throughput problems

[danIrl]

Hi,

I have running throughput tests with mvpmc and am only gettings ~2mbs with my wired setup, and terrible stutter on video playback. (mpeg-2)

MVP<->Router<->LAN Adapter (Devolo 85Mbs) <-> LAN Adapter (Devolo 85Mbs) <-> PVR Server (on board NIC card)

I have tried tweaking the TCP settings, but this has very little effect.

I then setup a wireless adapter on the PVR Server and then the throughput went up to 5.5mbs, with no stutter on playback.

However I want to use the wired option only. I am hoping it is just the onboard NIC that is at fault and not the devolo hardware! I have another PC with a PCI NIC card, that I will try next.

Just wondering if anyone else experienced something similar with either powerline and/or onboard NIC setups?

[coachie]

I would do two things;
1. run a long patch cable directly between your router and server eliminating the devolos, then replace the lan card if necessary.

2. Despite the plugs being "plug and play" I would run the devolo utility on the server to see what effective speed the plugs are talking to each other at. They will always show 100mbps on the XP network status. Remember, 85mbps is a theoretical maximum, just like 54mbps for wireless.

If it is too low, I would suggect moving the plugs closer together until you get an increased connection speed. Obviously this isn't a permanent solution, just a test to see if it will improve the signal, as you may have electrical devices/ poor connections interfering with the signal.

HTH

Mark

BTW You are plugging the devolos directly into the wall and not into surge protectors, aren't you?

[danIrl]

Hi,

Yes devolo plugs are straight into the sockets. I brought the server down and plugged it in beside the MVP and there were no stuttering. Anywhere on the same ring main was fine, but one floor above (different ring main) and there was some stuttering, two floors above and it is unusable.

The devolo utility always stated a high bitrate (~50mbits) but it seems like it cannot maintain a constant throughput across different circuits.

Looks like it is back to the wireless option.

[coachie]

Aargh, this thread must be jinxed, as I now have the same problem!!!!
I started to notice some stuttering on my MVP (D3A) whilst watching live tv (UK DVB) only on certain channels, BBC1 especially. I think this has the highest broadcast bitrate in the UK.

I decided to do a few crude and simple tests on my network.
With my laptop and GBPVR server connected directly to a 100mbps switch, I transferred a 140MB file across the network. This took around 17 sec, with about 75% network utilization in the task manager graph.

Then I disconnected the laptop, connected 2 homeplugs next to each other onto a 6 way power extension lead and repeated the exact same test.

They were connected this way so in theory there is no other interference from other devices in the house, reducing the signal quality. Indeed, the powerline utility confirmed that the two devices were talking perefctly at 85mbps, however the time taken was 59 seconds to transfer the same file with a network utilization of 25%, approx 3x slower than the standard connection!

Despite this loss in speed, 25% of 100mbps is still 25mbps so that is easily enough to stream a 5mbps MPEG stream, right?

I now swapped the laptop for an MVP and plugged straight into the switch. Whilst viewing BBC1, the network utilization oscillated from 3 to 8% every few seconds in a rough sawtooth graph plot. No stuttering.

Through the homeplugs, the peaks were flattened off and didn't rise above about 6%. The result on screen is watchable, but annoying (especially to OH)

I believe it is a latency problem, not a simple bandwidth problem and I am going to move up to a pair of 200mbps homeplugs and report back in a few days, before attempting to tweak any PC/MVP/Homeplug/network settings.

Apparently, the 200mbps versions have been designed for multimedia streaming from the outset, which kind of implies that the manufacturers know that the 85mbps devices were not up to the job.

Tom's Hardware Guide has a few good (ie bad!) reviews of homeplug devices that I gleaned some information from.

Mark

[coachie]

The 200mbps homeplugs arrived yesterday and they completely solved my stuttering MVP problem over two floors.

I would estimate the real world performance to be double the 85mbps plugs, but still lower than a 100mbps lan connection!

Over the next week I will attempt to run 2 MVPs through the homeplug AV network, although I envisage problems doing so.

Mark