MTP Specifications and Deployment for 40GBASE-PLRL4 QSFP+

Commonly, QSFP+ transceiver designed with LC interface works with single-mode fiber for long distance application, while QSFP+ transceiver with MTP/MPO interface is used over multimode fiber for short distance transmission. For instance, 40GBASE-ER4 QSFP+ is designed with LC duplex interface, and it supports maximum transmission length of 40 km over single-mode LC duplex fiber; 40GBASE-SR4 QSFP+ with MTP/MPO interface supports a transmission distance no more than 150m over multimode fiber. However, in order to meet user’s diverse needs in real applications, some 40G transceivers are designed not following this rule, like 40GBASE-PLRL4 (parallel LR4 Lite). This transceiver is with MTP/MPO interface design but is used over single-mode fiber for long distance transmission. This article will introduce the MTP/MPO specifications for this transceiver and its deployment cases.


MTP Specifications for 40GBASE-PLRL4 QSFP+

QSFP-40G-PLRL4 transceiver uses MTP-12 interface to achieve parallel transmission, supporting maximum data links up to 1.4 km. The cable type required for 40GBASE-PLRL4 is an APC (angle polished connector) single-mode MTP-12 cable. The cable is similar to the 40G-SR MTP or MPO, with the only change being the use of single-mode fiber. UPC (ultra polished connector) is another type of connector for MTP-12 cables, but it is not suited for single-mode fiber in market. APC is the only available type for single-mode MTP-12 fiber. The MTP-12 connector plugged into the QSFP-40G-PLRL4 transceiver carries the 40G signal over only 8 of the 12 fibers, remaining four fibers unused, and these four can optionally be not presented in the cable for economic reason. The used 8 fibers are mapped as 4x10G Tx and Rx pairs. In addition, the MTP cables connected to QSFP-40G-PLRL4 transceiver can be either MTP trunk cables or MTP splitter cables.

Deployment of 40GBASE-PLRL4 QSFP+

The QSFP-40G-PLRL4 is optimized to guarantee interoperability with any IEEE 40GBASE-LR4 and 10GBASE-LR. So when the link for 40G network and 10G to 40G migration is less than 1.4 km, it will be very appropriate to use 40GBASE-PLRL4 QSFP+ transceiver with single-mode MTP cables.

In the first case, you can choose a MTP trunk cable together with the 40GBASE-PLRL4 QSFP+ module for direct 40G connection. The following picture shows two 40GBASE-PLRL4 QSFP+ transceivers connected by a single-mode 12-fiber MTP trunk cable.


In the second case, you can simply use an 8-fiber MTP to 4xLC duplex harness cable with one 40GBASE-PLRL4 QSFP+ and four 10GBASE-LR SFP+ to achieve 10G to 40G.


You can see in the above two cases, MTP cable plays an important role and due to the special requirements of 40GBASE-PLRL4 for single-mode MTP APC fiber, it is necessary to choose the right MTP products connected to this 40G QSFP+.


40GBASE-PLRL4 QSFP+ module has special interface design which can be only compatible with single-mode MTP connector. During the deployment of 40GBASE-PLRL4 QSFP+ module, selecting proper MTP assemblies are essential to successfully accomplish the link. FS.COM is a professional fiber optic transceiver vendor and MTP product manufacturer, supplying compatible 40GBASE-PLRL4 QSFP+ transceiver of different brands, such as Cisco, Arista, Brocade, Huawei, etc. Also other customized compatible brands are available for your requirements. MTP cables and assemblies are available for same-day shipping at low prices, including customized 8 fibers MTP/MPO trunk cable. You will be surprised to see how many kinds of network devices FS.COM can offer and you will get more than cost-effective products but also impressive service.

MTP-8: Simplest Way to Get 40G Connection

As data centers networks are shifting from 10G to 40G and beyond, it is necessary to seek ideal ways to connect 40G high speed switches populated with higher rate transceivers QSFP+, and to connect 40G switch to existing 10G elements populated with SFP+ modules. There are different approaches to connect 40G switches, or to connect 40G switch to 10G switch. However, by using MTP-8 solution, the simplest way to achieve direct 40G connectivity has been proved feasible and favorable in real applications. This article will introduce the deployment of MTP trunk cable in 40G to 40G connection, and MTP harness cable in 10G to 40G connection.

Basis of MTP Trunk and Harness Cable

MTP trunk cable has MTP connectors terminated on both ends of the fiber optic cable. It is often used to connect MTP port modules for high density backbone cabling in data centers and other high dense degree environments. Currently, most of the MTP trunk cables for high data rate like 40G and 100G are still 12-fiber or 24-fiber. MTP harness cable, also called MTP breakout or fan-out cable, has MTP connectors on one end and discrete connectors (duplex LC, SC, etc.) on the other end. The most common configurations of MTP-LC harness cables are 8-fiber MTP to 4 LC duplex, 12-fiber MTP to 6 LC duplex and 24-fiber MTP to 12 LC duplex. A single MTP connector is able to terminate the combination of 4, 8, 12, 24, 48 fiber ribbon cables. The multi-fiber design provides quick deployment and scalable solution that improves reliability and reduces installation or reconfiguration time and cost.

10G to 40G Connection via MTP Harness Cable

In order easily and quickly finish the migration from 10G network to 40G network, you can use 8-fiber MTP to 4 LC duplex harness cable, 40GBASE-SR4 QSFP+ and 10GBASE-SR SFP+ modules. The configuration of such a link is illustrated by figure 1. On the left the 8-fiber MTP connector is plugged into the MTP port of the 40GBASE-SR4 QSFP+ transceiver installed on the 40G switch; on the right side four duplex LC connectors are plugged into the ports of four 10GBASE-SR SFP+ transceivers installed on the 10G switch. In 10G to 40G migration, using 8-fiber MTP to LC harness cable can ensure every strand of fiber be used, and no one wasted.

10G to 40G via MTP-8 harness

Figure 1: 10G to 40G Migration via MTP-LC Harness Cable

40G to 40G Connection via MTP Trunk Cable

To support your 40G networking needs, you can simply use 12-fiber MTP trunk cable and 40GBASE-SR4 QSFP+ transceiver to accomplish a quick connection for two 40G switches in your network. The following figure shows a concrete example which uses one 12-fiber MTP trunk cable and two 40GBASE-SR4 QSFP+ transceivers to connect two 40G switches. Though the MTP trunk cable in this case is base-12, the fiber count actually in use is eight, leaving four strands unused. That is to say delivering 40G over 4 lanes multimode fiber at 10 Gb/s per lane. Totally only eight fibers (4 transmit, 4 receive) are required for the 4x10G solution. It is the same as the 4x25G solution for 100G.

40G to 40G via MTP-8 trunk

Figure 2: 40G to 40G Connection via MTP Trunk Cable

The above two examples are both applications of MTP-8 solution in 40G connectivity. You will find that only a few components are needed in the whole installation, and the link will be very easy and flexible, as well as cost-effective.


Current 40G connectivity can be obtained by MTP-8 solution. Though present market is still popular with 12-fiber or 24-fiber MTP, 8-fiber MTP solutions that are starting to hit the market are considered the most efficient option since they support current and future duplex fiber applications (such as 200G and 400G) and using modules that break out 8-fiber MTPs to duplex LCs, as well as current and future 8-fiber applications without the need for conversion cords or modules.