25G Switches: A Key Choice for Future Networks

25G switches are currently very popular with customers. ince its introduction in 2014, 25G Ethernet has existed for approximately five years. The market for 25G Ethernet has experienced many ups and downs over the years. If we compare the advanced methods of 10G-25G-100G and 10G-40G-100G, we will discover that customers seem to prefer 25G Ethernet because it appears to be more refined. Why go with 25GbE? How can the advantages of 25GbE be understood? The possibility of 25G switches will be discussed from various angles in this article.

The Development of 25G Ethernet

Due to virtualization and cloud computing, networks are now facing modern challenges requiring increased bandwidth. Even with the rapid development of 10G, the most important TOR switch in the data center has been difficult to meet the needs of existing network data. The standards for 100G and 40G were later endorsed by the IEEE. However, while 100G is relatively costly and difficult to implement, 40G is neither expensive nor efficient for cloud providers in terms of TOR switching.
IEEE 802.3 has developed a 25G Ethernet connection standard for the above situations. It facilitates the upgrade deployment of cloud-based database environment and enterprise environment, and also helps expand the 25G switch market. IEEE 100G Ethernet serves as the basis for 25G Ethernet, utilizing Ethernet’s single-lane 25Gbps connection and 4 x 25 Gbps lanes.

Why choose 25G Ethernet?

Due to the growth of Internet data, 25G switches are also designed with high-density ports to meet enterprise needs. So, compared with 10G or 40G networks, what breakthroughs does 25G Ethernet have at the technical level? Why will 25G Ethernet still be popular in the future.
Serializers and deserializers channels: A combination transceiver or circuit known as a SERIALIZER/DESERIALIZER (SERDES) is utilized for high-speed transmission, serial data conversion to an aligned interface, and other purposes. To connect one end point of the 25G Ethernet card to the other end point of the 25G Ethernet card, we only require one SERDES channel at 25Gbps.
25G Ethernet NICs: The popular Intel Xeon CPU provides 40 lanes of PCI Express 3.0 with a bandwidth of about 8Gbps per lane. We use a lane called PCI Express to connect the NIC to the CPU. A 25G Ethernet network card requires a single PCI Express 3.0×8 channel, and the usage efficiency is 25G2/(8G8)=78%. In terms of PCI Express lanes, the 25G network is more flexible and efficient than the 40G network.
Cost-effective cabling: SFP28 optical modules are used in 25G Ethernet switches and boards. Since they are single-lane links, they can be used with 10G Ethernet LC optics. You can save money and time by not having to change cables when you upgrade from 10G network to 25G network.
Benefits of 25G I/O switch: The most significant switch I/O representation and fabric capacity are provided by 25G Ethernet. The network bandwidth of 10G Ethernet has the potential to increase the network scale and profit of cloud companies by 2.5 times. 25G switches can also achieve network scalability and higher-density port applications through single-channel transmission.

Why Do We Need 25G Switches?

Switch Compatibility
Most of the available 25G switches are backward compatible because most of their supporting optical modules use SFP28. For 25G signal transmission, SFP28 is an improved version of SFP+. SFP+ transceivers can be connected to SFP28 ports since they have the same form factor. Fiber optic cabling in data centers can also be used with SFP28.
Therefore, re-architecting your data center with 25G Ethernet switches can save a lot of money and give you more flexibility to increase bandwidth during migration.
Port and System Density
25G technology is similar to 10G, but with 2.5 times higher performance. 25G technology significantly reduces power consumption and cost per gigabit, which means it requires 25G switches to provide higher port and system density. Using four 25 Gb/s data streams, for instance, a compact 100G path over copper or fiber optic cables is possible. Additionally, this method conserves energy and requires fewer TOR switches and cables, resulting in significant OpEx savings for data center operators.
Price and Performance
When price and performance are taken into consideration, 25G Ethernet is significantly less expensive per Gbit/s of bandwidth than 10G Ethernet. 25G switches or transceivers are priced very competitively on the market, only 30-40% more expensive than 10GbE, and this premium is expected to go down over time. In this case, 25G equipment needs to be deployed, such as 25G data center switches, 25G campus switches, etc.
The Crehan forecast below demonstrates that 25G is superior in both price and performance.
Figure 3: Price Comparison by Connection Speed

Explore the Features of 25G Switches

With the landing of the 25G standard, its supporting equipment has also been launched in 2016, such as 25G SFP28 transceivers, DAC cables, 25G adapters, 25G switches, etc. According to application scenarios, 25G equipment is also divided into 25G data center switches and 25G campus switches, etc., and their respective performances will also have some differences.
The 25G Ethernet switch market is mainly dominated by some brand vendors, such as 25G Dell, Cisco, Juniper, Arista, and Mellanox switches. Generally, 25G 48-port switches are the most popular type. Most 25G switches today offer two types of 25GbE interface form factors: QSFP28, which can support 4x25Gbps, and SFP28, which can support 1x25Gbps.
For example, FS N8500-48B6C is a 25G Ethernet switch with 48 x 25Gb SFP28, with 8 x 100Gb QSFP28 ports, which can be used to build a data center network. Whether it is a TOR (Top of Rack) switch or a switch deploying a spine-leaf architecture, a 25G network switch is a good choice.
Figure 2: FS 25G Ethernet Switch N8500-48B6C
     ”Also Check- N8500-48B6C Switch


With the trend towards higher Ethernet bandwidth, the demand for 10G Ethernet has been declining. Regardless of market research, 25G inevitably looks like the ideal choice because it is cost-effective, offers high bandwidth and requires low power consumption. In this context, equipment such as 25G switches play an indispensable role.