On 9/30/12 12:05 PM, Jimmy Hess wrote:
On 9/29/12, Masataka Ohta <mo...@necom830.hpcl.titech.ac.jp> wrote:
Jared Mauch wrote:
...
The problem is that physical layer of 100GE (with 10*10G) and
10*10GE are identical (if same plug and cable are used both for
100GE and 10*10GE).
Interesting. Well, I would say if there are no technical
improvements that will significantly improve performance over the best
possible carrier Ethernet bonding implementation and no cost savings
at the physical layer over picking the higher data rate physical
layer standard, _after_ considering the increased hardware costs
due to newly manufactured components for a standard that is just
newer.
There is a real-estate problem. 10 sfp+ connectors takes a lot more
space than one qsfp+. mtp/mpo connectors and the associated trunk ribbon
cables are a lot more compact than the equivalent 10Gbe footprint
terminated as LC. When you add cwdm as 40Gb/s lr4 does the fiber count
drops by a lot.
E.g. If no fewer transceivers and fewer strands of fiber required,
or shorter wavelength required, so it doesn't enable you to achieve
greater throughput over the same amount of light spectrum on your
cabling, and therefore lower cost at sufficient density, then: in
that case, there will probably be fairly little point in having the
higher rate standard exist in the first place, as long as the
bonding mechanisms available are good for the previous standard.
Just keep bonding together more and more data links at basic units of
10GE, until the required throughput capacity has been achieved.
It's not as if a newer 1 Tbit standard, will make the bits you send
get read at the other end faster than the speed of light. Newer
standard does not necessarily mean more reliable, technically better,
or more efficient, so it is prudent to consider what is actually
achieved that would benefit networks considered to be potential
candidates for implementation of the new standard, before actually
making it a standard...
--
-JH
