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On Wed, Nov 2, 2011 at 5:05 PM, Simón Ruiz <[email protected]> wrote: > On Wed, Nov 2, 2011 at 12:28 PM, Jeremy Nelson <[email protected]> > wrote: >> I may be missing something here, but if I'm reading this correctly, I >> believe you're planning to buy multimode fiber. > > We were actually planning on single-mode before I realized it was > incompatible with all the fiber equipment we currently have. > > Now I'm just in the middle of trying to wrap my head around the > implication of the choices, so we can pick the best for our needs. > >> Based on my experience, I >> believe you're going to definitely want single mode, so that you can run 1G >> for now, and 10G later by just swapping transceivers. I'm pretty certain >> that if you put multimode under the golf course now, you're going to be >> limited physically to 1G, no matter what transceiver you use. > > See, I'm nervous to go multi-mode because of just this possibility. > But do you, or anyone, know this for a fact? > > I've yet to see this stated definitively anywhere—I only ever see the > statement that there *are* no 10G transceivers, not that there never > will be—and my brain just doesn't feel comfortable accepting it > without some sort of corroborating explanation, as it clashes with > both my pre-conceived notions and my ideal world. ;-) > > All the explanations I've read for why we're limited to 1 Gigabit only > seems to explain "why multi-mode can't transmit the same bandwidth at > the same distance as single-mode", not "why multi-mode can never reach > a speed of 10G". Reading through theory of multi-modal dispersion, I > can't find a concrete reason why 10G modules at this distance *can* > never exist. > > I can also *imagine* (through a haze of ignorance) that at some point, > when Fast Ethernet was expensive, that there were Fast Ethernet > modules for fiber, and that maybe when Gigabit modules first came out, > the general wisdom and all the documentation at the time said that if > you used multi-mode fiber you would only be able to achieve Gigabit on > short runs, so if you had a longish run that you might ever want to > use for Gigabit, you should definitely get single-mode because > otherwise you'd be limited to Fast Ethernet speeds. > > But, then times changed... > > Or is this a far cry from what actually happened? (Like I said, I'm > brimming with ignorance, here) > >> Any time I undergo a fiber project, I always make sure I match up fiber, >> transceivers, Ethernet standard, and my switches in advance. This may not >> be an issue for you, but I've run into situations where I had a fiber and >> transceivers to function with a particular standard, only to discover later >> that while electrically compatible, the switch wouldn't support it. > > I've come across the issues of HP switches not recognising "generic" > GBICs, and having to buy specifically ProCurve compatible ones. That's > been our one weird mismatch. > >> So, for example, it sounds to me like you want: >> Single mode fiber running 1000BASE-LX, with the ability to upgrade to >> 10GBASE-LR later. > > That sounds possible; probably likely. > > If so, though, all the existing multi-mode infrastructure at campus B > (fiber runs, patch cables, even GBIC modules...) becomes more or less > obsolete/useless. > >> Hope that helps. >> Jeremy > > Thanks for your thoughts. > Simón > > _______________________________________________ > Fwlug mailing list > [email protected] > http://mail.fortwaynelug.org/mailman/listinfo/fwlug_fortwaynelug.org > > This is a public list and all posts are archived publicly. Please keep this > in mind before posting. > -- ~ Andrew "lathama" Latham [email protected] http://lathama.net ~ _______________________________________________ Fwlug mailing list [email protected] http://mail.fortwaynelug.org/mailman/listinfo/fwlug_fortwaynelug.org This is a public list and all posts are archived publicly. Please keep this in mind before posting.
