25G

25G, in the context of networking, refers to 25 Gigabit Ethernet, a family of Ethernet standards that operate at 25 Gbit/s. Introduced to provide a higher-bandwidth alternative to 10G Ethernet while improving efficiency and port density, 25G has found extensive use in data centers and cloud networks. It encompasses a range of media and reach options, from copper to fiber, to support different deployment scenarios.

The 25G ecosystem includes multiple physical-layer specifications and transceiver formats. Common optical variants are designed for fiber links and include short-reach and long-reach options, enabling connections over multimode and single-mode fiber. Copper variants exist as well, enabling 25G over high-speed copper cables. Transceiver modules and connectors such as SFP28 and QSFP28 are widely used to deliver the 25 Gbit/s rate in compact, hot-pluggable form factors, facilitating modular upgrades from older 10G deployments.

In practice, 25G is deployed to increase aggregate bandwidth in data centers, support high-performance servers, and enable faster storage networking. It often allows upgrades with minimal changes to existing infrastructure, and it can be used with breakout configurations to connect to multiple lower-speed links as hardware supports such configurations. The standard emphasizes power efficiency and higher port density, delivering more bandwidth per port compared with 10G electronics.

Challenges in adopting 25G include ensuring compatible cabling and optics across the network, as well as upgrading switch hardware and fabric to support the higher data rate. While 25G is widely used in modern data center environments, integration with legacy networks may require planning and staged upgrades.