my bandwidth was ok, my ping was 500ms. I tried pinging my PC, the ping times were all over the place, 1ms, 50ms, 100ms, and everything in between. Netflix worked fine, which I chalked up to streaming not being interactive and thus not caring about latency.

I at this point I knew it was something with my local network affecting both wired and wireless, but I had no idea what.

I had several command prompts open pinging devices around my house. All showed high pings. I expected less than one millisecond and the lowest was 5ms and very jittery.

I then thought about the problems I had with UNRAID. What if another port on my router’s switch is bad? My wife stopped watching Netflix and went into another room. I unplugged everything from my router and tried wifi, all good. I started plugging in all of my devices one at a time, testing in between each one. All good again. I opened up a couple of command prompts and started continuous pings, all good. I tried the NVIDIA game streaming test, the test failed just as before. I noticed something new this time though, my continuous pings were fine until the streaming test; during the test they were high. As soon as the test stopped they went back to normal. I started a movie on Netflix, the pings went bad again. I moved the Shield TV to a different port on my switch. The game streaming test succeeded. Netflix could play without jacking up the pings. It was another bad port in the router’s switch.

That left me with a switch that had four gigabit ports. One would say it was connected at a gigabit, but only pass 100mb/s of traffic. Another port messed up my entire wired and wireless network if any decent amount of traffic was passed. As a quickie fix I daisy chained another gigabit switch to one of the good ports. For a real long term fix I purchased another router.

Netflix was red herring. Watching Netflix would pass traffic over the bad port in the switch, jacking up the network. When I watch Netflix I’m not doing anything else on the Internet and therefor would not see the problem.

The router causing all of this was an ASUS NT-N66U. I got four years of use out of it before sending it to the trash. In the first year I had a pretty bad problem with it dropping my WAN connection.¬†Otherwise I was happy with it. Its a shame it didn’t last longer.