Network Infrastructure Blog

Base-16 is an MPO plug and play cabling system that utilizes an MPO-16 connector vs. the MPO-12 connector that is used for more commonly in Base-8 or Base-12 cabling systems. The MPO-16 connector has specifications that are defined in TIA-604-18 released in 2018 and IEC 61754-7-1 released in 2014, but the connector has seen limited market adoption.

With the recent introduction and promotion of Base-16 systems by some manufacturers, the time is right to share some helpful insights.

Is a Base-16 system required to support 400 & 800GbE?

No. Only one currently available 400G Ethernet application requires an MPO-16 connector – 400GBASE-SR8. All other current and planned IEEE 400G Ethernet applications use 2- or 8-fibers. There is expected to be very little market adoption of 400GBASE-SR8 because it uses the MPO-16, with almost no installed base. In addition, the SR8 application requires an MPO-16 with an Angled Polish Connector (APC) end-face, which is not standard for multimode fiber systems and may require specific installation and testing requirements. For 800GbE, there are several options that will utilize 2- or 8-fibers with an LC or MPO-12 interface.

Is Base-16 compatible with legacy installed Base-12 or Base-8 cabling systems?

No. The MPO-16 connector does not mate with MPO-12 connectors used in Base-8 or Base-12 systems. The MPO-16 connector has different alignment pin spacing and has an offset key vs. a centered key. This means you cannot directly connect an existing Base-12 or Base-8 system to a Base-16 system.

Can my Base-8 singlemode cabling system support 400G, 800G & 1.6TbE applications?

Yes. Most of the current and planned 400 & 800G Ethernet applications will utilize 2- or 8-fibers, so Base-8 will work great. For the few applications that do require an MPO-16 interface, Base-8 can easily be converted to 16-fiber for equipment connection by using a conversion cord or module that converts 2x8F to 1x16F. This can be done with multimode or singlemode for 400G, 800G or 1.6TbE applications if required. This means no need to rip and replace your Base-8 infrastructure to migrate to higher speeds.

Is the Base-16 system more cost-effective than Base-8 systems?

No. The price per fiber is approximately 20-25% higher for a Base-16 system. This is due to a few reasons…a higher cost connector with an APC end-face on MM, more polishing time for 16-fiber vs 8- or 12-, and a lower passing yield rate during production…all leading to higher costs to the market.

Do Base-16 trunk cables take up more space in the pathway since there are more fibers per cable?

Yes. The Base-16 cables are typically 20-30% larger than Base-8 cables with the same fiber count. Here are some examples:

• A 16F Base-16 trunk cable typically has an outside diameter (OD) of 4.9mm vs. a 16F Base-8 trunk cable which has an OD of 3.8mm
• A 48F Base-16 trunk cable typically has an OD of 9.1mm vs. a 48F Base-8 trunk cable which has and OD of 7.5mm

This means Base-16 requires more pathway space than Base-8 cabling.

Due to all the above reasons, Siemon continues to act as a trusted advisor to our clients and recommends Base-8 systems for new installations and will continue to only recommend solutions that solve problems, make sense for a given customer application, and are cost-effective.

Additional resources we think you’ll like:

• On-Demand TechTalk: The Journey to 400/800G Has Begun: Which Road Will You Take?
• White Paper: Optimizing New Short-Reach Singlemode Deployments with Verified Ultra-Low Loss (ULL) Components
• Application: Advanced Data Center Solutions & Applications Guide

Designing fiber optic networks and finding the right tools to optimize it is always a challenge. We need to find the right balance between demands of the network, cable performance and cost effectiveness. While fiber cable selection between singlemode and multimode networks is self-selecting, there is an array of options for multimode networks. The latest of which is OM5, which is designated as Wideband Multimode fiber (WBMMF) in the ISO/IEC 11801, 3rd edition Standard.

OM5 fiber is specified at 850 nm and 953 nm wavelengths. It was created to support Shortwave Wavelength Division Multiplexing (SWDM), which is used to transmit 400GBASE-SR4.2 over eight fibers. It can potentially be used to handle high-speed data center applications using two fibers to transmit from 40 Gb/s up to 100 Gb/s. However, this challenge can also be resolved with existing singlemode solutions.

All the current and future IEEE standards in development for 100/200/400/800 Gb/s data rates will work with either singlemode (OS2) or multimode (OM4). Some of these next-generation speeds, especially those operating at longer distances, will require singlemode. In addition, OM5 cabling costs about 20-30%  more than OM4. If you look at the cost of a full 100 Gb/s channel, including BiDi transceivers, the amount per channel is still 30-40% more than 100GBASE-SR4 supported by OM4.

A recent white paper published by Cisco “Understanding the Differences Between OM4 and OM5 Multimode Fiber”, discusses whether OM5 is an appropriate choice when OM4 will work just fine. There have been many claims that OM5 has better reach than OM4, although this is only true for a small handful of applications. For example, multi-wavelength transceivers with operating wavelengths that include longer wavelengths like 940 nm can leverage the reach advantage of OM5.

