SFP28 and QSFP28 Transceivers Cabling Solutions

Due to the increasing number of connected devices in use and their need for fast cloud-based data processing, the Ethernet interconnect standard widely used in data centers is evolving to move data more quickly and efficiently, which has driven the development of a 25Gbps version of Ethernet. Before 25G Ethernet was proposed, the next speed upgrade for data centers was expected to be 40G Ethernet (using four lanes of 10G) with a path to 100G defined as using 10 lanes of 10G as shown in the following table. However, the 25G Ethernet standard can provide a path to 100G and achieve higher total bandwidth than 40G. This article will discuss the different connection methods between 25G SFP28 and 100G QSFP28 transceivers.

total bandwidth of differnet Ethernet network

Note: 100G QSFP28 can be interfaced with 12-fiber MTP connector or duplex LC connector. In this post, the QSFP28 modules we mentioned all have MTP interface.

Direct Connectivity Solution

According to standard, since QSFP28 is 100G interface, SFP28 is 25G interface, four SFP28 transceivers must be needed to connect to one QSFP28 transceiver to achieve 25G to 100G transmission. In this scenario, an 8-fiber MTP-LC harness will be required to direct connect a QSFP28 port to the four corresponding SFP28 ports. This harness cable has four duplex LC connectors and the fibers will be paired in a specific way, assuring the proper polarity is maintained. Keep in mind that this direct connectivity method only recommended for short distance within a give row or in the same rack or cabinet.

Direct Connectivity Solution

Interconnect Solutions

Solution 1: This interconnect solution shown in the image below allows for patching on both ends of the optical network. The patching on the QSFP28 end is accomplished by using Type-A non-pinned MTP to non-pinned MTP jumper, which connects to the trunk cable, while the patching on the SFP28 end is accomplished using MTP modular cassette and duplex LC patch cable.

interconnect solution 1

Solution 2: In this scenario, a Type-B non-pinned MTP to duplex LC breakout cassette will be used to breakout an 8-fiber QSFP28 transceiver into a 2-fiber SFP28 patching field. This solution does reduce the amount of system attenuation by removing a MTP connector pair, however, it would be that the port breakout module has a limited tail length. Besides, this cabling solution only works best when the active equipment being connected is within the same row.

interconnect solution 2

Solution 3: This interconnect solution allows for an easy upgrade path moving from 2-fiber to 8-fiber connectivity. To connect to the SFP28s ports use the 8-fiber harness as shown in the following diagram, and an 12-fiber MTP trunk cable would be used from the adapter panel for the QSFP28 connectivity, thus allowing a mix and match upgrade patch without having to change out the patch panels. The SFP28 transceiver ports need to be located in the same chassis, which creates less flexibility.

interconnect solution 3

All the products introduced in the above solutions including SFP28 transceivers, QSFP28 transceivers, MTP breakout cassette, MTP adapter panel, MTP trunk cable, etc. can be purchased in FS.COM. We provide free and the same day shipping to the US now.

How to Deploy High Density MTP/MPO Cables in 10G/40G/100G Migration?

Just as large enterprise settle into 10G networking, bandwidth intensive applications and big demands are forcing companies to adopt 40G or even 100G network speeds. To address the upgrading from 10G to 40G/100G more efficiently and effectively, high density MTP/MPO cables are a good solution. In this post, I’d like to introduce the deployment of MTP/MPO cables (MTP harness cable, MTP trunk cable and MTP conversion harness) in 10G/40G/100G migration.

10G to 40G Migration: 8-Fiber MTP Harness Cable

8-fiber MTP-LC harness cable is one commonly used solution to directly connect 10G device to 40G device. As the following image shows, the MTP harness cable is in conjunction with a QSFP+ port carrying 40GbE data rates, then breakouts into four LC duplex cables which will be plugged into four 10G SFP+ transceivers.


40G to 40G Connection
Solution 1: 12-Fiber MTP Trunk Cable

For 40G to 40G direct connection, 12-fiber MTP trunk cable is the first choice. In the following scenario, 12-fiber MTP trunk cables are needed to connect the 40G transceivers (four fibers transmit, four fibers receive, leaving four fibers unused), adapting to the QSFP+ ports on the two 40G switches.


Solution 2: 2×3 MTP Conversion Module

In this scenario, 2×3 MTP conversion module is used. For every two 12-fber MTP connectors in the backbone cable, you can create three 8-fiber links. There is an additional cost for the additional MTP connectivity, but that is offset by the cost savings from 100 percent fiber utilization in the structured cabling. The 2×3 conversion module must be used in pairs—one at each end of the link. As the following image shows, the eight live fibers from each of the three QSFP+ transceivers are transmitted through the trunks using the full 24 fibers. The second 2×3 module unpacks these fibers to connect to the 3 QSFP+ transceivers on the other end.


Solution 3: 2×3 MTP Conversion Harness

For those needing a direct connection with 100 percent fiber trunk utilization, 2×3 MTP conversion harness (two 12-fiber MTP connectors on one end going to three 8-fiber MTP connectors on the other end) is an alternative fanout solution available which has the same functionality as 2×3 conversion module. Connectivity of the conversion harness is identical to the 2×3 module, and they are interchangeable, but must be used in pairs—one (cable or module) at each end of the link.


10G to 100G Migration: 20-Fiber MTP Harness Cable

CFP is a very popular implementation when deploying 100G network. To achieve 10G to 100G migration, in this scenario, 20-fiber MTP MPO breakout cables will be used(ten fibers for transmit and ten fibers for receive, then breakout into ten duplex LC cables). Simply connect this cable to a CFP transceiver and the customer can access the 10 SFP+ individually transceiver pairs.

10G to 100G migration with mtp breakout cable

100G to 100G Connection: MTP Trunk Cable

For directly connecting switches with QSFP+ ports, 12-fiber MTP trunk cable can be used, while for connecting 100GBase-SR10 CFP equipped devices, 24-fiber MTP trunk cable will be deployed.



From the text above, we have introduced several 10G/40G/100G scenarios that use MTP/MPO cables for data transmission. MTP trunk cable is a common solution for device direct connection, MTP harness cable is used for easier upgrading to higher speed network, and MTP conversion harness can achieve 100% fibers utilization, saving costs. All the MTP/MPO cables that we mentioned can be purchased in FS.COM.