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vett93
2012-01-21, 17:25
What are the right througput levels for Transporter and SB Classic? I used the Network Test function and obtained about 1 Mbps throughput for them. Note that both of them are wired. 1 Mbps throughput on a wired network seems to be very low to me. Are there ways to improve the throughput?

I experimented server side transcoding and converted FLAC and Apple Lossless files to PCM before sending to Transporter and SB Classic. They play just fine. But when I use Wireshark to trace the packets, I see lots of packets from the server labeled as "TCP segment of a reassembled PDU". This seems to me that there are lots of packet retransmissions.

I also traced some packets for MP3 music. There are no such "TCP segment of a reassembled PDU" packets from the server side. This suggests that there is no packet retransmission for MP3 music.

I would be interested in tuning the system so that my Transporter and SB Classic can achieve higher throughput level. Thanks.

Mnyb
2012-01-22, 00:44
Network test is not 100% reliable in higher bitrates it loads the player more than real transmissions.
The code formthat have changed, I do remeber that i've sent more than that to a wired players but as the test does not work as well as it used to...

16/44.1 pcm is rougly 1.4mbps .

And if they play just fine there is really no problem to solve .

You may gain some reliability if you do serverside transcoding for flac on24/96 files with very high compression levels ( they can stutter) otherwise it serves no purpose .
Or you can reflac those files with level -0 or -5 then the TP manages fine

For alac you must trancode as they don't play it natively, but transcode to flac.

You only need half the troughput with flac for the same resolution, that why most transcoding is set up to flac in the first place.

I do remeber that my win XP never managed more than 1,5 mbps but ubuntu on the same PC got me up to 5 mbps when the test worked, the menu for it seems entirely gone on my boom ?
You may have to use a controller to start it.

vett93
2012-01-22, 01:49
My Transporter plays 16/44 and 24/96 PCM streams just fine. Since I am an engineer by education, I can't stand that the packets are dropped and then re-transmitted. :-)

I am guessing that the TCP window size is too big. The LMS sends more data than the Transporter can accept. This could lead to buffer overflow and then packet re-transmission.

Mnyb
2012-01-22, 02:16
My Transporter plays 16/44 and 24/96 PCM streams just fine. Since I am an engineer by education, I can't stand that the packets are dropped and then re-transmitted. :-)

I am guessing that the TCP window size is too big. The LMS sends more data than the Transporter can accept. This could lead to buffer overflow and then packet re-transmission.

ignorance is bliss :-)

vett93
2012-01-22, 02:20
Half of the fun is in tweaking the system and the other half is in listening to music! :-)

Mnyb
2012-01-22, 02:29
yea btw networks test is even wierder on squeezeplay devices .

but it serves it purpose , most people does not test functioning networks , thay usually have problems usually with wifi , here the test is still god enough and gives you some valuable info .

I reinstalled the network test plug and managed 1500k to my boom (wired).

vett93
2012-01-22, 02:45
I sometimes get 1.5Mbps, measured by Network Test, on my wired SB and Transporter too. When I play 24/96 PCM streams to the Transporter, I get 5+Mbps as measured by the Wireshark on the PC (Windows Vista). It plays fine. But I see lots of retransmissions....

bpa
2012-01-22, 02:56
Packet reassembly problems doesn't necessarily mean retransmisiion - it could mean a Max PDU size mismatch somewhere - I had a problem a few years ago with a network driver which had this issue.

You could use netstat on the Windows PC with "-s" and check stats on IP and TCP protocols. THis is easier than Wireshark to check what PC actually "sees".

vett93
2012-01-22, 21:39
Good point. I used "netstat -s" and found not too many re-transmissions. So I sent the wireshark traces to a friend who knows more about this tool. He told me the reassemblies were from the upper layers. So I don't have a transmission problem.

Thanks all for the help. Guess the throughput testing on Transporter and SB3 is not accurate at all.