Speed |
IEEE Application |
Fibre Type |
# of Fibres |
Interface |
Distance |
10 Gb / s |
10GBASE-SR |
Multimode OM3 / OM4 |
2 ( 1f x 10G ) |
Duplex LC |
300m / 400m |
25 Gb / s |
25GBASE-SR |
Multimode OM3 / OM4 |
2 ( 1f x 25G ) |
Duplex LC |
70m / 100m |
40 Gb / s |
40GBASE-SR4 |
Multimode OM3 / OM4 |
8 ( 4f x 10G ) |
8 / 12F MPO ( 8 ) |
100m / 150m |
50 Gb / s |
50GBASE-SR 1 |
Multimode OM3 / OM4 |
2 ( 1f x 50G ) |
Duplex LC |
70m / 100m |
100 Gb / s |
100GBASE-SR2 1 |
Multimode OM3 / OM4 |
4 ( 2f x 50G ) |
2 x Duplex LC |
70m / 100m |
100 Gb / s |
100GBASE-SR4 |
Multimode OM3 / OM4 |
8 ( 4f x 25G ) |
8 / 12F MPO ( 8 ) |
70m / 100m |
200 Gb / s |
200GBASE-SR4 1 |
Multimode OM3 / OM4 |
8 ( 4f x 50G ) |
8 / 12F MPO ( 8 ) |
70m / 100m |
400 Gb / s |
400GBASE-SR16 1 , 2 |
Multimode OM3 / OM4 |
32 ( 16f x 25G ) |
32F MPO ( 32 ) |
70m / 100m |
100 Gb / s |
100GBASE-DR 1 |
Singlemode OS1 / OS2 |
2 ( 1f X 100G ) |
Duplex LC |
500m |
200 Gb / s |
200GBASE-DR4 1 |
Singlemode OS1 / OS2 |
8 ( 4f x 50G ) |
8 / 12F MPO ( 8 ) |
500m |
400 Gb / s |
400GBASE-DR4 1 |
Singlemode OS1 / OS2 |
8 ( 4f x 100G ) |
8 / 12F MPO ( 8 ) |
500m |
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will be dominated by 2- and 8-fibre solutions . Table 1 clearly shows that the Ethernet Optical Transceiver Roadmap includes fibre applications that are always divisible by either two or eight fibres . What does this mean for existing 12-fibre MPO / MTP connections ?
For applications like 40Gb / s ( 40GBASE-SR4 ) and 100Gb / s ( 100GBASE-SR4 ) that are based on eight multimode optical fibres , as well as future 400Gb / s , the use of 12-fibre MPO / MTP solutions means that 33 per cent of the optical fibre goes unused . One way that data centre managers can ensure 100 per cent utilisation of optical fibre with 12-fibre MPO / MTP solutions is to use conversion cords or modules that transition two 12-fibre or one 24-fibre trunk from backbone cabling to three 8-fibre MPO / MTPs for connecting to 40 and 100Gb / s equipment . This is ideal for those data centres that already deployed 12-fibre or 24-fibre backbone trunk cables .
However , 8-fibre MPO solutions that are starting to hit the market are considered the most efficient option since they support current and future duplex fibre applications using modules that break out 8-fibre MPOs to duplex LCs , as well as current and future 8-fibre applications without the need for conversion cords .
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Table 1 : Ethernet Optical Transceiver Roadmap includes multimode and singlemode fibre applications that are always divisible by either two or eight fibres |
Make it manageable
Regardless of whether 12- or 8-fibre MPO solutions are deployed , staying within optical insertion loss budgets remains essential for ensuring proper transmission of data signals between switches . The cable length and number of connections within a channel all contribute to link loss , and higher speeds have more stringent loss requirements . Loss budgets therefore need to be carefully considered during the early design stages — especially in today ’ s flatter , more reliable data centre designs that have fewer switch tiers and utilise redundant mesh topologies where every switch is connected to every other switch . These flattened mesh designs result in more active connections and longer cable runs between switches that can be difficult to deploy and manage . Further , adding new switches presents the challenge of adding additional long fibre runs to already populated pathways .
To maintain flexibility and ease deployments , many data centre managers prefer to deploy distribution points or cross connects between switches , also referred to as patching areas . These patching areas connect via permanent or fixed high count fibre cabling , enabling the deployment of shorter fibre links from the patching area to equipment and improving
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manageability . Unfortunately , the use of patching areas adds more connections and link loss within the channel . The use of specially qualified low loss 8- or 12-fibre MPO / MTP connectors and fibre cable in the data centre is therefore essential .
Accessibility of connections and manageability of fibre jumpers at the patching areas is also a concern , especially as the number of connections within a single rack unit of space continues to increase . Thankfully today ’ s ultra high density fibre enclosures can support up to 144 fibres in a 1U space . But here is more to consider . When choosing a fibre connectivity solution for high speed applications , data centre managers need to consider ease of migration from 10Gb / s speeds to 40 and 100Gb / s and beyond , the availability of 8-fibre MPO / MTP solutions , accessibility of connections at both the front and rear of enclosures and high visibility labelling for easier administration . Jumper capacity , cable management and fibre protection also need to be considered , including proper strain relief and enclosure designs that eliminate pinch points .
Navigating the fibre landscape has become more complex than ever . Understanding current and future fibre choices is essential to meet the demands of IoT and Big Data in the data centre .
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30 | March 2017 |