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MTP (MPO) Fibre Networking
Frequently Asked Questions

10G and 25G | 40G and 56G | 100G and 120G

What is an MPO connector?
MPO is a generic name for a multi-fibre connector. The term MPO stands for “multi-fibre push on”. The majority of MPO connectors have 12 fibres which are aligned along the centre of a rectangular ferrule. They mate together in the same way as traditional LC, SC and ST connectors except that MPO connectors require a male connector to be connected to a female connector.
A male connector has guide pins and a female one has holes for the pins. MPO connectors also have a key (similar to single fibre connectors) and this only allows connection one way when connected through an MPO adaptor.

What is the MTP Connector?

At the time of writing, one brand of MPO connector has become dominant – the MTP® connector. This is used across many major multinational structured cabling brands.
The MTP range of MPO connectors has 8, 12, 16, 24, 48 and 72 fibre connectors. All these connectors are the footprint of an SC connector yet hold up to 72 fibres, thereby enabling high density connectivity.
For more information on the MTP Connector
Male 12 fibre connector
MTP Male 12 Fibre Connector
Aqua Housing typically denotes multimode fibre

What is the most common use of MPO (MTP) Cables?

M400 MTP 12 Fibre Patch Cable

1. MPO Patch Cables for 40G and 100G

The demand for MPO cables has been driven by the development of 40G and 100G transceivers (QSFP+ and QSFP28 transceivers respectively) with MPO ports (as opposed to 10G SFP+ transceivers or even 1G SFP transceivers which have LC duplex ports).
QSFP+ and QSFP28 transceivers used for transmission over short distances, connecting ports in switches in data centres for example, will typically transmit over multimode and require MPO OM3 or OM4 cables. The simplest connection is a direct connect between two transceivers and this is achieved using one MPO – MPO multimode patch cable.
M400 MTP - LC Breakout Cable

2. MPO to LC Breakout Cables for 40G to 10G (x4)

Similarly, as 40G and 100G multimode transceivers have been adopted into existing networks, there is a need to connect these to existing 10G  host equipment (routers, switchers, servers, storage). MPO to LC breakout cables enable one 40G (or 100G) port to be connected to up to four 10G ports (or 25G ports).
What MPO Cable do I need for QSFP+ 40G Ethernet Transceivers?

Over Multimode Fibre

QSFP+ SR4 transceivers transmit over multimode fibre. These transceivers require an 8 fibre MPO – MPO OM3 or OM4 fibre cable . If the connection is directly between two transceivers then the MPO cable will need to have female connectors on both ends and the cable polarity will be B.

Over Singlemode Fibre

There are two types of QSFP+ transceivers for transmission over singlemode. Most use only two fibres and require a standard LC duplex multimode (OM3 or OM4) patch cord. A QSFP+ PSM4 transceiver will require an MPO singlemode 8 fibre cable. Again with female connectors and Polarity B

12 Fibre Cable or 8 Fibre Cable? 12 Fibre Connectors or 8 Fibre Connectors?

These are two questions that we are most commonly asked.
40G transceivers that require fibre cables with MPO connectors only need 8 fibres to operate so it would make sense to assume that MPO cables for 40G transceivers have 8 fibre MPO connectors and use 8 fibre cable.
However, MPO connectors are also used in 10G networking where the 12 fibre MPO connector is used along with 12 fibre cable. To make it easier for manufacturers, most only use the 12 fibre connector as this will work in all applications and then choose where to use this with either 8 fibre or 12 fibre cable.
So a 12 fibre MPO cable with the correct polarity will work in exactly the same way when used in a 40G transceiver as an 8 fibre cable. The only difference is that 4 of the fibres will not be used (they will be dark).

QSFP+ Optical Transceiver Module
QSFP+ Transceiver LR4 PSM4
40G Transceivers

What type of cable is used with MPO Connectors?

M310 MTP 24 Fibre Trunk Cable with Caps
24 core cable. Split into two 12 core tails
with MTP 12 fibre connectors

1. Cable Construction

MPO cables are most commonly used within data centre applications. These applications typically use high volumes of cables and have limited space.  This has led to the adoption of most manufacturers of using a small, light and flexible cable called micro cable or microcore cable. The construction has 250um buffered fibres, an aramid yarn strength member and a single or dual outer sheath.
Readily available in core counts from 8 to 144 fibre cores the cable is typically built using 8 fibre or 12 fibre sub-units which are housed in an outer sheath. Note – 8 to 24 cores generally do not require the outer sheath as all fibres are within one unit. This cable construction gives about 65% reduction in space when compared to traditional tight buffered or loose tube cables and similar reduction in weight. The cable also has a smaller bend radius and these 3 factors make this cable the best option for high density fibre applications, mainly because more cabling can be installed per cabinet / cable tray.

