Slow network performance

Hi,

Yesterday I received my Vero 4k+, fully updated it and added a NFS share from my Synology NAS. The problem I have is that network is really slow on both ethernet and wifi. Actually yesterday I could not even play a 6GB 2h mkv file, not to mention the second one which is 68GB. Today I made another attempt and the smaller one stared to work fine every time I tried despite me not doing anything in the meantime. Still the large file will not play smoothly and buffers all the time. When I display playback info buffer goes down to empty pretty quick. Not sure what to do next.

Here’s some info:

  • 100Mbps Lan
  • DHCP connection
  • content is on Synology Diskstation NAS via NFS share
  • copying a file from the NAS to a Windows 8 PC is at a rate of 9000-10000kBps so that would give around 72-80Mbps. Measured in Total Commander. Copied from a mounted network drive.
  • the average total bitrate of the large file is 64.6 Mbps

How are the shares mounted?

For a file size of 68GB, you will benefit from Gigabit speeds if not using an fstab mount

From my PC I access them as network folders, like \DISKSTATION\home. From Vero it’s a NFS share.

If you are limited to 100Mbps, you will likely need to use an OS mount

Measure the actual network throughput with iperf3 and also use fstab based nfs mounts to get most of your 100 MBit connection.

Thanks guys for your responses. So I have now shared the videos using fstab nfs mount but have not really experienced a significant improvement. I have also installed iperf3 and performed the tests, results are below. Copying from mapped drive as described above still works fine as it did before.

osmc@Vero:~$ iperf3 -R -c 192.168.2.247
Connecting to host 192.168.2.247, port 5201
Reverse mode, remote host 192.168.2.247 is sending
[  4] local 192.168.2.237 port 56998 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec   253 KBytes  2.07 Mbits/sec
[  4]   1.00-2.00   sec   141 KBytes  1.16 Mbits/sec
[  4]   2.00-3.00   sec   148 KBytes  1.22 Mbits/sec
[  4]   3.00-4.00   sec  11.3 KBytes  92.6 Kbits/sec
[  4]   4.00-5.00   sec   198 KBytes  1.62 Mbits/sec
[  4]   5.00-6.00   sec   583 KBytes  4.77 Mbits/sec
[  4]   6.00-7.00   sec   331 KBytes  2.71 Mbits/sec
[  4]   7.00-8.00   sec   515 KBytes  4.22 Mbits/sec
[  4]   8.00-9.00   sec   240 KBytes  1.97 Mbits/sec
[  4]   9.00-10.00  sec  0.00 Bytes  0.00 bits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  2.40 MBytes  2.01 Mbits/sec  140             sender
[  4]   0.00-10.00  sec  2.36 MBytes  1.98 Mbits/sec                  receiver

iperf Done.

.

admin@DiskStation:~$ iperf3 -s
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------
Accepted connection from 192.168.2.237, port 56997
[  5] local 192.168.2.247 port 5201 connected to 192.168.2.237 port 56998
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec   264 KBytes  2.16 Mbits/sec   19   4.24 KBytes
[  5]   1.00-2.00   sec   185 KBytes  1.52 Mbits/sec   10   1.41 KBytes
[  5]   2.00-3.00   sec   120 KBytes   985 Kbits/sec    9   1.41 KBytes
[  5]   3.00-4.00   sec  0.00 Bytes  0.00 bits/sec    5   1.41 KBytes
[  5]   4.00-5.00   sec   246 KBytes  2.02 Mbits/sec   20   4.24 KBytes
[  5]   5.00-6.00   sec   546 KBytes  4.47 Mbits/sec   24   1.41 KBytes
[  5]   6.00-7.00   sec   365 KBytes  2.99 Mbits/sec   10   2.83 KBytes
[  5]   7.00-8.00   sec   489 KBytes  4.01 Mbits/sec   26   1.41 KBytes
[  5]   8.00-9.00   sec   239 KBytes  1.96 Mbits/sec   16   1.41 KBytes
[  5]   9.00-10.00  sec  0.00 Bytes  0.00 bits/sec    1   1.41 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec  2.40 MBytes  2.01 Mbits/sec  140             sender
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------

I’m reminded of this post Wired Network Slow - Wireless Fast - #18 by sid6581 where it seemed like there was an issue between a Vero4K+ and a Synology NAS.

