How to choose the correct branch jumper for the switch

This article will serve as a guide for using MTP to LC breakout cables in structured cabling applications, focusing on 12-core and 8-core MTP to LC breakout cables that are widely used in LAN and SAN switch LC duplex optical ports from different manufacturers.

What is MTP-LC branch cable?

A branch jumper is a cable assembly with a multi-core MTP connector on one end and a sheathed branch with a single-core or double-core LC connector on the other end. It provides a transition for the back of a trunk cable with an MTP connector, a trunk extension cable, or a single-core/double-core connector module. Figure 1 shows some examples of branch jumpers with different configurations.

What are the benefits of using MTP-LC branch cables?

When designing a network system, it is very important to plan the structured cabling in advance. Our goal is to solve current network needs and adapt to future development. Structured cabling systems can flexibly handle the tasks of moving, adding or changing infrastructure as the network grows. Using MTP-LC branch jumpers in high-density LANs or storage switches can help you improve structured cabling.

Some of the main advantages of using branch jumper assemblies over traditional jumpers:

1. Breakout patch cords provide a neat, high-density method to achieve high-density switch port duplication, which reduces the risk of switch port damage or errors.
2. Branch patch cords take up less space in the cabinet and have better vertical management than traditional patch cords. The branches at one end of a 12-core branch patch cord are much smaller than those of a patch cord with the same number of cores.
3. Reduces fiber optic cable congestion for LAN and storage networks; improves airflow for increased cooling and makes moves, adds and changes easier (MACs).
4. Branch patch cords provide staggered LC branches that can be used to match the network ports of electronic devices, including engineering customization, to provide seamless integration between cabling infrastructure and electronic devices.

What are the typical applications of MTP-LC branch patch cords?

MTP-LC branch patch cords are used to replicate the ports of blade switch boards, making it easier for these ports to connect to other devices. Based on the specific application and what components are inserted, there are two types of branch patch cords, module branch patch cords and trunk branch patch cords.

Modular breakout cables connect directly to the back of the MTP-LC module, duplicating the switch ports to a patch panel located in the same or adjacent rack. Typically this application is used when the switch is located in an MDA or head-of-row switch. Figure 2 depicts an example of a modular breakout cable application.

The switch-mirroring patch panel is located somewhere other than where the switch is located. This application is typically deployed when you have a common switching area and port duplication is required in the main distribution area (MDA). Figure 3 depicts an example of a trunk-breakout patch panel application.

What LC branch length should be used for MTP-LC branch patch cords?

***The LC branch length of the branch jumper will depend on the following factors: chassis model, blade type, number of blade ports, port direction and cabling routing. This article provides customized staggered branch jumpers for different industry manufacturers to match the ports of each of their data center switch product series, providing seamless integration between cabling infrastructure and electronic equipment.

Staggered Types 1, 2, 3, and 5 are precisely designed lengths to specifically match the layout of switch ports on different manufacturers. In addition, this article provides various uniform length/non-staggered branch lengths (e.g. 6 inches (Staggered Type 4 branch), 12 inches, 24 inches, and 36 inches) based on your cabling needs. Figures 4 and 5 show different staggered type configurations.

Which direction of MTP-LC breakout cables should be selected when wiring a switch?

The best switch cabling direction will depend on two factors, the orientation of the blade cards and the fan/intake location. For example, if your switch is horizontal with the blade cards and fan/air intake location, it does not prevent the breakout patch cords from coming from the left or right, it can come down to customer preference. On the other hand, if the fan/intake is located on one side of the switch, you should route your breakout patch cords from the other side.

This also applies to switches with vertical blade cards. This article provides the best wiring directions for different industry manufacturers based on different switch chassis products. Figure 6 shows different wiring directions.

With the widespread availability of switches in the networking market, there are several configurations of MTP-LC breakout cables available. The information in the rest of this document will help you decide which breakout cables are best suited for storage network or LAN switch cabling. On the next page are Tables 1 and 2 that summarize the use of 12-fiber or 8-fiber breakout cables based on switch manufacturer, module, number of ports, port orientation, and cabling direction. The part numbers for each different breakout cable type are in Tables 3 and 4. Illustrated examples of MTP-LC breakout cables for different switch/blade installations can be found in Appendix A of the document.