The promise of 100GbE, ratified nearly a decade ago, is now finding its way into the networks of today’s data centre deployments, with tomorrow’s 200GbE and 400GbE solutions waiting in the wings. Servers with 10GbE connections are being upgraded to more powerful servers that utilise 25, 50, 100, and even 200GbE connections. The 70 billion metres plus of wired legacy Cat5e / Cat6 backbone networks that support wireless access points are being upgraded from Gigabit Ethernet to 2.5 or 5GbE to support the higher bandwidth requirements of the next generation of WiFi. Ethernet standards are enabling network backbones using 10Mb/s Ethernet, 100Mb/s Ethernet, and Gigabit Ethernet in what will amount to hundreds of millions of vehicles in the next decade, making them ‘data centres on wheels.’
The next generation of Power-over-Ethernet is coming, as the latest Ethernet standard that enables up to 71.3 watts to be delivered to devices was ratified in September 2018.
The new era
The deployments above illustrate the realities of the diversity of the new Ethernet era – while there is an industry fascination with the latest ‘next’ speed of Ethernet, the simple reality is that that speed is dependent on what application space one is discussing. The next era of Ethernet is one consisting of myriad applications, ranging from DC all the way up to 400GbE.
These applications are also fundamentally different in nature. Data centre networks and server connections are essentially upgrading known application spaces, where the infrastructure may be upgraded if necessary. This is juxtaposed by the upgrade to the legacy infrastructure in place to support next generation WiFi, where there is a huge incentive to not change the underlying deployed Cat5e / Cat6 cabling in buildings. And then there are emerging application spaces, such as automotive Ethernet, which has the potential to have subsequent impacts on the supporting infrastructure to support autonomous driving and vehicle-tocloud communications.
If we shift our attention to Ethernet standards that are currently in development, we will find that the diversity of the Ethernet ecosystem is continuing to grow, and that there are further examples of new emerging application spaces. Let’s consider the IEEE P802.3cn project that is developing 50GbE, 200GbE and 400GbE solutions for 40km and 100GbE and 400GbE solutions for 80km over DWDM systems.
The 40km solutions will address mobile backhaul networks, in particular, in China. Initial data (Figure 1) on mobile networks presented during the project formation in 2017 highlights the impact of geographical diversity on bandwidth requirements. Given the near-term explosion of mobile network data in China, Ethernet solutions based on 50Gb/s PAM4 optical technology, developed as part of the recent ratified IEEE Std 802.3bs-2017 for 200GbE/400GbE, are being leveraged to quickly develop 40km solutions.
The 80km solutions, on the other hand, will target cable/multiple-system operator (MSO) networks, mobile backhaul networks, and data centre interconnect, having reaches greater than 40km or have limited fibre availability to support multiple instances of Ethernet over a DWDM system. This effort is targeting a reach never standardised by the IEEE 802.3 Ethernet Working Group, as well as over a DWDM system, which is also a new area. So, the noted diversity of Ethernet continues to expand. In 2012 the IEEE 802.3 Ethernet Working Group produced its first Ethernet Bandwidth Assessment. This assessment noted a simple equation to understand bandwidth explosions
This simple equation illustrates how any of these factors can cause a bandwidth explosion. In the case of the mobile network needs of China, it is easy to understand how the number of users, the growth of consumer video, and increasing mobile connectivity rates are combining to create the massive bandwidth explosion presented. This assessment also forecast that, on average, the bandwidth growth of networks would increase by a factor of 10 every five years between 2010 and 2020. This forecast was used to justify the development of 400GbE, in order for the Ethernet community to provide a solution to meet these forecasted bandwidth requirements.
With 400 Gigabit Ethernet ratified, the IEEE 802.3 Ethernet Working Group has begun work on its next bandwidth assessment. The effort will need to address the growing expansion of the Ethernet ecosystem with new applications and diversity. Furthermore, given the growing interconnectivity between these application spaces and solutions, it seems unlikely that such an assessment would develop the same simple forecast of 2012 to cover the entire spectrum of Ethernet applications. Instead, the various application spaces will need to be considered individually initially, and then pondered collectively in order to assess when the next rate of Ethernet will be necessary.
John D’Ambrosia is senior principal engineer at Futurewei, chair of the IEEE 802.3 New Ethernet Applications Ad hoc, and chairman of the Ethernet Alliance