The TIA standard for OM4 only mandates a bandwidth of 4,700 MHz∙km at the 850 nm measurement wavelength. In contrast, OM5 has a requirement of 4,700 MHz∙km at 850 nm, but also has a requirement for 2,470 MHzkm at 953 nm. Does that mean OM5 is the better option? Not necessarily. Most of Cisco’s multimode transceivers are single-wavelength devices operating at 850 nm; therefore, there is no difference in reach for these transceivers whether OM5 or OM4 is used. BiDi uses two wavelengths and similarly the wavelength range does not present an opportunity to realize significant benefits from OM5.

The white paper concludes by stating that, “It’s an engineering truism that there’s no perfect solution, just the best solution for the application at hand. OM5 cable is not intrinsically better than OM4 cable. OM5 only delivers increased reach for transceivers with lanes operating at 940 nm. For conventional multimode transceivers operating at 850 nm alone, OM4 provides a cost-effective solution.”

Read the full Cisco White Paper

Additional resources we think you’ll like:

• On-Demand TechTalk: What are the benefits of OM5?
• Blog: Is OM5 fiber a good solution for the data center?
• Application: The journey to 400G and 800G has begun: which road will you take?

I created a blog on this topic back in April 2017…this content is updated with current standards and applications…but it is still very much true today…4 ½ years later…Make sure you work with people & companies you can trust that have your best interests in mind.

Wideband Multimode fiber (WBMMF) was introduced as a new fiber medium in ANSI/TIA-492AAAE, in June 2016. The ISO/IEC 11801, 3rd edition standard is now using OM5 as the designation for WBMMF. OM5 fiber specifies a wider range of wavelengths between 850 nm and 953 nm. It was created to support Shortwave Wavelength Division Multiplexing (SWDM), which is one of the many new technologies being developed for transmitting 40 Gb/s, 100 Gb/s, and beyond.

OM5 is being presented as a potential new option for data centers that require greater link distances and higher speeds. However, many enterprise IT and data center managers are increasingly adopting Singlemode fiber systems to solve these challenges.

So, what are the reasons a data center might consider installing OM5?

“OM5 offers a longer cabling reach than OM4.”

The difference is minimal.

For the majority of current and future Multimode IEEE applications including 40GBASE-SR4, 100GBASE-SR4, 200GBASE-SR4, 400GBASE-SR8 and future 400GBASE-SR4, the maximum allowable reach is the same for OM5 as OM4 cabling. There are only 3 current Ethernet applications that state an additional 50 meter reach with OM5. If a data center is using non-IEEE-compliant 100G-SWDM4 or BiDi transceivers, they would see a 150-meter reach with OM5 – only 50 meters more than OM4. For most cloud data centers, if they have cabling runs over 100 meters, they will likely use Singlemode for 100 Gb/s and greater speeds. Additionally, any installed OM5 cabling beyond 100m may be limited in its ability to support of future non-SWDM applications.

“OM5 will reduce costs.”

It won’t.

OM5 cabling costs about 30-40% more than OM4. In addition, if you look at the cost of a full 100 Gb/s channel, including BiDdi transceivers, the amount per channel is still 40% more than a 100GSR4/OM4 channel. The costs of Singlemode transceivers have declined considerably over the past 12-18 months due to silicon photonics technologies and large hyperscale data centers buying in large volumes. When comparing the price of 100 Gb/s transceivers, 100G-PSM4 using Singlemode fiber is the same price as 100GBASE-SR4 using Multimode fiber.

“OM5 is required for higher speeds.”

Not true.

All of the current and future IEEE standards in development for 100/200/400/800 Gb/s will work with either Singlemode (OS2) or Multimode (OM4). The majority of these next-generation speeds will require Singlemode. IEEE always strives to develop future standards that work with the primary installed base of cabling infrastructure so customers can easily migrate to new speeds. The latest draft of IEEE P802.3db standard includes 400GBASE-SR4 (a lower cost, less complex, more attractive alternative to 400GBASE-SR4.2) which will have the same reach for OM4 & OM5.

“OM5 will create higher density from switch ports.”

It won’t.

It has very been common for data centers using 40GBASE-SR4 and 100GBASE-SR4 to increase port density by breaking out 40 or 100 Gb/s ports into 10 or 25 Gb/s channels. If a data center manager decides to use SWDM4 or BiDdi modules with OM5 cabling, they cannot break out into 10 or 25 Gb/s channels. This is a major disadvantage of using this technology.

“Do the leading switch manufacturers recommend using OM5 cabling with their equipment?”

No, they show OM3 & OM4

Example from Cisco: “In 40-Gbps mode, the Cisco QSFP 40/100-Gbps BiDi transceiver supports link lengths of 100 and 150 meters on laser-optimized OM3 and OM4 Multimode fibers, respectively. In 100-Gbps mode, it supports 70 and 100 meters on OM3 and OM4, respectively.” Example from Arista: “100GBASE-SWDM4: Up to 70m over duplex OM3 Multi-mode fiber or 100m over duplex OM4 Multi-mode fiber”

Siemon does not see any good reason to currently recommend OM5 to large data center operators. For enterprise data centers looking at migrating to 40GBASE-SR4 or 100GBASE-SR4, OM5 offers no additional benefit over OM4. And larger cloud data centers are either already using Singlemode or planning to move to Singlemode in the near future for migration to 800 Gb/s and 1.6 Tb/s without changing out their cabling.

Learn more about Siemon’s Multimode and Singlemode solutions.

View webinar: Siemon TechTalk | What Are The Real Benefits of OM5?