Posh switches, fibre bridges, Cat5e and SFPs.

There has been some discussion of the use of fibre optic cables for network isolation, and of Cisco switches, most of which have SFP ports, recently, so I thought I would post my findings on this.
I’ve been running a fibre optic network for a couple of years now, prompted by the fact that out phone line has been hit by lightning twice now, and on the first occasion it destroyed everything with a wired connection to the router, including a Unitiserve. Using optical connections seemed like a sensible precaution, and I did it for the whole network rather than just a single fibre bridge. It was a bit messy, as it required the use of several media converters, with the inevitable SMPS’s cluttering up the house, but it did work well.
A recent house refurb prompted me to rethink all this, and I decided to try what I think is a neater solution, using switches with SFP ports instead of media converters. This has been running for a couple of months now, and I’m pretty happy with the result. Buying used Catalyst 2960 switches, and Cisco SFPs, on eBay, makes this a cheap thing to do - which is just as well, as it’s expensive stuff if you buy it new.
Here’s a pic of my router cupboard (still a bit of tidying up to do!)

And this is the 'posh' media converter that now feeds my NDX - prior to cable dressing and hiding under the sofa:

I suppose the real question is - does it sound any good? Well I was using an Airport Express as a temporary wireless connection while I set this up, and compared to that, I do think there's an improvement. Maybe that was just down to the removal of the electrically noisy AE, though. Is it better than a simple Cat5e network? I don't know, if you want to find out, you'll have to try it for yourself!

Finally, thanks to @Simon-in-Suffolk for various bits of advice, and for his tolerance of us amateurs blindly dabbling in his professional world.

Original Post
Lord_HIllier posted:
Question; why use Cat5e and not Cat6a, is the Cat5e shielded i.e. STP?

It’s just regular Cat5e UTP from switch to NDX, although a reasonable quality one rather than a spare that comes free with a router. To be honest, I haven’t spent much time experimenting with Ethernet cables - I’m a little sceptical of some of the claims people make about very expensive audiophile streaming cables, but to be honest, I’ve never tried one. I’m not sure if shielding is strictly necessary in a simple home network, and at the moment I’m more focused on removing potential sources of noise (such as SMPS on media converters and Airport Express) rather than using screened cables. 

Gazza posted:

Chris, what SFPs do you have/ recommend for the Cisco 2960 with SFPs Port. The range out there looks bewildering. I currently have a ws-2960 8tc s.

The type of SFP depends on the cable/connector as well as the switch. I used Cisco GLC-SX-MM. Non-Cisco branded ones are very cheap, but some will only work if you use the CLI to force the switch to recognise them. I did manage to figure this out, but it’s a bit of a faff if you’re not used to it. Fortunately, Cisco branded SFPs, normally very expensive, are very cheap on ebay. 

@Gazza for the Cisco SFPs I suggested, you want a multimode duplex cable with LC connectors. OM1 version is fine, OM2 or OM3 will also work. There are loads of online sources, try Cable Monkey or fs.com

 If all this terminology is unfamiliar to you, it can be a bit confusing, but setting it up is actually very simple. If your switches are set to factory settings it’s just plug and play. 

Thanks CHRISSU, but but more on how much of an improvement This Is all making please : )

So help me as I have the same Cisco 2960.

My current setup is Router (ethernet) to Cisco 2960 (ethernet) to TP Link Fibre link No.1 (fibre cable) to TP Link Fibre link No.2 (ethernet) to Nova.

So looking at your setup I can remove one TP Link Fibre link so I end up with as follows.

Router (ethernet) to Cisco 2960 (fiber cable) to TP Link Fibre link No.1, then (ethernet) to Nova ?

There is no point at all in using a Catalyst switch to go to an interrupted segment with a consumer fibre bridge... you are undermining the whole benefit of the low noise PHY clock on the switch and introducing an almost certainly noisier consumer one on the bridge...I suspect what you end with is just moving the noise profile around with these consumer fibre bridges.

When and if Naim support SFPs, one can then experiment between multimide and dual single mode fibre links... I suspect each one will ‘sound’ slightly different. Just remember with fibre to watch the minimum length... best check for corrupt frames on the managed switch and use attenuators if appropriate.

 

banging the stones together may give fire....i hope Obsydian will make some fire: put sfp on the cisco, run fiber optic to media converter then lan to the nova.  There will be only one tp link in the chain, not two as before. Perhaps it will sound better?    little cost, no risk.

Obsydian posted:

My current setup is Router (ethernet) to Cisco 2960 (ethernet) to TP Link Fibre link No.1 (fibre cable) to TP Link Fibre link No.2 (ethernet) to Nova.

So looking at your setup I can remove one TP Link Fibre link so I end up with as follows.

Router (ethernet) to Cisco 2960 (fiber cable) to TP Link Fibre link No.1, then (ethernet) to Nova ?

The 2960 with SFP is, in effect, a media converter. So if you only have one, and intend to use a TP Link on the other end, put the switch next to the streamer, and the TP Link at the router end. Better still, get two 2960s, one at each end, and completely eliminate the TP Links. 

But this is speculation on my part, based on observations reported here by Simon and others. I can’t say from experience what effect this will have on sound quality, and that was not my original reason for using it. Maybe I’ll try bypassing it with a regular Ethernet cable at some stage and see if I can tell the difference. 

DiscoVolante posted:

This is a step too far IMO - if you're concerned about SQ from network switches you probably have something missing in your life.

I'm quite sure that I have heard subtle differences in sound from different network setups, and due to a plentiful supply of used units, these things are pretty cheap to try. I've also found that these Cisco switches seem to be very robust, and controlling a streamer with the Naim app has become noticeably faster. Of course, I'm not suggesting that anyone needs to do this - a Cat5e cable straight from your router should work perfectly well, and if it does, just leave it at that.

Simon-in-Suffolk posted:

Just remember with fibre to watch the minimum length... best check for corrupt frames on the managed switch and use attenuators if appropriate.

Simon, if you don't mind me asking, how short do cables have to be for this to become an issue? I'm using 17 metre lengths of OM1 cable, and that seems fine, although I may add another, slightly shorter length later. I was under the impression that attenuators are more likely to be required on singlemode cables designed to transmit over a longer distance. 

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