In that case, an iperf3 between the Vero4K+ and a (wired) PC showed good figures but when it was between the Vero4K+ and the Synology NAS, the throughput was both disappointing and unstable, which is what you seem to be experiencing.

So, if possible, try iperf3 between the V4K+ and a PC.

I wonder if there’s some duplex mismatch here

Connecting to host 192.168.2.247, port 5201
Reverse mode, remote host 192.168.2.247 is sending
[  4] local 192.168.2.137 port 53000 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  11.0 MBytes  92.0 Mbits/sec
[  4]   1.00-2.00   sec  11.3 MBytes  94.8 Mbits/sec
[  4]   2.00-3.00   sec  11.3 MBytes  94.9 Mbits/sec
[  4]   3.00-4.00   sec  11.3 MBytes  94.9 Mbits/sec
[  4]   4.00-5.00   sec  11.2 MBytes  94.0 Mbits/sec
[  4]   5.00-6.00   sec  11.3 MBytes  94.9 Mbits/sec
[  4]   6.00-7.00   sec  11.3 MBytes  94.9 Mbits/sec
[  4]   7.00-8.00   sec  11.3 MBytes  94.9 Mbits/sec
[  4]   8.00-9.00   sec  11.3 MBytes  94.9 Mbits/sec
[  4]   9.00-10.00  sec  11.3 MBytes  94.9 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec   113 MBytes  94.7 Mbits/sec    0             sender
[  4]   0.00-10.00  sec   113 MBytes  94.7 Mbits/sec                  receiver

iperf Done.

Very possibly.

@paw3lk How is the V4k+ connected to the Synology NAS? Specifically, are they both directly connected to the same router or is there a switch (or switches) in the path?

Can you SSH to the V4K+ and run the command ethtool eth0. (You might need to install ethtool first: sudo apt-get install ethtool)

Then SSH to the NAS and again run ethtool eth0. (A quick check suggests that it should be installed.)

Post the output from both machines.

The intended layout is that the PC and the NAS are connected to a router, also there is a switch with AV equipment including V4k+ which is also connected to that router. Now I have taken that switch and other devices out of the equation so there is just the router with PC, V4k+ and NAS.

The ethtool results are as follows:
Diskstation
Settings for eth0:
Supported ports:
Supported link modes: Not reported
Supported pause frame use: No
Supports auto-negotiation: No
Advertised link modes: Not reported
Advertised pause frame use: No
Advertised auto-negotiation: No
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 8
Transceiver: internal
Auto-negotiation: off
Supports Wake-on: d
Wake-on: d
Link detected: yes

Vero4k+
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Link partner advertised pause frame use: Symmetric
Link partner advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: external
Auto-negotiation: on
Cannot get wake-on-lan settings: Operation not permitted
Current message level: 0x0000003d (61)
drv link timer ifdown ifup
Link detected: yes

I have also tried replacing the router with the switch but I’m getting the same results.

According to the ethtool output, your Synology Diskstation doesn’t support auto-negotiation, which is a bit of a surprise. It also says the connection is 100 Mbits/sec / full duplex.

From the Vero4K+ ethtool output, we can see that the router is 100 Mbits/sec and supports auto-negotiation.

Where the NAS can’t auto-negotiate, I would expect the router to follow the standard protocol and fall back to half duplex – which, if correct, will cause a duplex mismatch, since we see that the NAS is still using full duplex. The problem with this hypothesis is that you’ve reported 72-80 Mbps from the NAS to a Windows 8 PC, so I’m hedging my bets for now.

If you can get any further information from the router, that’s going to help with the diagnosis.

One other thing, your iperf3 figures are all for reverse mode. What happens when you run it “normally”?

