Cisco switch

Simon-in-Suffolk posted:

Mrs Wogan's lemon drizzle cake posted:

Funnily enough we have a stack of old 2960s ready for the skip (I'm a network engineer by day). 

However, there is nothing magical about this switch.  Ultimately It's just switching frames from one port across it's backplane (crossbar) to another.   Same as any other layer two switch in principle (apart from the fact that traditionally Cisco use their own ASICs, as opposed to merchant silicon).

I've read various vague and unsupported claims regarding increased sound quality due to using this particular switch,  none of which make any sense, at all.

I am also a network design engineer with a background in system and RF engineering, and in my line of work it makes total sense... by the way you are right it nots specific to the 2960 including the new models, but it does seem specific to the various Catalyst switches I have tried including layer 3 Catalyst switches... The EM response to physical differential line driver layouts and the PHY clock stability and its lack of intermodulation products would appear to be helping. The effects or otherwise are taking place before (or after depending on your perspective) of the ASIC(s)

What I have found in my experience is that it  is nothing or very little to do with the devices powersupply. But being an engineer I observe (and listen) and then look to evaluate why one experiences an outcome. I believe it was myself who first discovered this ‘benefit’ of using, as it was then, a 2960 Fast Ethernet switch device a few years back, when I discovered it by accident when I was was narrowing down an issue of Ethernet intermodulation PHY layer clock frequency products from a particular home network switch product affecting stereo decoding birdies on my FM tuner... and I investigated further.

i have also found and analyzed sound differences between different media servers based in inter Ethernet frame timing consistency... I had shared my findings with Naim... and well what I can say is that the network  streaming module design of the newer devices has changed.... its good to have an open mind and the where with all and tools to investigate further ... you never know little discoveries have the possibility of improving our Hi-Fi products further...

Out of interest, why would the likes of Naim not build in what ever technical wizardry you’ve described above in to their products if it brings such a benefit

Mercky posted:

Simon-in-Suffolk posted:

Mrs Wogan's lemon drizzle cake posted:

Funnily enough we have a stack of old 2960s ready for the skip (I'm a network engineer by day). 

However, there is nothing magical about this switch.  Ultimately It's just switching frames from one port across it's backplane (crossbar) to another.   Same as any other layer two switch in principle (apart from the fact that traditionally Cisco use their own ASICs, as opposed to merchant silicon).

I've read various vague and unsupported claims regarding increased sound quality due to using this particular switch,  none of which make any sense, at all.

I am also a network design engineer with a background in system and RF engineering, and in my line of work it makes total sense... by the way you are right it nots specific to the 2960 including the new models, but it does seem specific to the various Catalyst switches I have tried including layer 3 Catalyst switches... The EM response to physical differential line driver layouts and the PHY clock stability and its lack of intermodulation products would appear to be helping. The effects or otherwise are taking place before (or after depending on your perspective) of the ASIC(s)

What I have found in my experience is that it  is nothing or very little to do with the devices powersupply. But being an engineer I observe (and listen) and then look to evaluate why one experiences an outcome. I believe it was myself who first discovered this ‘benefit’ of using, as it was then, a 2960 Fast Ethernet switch device a few years back, when I discovered it by accident when I was was narrowing down an issue of Ethernet intermodulation PHY layer clock frequency products from a particular home network switch product affecting stereo decoding birdies on my FM tuner... and I investigated further.

i have also found and analyzed sound differences between different media servers based in inter Ethernet frame timing consistency... I had shared my findings with Naim... and well what I can say is that the network  streaming module design of the newer devices has changed.... its good to have an open mind and the where with all and tools to investigate further ... you never know little discoveries have the possibility of improving our Hi-Fi products further...

Out of interest, why would the likes of Naim not build in what ever technical wizardry you’ve described above in to their products if it brings such a benefit

That was exactly what Simon said. Naim incorportated his findings in the next generation of the streamers.

Yeh I know he did but why do we hear benefits by using a 2960 then? Or does he mean future yet to be released streamers?

