How to judge lag based on upload speed? (minecraft server)

[night]

I don't quite know how to phrase a title... but I have thrown together an old comp to use for a MC server for my kids. It has been working well over lan, but my brother joined and he gets a lot of lag. Especially with mobs.
Messing around, he made his own on his comp and when I connect I get the same. We have 4.5 and 6mb upload speeds and for a single remote player I don't understand why it does this.

The comps are more than capable, the game runs fine for everything except off-site play.

 

[dave_the_nerd]

1) Try configuring, say, FTP or something on both servers, and see what kind of actual throughput you get transferring a known block of data from point A to point B. (You may not be getting the performance from your ISP that you think you're getting.)

2) Server specs?

 

[night]

I have ssh setup and use bitvise. I've not really checked a number on it, but i have transferred stuff from work and it was absolutely fine. So far as it was no wear near slow enough to wonder if something was wrong.
Our numbers are according to speedtest.

mine is a ubuntu server 939 opteron 185 with the game on an ssd. my brother ran his with client and server on the same comp, win 7, a 4670k @ 4.5ghz, 16gb ram, also from an ssd.

 

[dave_the_nerd]

Those server specs should be fine.

If you're using SSH, try an scp command.

Thing is, you can check speedtest results but it doesn't mean anything. Likewise with transferring files from work to your home (limited by your download speed, not you're upload.)

What you need is a benchmark of is the path between your server and his server, or your house and his house, in both directions. Preferably during peak hours. If you don't have that info, you really don't have anywhere to start troubleshooting it.

That said, if you're using BitVise to create a VPN or SSH Tunnel between your network and his network, that would also be a potential chokepoint. (Traffic has to be encrypted/decrypted/routed.)

 

[Emulex]

VPN's and tunnels can mess up the default MTU which can cause fragmentation of packets which adds latency! I'd suggest diagramming the entire network path between both parties and measuring (or guessing) which latency you can control and which you cannot.

ie comcast going to washington DC to come back down to Atlanta to reach u-verse - just 'cause' adds massive latency depending on the bgp4 gods!