top of page

Total Cost of Ownership

Total Cost of Ownership

Energy costs are soaring across Europe as a result of the Nord Stream pipeline shutdown and the skyrocketing costs of obtaining natural gas. European energy ministers are meeting in Brussels to debate plans for price intervention. According to a Goldman Sachs report, short of dramatic intervention, many countries in Europe could see electric rates increase by 200%. However, according to a Wall Street Journal article, not much is expected to change in the short term, as difficult proposals are discussed. A similar situation is unfolding in the United States. Soaring temperatures across the country and the decommissioning of some powerful nuclear generating plants are causing an energy imbalance resulting in threats of rolling blackouts and higher prices.

It is through this lens that we take a look at Total Cost of Ownership (TCO) calculations when purchasing network equipment. With energy costs on the rise, it is important to include the year-over-year cost of powering the equipment in your network.

The purchase price of a switch, router, and network tools has a direct capital cost. However, the equipment cost is only the beginning. Other costs such as maintenance, power consumption, and cooling must also be considered. These costs are ongoing for the life of the products chosen. Unlike sunk capital equipment costs, variable expenses are subject to year-over-year increases. When building a complex network with a variety of components, ongoing variable costs must be included in the purchase decision.

Primary Power vs Secondary Power

When considering the long-term costs for primary power, we look at the direct cost of providing power to the unit. This part is fairly simple because most equipment will specify the power draw necessary. Two ports are required for full duplex operation at 10Gbps in each direction. An estimation of the power draw for two SPAN ports on a switch is about 20Watts. Note that each component will likely be operational 24 hours a day, 7 days a week, 365 days per year (8760 hours). For example, the per port power consumption is approximately US$26 annually. That is US$52 for each full duplex link. Of course, specific costs change by country, depending on energy rates and regulations in local areas. In the UK, the annual cost is about £34 or £68 for a duplex link. Note that there are usually many network tools required to support each link for monitoring, diagnostics, performance, and security. In addition, most networks have multiple links. For network-wide visibility, power costs add up the number of SPAN ports times the number of tools per link times the number of links. As you can see, particularly in large, complex networks, these power numbers can add up to significant annual operating costs.

Secondary power refers to the power required for heat dissipation. Equipment using electric power generates heat that must be mitigated. Therefore, connecting tools using powered SPAN ports creates additional heat generation and therefore increases the need for more air conditioning in the switch room to keep the equipment cool. While many variables determine the BTU requirements for equipment room or lab air conditioning, here is a broad rule of thumb…more electrical equipment equals more air conditioning required. Some switch rooms in certain warm climates require dual doors providing a pressure buffer between the outside temperature and the equipment room temperature which can vary by as much as 4.5C.

The No Power Visibility Alternative

What if all monitoring, security, diagnostic, and performance tools can be connected to links without using any power at all? It is not only possible to provide necessary network tool visibility without using power or generating heat, there are other benefits as well. We will get to the other benefits further on, but first, let’s discuss optical TAPs.

Passive Ethernet TAPs from Network Critical provide secure, simple, and accurate access to live traffic in high-speed production networks. Using optical fiber and mirrors, these TAPs do not require power and do not introduce latency or point of failure to the network. When Network Critical fiber TAPs are installed on network links, they provide full-duplex traffic including errors to your monitoring network for unbeatable visibility. Using mirrors to split the optical light budget, these TAPs provide maximum flexibility for the user. The internal mirrors can be custom designed to determine the amount of light that stays in the live network and the amount of light that is used to send mirror data to the connected tools. Passive optical TAPs are available for a variety of speeds and bandwidth requirements:

Network Critical Passive Fiber TAPs
  • 1Gb/10Gb Multimode LC Fiber Breakout TAPs

  • 1Gb/10Gb Fiber Singlemode LC Breakout TAPs

  • 40Gb/100Gb Bidirectional TAPs

  • 40Gb/100Gb Multi-Fiber Push On (MPO) TAPs

Passive optical TAPs from Network Critical are designed to provide visibility solutions for a broad range of network requirements from simple high-density 1Gbps solutions to specialized Cisco high-speed networks. More detail and data sheets can be found here:

Other Benefits of Optical TAPs

As promised, this is where we will cover some of the other benefits of using optical TAPs over powered SPAN ports for traffic visibility:

  • When comparing SPAN ports to optical TAPs, you must remember that two SPAN ports must be ordered to provide for duplex traffic. Optical TAPs are predesigned for duplex traffic so each TAP will pass full duplex traffic.

  • Electrical to Optical transceivers need to be purchased for each SPAN port at an average cost of US$40 each for a standard 10Gb transceiver. Depending on type, brand, and speed, they can cost up to US$800 each.

  • The engineering cost to configure each SPAN port is about US$50.

  • SPAN ports can double the internal traffic in a switch causing performance drag and potential dropped packets during busy hours. Randomly dropped packets may impact the accuracy of traffic reports.

  • Network Critical optical TAPs are designed for the highest port density using minimal rack space. With no power requirements, rack power source space and cabling is also reduced.

Optical TAPs provide speed, accuracy, simplicity, safety, and greatly reduced direct energy costs. It is also important to note that energy costs are forever and, seemingly, forever increasing. The total cost of ownership in any product includes the cost of deployment, maintenance, power, space, and cooling. Optical TAPs provide a clear advantage when all the ownership costs are calculated over the life of the product. An excellent source for design ideas, whether you are working on a new network or upgrading an existing network can be found here:




  • Twitter Social Icon
  • LinkedIn Social Icon
  • YouTube Social  Icon
  • Vimeo Social Icon
bottom of page