Duplex Connectivity And Parallel Connectivity in Data Center

As the size of data center becomes larger and larger, the network deployment in data center is more and more complicated. In data center, duplex connectivity and parallel connectivity are two of the most commonly deployed cabling system. However, to satisfy different requirements for cabling system, these two connectivity solutions are often utilized together. This article is going to introduce duplex connectivity and parallel connectivity in data center as well as their cross-connectivity solutions.

Duplex Connectivity

It is not difficult to understand that duplex connectivity is completed by two fibers. When it comes to duplex connectivity, what first appears in the mind is the LC duplex cable. According to TIA standard, there are two types of LC duplex patch cables: A-to-A patch cable and A-to-B patch cable. From the figure below we can see that the former one is a cross version while the latter one is a straight one. As is often the case, A-to-B patch cable is used in the cabling system.

A-to-A patch cable and A-to-B patch cable

As shown in the following figure, the duplex direct connectivity can be achieved by using A-to-B patch cable to connect two SFP+ transceivers with LC interface.

Duplex Direct Connectivity

Parallel Connectivity

Parallel connectivity is accomplished by two or more channels. It is usually used for high speed data transmission, such as MTP link for 40G and 100G network applications. For 40G network application, 12 fibers MTP trunk cable can be used, 4 fibers for Tx and 4 fibers for Rx; for 100G network application, 24 fibers MTP trunk cable can be used, 12 fibers for Tx and 12 fibers for Rx. As shown in the following figure, the parallel direct connectivity can be achieved by using 12 fibers MTP trunk cable to connect two QSFP+/QSFP28 transceivers with MTP interface.

Parallel Direct Connectivity

Duplex and Parallel Cross-connectivity

This type of connectivity solution is commonly used for conversion between 10G and 40G network. The following figure shows the simplest connectivity solution from parallel to duplex connectivity. To realize the conversion between 40G QSFP+ transceiver and SFP+ transceiver, MPO LC fanout cable is needed. The MPO LC fanout cable has four LC duplex connectors and the fibers will be paired in a specific way, assuring the proper polarity is maintained.

parallel to duplex connectivity

The following connectivity solution uses MTP adapter panel (Item 2) and MPO cassette (Item 4). It allows for patching on both ends of the fiber optic link.

Parallel to Duplex Interconnect

The following figure shows two duplex and parallel cross-connectivity solutions. The main difference for one above and one below is on the QSFP+ side. The below cross-connectivity solution is better for a greater distance between distribution areas where the trunk cables need to be protected from damage in a tray.

Duplex and Parallel Cross-connectivity


The connectivity solutions mentioned above are simple explanations to duplex connectivity and parallel connectivity in data center. It seems that different cabling environments require different connectivity solutions, and different fiber optic components will be utilized.

What Is Pre-terminated Cabling System in Essence?

As 40G and 100G have been applied in data centers to satisfy the demands of massive data transmission, high-density cabling system has become a common phenomenon. Solutions characterized by quick installation are preferred since they can save time and money. Pre-terminated cabling system has come into data center managers’ sight in recent years, because it can provide quick, plug-and-play network deployment for structure cabling. Then, what is pre-terminated cabling system in essence? And what we can expect from this cabling alternative? The information about pre-terminated cabling system will be fully covered in this article.

Overview of Pre-terminated Cabling System

Pre-terminated cabling system refers to factory manufactured cables and modular components with connectors already attached. Usually those cables and modular components have been tested, qualified and are ready to plug and play in network deployment. In addition, they are available in both fiber and copper cabling. Pre-terminated cabling system simplifies the installation of network devices by providing high-density and plug-and-play solution. Pre-terminated assemblies come in various forms, such as MTP trunk cable, MTP fanout cable or MTP breakout cable, MTP fiber optic cassette and pre-terminated cable bundles with protective pulling grips installed over the connectors at one end (shown as the following figure).

pre-terminated assemblies

Advantages of Pre-terminated Cabling System

Pre-terminated cabling system can bring a raft of advantages to cable installers and end-users.

Time Saving

The high speed deployment offered by pre-terminated cabling system is an equally important feature which helps to save time in various ways. The quick plug-in connections of network devices allow fiber and copper links to be installed in significantly less time than traditional field-terminated links. In addition, since the assemblies are factory terminated, the transmission testing is performed by the manufacturer before shipment. This greatly saves testing and troubleshooting time. Also, pre-terminated assemblies are factory terminated which reduce many of the problems that may occur with field terminations.

Space Saving

For data centers, the available space for high-density cabling is always precious. Components that contributes to promoting space utilization will gain popularity among data center managers. With massive cables being adopted in the data centers to carry out data transmission, pre-terminated assemblies offer cabling with much higher density and flexibility for data center upgrades.

Labor Saving

With pre-terminated assemblies, you don’t need as many on-site engineers pulling cables in and terminating them. As the pre-terminated links have been pre-tested, this vastly mitigates the need for troubleshooting and retesting.

Cooling Advantage

It is necessary to pay attention to heating and cooling issues in high-density cabling environment. Pre-terminated cabling system allows much more flexibility in configuration for installers working in compact space. It is also able to optimize airflow by using pre-terminated assemblies such as MTP trunk cable and MPO cassette, in conjunction with high density frames.

Applications of Pre-terminated Cabling System

Pre-terminated cabling system is commonly used in two fields: data center and open office. In response to the accelerated network capacity and application processing demands, data centers are expanding dramatically both in number and size. Pre-terminated cabling system provides an ideal plug-and-play solution for links between switches, servers, patch panels, and zone distribution areas in the data center. The open office also benefits from the pre-terminated cabling system which can be quickly reconfigured to match the moves, adds and changes. Pre-terminated cabling system offers unsurpassed advantages over conventional field installed system, which partially explains why the use of factory pre-terminated assemblies continues to grow, especially for data centers.


With several advantages of time saving, space saving, labor saving and cooling, pre-terminated cabling system provides an increasingly popular way of delivering a project in a more timely and cost effective manner. If your data center or network application needs speed and testing simplified installation, pre-termination cabling system is an ideal choice.