[vcf-midatlantic] SX GBIC fiber cable speed
jakari at bithose.com
Mon Feb 15 20:06:23 UTC 2021
On 2021-02-15 14:38, Ethan O'Toole wrote:
> FS.COM is pretty good.
I'm hard-pressed to think of anyone else that provides the same kind of
> 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
We had it to span a 12-story building with waaaaay to large a collision
But it sounds like 10base-FL (forgot that name...) saved your computers?
> 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.
I have some mild interest in these things. :)
> 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
>> - 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 noise.
>> - 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
>> 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
>>> 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
>>> figure out if I
>>> should go fiber or copper in my home. Here's what I know from my
>>> - 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
>>> 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
>>> Any pointers?
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