Is 25GbE the New 10GbE?

March 4, 2020

As the demand for high bandwidth is soaring, 10GbE has met its bottleneck in switch-to-server connections. And 25G Ethernet is the new standard offering significant density, cost and power benefits for server to switch links. This makes 25G switch very popular in recent years. Some even said the 25G will take over 10G to become the building block of the Ethernet future. Is that possible?

The Rise of 25G

It was forecasted by Mellanox on 2016 Open Data Center Summit that 25G would become the mainstream network of data centers in the next three years. By the year of 2019, the price of a 25G SFP28 was almost the same as a 10G SFP+. The 25G technology and 25G product portfolio develop nonstop driven by data center applications and 5G technology.

Driven by Data Center Topology Upgrade

More and more cloud computing companies like Amazon, Facebook, Google, and Microsoft have been deploying 100G Ethernet in their data centers, but the terminal devices outgrowing 10GbE capabilities. More bandwidth is required as data moves down into the fabric or top of rack. There is, consequently, a continued adoption of 25GE at the access between servers and ToR switches. 25G migration has boosted overall system throughput by 2.5x with small incremental costs. Moreover, 25GbE provides a simpler path to Ethernet speeds of 50 Gbps, 100 Gbps and beyond. With 25G technology maturing in the near future, end users can expect seamless operation between the main components within the datacenter network.


Boosted by 5G Technology

The 5G network structure consists of front-haul, middle-haul and back-haul sections which have different requirements of the transceiver module. For instance, 25G optical transceivers comprise a large part of the front-haul infrastructure, as the granularity of the 5G front-haul network is 25Gbps. Standard 25G optical transceivers like 25G SFP28 SR4 and LR4 are used intensively for point-to-point direct fiber optic connection. Moreover, 5G technology generates abundant applications. IoT technology becomes prevailing. Artificial intelligence is on the rise. All these make higher requirements on the network coverage and the network capacity. 25 BiDi optical transceiver with long transmission distance present as the cost-effective solution to address the issue.

10G vs. 25G

Besides replacing the 10G in the access layer and serving as the pivot in the 5G front-haul, 25G also presents many more advantages.

Speed of port Channel rates Number of channels per port Available port Total broadband
10G 10 1 128 1280
25G 25 1 128 3200

1.25GbE provides 2.5 times the performance of 10GbE. Since SFP28 form factor shares the same shape with SFP+, 25G switch provides 2.5 times the bandwidth of the 10G switch at the same port density.

2.25GbE offers higher bandwidth at the same power consumption of 10GbE.

3.25GbE is at the price of 10GbE.

4.25GbE Ethernet supports 10GbE technology advancements in packaging and silicon.

In the future, data centers, wireless networks, access networks and transmission networks will form a cooperative demand for 25G optical transceivers, rising to the breaking point for newer demands. However, the 10G optical transceiver market has seen a shift with customer demands falling rapidly.

The necessity of 10G to 25G Migration

It is hopeful that 25G will take over 10G to become the building block of the Ethernet future. The prospects lie in the following perspectives.

25G: the Enabler of Data Center Migration

In data centers, upgrading from 10GbE to 25GbE speeds offers both CapEx and OpEx savings through backward compatibility, for investment protection and seamless migrations with consistent rack-design and reuse of the existing cabling infrastructure, avoiding costly and complex changes. The involvement of 100/400G technology in data centers and cloud computing leads the structure upgrading, and 25G prevails over 10G at the access layer.

5G Front-Haul Network Pushes 25G Development

The explosive data in 5G era will requires more bandwidth and higher speed in the front-haul network. 10GE transceivers are unqualified. Now there emerges 25/50G to make the transition. At present, 25G optical transceivers are relatively mature, except 25G tunable optical transceiver which is under research and development, and 25G BiDi undergoing prototype test. With the increasingly perfect product portfolio, 10GE replacement with 25GE is happening.

High Cost-performance of 25G Against 10G

The prosperity of 25GbE is not inconspicuous, so lots of vendor flood in to take a share of the 25G technology, resulting in the decreasing of the product price. For example, 25G optical transceivers deliver 2.5 times the performance of 10G optical modules while at almost the same cost. It is promising that 25G will become the new 10G.


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