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RE: High Density Multimode Runs BCP?

  • From: Hannigan, Martin
  • Date: Thu Jan 27 00:59:18 2005



Just in case some folks are wondering what we are
talking about, here's a decent URL covering it:


http://images.google.com/imgres?imgurl=http://www.tpub.com/neets/tm/30NVM053
.GIF&imgrefurl=http://www.tpub.com/neets/tm/107-8.htm&h=387&w=397&sz=13&tbni
d=gGUI7fKu6OwJ:&tbnh=116&tbnw=119&start=16&prev=/images%3Fq%3Dfiber%2Bribbon
%2Bcable%26hl%3Den%26lr%3D%26c2coff%3D1





--
Martin Hannigan                         (c) 617-388-2663
VeriSign, Inc.                          (w) 703-948-7018
Network Engineer IV                       Operations & Infrastructure
hannigan@verisign.com



> -----Original Message-----
> From: Scott McGrath [mailto:mcgrath@fas.harvard.edu]
> Sent: Wednesday, January 26, 2005 10:44 PM
> To: Hannigan, Martin
> Cc: nanog@merit.edu
> Subject: RE: High Density Multimode Runs BCP?
> 
> 
> 
> Hi, Martin
> 
> Yes indeed the ribbon cable.  Tho' due to the damage factor I probably
> would not specify it again unless I could use innerduct to 
> protect it as
> we had some machine room renovations done and the construction workers
> managed to kink the underfloor runs as well as setting off the Halon
> system several times...
> 
> 
> The ribbon cables work well if they are adequately protected.  If the
> people in the machine room environment are skilled at handling fiber
> there should be no problems.   If however J. Random Laborer 
> has access I
> would go with conventional armored runs.
> 
> 
>                             Scott C. McGrath
> 
> On Wed, 26 Jan 2005, Hannigan, Martin wrote:
> 
> >
> > The ribbon cable?
> >
> >
> >
> >
> > --
> > Martin Hannigan                         (c) 617-388-2663
> > VeriSign, Inc.                          (w) 703-948-7018
> > Network Engineer IV                       Operations & 
> Infrastructure
> > hannigan@verisign.com
> >
> >
> >
> > > -----Original Message-----
> > > From: Scott McGrath [mailto:mcgrath@fas.harvard.edu]
> > > Sent: Wednesday, January 26, 2005 6:44 PM
> > > To: Hannigan, Martin
> > > Cc: Thor Lancelot Simon; nanog@merit.edu
> > > Subject: RE: High Density Multimode Runs BCP?
> > >
> > >
> > >
> > > Hi, Thor
> > >
> > > We used it to create zone distribution points throughout our
> > > datacenter's
> > > which ran back to a central distribution point.   This
> > > solution has been
> > > in place for almost 4 years.   We have 10Gb SM ethernet links
> > > traversing
> > > the datacenter which link to the campus distribution center.
> > >
> > > The only downsides we have experienced are
> > >
> > > 1 - Lead time in getting the component parts
> > >
> > > 2 - easiliy damaged by careless contractors
> > >
> > > 3 - somewhat higher than normal back reflection
> > >     on poor terminations
> > >
> > >                             Scott C. McGrath
> > >
> > > On Wed, 26 Jan 2005, Hannigan, Martin wrote:
> > >
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Thor Lancelot Simon [mailto:tls@netbsd.org]
> > > > > Sent: Wednesday, January 26, 2005 3:17 PM
> > > > > To: Hannigan, Martin; nanog@merit.edu
> > > > > Subject: Re: High Density Multimode Runs BCP?
> > > > >
> > > > >
> > > > > On Wed, Jan 26, 2005 at 02:49:29PM -0500, Hannigan, 
> Martin wrote:
> > > > > > > >
> > > > > > > > When running say 24-pairs of multi-mode across a
> > > > > datacenter, I have
> > > > > > > > considered a few solutions, but am not sure what is
> > > > > > > common/best practice.
> > > > > > >
> > > > > > > I assume multiplexing up to 10Gb (possibly two links
> > > > > thereof) and then
> > > > > > > back down is cost-prohibitive?  That's probably the
> > > > > "best" practice.
> > > > > >
> > > > > > I think he's talking physical plant. 200m should be
> > > fine. Consult
> > > > > > your equipment for power levels and support distance.
> > > > >
> > > > > Sure -- but given the cost of the new physical plant
> > > installation he's
> > > > > talking about, the fact that he seems to know the present
> > > maximum data
> > > > > rate for each physical link, and so forth, I think it does
> > > > > make sense to
> > > > > ask the question "is the right solution to simply be more
> > > economical
> > > > > with physical plant by multiplexing to a higher data rate"?
> > > > >
> > > > > I've never used fibre ribbon, as advocated by someone else in
> > > > > this thread,
> > > > > and that does sound like a very clever space- and
> > > possibly cost-saving
> > > > > solution to the puzzle.  But even so, spending tens of
> > > thousands of
> > > > > dollars to carry 24 discrete physical links hundreds of
> > > > > meters across a
> > > >
> > > > Tens of thousands? 24 strand x 100' @ $5 = $500. Fusion splice
> > > > is $25 per splice per strand including termination. The 100m
> > > > patch chords are $100.00. It's cheaper to bundle and splice.
> > > >
> > > > How much does the mux cost?
> > > >
> > > >
> > > > > datacenter, each at what is, these days, not a
> > > particularly high data
> > > > > rate, may not be the best choice.  There may well be some
> > > > > question about
> > > > > at which layer it makes sense to aggregate the links --
> > > but to me, the
> > > > > question "is it really the best choice of design
> > > constraints to take
> > > > > aggregation/multiplexing off the table" is a very
> > > substantial one here
> > > > > and not profitably avoided.
> > > >
> > > > Fiber ribbon doesn't "fit" in any long distance (+7') 
> distribution
> > > > system, rich or poor, that I'm aware of. Racks, 
> cabinets, et. al.
> > > > are not very conducive to it. The only application I've seen was
> > > > IBM fiber channel.
> > > >
> > > > Datacenters are sometimes permanent facilities and it's better,
> > > > IMHO, to make things more permanent with cross connect than
> > > > aggregation. It enables you to make your cabinet cabling and
> > > > your termination area cabling almost permanent and maintenance
> > > > free - as well as giving you test,add, move, and drop. It's more
> > > > cable, but less equipment to maintain, support, and reduces
> > > > failure points. It enhances security as well. You can't open
> > > > the cabinet and just jack something in. You have to provision
> > > > behind the locked term area.
> > > >
> > > > I'd love to hear about a positive experience using ribbon cable
> > > > inside a datacenter.
> > > >
> > > >
> > > > >
> > > > > Thor
> > > > >
> > > >
> > >
> >
> 




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