Poor LAN performance - new router required?

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drdrake

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#115959 13-Apr-2013 15:09

I've searched all over the forums, and can find some similar questions, but no real answers, so here goes...

I have a Linksys WRT610N router (with DD-WRT firmware) acting as a WAP for most of my hardware (XBox 360, Macbook Air, assorted iOS devices, etc). It also has two hard wired connections - a 2010 Mac Mini HTPC (latest OSX version) and a new Synology DS413J NAS (latest DSM version). The router shows a gigabit connection, as do the NAS and HTPC. Main cable run is Cat 6 (approx 20m), with patch cables assorted Cat 5/5e/6.

My aim is to increase the file transfer rate between the HTPC and NAS. File streaming for Plex, music etc is fine, but large file transfers eg. copying a 5-10GB file, seem to run very slowly - occasional peaks of 60-80Mbps, but typically 3-5 Mbps at best. The HTPC and NAS both show low usage of CPU, RAM etc (using OEM tools to monitor during file transfer). The NAS and drives are brand new, with NAS specific 7200RPM drives, and the HTPC has a 120GB SSD and 8GB RAM.

Because the HTPC and NAS hardware seem to be barely running above idle during these file transfers, I'm guessing the problem lies in between. I can change the MTU in the HTPC and NAS to support jumbo frames, but the router MTU can't go above 1500.

1. Should I find a newer/better gigabit switch that supports jumbo frames, and just use the WRT610N as a WAP?

2. Will changing the MTU make a useful difference?

2. Should I buy new Cat 6 patch cables?

3. Any other tests I should run, or configuration changes I should make?

cyril7

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#798788 13-Apr-2013 15:18

Hi, the routers MTU only relates to traffic passing via the NAT to/from the WAN, if you have the PC and NAS connected via LAN ports of the router then its just a L2 switched connection.

My be a better description/diagram would help.

Cyril

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drdrake

27 posts

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#798796 13-Apr-2013 15:33

Rough outline, but hopefully makes it clearer. The patch cables are 1.5m, the wiring run is approximately 20m. A keystone jack in the lounge wall connects the patch cable and wiring at the HTPC end. At the other end, the Cat 6 goes straight into the router (which is sitting in a well ventilated cupboard in my office, right next to the NAS). None of the terminations are home made.

Hammerer

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#798799 13-Apr-2013 15:38

Before reconfiguring anything I'd try to more clearly identify the scope and source of the problem. For example, I'd attach a third device like a Windows laptop and do large file transfers to and from the HTPC and the NAS. If you have no problems in some cases then you may identify that only one device has the problem. Likewise, if you think it is the router then try it with wireless switched off or swap in another router/switch to test the HTPC and NAS link.

cyril7

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#799016 14-Apr-2013 07:59

Hi, is the ADSL router connected to the wireless router via its WAN port, if so then you are double, NAT'ing, not that this should affect NAS to HTPC traffic only Internet traffic but to configure the wireless router as a simple AP/Switch would fix that, unless of courts the DSL modem is in half bridge, in which case ignore all that.

Have you tried ipef testing.

Cyril

drdrake

27 posts

Geek

#799086 14-Apr-2013 10:35

The ADSL modem is connected via the WAN port and it does indeed double NAT. It's a DLInk DSL-526B that won't operate correctly in Bridge mode (despite a lot a forum searches and trying different things). In reality, it hasn't created any issues. I am going to switch to fibre soon (I'm in Palmerston North and could have Orcon or Telecom right now, but I'm waiting to see what Vodafone offer before I sign a contract), so that will solve those issues and relegate the WRT610N to being a second AP.

I have no idea what iperf is...

drdrake

27 posts

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#799104 14-Apr-2013 11:10

So I think I will put this down to a dodgy patch cable. I've just installed all new Cat 6 patch cables from Jaycar, and I'm now getting a pretty consistent 70-80MB/s download from the NAS, and 45-50MB/s upload to the NAS. At which point the NAS CPU is sitting around 95%, so that will probably be the limiting factor for increasing upload performance any further.

Unless anyone has some other (practical) ideas on how I could boost this performance any further, I'm happy.