The document discusses data centre environments and the use of optical fibre cabling within them. It notes that optical fibre offers benefits over copper like lower loss, higher bandwidth, and lower power consumption. It also covers trends in the industry like higher speeds of 40Gb/s and 100Gb/s and the use of multimode fibre which can support these speeds over longer distances than copper.

1. Data Centre Environments
CCS Commercial Overview - Session 2
Optical Fibre in the Data Centre
4th December 2008
Paul Mathews MInstSMM
Global Channel Manager

2. Introduction to Data Centres
• The heartbeat of any business, designed to manage the flow, processing and
storage of information
• Must be reliable, secure and flexible to enable growth and reconfiguration
• A data centre can support small singular businesses through to thousands of
clients ecommerce facilities
• “A building or portion of a building whose primary function is to house a
computer room and its support areas,” according to TIA 942

3. What created the demand for Data Centres
• Data storage and record keeping
• Bandwidth hungry applications on the internet such as video
• E-commerce required 24-7
• Online learning
• Supercomputing applications

4. Data Centre Dynamics
1.0 Physical location of the data centre
2.0 Physical sizing and capabilities
3.0 Electrical systems to and within the data centre
4.0 Fire minimisation, detection, alarm and suppression
5.0 Heating, Ventilation and Air Conditioning (HVAC)
6.0 Communications Cabling within and to the data centre
7.0 Cabling containment within the data centre (including
raised floors)
8.0 Equipment racks and cabinets
9.0 Information Technology equipment
10.0 Security, Access and CCTV
11.0 Project management
12.0 Ongoing maintenance

5. Current and future trends driving data centres
• Government data warehousing legislation
• Medical and Financial Industries
• Redundancy against catastrophic loss (natural disaster / terrorism)
• Faster Data Centres and Storage Area Networks (SAN)
• Speeds of 40Gb/s and 100Gb/s depending on the application

6. Why specify optical fibre?
• Low loss and high bandwidth
• Small size – high density and compact
• Lower power consumption
• Lower generation of heat

7. Network Architecture
• Enterprise networks are moving towards 10Gbs optical fibre backbone to
support 1Gbs copper/fibre horizontal links
• Star topology still dominant infrastructure design
• Trends are changing towards Fibre-To-The-Enclosure (FTTE) because of
extended performance capabilities with fibre closer to the workstation
• Data Centre LANs are moving towards optical fibre because of the amount of
data being stored, processed and managed
• A Data Centre typically consists of bank of server racks, connected to the
SAN on one side and the Intranet for LANs and Internet links for the world
wide web on another

8. Network Protocols – Computer Room LAN
• Switches and Servers typically transmit Ethernet – currently 10Gbs is the top
speed:
IEEE 802.3an 10GBASE-T Copper (published 2006)
IEEE 802.3ae 10GBASE-F Optical Fibre (published 2002)
• IEEE is currently working on standards for Ethernet 40Gbs and 100Gbs
• IEEE identifies standards for transceiver port types and the requirements and
characteristics of the physical layer

9. Network Protocols – Storage Area Network
• Within the SAN area of a Data Centre – Fibre Channel is the popular protocol,
transmitting top speeds as:
2GFC, 4GFC, 8GFC – next focus is 16GFC
• Base2 speeds have doubled in speed each time standards have been
publishing
• Fibre Channel also uses Base10 for inter-switch links and core connections
(10GFC was published just as 10GBaseT, incorporating serial vertical cavity
surface emitting laser technology – VCSEL – max distance 300m on OM3)
• Fibre Channel is now looking towards 20GFC and 40GFC as Base10 speeds

10. Multimode fibre benefits
• Longer lifespan than copper – as looking ahead at 40Gbs and 100Gbs looks
like copper will only support short distances – 10m approx
• Singlemode fibre has very high bandwidth but requires advanced
optoelectronics for transmission (approx 25-30% higher)
• 40Gbs and 100Gbs transmissions can be achieved on distances of 200-300m
on OM3 optical fibre
• OM3 laser-optimised fibre, OM4 extended length laser-optimised fibre
• Optical fibre differences between multimode and singlemode are (relating to
cost differences) explained on the next slide:
1) Wavelength of operation
2) Size of the optical fibre core where light is carried