2. Glass Cores

Whereas the cable construction is quite similar across varying manufacturers, the glass cores used vary. There are around 5 large manufacturers of fibre glass cores and although all produce to the international standards of OM3, OM4, OS2 (singlemode), G657.A1 and G657.A2 (bend insensitive singlemode) the performance of the glass differs.
Most MPO cabling will be used within high data rate applications. For simple short direct connections, the brand of glass being used will make negligible much difference to performance. However, networks become more complex and introduce longer channels the brand of glass and the construction of the cable becomes a performance limiting factor.
What makes up a MPO connector based fibre networking system?

Based around 5 components

MPO – LC cassette modules
Typically 12 fibre or 24 fibre. These MPO cassettes offer LC port presentation at the rack front and rear MPO ports for trunk cable connections. These MPO cassettes enable a high concentration of LC ports per 1U rack space and are are easier to install than a similar fibre density using traditional fibre.
   MPO to MPO trunk cables
Typically 12 fibre or 24 fibre. Combined with MPO to LC cassettes these form the core part of most MPO based fibre networks.
   MPO cassette housing panels
Typically from 1U to 4U. 1U panels are ideal for top-of-rack connectivity where as 2U to 4U panels are ideal from distribution areas.
   MPO Adapter / Coupler Modules
These enable a MPO port presentation within racks for either trunk extensions or patch MPO cables directly to equipment for higher data rate applications.
   MPO patch cords and breakout cables
These enable 40G and 100G connectivity as described above.
MX Cass to Cass DSC_4066 crop white 1250 02
MX Series 2U Housing Panel
Top: MTP – LC cassettes with MTP trunk cable
Below: 2U Housing Panel with MTP cassette modules

What are the main benefits of MPO Fibre networks?

Spine and Leaf - In Row 1
Speed of install / Build on Demand / Supports 10G to 200G
The benefits can be split into 3 different types: installation, financial / ROI, improved networking capability. Some of the main ones are highlighted below.
   MPO based solutions are modular. Extra fibre capacity or network expansion can be added on demand
   Installation of MPO networks is faster
   Installation of MPO networks is less disruptive and cleaner.
   Upgrading to higher data rates is possible
   Change can be carried out at a convenient times
   MPO Components freed up through changes can be re-used and easily moved
   Higher port density is possible
   Different types of ports can be housed in the same 1U space. Mixing singlemode with multimode or MPO ports with LC ports or even CAT6 or CAT6a ports

View one of our fibre systems

MPO Cassettes and Trunk Cabling

MPO Connectors are most commonly used to build duplex networks which offer up to 25G channels.

MPO to LC Cassettes connected by MPO trunk cables create 1G, 10G and 25G duplex fibre networking.

MX Fibre System
MPO MTP M310 Series OM4 12 Fibre Patch Cord

MPO Cables for 40G and 100G Ethernet

QSFP+ 40G Ethernet multimode transceivers have MPO connector ports.

So to connect 40G switches and routers to a network an MPO connector based fibre networking is required.

MPO Cables for 200G Ethernet

MPO connectors are also required for 100G SR10 Ethernet fibre networking and 200G DD Ethernet.

cisco cpak sr10 compatible mpo cable

Designing an MTP Network

The main difference to take into account when designing a network using a modular MTP solution over a traditional fibre solution is that the number of mated connector pairs in any fibre channel will increase. This increase in mated pairs increases the losses in the channel and these need to be understood in order to maintain the required performance.

MTP Fibre Channels

What distances can OM3 and OM4 run over using MTP solutions?

How can rack space be minimised?

What are the options to create longer fibre channels? See our section on typical fibre channel, follow this link:

How do I use MTP to reduce rack space requirement for cabling?

One of the main reasons for choosing an MTP solution is to increase the in-rack connectivity. This can be done in several ways: –
1. Use MTP-LC harnesses which connect directly to equipment from 1U MTP Panels (up to 576 fibres in 1U)
2. Use Zero U (side mounted) MTP Adaptor Plates
3. Use MTP direct equipment connections. Switch manufacturers, such as CISCO and Brocade, are now producing equipment with MTP connectivity.

How is the solution modular?

The starting point can be a 12 fibre link between 2 cassettes and 1 x 12 fibre trunk cable. This will give LC – LC (or SC- SC) connectivity for 12 fibre connections.

