[vcf-midatlantic] SX GBIC fiber cable speed
telmnstr at 757.org
Mon Feb 15 19:38:36 UTC 2021
FS.COM is pretty good.
I used to work at a place that used 10baseFL. It was a big waste of money.
Every computer that came in had an Intel 100mbps nic, it got yanked and
replaced with a $400 10 megabit fiber card. But when lightning struck near
one of the buildings, it blew out like $100K worth of Lucent Definity
phone boards and every HP cat5 jetdirect board.
Now at the $day_job at my best point it's a quad LAG of 100-gigabit, for
400 gigabit total. How far things have come. At last job I saw a rack
half-full roughly sustaining a terabit per second to the internet. 12 x 1u
I still have a Sun and Indigio2 FDDI card or two somewhere, and one for
Indy. At one point in time I had like 5 Indy/Challenge S all on FDDI. Will
probably bring some of it to the next swap event.
On Mon, 15 Feb 2021, Jameel Akari via vcf-midatlantic wrote:
> Before somebody says "it's not vintage!" consider that 1Gb Ethernet on fiber
> was spec'd for FDDI cables, and there were optical transceivers for even 10Mb
> Ethernet - I brought a set of AUI to 2xST for the Unix Town networking, just
> because I had them. Also, early 1Gb Ethernet was all 1000base-SX with SC
> connectors, at least that I saw. It took a while for copper UTP to be
> supported. I have a few Digital and Sun 1Gb NICs that are optical, and so I
> run them that way.
> Now, at 25m, you /really/ don't need fiber for 1Gb Ethernet. Properly
> installed UTP copper should work reliably for years in normal environments.
> It's surprising and unusual you had some fail. Exception: crimped RJ45 ends
> on solid conductor UTP cable is likely to fail over time if there's any
> movement or vibration. Punch on some jacks and use premade jumpers.
> You can run 10Gb over Cat6A UTP at this distance as well. This is harder to
> terminate by hand, but you could just get premade patch cables (they will be
> 26-28 AWG stranded, most likely)
> But since you've already got optics and fiber is a lot cheaper than it used
> to be... why not?
> - You're better off not trying to use the same cabling for 1Gb and 10Gb, but:
> - You *can* do short-range 1000base-SX with OM3, though it's not spec
> depending on where you look. It will work.
> - By the book, use OM2 for 1Gb and OM3 for 10Gb, assuming short-range optics
> like your SX SFPs. (SFP, not GBIC, if you're talking LC connectors)
> - OM2 is usually orange and OM3 is usually aqua-blue.
> - As far as I can tell, you don't need mode conditioning for SX (short-range)
> optics. If you needed to use LR 1Gb optics, or use single-mode optics into
> MMF cabling plant, then you'd use a mode-conditioning cable to clean up the
> - Bend radius is typically 10x the outside diameter of the cable, unless
> otherwise specified. Here, it's a single strand of a duplex cable. So if
> it's about 3mm across, bend radius is 30mm. (but see below on
> bend-insensitive cable). When I dress cables I usually eyeball 3-4" diameter
> loops. Any smaller just doesn't look or feel right anyway.
> I'm assuming that at only 25m you're buying pre-terminated cables with LC
> plugs both ends. This means you need large enough holes in things for those
> plugs to fit through. Otherwise it's definitely not worth splicing your own
> at this scale.
> https://www.fs.com/products/74386.html?attribute=226&id=99219 - for $16.72
> each at 25m, you get new "bend insensitive" cable (7.5mm radius!)
> I love FS.com for all manner of fiber and related cabling:
> These have some rule-of-thumb charts.
> I think that covers it?
> Jameel Akari
> On 2021-02-15 12:25, Neil Cherry via vcf-midatlantic wrote:
>> I've posted this in the CDL list also. I don't know of a polite way to
>> post once to both and
>> I'm not sure it's a good idea to try. :-)
>> It has been a while since I played with fiber (2010) and I'm trying to
>> figure out if I
>> should go fiber or copper in my home. Here's what I know from my current
>> - SX GBIC
>> - LC
>> - duplex
>> - MMF
>> I want to buy about 25M of fiber. I think the price is competitive
>> with copper. I'm also
>> hoping that the fiber will age better than the copper. I'm seeing a
>> few old copper drops
>> fail to lower settings. One went to 10/half (wow, that's bad).
>> The GBIC & switch I have handle 1G. So I can easily pop in a few
>> 1000baseT, put them
>> into a LAG and get 4G (4 ports). So I'm covered for a while.
>> - Can the same piece of fiber handle 1G or 10G? (in case I upgrade in
>> the future).
>> - Does anyone know the bend radius of this fiber?
>> - What color should I expect for SX fiber. ?
>> - What's a "mode-conditioning patch cord" ?
>> I'm seeing a $35 price for 25 Meter OM3 LC LC Fiber Patch Cable
>> (Corning 50/125um core/cladding)
>> and it says 1G but with a "mode-conditioning patch cord" (an attenuator?).
>> Any pointers?
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