Couple of more tests. Now the reverse mode from the PC results in the following:

Connecting to host 192.168.2.247, port 5201
Reverse mode, remote host 192.168.2.247 is sending
[  4] local 192.168.2.137 port 50914 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  8.58 MBytes  72.0 Mbits/sec
[  4]   1.00-2.00   sec  11.0 MBytes  92.5 Mbits/sec
[  4]   2.00-3.00   sec  7.98 MBytes  67.0 Mbits/sec
[  4]   3.00-4.00   sec  11.1 MBytes  93.1 Mbits/sec
[  4]   4.00-5.00   sec  8.20 MBytes  68.7 Mbits/sec
[  4]   5.00-6.00   sec  11.1 MBytes  93.1 Mbits/sec
[  4]   6.00-7.00   sec  7.54 MBytes  63.2 Mbits/sec
[  4]   7.00-8.00   sec  11.1 MBytes  93.3 Mbits/sec
[  4]   8.00-9.00   sec  7.38 MBytes  61.9 Mbits/sec
[  4]   9.00-10.00  sec  11.0 MBytes  92.5 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  95.2 MBytes  79.9 Mbits/sec  730             sender
[  4]   0.00-10.00  sec  95.2 MBytes  79.8 Mbits/sec                  receiver
    iperf Done.

Reverse mode from V4k+ - no change

Normal modes:
PC:

Connecting to host 192.168.2.247, port 5201
[  4] local 192.168.2.137 port 50888 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  10.9 MBytes  91.1 Mbits/sec
[  4]   1.00-2.00   sec  11.2 MBytes  94.4 Mbits/sec
[  4]   2.00-3.00   sec  11.2 MBytes  94.3 Mbits/sec
[  4]   3.00-4.00   sec  11.4 MBytes  95.3 Mbits/sec
[  4]   4.00-5.00   sec  11.0 MBytes  92.4 Mbits/sec
[  4]   5.00-6.00   sec  11.2 MBytes  94.4 Mbits/sec
[  4]   6.00-7.00   sec  11.2 MBytes  94.4 Mbits/sec
[  4]   7.00-8.00   sec  11.4 MBytes  95.4 Mbits/sec
[  4]   8.00-9.00   sec  11.2 MBytes  94.4 Mbits/sec
[  4]   9.00-10.00  sec  11.2 MBytes  94.3 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec   112 MBytes  94.0 Mbits/sec                  sender
[  4]   0.00-10.00  sec   112 MBytes  94.0 Mbits/sec                  receiver

iperf Done.

V4k+:

osmc@Vero:~$ iperf3 -c 192.168.2.247
Connecting to host 192.168.2.247, port 5201
[  4] local 192.168.2.237 port 57341 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec  12.3 MBytes   103 Mbits/sec    0    199 KBytes
[  4]   1.00-2.00   sec  11.3 MBytes  95.0 Mbits/sec    0    209 KBytes
[  4]   2.00-3.00   sec  11.2 MBytes  94.1 Mbits/sec    0    209 KBytes
[  4]   3.00-4.00   sec  11.0 MBytes  92.2 Mbits/sec    0    209 KBytes
[  4]   4.00-5.00   sec  11.2 MBytes  93.8 Mbits/sec    0    209 KBytes
[  4]   5.00-6.00   sec  11.2 MBytes  94.3 Mbits/sec    0    209 KBytes
[  4]   6.00-7.00   sec  11.2 MBytes  94.0 Mbits/sec    0    209 KBytes
[  4]   7.00-8.00   sec  11.2 MBytes  94.2 Mbits/sec    0    209 KBytes
[  4]   8.00-9.00   sec  11.2 MBytes  93.6 Mbits/sec    0    209 KBytes
[  4]   9.00-10.00  sec  11.2 MBytes  94.1 Mbits/sec    0    209 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec   113 MBytes  94.8 Mbits/sec    0             sender
[  4]   0.00-10.00  sec   112 MBytes  93.9 Mbits/sec                  receiver

iperf Done.

Not sure what “further information from the router” I could get and how. When I log on to it there’s literally no detailed information, nothing close to what ethtool provides.

So to summarise so far:

  • The Vero4K+, PC and Synology NAs are all directly attached to your 100 Mbits/sec router.
  • Direct mode iperf3 from both NAS and Vero4K+ works at full speed (~94 Mbits/sec).
  • Reverse mode for the Vero4K+ still fluctuates greatly and gives an average of around 2 Mbits/sec
  • Reverse mode for the PC, which was a stable 94 Mbits/sec, has now deteriorated to a fluctuating average 80 Mbits/sec with a large number of retries. (Did you change anything here?)