The EM response to physical differential line driver layouts and the PHY clock stability and its lack of intermodulation products would appear to be helping.

Hi Simon, what does it appear to be helping with exactly?

I believe, per Simon, that the sound improvement is due to dealing with the Ethernet frame timing issue.

It would be interesting to know which streamers getting the benefit from the fix?

Frank Yang posted:

I believe, per Simon, that the sound improvement is due to dealing with the Ethernet frame timing issue.

It would be interesting to know which streamers getting the benefit from the fix?

Could you elaborate on what this timing issue is?

Simon would be a better person to explain it, my understanding is that the a wide variations in time of the frame arrivals causes some degradation, in another word,  it is the network jittery that causes some audio distortion.

Hi Simon - I take it that the variations in Ethernet frame timing will have minimal effect on the new streamers (based around the NP800 module) as these can buffer a whole track into memory and play straight from there rather than pulling data continuously across the network during playback?

James

Mercky posted:

Yeh I know he did but why do we hear benefits by using a 2960 then? Or does he mean future yet to be released streamers?

Two different things... the 2960 matter is I believe intermodulation products. The point about media server sq that I shared with Naim was about media streaming strategy, which, whether by coincidence or not Naim has completely redesigned the media streaming strategy to mitigate certain transport issues (where the peer allows)

james n posted:

Hi Simon - I take it that the variations in Ethernet frame timing will have minimal effect on the new streamers (based around the NP800 module) as these can buffer a whole track into memory and play straight from there rather than pulling data continuously across the network during playback?

James

It should do, as decoupling is increased, and the application memory allows the media to be cached far quicker. I have yet to evaluate the new platforms on this however. It could be the SQ changes now between spooling or not spoiling ie when the media is fully transferred.. feels unlikely.. but as I say I have not evaluated the new platforms

Mrs Wogan's lemon drizzle cake posted:

Frank Yang posted:

I believe, per Simon, that the sound improvement is due to dealing with the Ethernet frame timing issue.

It would be interesting to know which streamers getting the benefit from the fix?

Could you elaborate on what this timing issue is?

Yes it is the timing consistency between layer2 (Ethernet ) frames during a media transfer. It’s quite complicated as the transfer is not a consistent stream, but is is regular intermittent  ‘buzz’ of activity.  During the media transfer where the media frames are consistently spaced, and dynamic flow control was not initiated but instead transfer semaphoring was used by zeroing receive window and then opening, it the SQ seemed to improve (subjectively)

Where the interframe spacing was more variable, and dynamic flow control initiated then the SQ reduced slightly (subjectively).

The classic Naim streamers seem to support these two types of transport flow control, and is dependent on the rate of media transfer from the peer host.

i have created some wireshark settings to capture and graphically display this if you are interested.

in essence all I believe we are hearing is the noise caused by the NIC and TCP engine from the streamer module coupling into the DAC clock and analogue stages.

Simo

Simon-in-Suffolk posted:

GraemeH posted:

Mrs Wogan's lemon drizzle cake posted:

Funnily enough we have a stack of old 2960s ready for the skip (I'm a network engineer by day). 

However, there is nothing magical about this switch.  Ultimately It's just switching frames from one port across it's backplane (crossbar) to another.   Same as any other layer two switch in principle (apart from the fact that traditionally Cisco use their own ASICs, as opposed to merchant silicon).

I've read various vague and unsupported claims regarding increased sound quality due to using this particular switch,  none of which make any sense, at all.

Surely the smart thing to do is get them on ebay then!

G

Graeme, exactly, you can’t really go wrong... as only the now obsolete Fast Ethernet devices are all that is required for home audio.. 

Hi Simon,

I have a Cisco SG110 24HP switch sitting awaiting installation. How, in your view, does this product compare to the (widely recommended) 2960?

regards

Hi, I honestly don’t know... I haven’t evaluated it... I suspect however it may not bring the same benefits as the catalyst models... as it is probably built differently to a lower specification as it is designed and marketed to a low cost market ... but I am speculating...  certainly in my experience not all Cisco devices sound as good as the 2960/3560 series Catalyst  switches