11. Multimode or Singlemode in the Data Centre?
• Materials transmitting long wavelengths of 1310nm and 1550nm cost more
than short distance 850nm lasers
+
• Transceivers used to connect singlemode transmissions require tighter
alignment tolerances to couple, or capture light. Singlemode fibre core is
much smaller (9um)
+
• Singlemode optical fibre equipment consists of high-precision transceivers,
tighter tolerance connectors and careful cable installation and termination
=
• Considerable costs compared to multimode fibre for data centres

12. Optical Fibre Technologies
• Where optical fibre is installed in today’s data centres, 70% is OM3 or OM4
grade
• Vertical cavity surface emitting lasers (VCSEL) are the laser source for
transmission on OM3 and OM4
• Reduced differential mode delay (DMD) on OM3 and OM4; controlled core
ensures 10Gbs on low-cost 850nm serial applications
• OM3 supports 10Gbs up to 300m
• OM4 supports 10Gbs up to 550m
• OM4 is recommended for longer distances such as large building backbones,
medium length campus backbones and/or sensitive power budget
applications such as data centres
• OM4 will eliminate DMD in the fibre and will have a bandwidth of
4700MHz.km; more than double the requirement for IEEE 10Gbs 300m
support

13. Cassette Based Technologies
• MPO & MTP connectors (Connectix Starlight MTP):
- high density 12 core connections in one mating
- easy installation
- space savings (more connection possibilities)
- simplified connectivity within the network
- typically have higher connection or insertion loss rates than traditional
single-fibre connectivity
- Using OM4 MTP provides higher bandwidth to improve additional channel
insertion loss (ChIL) margin
- Using OM4 fibre allows better alignment for MTP against singlemode (bigger
cores)
- Using OM4 provides additional headroom in terms of network upgrades
(cable routing and installation), link degradation (from MACs) or from aging
electronics

14. Power Consumption – Copper v Optical Fibre
• Today’s data centres are over sized, consume too much power and waste
money on cooling
• Optical fibre has power savings over copper:
10GBASE-T transceiver uses approx 6 Watts (W) of power
10GBASE-SR transceiver uses less than 1 W to transmit the same signal
Optical fibre saves 5 W of power with each connection
• Major data centres consists of 10,000+ connections:
10,000 x 5 W = 50 kW

15. Cooling - General Guidelines
• The power used by transceivers is dissipated as heat – which
is removed from the computer room by cooling (CRAC units)
• CRAC units efficiency rating is 10 W (so 10W of power are
used to remove 1W of heat)
• Efficiency of air condition varies from 3:1 to 1:1, i.e it takes
between 300W and 1000W of electricity to remove 1kW of heat
with air conditioning
• Improving Cooling and Airflow – Connectix Article 14
http://www.connectixcablingsystems.com/library/detail.cfm?it
em=83

16. Future proofing cabling in Data Centres
• IEEE is currently developing 802.3ba 40Gbs and 100Gbs aimed at:
40Gbs – server links
100Gbs – core switching and routing applications
• IEEE 802.3ba also offers parallel optical fibre technology (using 4 or 10
VCSELs and detectors over optical fibres for 40Gbs or 100Gbs respectively)
• Delay SKEW (the difference in time between one signal on a fibre adjacent to
other cores in the cable) compensation is managed within transceiver
circuitry

17. Design considerations for Data Centre cabling
• System migration to higher speeds of 40Gbs and 100Gbs
• Performance and reliability needed on 10Gbs transmissions – headroom, this
can be achieved by:
Using higher bandwidth cable to reduce intersymbol interference (ISI); occurs
when bits of data run together
Specifying lower loss connectors which improve headroom margin
Specifying optical fibre rated for longer distance than will be used (OM3 and
OM4)

18. Data Centre Whitepapers
• Data Centre Design Whitepaper
http://www.connectixcablingsystems.com/library/detail.cfm?item=10

19. Connectix Technical Articles
• Log on to www.connectixcablingsystems.com for full access to our data
centre and high speed LAN support articles
• Log on to www.connectixcablingsystems.com/events for details of our Data
Centre Design Principle Seminars run in association with The IET
IET Endorsed
CIBSE Continuing
Training Professional Development BICSI Continuing Education Credits
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