The asymmetric nature of the iperf3 results still suggests it could be a duplex mismatch. Quite why the V4K+ is affected differently is unclear.

Unfortunately, I don’t know much about Synology boxes. You might be able to run ethtool -s eth0 duplex half to see if that improves matters but you might have to reboot it if it becomes unreachable.

Yes the summary is spot on. I don’t know why it deteriorated, the only thing I did in the meantime was I replaced my router with the switch and then back to the router. I did not reboot anything in the meantime.

I’ve run the command you suggested and now the results are as follows:

V4k+

osmc@Vero:~$ iperf3 -R -c 192.168.2.247
Connecting to host 192.168.2.247, port 5201
Reverse mode, remote host 192.168.2.247 is sending
[  4] local 192.168.2.237 port 57433 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  4.55 MBytes  38.2 Mbits/sec
[  4]   1.00-2.00   sec  3.80 MBytes  31.9 Mbits/sec
[  4]   2.00-3.00   sec  3.68 MBytes  30.9 Mbits/sec
[  4]   3.00-4.00   sec  3.73 MBytes  31.3 Mbits/sec
[  4]   4.00-5.00   sec  4.08 MBytes  34.3 Mbits/sec
[  4]   5.00-6.00   sec  1.82 MBytes  15.3 Mbits/sec
[  4]   6.00-7.00   sec  3.13 MBytes  26.3 Mbits/sec
[  4]   7.00-8.00   sec  3.88 MBytes  32.5 Mbits/sec
[  4]   8.00-9.00   sec  3.65 MBytes  30.6 Mbits/sec
[  4]   9.00-10.00  sec  4.08 MBytes  34.2 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  36.4 MBytes  30.6 Mbits/sec  439             sender
[  4]   0.00-10.00  sec  36.4 MBytes  30.6 Mbits/sec                  receiver

iperf Done.
osmc@Vero:~$ iperf3 -c 192.168.2.247
Connecting to host 192.168.2.247, port 5201
[  4] local 192.168.2.237 port 57436 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec  9.00 MBytes  75.5 Mbits/sec    0    174 KBytes
[  4]   1.00-2.00   sec  8.35 MBytes  70.0 Mbits/sec    0    197 KBytes
[  4]   2.00-3.00   sec  9.46 MBytes  79.4 Mbits/sec    0    208 KBytes
[  4]   3.00-4.00   sec  9.34 MBytes  78.3 Mbits/sec    0    208 KBytes
[  4]   4.00-5.00   sec  9.43 MBytes  79.1 Mbits/sec    0    208 KBytes
[  4]   5.00-6.00   sec  9.31 MBytes  78.1 Mbits/sec    0    208 KBytes
[  4]   6.00-7.00   sec  9.36 MBytes  78.5 Mbits/sec    0    208 KBytes
[  4]   7.00-8.00   sec  9.19 MBytes  77.1 Mbits/sec    0    208 KBytes
[  4]   8.00-9.00   sec  9.42 MBytes  79.0 Mbits/sec    0    208 KBytes
[  4]   9.00-10.00  sec  9.42 MBytes  78.9 Mbits/sec    0    208 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  92.3 MBytes  77.4 Mbits/sec    0             sender
[  4]   0.00-10.00  sec  91.2 MBytes  76.5 Mbits/sec                  receiver

PC:

Connecting to host 192.168.2.247, port 5201
Reverse mode, remote host 192.168.2.247 is sending
[  4] local 192.168.2.137 port 51323 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  8.34 MBytes  69.9 Mbits/sec
[  4]   1.00-2.00   sec  9.12 MBytes  76.5 Mbits/sec
[  4]   2.00-3.00   sec  9.31 MBytes  78.0 Mbits/sec
[  4]   3.00-4.00   sec  9.28 MBytes  77.8 Mbits/sec
[  4]   4.00-5.00   sec  9.51 MBytes  79.7 Mbits/sec
[  4]   5.00-6.00   sec  9.50 MBytes  79.8 Mbits/sec
[  4]   6.00-7.00   sec  9.64 MBytes  80.9 Mbits/sec
[  4]   7.00-8.00   sec  9.69 MBytes  81.3 Mbits/sec
[  4]   8.00-9.00   sec  9.39 MBytes  78.8 Mbits/sec
[  4]   9.00-10.00  sec  9.61 MBytes  80.6 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  93.5 MBytes  78.5 Mbits/sec    0             sender
[  4]   0.00-10.00  sec  93.5 MBytes  78.5 Mbits/sec                  receiver

iperf Done.


