Easily Upgrade Your Network with the SFP28

When thinking about choosing the SFP+ to SFP28 transceiver upgrade path, think of buying a brand new house, with an unfinished basement. It may not be ready for use upon move-in, but the potential to add those finishing touches are there! You have the capacity to do so much more with your house than they’d originally thought, and the foundation is already there for you to execute. The same could be said about many of the network switches and routers out there. You may not know this, but 10G SFP+ ports will also support the newer 25G pluggable transceiver, the SFP28. It could very well be the easiest upgrade a network engineer could ever make!

So why SFP28? It may seem like an odd jump in data rate, considering the historical 100M to 1G to 10G ethernet evolution. The 100G QSFP28 may have had a bit of a role in that. With the widespread adoption of a 4-lane, 4x25G approach as the industry standard for 100G applications, single-lane 25G applications were to naturally evolve. The SFP28 leverages off over a decade of development in 25G optics and the associated electrical interfaces which means a surprisingly mature technology base for a relatively new transceiver form-factor.

The SFP28 MSA (SFF-8402) specifies the same form-factor and electrical pinout as the previous SFP+ MSA, just as the SFP+ was based on the original SFP (small form-factor pluggable) specs. A tightening of the electrical connector specifications for the SFP28 helps support the electrical signal integrity performance necessary for the higher data rate. An SFP28 port will typically be backwards compatible with SFP+, and in fact, many of your switch/router 10G ports were built with 25G support already because of the availability of 25G PHYs (the electrical components driving 25G data).

The power dissipation of a SFP28 SR or LR transceiver will fall very close to the same power envelope as a similar SFP+, typically under 2W. This means that most of your 10G provisioning rules are the same for your 25G upgrades. Check your SFP28 and switch specs!

Upgrading from SFP+ to SFP28 allows you to leverage off the existing fiber plant, which means you are simply switching out the transceiver, not rerouting cabling. This applies to duplex and bidirectional (BIDI) links. And SFP28 CWDM and DWDM will use the same channel grids and thus the same passive mux/demux/splitters in your network.

Where are we seeing SFP28s being introduced? As optical technology so often goes, initial applications have been SFP28 SR multi-mode, typically inter- and intra-rack datacenter upgrades from 10G. With the release of SFP28 LR singlemode (both 2km and then 10km), edge datacenter connectivity, access and wireless front and mid-haul applications can make use of 25G links.

• Instant 2.5x bandwidth upgrade from 10G to 25G ethernet
• Router to top-of-the-rack (TOR) switch connectivity as well as server/storage links
• 5G and LTE-A wireless has already pushed fronthaul connectivity from 1G to 10G, with 25G right around the corner. CPRI option 10 defines a 24.3302Gbps datarate for wireless fronthaul
• 100G to 4x25G breakout applications to maximize faceplate density on your core to edge router connections

As with 10G SFP+, SFP28s are available in graywave (850nm and 1310nm), bidirectional (BIDI), as well as CWDM and DWDM. The SFP28 form-factor is also available as a DAC (direct-attached copper cable) and AOC (active optical cable), in both single lane and breakout form.

It may not be as dramatic as finishing a basement, but digging into your router, switch, or server specifications and provisioning rules may yield some additional features and capabilities and often, your easiest upgrade is a simple SFP+ to SFP28 switch. Reach out to your Integra Optics sales or engineering team for additional support to help unlock any hidden potential in your optical network!