Local network appearing to use internet for transfers

lifereinspired

Junior Member
Sep 10, 2015
4
0
66
Hello,

I'm confused about something. I was under the impression that computer to computer local file transfers are supposed to use the LAN and not the actual internet (WAN). This would mean that the file speeds can be substantially higher as they aren't limited by internet bandwidth but rather router capability and networking card capability. However, this should still be substantially higher than the average internet connection, including most broadband outside of gigabit fiber.

This doesn't appear to be the case in my network. If I'm downloading a file from the internet and then move a file between computers, my download speeds are immediately affected until the file transfer completes. In addition, my file transfers are much slower than I would anticipate on a high speed LAN. I'm only getting an average of 9MB/s transfer speed for local files.

My router is a Netgear R8500 (x8). This has the triband, 5300mbps AC chip (from Broadcom, I believe) and supports gigabit wifi on 2.4ghz and over 2 gigabit for the two 5ghz. Given that my laptop wifi is also a fairly new card, I should think I'd be able to better my local transfer speeds. The computer I'm transferring is connected via wired gigabit ethernet.

What I'm not sure is what to do about it or how to even go about trying to fix this. I know enough to be fairly sure that the local transfer speeds should be faster and not affecting my internet download speeds as they are. This also has other implications, though, because our primary TV watching is via Netflix, hulu, Amazon Instant, Acorn, YouTube or Plex. Obviously the streaming services use the internet itself but I thought that Plex should be also using the LAN rather than the WAN. However, I'm thinking that this also isn't what's actually happening, because I have issues periodically with Plex playing smoothly (and all the settings are much lower than our actual bandwidth) and downloading a large file on another computer, will sometimes make a video playing through Plex either fail completely or skip badly. If it were using the LAN alone, I can't imagine that it would behave this way.

What do I do about this? How do I figure it out, troubleshoot and correct the problem. I know enough to get around, I manage most of our family networking and have managed some tricky setups in the past with bridges, repeater, etc. I have all my local IP's mapped to the MAC addresses so that I'm not relying on UPnP for port forwarding and things like my Hue lights don't change IP addresses on me. I can learn and I'm fairly quick, but I don't consider myself an expert, or I'd be able to figure this out on my own. I'm not even sure what info would be needed to work on this. My router info is above, my internet is stable with 50/12mbps and generally this is a minimum rather than a theoretical maximum. I'm happy to supply whatever other info is needed. Please help point me in the right direction. I'd so appreciate any help in fixing this. Thanks so much.
 

Red Squirrel

No Lifer
May 24, 2003
67,339
12,099
126
www.anyf.ca
It sounds like you're using a switch and not a router, what port is your internet plugged into the router? There should be a WAN port, make sure it's plugged in there. If it is, check router settings to make sure NAT is enabled. You could also check your local IPs to confirm if they are 192.168 or 10, or internet ISP assigned IPs.
 

Pandasaurus

Member
Aug 19, 2012
196
2
76
My first thought would be either a NIC or the router is toast. Easy to determine if you have a spare NIC and router to test with.

I'm sure there's probably a much more in-depth and technical possibility, but I'm really tired and want to go home (just waiting for the next guy to show up...), so I can't think of much right now.

In theory, it shouldn't be possible for your LAN traffic to go over the internet (and then back to your LAN). Even if you are unknowingly using public IP's for all of your computers, you're still connected to the router, and either A) everything is on the same subnet, therefore it does not need to get routed, or B) everything is on different subnets, but you're still connected to a router, which will be aware of each connected device, and be able to route the traffic without going out to the internet. Regardless, I find it highly unlikely that your LAN traffic is actually going out to the internet and then straight back to your LAN. The level of WTF needed to make that happen (unintentionally, no less) is absurd.
 

sdifox

No Lifer
Sep 30, 2005
94,956
15,096
126
So you are downloading on computer one on hardwire, then transfer file from hardwired computer two to computer three on wifi?