Network Infrastructure Blog

Optical Network Tapping, also known as packet tapping or network monitoring, is a technique used to verify the performance and integrity of data streams as they flow between different devices on a network. This practice is often employed in data networks for various purposes, including network troubleshooting, security analysis, performance monitoring, and data collection. In this blog post, you will learn about the different types of network tapping, the most common optical split ratios, what a common network architecture looks like, and how to calculate the channel loss budget for a common network architecture.

What are the Different Types of Optical Network Tapping Available?

Tapping is the process of passively or actively monitoring network traffic by inserting a device called a network tap (traffic analysis point or test access point) into the network. There are two main types of network TAPs: Passive TAPs and Active TAPs

Passive TAPs are a hardware device, inserted into the network, designed to redirect a portion of the power on an optical circuit to an off-board network performance monitoring application. Passive taps are less expensive than active taps and do not introduce network lag, however, passive taps are also focused on network performance monitoring.

Active TAPs are a hardware device, inserted into the network, that direct 100% of the fiber to a third-party network analyzer; this network analyzer then replicates the traffic for further processing. The replication step provides a higher level of visibility but also introduces network lag as 100% of the traffic is replicated. While active taps are more expensive, a network manager has the ability to do more than just network monitoring, for instance, certain inspection applications allow for packet snooping and other similar services (utilizing SPAN – Switched Port Analyzer), thereby potentially damaging the integrity of the data.

SPAN is also available in two basic types. Local SPAN and Remote SPAN. Local SPAN mirrors traffic from one or more source ports on the same switch to one or more destination ports on the same switch. Remote SPAN (RSPAN) mirrors traffic from one or more source ports on one switch to one or more destination ports on another switch. However, they can impact network performance and the data they capture may not be forensically sound.

Whether using passive or active tapping, there are five common reasons to implement an optical network tapping infrastructure.

1. Network Security: By monitoring network traffic, organizations can identify suspicious activities, potential security breaches, and unauthorized access attempts.
2. Network Performance: Network administrators can use network tapping to analyze traffic patterns and identify bottlenecks or other performance issues in the network.
3. Network Troubleshooting: Tapping can help diagnose network problems, such as connectivity issues, packet loss, or high latency, by providing insights into how data flows through the network.
4. Compliance and Data Collection: In regulated industries, organizations might be required to monitor and record network traffic for compliance purposes. Network tapping can also be used to collect data for analysis and reporting.
5. Intrusion Detection and Prevention Systems (IDPS): These systems monitor network traffic for signs of potential intrusion or malicious activity and can alert administrators or take automated actions to prevent attacks.

The focus of this tech brief is Passive TAP solutions. Passive hardware taps are placed in the data network optical fiber infrastructure between network equipment. They are typically connected between switch-to-switch links, for example, Spine switch to Leaf switch, supporting Ethernet protocol, or can also be used in Storage switch to Storage switch connections supporting Fibre Channel protocol.

Figure 1: Sample switch-to-switch channel using a TAP module

Examining figure 1, this configuration is a basic structured cabling channel and is comprised of two MTP-to-LC modules connected by an MTP-to-MTP fiber trunk with LC-to-LC jumpers into the network device switch ports. The MTP- to-LC module on the left is the TAP module identified by the red MTP adapter in the rear of the module. From the rear, the MTP TAP port is connected to an LC adapter plate using an MTP-to-LC equipment cord which supports available TAP ports that plug into the monitoring device.

What are the Most Common TAP Split Ratios?

The optical signal in the TAP modules is commonly split into 50/50, 60/40, 70/30, 80/20 and 90/10 ratios. The first number is the portion of the signal to remain as live traffic, while the second number is the portion of the signal that is available for the TAP to utilize for the monitoring device. The 70/30 split ratio is mostly used for shorter distance links running at 1G to 10G. The 50/50 split ratio is the most common today as this better serves the higher speeds that today’s switch-to-switch links are operating at speeds of > 10G.

Passive TAPs work with both singlemode and multimode fiber regardless of the split ratios. As with standard fiber links, singlemode fiber has a longer reach than multimode fiber, especially in distances over 100 meters. The individual optical transceivers that are used in the switch-to-switch channels will have defined operating parameters by the manufacturer and provide specifications on the best fiber to use for the application.

How do TAPs factor into Loss Budget Calculations?

For the live network and the TAP monitor links to function properly, the loss budget for each path needs to be maintained. To determine this, the link insertion loss needs to be calculated. Table 1 below shows the different multimode TAP module component losses. If a performance issue arises, there is an option to look at other vendors optical transceivers. These other optics could provide less stringent loss budgets to better function for the channel that is to be tapped.

