Hi,
I have a problem using iRadio on my NDX - it has been there since new. Whenever I use the higher bit-rate stations (such as Radio Paradise 320k, but it happens with other stations too) I experience dropouts. These dropouts can be directly correlated with the buffer level display on NDX falling to zero. The buffer then refills, and the music restarts for about 5 seconds, and the whole cycle keeps repeating. This problem happens sometimes with lower bitrate stations, but is less acute.
I used to have a similar problem with UPnP streaming but this was emphatically solved by the introduction of a small unmanaged Cisco switch and the use of wired ethernet.
My setup is,
NDX, wired ethernet to a switch. This same switch has my NAS wired to it. A third switch port has a wired connection to the ethernet port of an Airport Express.
The airport express is set to join my existing wireless network which is run from a Apple Time Capsule (which is, for these purposes, an Airport Extreme). The reason that I am using this wireless link is that the TC is in a separate room, and I do not wish to use ethernet over mains.
The TC has its WAN port connected to a Motorola cable modem which provides the route out to the internet.
I have perfect UPnP performance, even streaming 24/192 files, however, the iRadio performance is deficient.
I am aware that the iRadio network traffic is traversing the wireless network, whereas the UPnP traffic is confined to the switch LAN, so it seems likely that this problem is likely to be related to the wireless network performance, although all my wireless devices (iPad, iPhone, Mac laptop) all work perfectly.
Does anyone have any suggestions on how to troubleshoot the problem?
Regards,
David.
Posted on: 07 May 2013 by Hudsy
Check to see if your router can perform QoS (Quality of Service) or traffic shaping. Give your NDX a static IP address then in the router set the NDX's IP to high or higher priority.
If you have heavy internet usage from within your home network out to the web then this should help.
Posted on: 07 May 2013 by DavidR99
I do not possess an ethernet cable that is long enough to connect the switch (in a different room) to the router hub port. I will have to reconfigure the router in the lounge, which will take a bit of time but I will report back.
What I have done is attach my Mac laptop to the switch using ethernet, and using iTunes as the iRadio player. 320k stations play fine using this configuration. I then connected the ethernet cable from NDX to the same switch port as the Mac was on, but the NDX still has the same problem.
I then used the ethernet cable that the Mac was using, and the NDX still has the problem.
What seems to be apparent from the above is that there is no problem with the cable or switch port, and also that the wireless network seems not to be at fault.
All that I can think of is that the Mac has a different buffering scheme and/or a larger input buffer than NDX. Does anyone know the answer to this question?
In any case, the problem is still there, so I will follow-up with Phil's suggestion later.
Posted on: 08 May 2013 by Simon-in-Suffolk
Hi, I have seen this or similar happen before with customer configurations. (not hifi related) although there are a multitude of possibilities, assuming your wifi has enough bandwidth can you confirm
A) does this happen when your Internet link is being used for other purposes, if so what?
B) what is the speed of your Internet feed? If very fast say fibre and you are then channelling into a slow wifi link especially with but not always with other traffic on the internet link, the TCP windowing can retries can oscillate. Only wire shark can confirm.
If this is the case basic shaping might be required on your router/wifi if it has the option, to prioritise the NDX as stated above. Advanced routers have a technique called WRED for encourage TCP window parameters to adjust to busy links or the conditions.
I do think perhaps Naim can improve this tweaking the TCP windowing buffers given that consumer routers don't tend to have this... Perhaps reduce TCP window size and increase payload buffer.
I do see this with Radio Paradise from time to time and I am sure it's TCP windowing related. If a leave a few hours, the underlying Internet conditions have usually changed and I am back to normal.
Network performance end to end is a dynamic thing....
Simon
Posted on: 08 May 2013 by DavidR99
Hi,
I have now tried (in effect) Phil"s suggestion, by moving the router and cable modem into the lounge (where the hi fi is). There is no difference - I still get the drop-outs. I guess this means that the wireless network element is not the problem.
Simon - your comments are interesting. I do indeed have a fast fibre network into my apartment. Nominally it is a 100 Mbit/sec service, and I have seen it very close to that actual speed.
Unfortunately (perhaps someone more knowledgeable can correct me), it seems that my Apple Time Capsule (Airport Extreme) has no way to prioritize traffic via Quality of Service settings, although I could setup a dedicated IP address for the NDX.
Perhaps my only real recourse is to purchase a better-specified router with quality of service controls. Does anyone have any recommendations?
Thanks.
Posted on: 08 May 2013 by Phil Harris
Originally Posted by DavidR99:
Hi Phil - I just reconfigured the NDX so use the wireless network (no ethernet cable connected), and the the behaviour is identical. Still drop-outs.
Hmmm ... interesting ...
So neither a wireless connection to your network nor a wired connection to the switch (and then wired up to your router) work? (We use a different buffering schema on wireless to wired to allow for additional latency on wireless networks so wanted to check that one out.)
In that case can we just as a final check try wired directly into your router from the NDX?
( I do realise this may sound long winded but it's just isolating down where the issue is coming in - a PC generally tends to have a lot more memory and is able to employ much more flexible buffering schemes than an embedded device however obviously doesn't sound as good...)
Cheers
Phil
Posted on: 08 May 2013 by DavidR99
OK, I reconfigured my network so the TC and cable modem are in the lounge, and connected the NDX direct to a LAN port on the TC.
The behaviour is identical, so still drop-outs with about a 5 second frequency.
I guess this conclusively rules out the wireless network, switches and cables, and firmly points to the router or internet connection. The connection is a very modern (this is SIngapore...) fibre circuit that is nominally 100 mbits ps. It is delivered into my apartment as coax cable. It is very reliable and fast for every other purpose.
Am I now looking at a new router that has more sophisticated QoS controls as suggested previously?
Posted on: 09 May 2013 by Phil Harris
You shouldn't need a "more sophisticated" router though - we've got AirPort Extremes and AirPort Express' in use here with no issues - so I certainly wouldn't go and buy something without trying it first and checking that it does resolve the issue.
I'm wondering whether it's an issue with the cablemodem / ISP and the fact that we're generally working with small but frequent buffer refreshes ... I know we had a customer out in Singapore who had a similar problem and was never able to get round it. His "network" (router, NAS, server and streamer) worked fine when transferred to a different location but on his network he just had continual buffer cycling and when we looked at the traffic from the WAN side of the router we were simply getting very intermittent data flow.
In the end he used a UPnP server on his PC that could squirt out the capture of the PCs sound card as a UPnP stream and listened to Internet Radio that way - not ideal but it worked.
Phil
