LX200V50 Not achieving spec speeds

WisLink WisLink PLC
1

I have the LX200V50 WisLink 1000 Mbps PLC Module + EVB and am testing with the provided 18AWG cables. I am testing with a single pair (2 wires) on the Pin1 - Pin2 as described here.

I am running iperf3 on both sides of the connection. I have tried twisting the conductors, but nothing has improved the speed. This is running only 3ft of distance.

When I run with 1 pair I only get ~270Mbps.

[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec  34.7 MBytes   291 Mbits/sec    0   1.57 MBytes
[  4]   1.00-2.00   sec  33.0 MBytes   277 Mbits/sec    0   3.11 MBytes
[  4]   2.00-3.00   sec  32.5 MBytes   273 Mbits/sec    0   3.15 MBytes
[  4]   3.00-4.00   sec  32.5 MBytes   272 Mbits/sec    0   3.15 MBytes
[  4]   4.00-5.00   sec  30.8 MBytes   259 Mbits/sec    0   3.15 MBytes
[  4]   5.00-6.00   sec  31.0 MBytes   259 Mbits/sec    0   3.15 MBytes
[  4]   6.00-7.00   sec  30.8 MBytes   259 Mbits/sec    0   3.15 MBytes
[  4]   7.00-8.00   sec  30.9 MBytes   259 Mbits/sec    0   3.15 MBytes
[  4]   8.00-9.00   sec  31.2 MBytes   261 Mbits/sec    0   3.15 MBytes
[  4]   9.00-10.00  sec  31.7 MBytes   267 Mbits/sec    0   3.15 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec   319 MBytes   268 Mbits/sec    0             sender
[  4]   0.00-10.00  sec   318 MBytes   267 Mbits/sec                  receiver

I tried 2 pairs with 3 conductors and saw an increase in speed, but far more variability.

[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec  47.8 MBytes   400 Mbits/sec    0   2.01 MBytes
[  4]   1.00-2.00   sec  54.1 MBytes   454 Mbits/sec    0   3.01 MBytes
[  4]   2.00-3.00   sec  27.2 MBytes   228 Mbits/sec    0   3.01 MBytes
[  4]   3.00-4.00   sec  20.7 MBytes   174 Mbits/sec    0   3.01 MBytes
[  4]   4.00-5.00   sec  23.1 MBytes   194 Mbits/sec    0   3.01 MBytes
[  4]   5.00-6.00   sec  25.5 MBytes   215 Mbits/sec    0   3.01 MBytes
[  4]   6.00-7.00   sec  35.0 MBytes   293 Mbits/sec    0   3.01 MBytes
[  4]   7.00-8.00   sec  46.2 MBytes   387 Mbits/sec    0   3.01 MBytes
[  4]   8.00-9.00   sec  53.8 MBytes   451 Mbits/sec    0   3.01 MBytes
[  4]   9.00-10.00  sec  53.8 MBytes   451 Mbits/sec    0   3.01 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec   387 MBytes   325 Mbits/sec    0             sender
[  4]   0.00-10.00  sec   386 MBytes   324 Mbits/sec                  receiver

I have confirmed I have gigabit connection without PLC

[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec   107 MBytes   898 Mbits/sec
[  5]   1.00-2.00   sec   112 MBytes   936 Mbits/sec
[  5]   2.00-3.00   sec   112 MBytes   936 Mbits/sec
[  5]   3.00-4.00   sec   111 MBytes   929 Mbits/sec
[  5]   4.00-5.00   sec   111 MBytes   931 Mbits/sec
[  5]   5.00-6.00   sec   111 MBytes   929 Mbits/sec
[  5]   6.00-7.00   sec   111 MBytes   929 Mbits/sec
[  5]   7.00-8.00   sec   112 MBytes   938 Mbits/sec
[  5]   8.00-9.00   sec   109 MBytes   918 Mbits/sec
[  5]   9.00-10.00  sec   111 MBytes   930 Mbits/sec
[  5]  10.00-10.04  sec  4.57 MBytes   939 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.04  sec  1.08 GBytes   928 Mbits/sec                  receiver
2

Hi Ryan

I am doing exactly the same iperf3 tests with a pair of V50s and getting very similar results using the included 0.5m 3 core flat cable, although I’m not seeing the same variability down three wires.

My understanding is that the specified speeds are interface signalling speeds (ie kind of the clock rate on the twisted pairs) rather than the actual throughput of data. So it doesn’t include handshaking, error correction and detection, retries and other arcane stuff.

In the product page it says:
Note: The maximum data rate parameter is given for the physical layer. The speed for the data layer will be lower

What speed did you anticipate?
Hope this is helpful :slightly_smiling_face:

Bob