NOTE: The use of Siemon’s Ultra-Low Loss (ULL) MTP trunks, MTP-to-LC modules, and LC BladePatch® jumpers are required throughout the channel to meet the below performance specification and help minimize overall channel loss

As an example, let’s calculate the link loss of the OM4 network shown in Figure 1, using a 70/30 split TAP module and Ultra-Low Loss (ULL) components. Note: The connections into the optical transceivers are not used in calculating loss budgets.

To start, in Figure 2 below, we have applied the connectivity losses to the model previously illustrated in Figure 1 :

Figure 2: Sample channel using TAP module with component losses

For the live network link in blue, the calculation begins with adding the maximum loss for the live splitter segment in the TAP module of 2.20 dB as shown in Table 1. Next add the maximum loss for the MTP (0.20 dB) and LC (0.15 dB) connections on the TAP module which add up to 0.35 dB. Next, add the loss for the length of the fiber trunk in between the two MTP-to-LC modules. The maximum loss for this length of OM4 fiber is 0.30 dB at 100 meters. In most structured cabling implementations, the length of the MTP fiber trunk would be less than 100 meters, but for this example the maximum value will be used. Lastly, add the loss from the standard ULL MTP-to-LC module of 0.35 dB. The total maximum channel loss is 3.20 dB for the live channel as shown in Figure 3 .

Figure 3: Multimode LIVE channel loss calculations

For the TAP monitor link shown in red, the calculation begins with adding the loss for the standard ULL MTP-to-LC module of 0.35 dB. Next, add the loss for the length of the fiber trunk in between the two MTP-to-LC modules. The maximum loss for this length is 0.30 dB at 100 meters. Then add the loss of the incoming MTP for the TAP module of 0.20 dB. Next add the tap splitter loss off 5.80 dB as shown in Table 1, and then add the loss of the outgoing MTP adapter of for the TAP module of 0.20 dB. For the purpose of this exercise, we will assume the MTP-to-LC breakout cable length is short, so loss is negligible. Lastly, add the loss from the LC adapter plate of 0.15 dB. The total maximum link loss is 7.00 dB for the tap portion of the OM4 network as shown in Figure 4 .

Figure 4: Multimode TAP channel loss calculations

The network architecture above is just one example of how to design an optical channel with passive TAP modules. Please contact your local Siemon representative for more information regarding other potential network architectures.

After reading this blog post on networking performance monitoring using passive TAP modules, you should know what a TAP module is, what the difference between active and passive network tapping, what the term optical split ratio means, how to calculate channel loss budgets and finally what a typical network architecture looks like. If you are looking to add network performance monitoring using Passive TAP modules, please reach out to Siemon today.

Learn more about our LightVerse® TAP Modules

In the world of data centers (DC) and Intelligent Buildings (IB), copper and fiber cabling are widely recognized as the primary media types for network connectivity. The ability to seamlessly integrate these two types of cabling offers a multitude of installation options to address various cabling applications, network topologies, and equipment connectivity requirements. In this blog post, we will delve into the challenges faced by network engineers when dealing with the integration of copper and fiber media types and explore best practices to overcome the most common obstacles.

Traditionally, copper and fiber connectivity each had their own dedicated mounting styles onto racks or inside cabinets. Copper cables are typically housed in fixed open 1U or 2U patch panels with labeled front ports for easy identification. On the other hand, fiber connections are typically accommodated in larger 1U to 4U enclosures with sliding trays to access the fiber connections within. While these fiber enclosures offer excellent cable management, splicing capabilities, and security, they can often pose a challenge for installation and maintenance in space-sensitive environments.

What’s driving the need to mix connectivity?

While copper offers significant advantages in Intelligent Buildings and for short-distance connections in data centers, fiber cabling excels in long-distance connections and scenarios requiring enhanced security, its inherent difficulty to tap provides a higher level of data protection compared to copper, ensuring the integrity and confidentiality of critical information. Fiber is ideally suited for connections exceeding 100 meters, delivering higher bandwidth capacity and immunity to Electromagnetic Interference (EMI) as well as reliable and high-performance connectivity over extended distances, making it an ideal choice for interconnecting telecommunication rooms and in and between data centers.

More recently, due to the ongoing increase in bandwidth requirements, fiber has become more common for short-distance applications as well, replacing copper uplinks. Today’s data centers are running more fiber links, replacing traditional copper switch-to-server connectivity to achieve speeds up to 100 Gb/s. This has driven users to a mixed infrastructure approach, where fiber is required for high speed and copper for lower speed.

These trends make the usage of a panel that allows users to combine their copper and fiber connectivity within a single patch panel the ideal choice, and when deployed in the right configurations, it helps them to enhance their space usage and design flexibility and scalability into their network infrastructure.

What do you need to factor into your approach when mixing copper and fiber?