Connecting to host 192.168.2.247, port 5201
[  4] local 192.168.2.137 port 51327 connected to 192.168.2.247 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  9.25 MBytes  77.5 Mbits/sec
[  4]   1.00-2.00   sec  8.38 MBytes  70.3 Mbits/sec
[  4]   2.00-3.00   sec  9.75 MBytes  81.8 Mbits/sec
[  4]   3.00-4.00   sec  9.62 MBytes  80.7 Mbits/sec
[  4]   4.00-5.00   sec  9.25 MBytes  77.6 Mbits/sec
[  4]   5.00-6.00   sec  9.62 MBytes  80.7 Mbits/sec
[  4]   6.00-7.00   sec  9.50 MBytes  79.7 Mbits/sec
[  4]   7.00-8.00   sec  9.62 MBytes  80.7 Mbits/sec
[  4]   8.00-9.00   sec  9.38 MBytes  78.6 Mbits/sec
[  4]   9.00-10.00  sec  9.50 MBytes  79.8 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec  93.9 MBytes  78.7 Mbits/sec                  sender
[  4]   0.00-10.00  sec  93.8 MBytes  78.7 Mbits/sec                  receiver

iperf Done.

Dzień dobry.

The reverse-mode iperf3 figures from the V4K+ are still relatively low – though a lot better – and show a large number of retries. I’d be interested to see what ethtool eth0 now shows on the NAS.

I don’t have a Synology NAS and nor do I have a Vero4K +, but I do have a 100 Mb/s Vero4K and a Raspberry Pi3 running OSMC. I therefore tried to create a duplex mismatch on the Pi3, as follows:

ethtool eth0 # check current status
sudo ethtool -s eth0 autoneg off
sudo ethtool -s eth0 duplex half # separated from autoneg, just to be sure
ethtool eth0 # confirm new status
iperf3 -s

After the duplex was changed to half on the Pi3, ethtool eth0 confirmed its status:

osmc@osmc:~$ ethtool eth0
Settings for eth0:
	Supported ports: [ TP MII ]
	Supported link modes:   10baseT/Half 10baseT/Full 
	                        100baseT/Half 100baseT/Full 
	Supported pause frame use: No
	Supports auto-negotiation: Yes
	Advertised link modes:  Not reported
	Advertised pause frame use: No
	Advertised auto-negotiation: No
	Speed: 100Mb/s
	Duplex: Half
	Port: MII
	PHYAD: 1
	Transceiver: internal
	Auto-negotiation: off
Cannot get wake-on-lan settings: Operation not permitted
	Current message level: 0x00000007 (7)
			       drv probe link
	Link detected: yes

Running iperf3 on the Vero4K, we see:

osmc@osmc-4k:~$ iperf3 -c 192.168.8.33
Connecting to host 192.168.8.33, port 5201
[  4] local 192.168.8.32 port 38460 connected to 192.168.8.33 port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec  3.70 MBytes  31.0 Mbits/sec  137   4.24 KBytes       
[  4]   1.00-2.00   sec  3.33 MBytes  28.0 Mbits/sec  124   5.66 KBytes       
[  4]   2.00-3.00   sec  3.37 MBytes  28.3 Mbits/sec  107   5.66 KBytes       
[  4]   3.00-4.00   sec  3.37 MBytes  28.3 Mbits/sec  103   7.07 KBytes       
[  4]   4.00-5.00   sec  3.43 MBytes  28.7 Mbits/sec  105   7.07 KBytes       
[  4]   5.00-6.00   sec  3.44 MBytes  28.8 Mbits/sec  125   7.07 KBytes       
[  4]   6.00-7.00   sec  3.22 MBytes  27.0 Mbits/sec  117   5.66 KBytes       
[  4]   7.00-8.00   sec  3.40 MBytes  28.5 Mbits/sec  118   7.07 KBytes       
[  4]   8.00-9.00   sec  3.51 MBytes  29.5 Mbits/sec  125   4.24 KBytes       
[  4]   9.00-10.00  sec  3.50 MBytes  29.3 Mbits/sec  115   5.66 KBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  34.3 MBytes  28.7 Mbits/sec  1176             sender
[  4]   0.00-10.00  sec  34.3 MBytes  28.7 Mbits/sec                  receiver

