Components
To support the changing and fast-growing bandwidth
demands of Data Centers (DCs), the IEEE recently ratified
standards for supporting 40 Gigabit and 100 Gigabit
Ethernet, known as IEEE 802.3ba.
PANDUIT actively participated in the development of this
standard by leading the effort to include OM4 fiber optic
cabling as physical layer option.
This Just the Facts document is a quick-reference guide
to increase your familiarity with the critical issues and the
industry terms used in the migration to 40 and 100 GbE
systems.
Existing Fiber Infrastructure
FACT: Both 40 & 100 Gbs Ethernet can be deployed
using the same cabling systems in use today.
Multimode will employ parallel optics using MPO
interconnects and require additional cable
infrastructure depending on the system deployed
while single mode fiber will employ serial transmission
and use LC or SC connectors.
The approach used for the higher speed data rates is
based on advanced transceiver technologies engineered
to take advantage of the full bandwidth of laser optimized
fibers. This allows DCs to leverage their existing
investment in higher-grade fiber media. Both single mode
fiber (SMF) and multimode fiber (OM3, OM4) were
approved in the standard.
Bandwidth
FACT: Specifying the highest bandwidth OM3/OM4 fiber is
not sufficient to ensure optimum system performance. In
addition to fiber cables from suppliers that have the latest
technology in DMD measurement and who specify
DMD/EMB performance in excess of standard
specifications low-loss connectivity must also be used to
ensure the best system performance.
Per the standard, the bandwidth of the fiber is ensured by
meeting the Effective Modal Bandwidth (EMB) specification;
however, other factors, such as, calculated EMB (EMBc) and
Differential Mode Delay (DMD) can impact a fiber optic cables
performance. PANDUIT Laboratories channel certification
testing methodologies are a true measure of network
performance since additional factors are taken into account that
can impact performance, for example, induced cable stress.
These parameters are independent of fiber’s intrinsic
bandwidth.
40/100 GbE Fiber Optic Trends
Data Rate 40 Gb/s 100Gb/s
A
pplication
Access layer
apps (e.g., blade
servers,
virtualization)
High-
performance
computing
(HPC) clusters
SAN Inter
Chassis Links
Core switching
and routing
Data center
aggregation
Internet service
provider peering
points
High-demand
apps (e.g.
streaming video)
Min. Reach
100m
10km
40km
MMF
SMF
Not supported
MMF
SMF
SMF
Media Type
MMF
SMF
Serial or Parallel
Duplex or 12-fiber
ribbon cables
Parallel Optics
12 / 24-fiber
ribbon cables
(20 fibers per
channel)
Wave Division Multiplexing (WDM)
4x10G / 4x25G duplex cables
Implementing Parallel Optics
FACT: 10G (serial) MTP systems in use today will
require that the cable plant move to be scaled-up in
order to migrate to parallel optics based systems.
For example, a one-to-one transceiver swap from six serial
10 Gb/s links to six parallel 40 Gb/s links would involve the
addition of five new 12-fiber ribbon cables along the
permanent link and twelve MTP equipment cords.
Customers may choose to build incrementally
.
10G to 40G Example:
10Gb/s Ethernet 2-Cassette Channel
40Gb/s Ethernet Migration
(Original Trunk Cable is saved)
Converting those same six 10Gb/s serial links to six
100Gb/s parallel links could require as many as 24 new
MTP equipment cords and 11 new MTP trunk cables
depending on how the 100Gb/s link is implemented.
40GBASE-SR4 (40GbE) Optical Lane Assignments
40G is implemented using eight of the twelve fibers in an
MPO connector. Four of these eight fibers are used to
transmit while the other four are receive. Each Tx/Rx
pair is operating at 10G.
Trunk Cables
MTP Patch Cords
MTP Patch Cords
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