Cassettes are housed in either 1U sliding panels (each with the ability to hold 3 cassettes) or 3U fixed panels holding (1 to 14 cassettes).

However, most installations use 24 fibre cassettes are used as standard. Each of these takes one 24 fibre trunk cable with 2 MTP connectors on each end. If each 24 fibre link (two 24 fibre cassettes and one 24 fibre trunk) is called a unit then units can be added 1 at a time as the requirement grows.

Thereby giving a modular approach in 24 LC-LC connection steps. To minimise costs within a network, each unit can be chosen from either the M300 or M310 product series to ensure that the higher performance / lower loss M310 products are only used where necessary.

MTP adaptor plates can be added in exactly the same way. The 1U and the 3U housing for LGX cassettes can also be used to house the adaptor plates thereby enabling the minimum of rack space to be used.

What Installation skills are required?

The same principles apply whether you are installing a 24 fibre link either between 2 buildings, connecting an office floor to a comms room or creating hundreds of channels in a data centre.

There are 4 main principles to adhere to: –
1. Ensure that the link being created (distance and number of connector matings) meets the required standard.
2. Ensure that the polarity is managed across the link and in line with the network design
3. Ensure physical forces on the cables and connectors are managed by using strain relief on the cables to limit the tension in the cabling and maintain bend radii in both the cabling and patching accordng to the allowed specifications.
4. Follow the fibre connection procedures that you should use when connecting any type of fibre connectors together.

The MTP Connector

Used by all the leading high density fibre manufacturers the MTP® Connector is at the heart of the Complete Connect solution. The 12 fibre connector has been designed to provide enhanced “overlife” performance and is key to maintaining a robust network. Read more

We believe the market leading MPO connector in terms of performance and durability is the MTP® connector produced by USConec – which is why our range is standardised on this product and is also probably why the connector is used by many other brands including Corning, Systimax by Commscope, TYCO Amp Net Connect / ADC Krone, Panduit, Siemon and many others.

Do I need expensive tools to install HDFO?

Simple answer NO.

1. LC cleaning tool (no different than any traditional cleaning tool for LC connectors)
2. MTP cleaning tool (approved by USConec)
3. Appropriate light source and power meter with MTP adptors.
4. Appropriate reference patch leads.
5. Visual scope.
6. Light Source and Power Meter.

Is an OTDR required? In our view this is not essential as a test completed with a Light Source and Power Meter will establish the performance of the links.

Are any field terminations required?
The simple answer is NO.
All products are pre-terminated to enable an equipment to equipment link to be established without any on-site fibre terminations.
Flexibility is maintained by using MTP® adaptors to enable 2 trunk cables (or a trunk and a ruggedised fan-out) to be simply plugged together. LC or SC Cassettes are simply plugged into trunk cables using MTP® adaptors mounted in the rear of each cassette.

When is it sensible to use an MTP solution?

I don’t work much in data centres, are the products worth using in other situations?
The simple answer is YES. The products are becoming increasing used in standard office and commercial buildings (risers) as well as campus environments. The main reason for this uptake is that when a cost/benefit analysis is completed against using traditionally field terminated product sets, the pre-terminated MTP solutions start to come out on top.

Main benefits from pre-terminated include

  • the improved quality and consistency of the final links

The quality of field terminated fibre is always variable where as the pre-terminated MPO trunk cables, cassettes and fan-outs are constructed under controlled factory conditions and so give consistency high performance

  • the reduced time on site to complete the installation

Installation costs rise as time on site increases. It takes longer to set up a site termination and produce a high quality connection than to complete the same connection in a factory. It is easy to see that completing 48 fibre terminations (using any of the many types of field termination) in a site environment will take longer than in a properly equipped factory.

Access to site is becoming more restricted
Reducing on-site installation time is usually of benefit to the end-user. With pre-terminated fibre the time on site is dramatically reduced.

  • the reduction in skill required by installers

Fibre termination skills vary between individuals (in both factory and field situations). The site can have an impact on the ease of termination and hence the quality. People need to be properly trained and equipped to terminate fibre on site. This generally means that there is a shortage of available labour (with the right equipment in the right place) at the right time.

  • the reduction in cost of fibre termination and test equipment

Fibre termination tools / fusion splicers / connectors / test equipment / termination consumables – these all cost money and are constantly needing to be replenished. these tools are not being used all the time and are often in the wrong place at the wrong time requiring multiple kits to be purchased.

  • increased speed of installation

With our UK manufacturing and stock holding a large quanitity of fibre links can be delivered within days. Therefore, a fibre installation that could have previously taken weeks to complete can be done so in a greatly reduced timespan

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