Optical Network Configurations

3 hours ago, Assisi said:

I always thought that there was a benefit with the optical.  I also thought that there was a very small disbenefit. 

May be a trade-off, or preference.  Wire can allow noise into the devices it is connected to, fibre doesn't but generates noise of its own.

3 hours ago, Assisi said:

Where is the noise initially induced so that it can be conducted.  Is it before your network starts or happens during the transmission journey through your network?

From my observations and tinkering, the noise can have multiple types and sources possibly at the input and certainly during the transmission journey ... and even other parts of the network not in the line of the journey.  It seems to come from power, the environment (eg. RF, vibration), the electronics in switches and routers, algorithms, and so on.  Each source could be tiny but it all adds up ... the network seems to have its own noise floor.

1 hour ago, jabbr said:

The most obvious conclusion is that you prefer some degree of common mode noise.

I don't have a DAC cable, just going from what others say and the other thread.  Maybe they prefer the common mode and other noise from the DAC cable more than the SFP noise.

1 hour ago, jabbr said:

the eye pattern

Maybe that eye pattern thing is not a good measure for what we hear.

1 hour ago, jabbr said:

The fundamental issue is that when you hear a SQ difference after making a change, you are ascribing that to something technical without establishing the link between your hearing and the technical terms you are using. This isn’t just “logic”. What you hear is what you hear. Your explanations however are not substantiated — 

I hear the effect as a result of the cause and I'm pretty sure I'm not imagining it, and that I'm not alone with these types of observations.

I'm not criticizing you or what you are saying.  Just pointing out that what you seem to have great faith in, for very sound reasons, might not be the total solution for the issue of transmitting high resolution audio files for payback on audiophiles systems (which in the scheme of things are relatively extreme revealing).

I commend you for sharing your knowledge that many people have benefitted from by adopting fibre and especially 10G/SFP+.  For example, in my case the CRS 305 is an excellent solution for a router.  And I have managed to improve its performance considerably (in my view), especially using Synergistic Research Tranquility POD, ECT, FEQ, grounding and MIGs (no play dough though).

Let's just accept we have different experiences and try to learn from one another and leverage from that rather than needing to provide proof - that tends to deteriorate good discussion toward being unpleasant.

I seem to have stirred the flow of this thread somewhat and caused discussion that is not strictly on topic, however I consider it is relevant to flesh out a bit how dependable the 10G spec may or may not be.  For example, in my experience the CRS 305 is excellent, especially considering the cost, but inferior to EtherRegen which is 1G in 100M out.

I have been using optical (SFP + CommScope TeraSPEED) for a long time.

At the same time implementing at lot of elements to reduce/eliminate potential common mode noise.

I than bought Amphenol SFP+ 10GbE direct attach passive copper cable (DAC) and did a comparison.

I still enjoy the DAC cable.

2 hours ago, Jud said:

 

If I were to look at potential causes (I don't have the facilities to measure, nor have I seen measurements), then greater common mode noise is certainly one possibility, dependent on the particular system. (That is, do the specific network components in the specific system configuration result in a common mode noise current flowing through the system such that there's an audible difference?)

 

Another possibility that occurs to me is electrical noise from the final opto-electronic conversion, again dependent on the particular system.

well ha ha *you* aren't throwing out scientific sounding explanations for what you are hearing.

I agree with you and frankly that's why I chose to use fiber which we know doesn't transmit common mode noise, and why I chose to use 10G or faster where I know *someone* has measured jitter and differential mode noise. As I've said, I can't hear a difference between 10G and 100G so really whatever the jitter,noise amounts are its below my threshold. There are *far* more things that I can hear such as filters,modulators,amplifiers, room correction, speakers etc. 

Now ... I *am* using my network to do computing so this isn't at all a waste for me...

2 hours ago, dbastin said:

Maybe that eye pattern thing is not a good measure for what we hear.

Exactly!!! who is claiming the eye pattern is a good measure for what we hear?

I'm saying this: fiber eliminates common mode noise, and the eye pattern of 10G (which is a measure of both jitter and differential mode noise) is measured to be very low. There is absolutely no reason to believe that a tigther Ethernet eye pattern is any sort of  measure of what we hear. You can work on optimizing everything else.

3 hours ago, Jud said:

 

It was less than 40, something like 32 or 36, for 10G optical as I recall. It was shown in UI, which I back calculated to ps. The slave jitter number of 20ps shown in your reference is quite close to my recollection of 16 or 18 for 10G copper.

For folks reading, this is end to end "jitter" not clock jitter, the component of the total jitter due to the clock is maybe 10% and most of it is due to the rest of the electronics -- you can't stick a femtosecond clock where a 10 femtosecond clock was and expend a 100 picosecond electrical circuit to improve, you have to design the entire circuit to be 10 femtoseconds ... that we could ever *hear* these differences.

8 hours ago, jabbr said:

Exactly!!! who is claiming the eye pattern is a good measure for what we hear?

 

I'm saying this: fiber eliminates common mode noise, and the eye pattern of 10G (which is a measure of both jitter and differential mode noise) is measured to be very low. There is absolutely no reason to believe that a tighter Ethernet eye pattern is any sort of  measure of what we hear. You can work on optimizing everything else.

I understand the benefits of fibre and 10G and its eye pattern, and have experienced both.  

I have implied your reiterating of the 10G spec and eye pattern as your contention that its rejection of noise is more than adequate for audiophile purposes.  It seems I have misunderstood you, my apologies.

11 hours ago, dbastin said:

I understand the benefits of fibre and 10G and its eye pattern, and have experienced both.  

 

I have implied your reiterating of the 10G spec and eye pattern as your contention that its rejection of noise is more than adequate for audiophile purposes.  It seems I have misunderstood you, my apologies.

I am saying:

1) Using a modern Ethernet network, the eye-pattern ensures that the rejection of noise is in fact more than adequate for audiophile purposes

2) There are transmission layers above Ethernet, e.g. the IP layer for which there has been virtually no discussion: "jitter" at these layers certainly causes audible effects, most obviously "pops" and dropouts, but more subtle audible effects have only been scantly investigated. The packet delays or "jitter" at the IP level is > 1,000,000 times that of the underlying Ethernet layer i.e. in the millisecond to 100s of millisecond range and most certainly audible

yeah Ravenna etc works to minimize this nonetheless the packet delay variation or packet jitter (network jitter) remains vastly higher by orders of magnitude than the ethernet clock jitter etc.

This may be an easy to understand link: https://www.nextiva.com/blog/network-jitter.html

https://store.ui.com/us/en/products/usw-aggregation

If I were putting in a new 10GbE network today this is what I would get

Ubiquiti is a great company and the products work together really well, with great configuration

Ubiquiti user interface, when I used it with Edge Router, seems much more friendly than Mikrotik.

I noticed this CRS (Cloud Router Switch) under switches ... 100G

https://mikrotik.com/product/crs504_4xq_in

This one is a bit more costly but conveniently has DC input (36v though) but inconvenient;y in an outdoor enclosure (I wonder if it can be removed from the enclosure)

https://mikrotik.com/product/crs504_4xq_out

This one is 40G ...

https://mikrotik.com/product/crs354_48g_4splus2qplusrm