To ensure efficient and reliable network infrastructures that meet the evolving demands of modern IT environments, it is essential to follow best practices when integrating copper and fiber cabling. Here are some recommendations to consider:

1. Utilize copper for distances less than 100 meters in IB applications and for short-distance connections, such as those between servers and switches in the data center space that are operating at 10Gb/s or lower speeds. Additionally, copper cabling is often more cost-effective than fiber, making it a practical solution for shorter runs. It is also ideal for distributing remote power such as Power over Ethernet (PoE) for IB applications. When higher speed is required, the few required fiber ports in IB environment can be mixed with a combo panel.
2. Leverage fiber for long-distance connections exceeding 100 meters. Fiber’s higher bandwidth capacity makes it ideally suited for connections between Telecommunication rooms, data centers, and the Internet. When dealing with extended distances, fiber provides reliable and high-performance connectivity.
3. Where higher speeds are required, the use of fiber, even for short distances, is recommended because of its application flexibility. The rise of 25/40/100 Gb/s uplink speeds is driving the increased adoption of fiber over copper. In this case, copper remains a requirement for the few Out-of-Band uplinks remaining, therefore mixing copper and fiber will save you critical rack space.

In conclusion, the seamless integration of copper and fiber cabling in data centers and Intelligent Buildings offers numerous advantages in terms of connectivity, flexibility, scalability and futureproofing. Siemon’s new LightVerse® Combo Patch Panels present an innovative solution that provides “the best of both worlds” combining the benefits of both media types while addressing the pain points experienced by network engineers worldwide. By following best practices and considering the specific requirements of each application, network experts can build efficient and reliable network infrastructures that will support their demands for many years to come.

Other resources we think you’ll like.

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

On September 29, 2022, ANSI released the latest revision of the ANSI/TIA-568.3-E, Optical Fiber Cabling and Components Standard.  A couple primary introductions of interest to most users will be the addition of two new connectivity (polarity) methods for array (MPO)-based duplex applications.  The revision also introduced revised guidance on pinning of connectors to better support future transition to end-to-end array systems.

Prior to the release of this revision of the Standard, connectivity methods for array-based duplex applications were limited to Methods A, B & C – each having its own strengths and weaknesses.  ANSI/TIA-568.3-E introduced two new “universal” methods: U1 and U2.  The advantage of these new methods is having the commonality components of Method B without the need for unique MPO*-to-LC modules on each end.  Customers can now use the same MPO-to-LC modules and duplex patch cords on either end of the channel in conjunction with a Type-B trunk – thus simplifying deployments.

Methods U1 and U2 both use Type-B array trunks and A-to-B duplex patch cords.  Where they differ is Method U1 uses Type-A (Key-Up to Key-Down) array adapters and Type-U1 fiber transitions which Method U2 uses Type-B (Key-Up to Key-Up) array adapters and Type-U2 fiber transitions as show below in Table 1 and Figure 1:

Table 1: New Duplex Connectivity Methods

Figure 1: Connectivity Method U1

The key advantage of Method U1 vs Method U2 is that the use of Type-A adapters enables support of both multimode and singlemode applications as standard singlemode MPO connectors utilize opposing angled physical contact (APC) endfaces which are necessary to provide the more stringent return loss requirements of singlemode applications.

Additionally, Method U1 MPO-to-LC modules are ideal for use as a breakout or aggregation module for optical transceiver applications as shown below in Figure 2.  For more information, see Siemon’s Tech Brief 40 to 400G Optical Transceiver Breakout Links.

Figure 2: Breakout Application via Type-U1 MPO-to-LC Module

Additional MPO connector pinning guidance was also introduced in this new revision of the Standard to better enable future transition of an array-based duplex system to an end-to-end array system.  When mating MPO connectors – which use alignment pins – it is a requirement that one plug is pinned and the other plug is unpinned.  As MPO active equipment ports are pinned, they accept only unpinned plugs.

Therefore, an optimally designed array-based duplex system intended to support a future transition to an end-to-end array system should specify the following as illustrated in Figures 3 and 4:

• Array trunk cables should be pinned on both ends
• MPO connectors within the MPO-to-LC modules should be unpinned
• Future array patch cords connecting MPO active equipment ports to the array cabling should be unpinned on both ends

Figure 3: Recommended Array-based Duplex System Pinning

Figure 4: Recommended Array System Pinning

With the release of Siemon’s new LightVerse® fiber connectivity platform, Siemon offers Type-U1 MPO-to-LC modules with unpinned MPO connectors in both Base-8 and Base-12 as the standard offering and recommends the use pinned array trunks ensuring the simplest design and implementation of array-based duplex systems, breakout applications and future transition to end-to-end array systems.

* MPO is a generic reference – Siemon uses MTP connectors which are a premium MPO connector for all array connectivity products

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?