iperf Done.
osmc@osmc-4k:~$ iperf3 -R -c 192.168.8.33
Connecting to host 192.168.8.33, port 5201
Reverse mode, remote host 192.168.8.33 is sending
[  4] local 192.168.8.32 port 38462 connected to 192.168.8.33 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec   799 KBytes  6.54 Mbits/sec                  
[  4]   1.00-2.00   sec   549 KBytes  4.49 Mbits/sec                  
[  4]   2.00-3.00   sec   451 KBytes  3.70 Mbits/sec                  
[  4]   3.00-4.00   sec   519 KBytes  4.25 Mbits/sec                  
[  4]   4.00-5.00   sec  1.24 MBytes  10.4 Mbits/sec                  
[  4]   5.00-6.00   sec   775 KBytes  6.35 Mbits/sec                  
[  4]   6.00-7.00   sec   670 KBytes  5.49 Mbits/sec                  
[  4]   7.00-8.00   sec   724 KBytes  5.93 Mbits/sec                  
[  4]   8.00-9.00   sec   792 KBytes  6.49 Mbits/sec                  
[  4]   9.00-10.00  sec   417 KBytes  3.42 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  6.84 MBytes  5.73 Mbits/sec  421             sender
[  4]   0.00-10.00  sec  6.80 MBytes  5.70 Mbits/sec                  receiver

iperf Done.

The figures are nothing like your latest figures, though the reverse-mode figures are similar to those you posted in post #6. It certainly looks like the Synology NAS has a quirky network interface that, according to ethtool, doesn’t support auto-negotiation. It’s unclear if this is correct or if ethtool is wrongly reporting the state. Out of interest, what model is it?

What was the giveaway? :slight_smile:

Here’s what ethtool shows on the NAS:

Settings for eth0:
        Supported ports: [ ]
        Supported link modes:   Not reported
        Supported pause frame use: No
        Supports auto-negotiation: No
        Advertised link modes:  Not reported
        Advertised pause frame use: No
        Advertised auto-negotiation: No
        Speed: 100Mb/s
        Duplex: Half
        Port: MII
        PHYAD: 8
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: d
        Wake-on: d
        Link detected: yes

I have Synology DS211j so nothing fancy. What I’m wondering is whether this is some sort of hardware limitation and I’m screwed or is there something that can be done. I don’t know much about how it all works, just seems counter intuitive that with PC it can work at full speed and that with V4k+ it cannot.

The DS211j dates from 2011 and seems to have a gigabit network interface, so IMO there’s no way it should not support auto-negotiation.

I did a bit of searching and your problem is by no means unusual. For example this. Unfortunately, I’ve not found anyone who has posted a solution. :frowning:

You can try the usual things such as changing ports and swapping cables but I can’t think of a simple solution off the top of my head. Whatever it is, it seems to be an issue with the NAS.

One other thing that might be useful is to see the dmesg output on the NAS when you run things like:

ethtool -s eth0 autoneg off
ethtool -s eth0 duplex half
ethtool -s eth0 duplex full
ethtool -s eth0 autoneg on

I have replaced my current router with a Cisco one to see if it makes any difference. It does not performance wise. What’s interesting is that NAS Network settings show this:

Use DHCP: Yes
IP address: 192.168.2.247
Subnet mask: 255.255.255.0
Network Status: 100 Mbps, Full duplex, MTU 1500

When I go to Port Management on the Cisco router it shows 100Mbps Half Duplex for that port when Auto Negotiation is selected which is the default option. So NAS tells me something different. I can force Full Duplex and the status of that port indeed changes to Full Duplex but it doesn’t seem to make any difference anyway performance wise. There is also a Flow Control checkbox available, cleared by default, again no noticable difference.