What are Port Breakouts and How to Deploy Breakout Cables and Transceivers?
The transceiver modules come with the division of channelized and unchannelized connectors. Channelized connectors are designed with multi lanes (such as QSFP+, QSFP28) while unchannelized connectors are built with a single lane (such as SFP, SFP+, SFP28). In networking connectivity, unchannelized ports deliver the same speed from one end to the other. However, high-speed and high-density port deployment is increasing in the system equipmets while lower speed access remains. This is where the multichannel port for breakout connection is deployed.
What is Port Breakout Mode?
Breakout mode is a function of an optical module connector with the ability to evenly distribute the whole bandwidth at one end into several lower-speed connectors at the other end. For instance, a QSFP28 module is capable of 100G QSFP28 to 4x 25G SFP28 connectivity.
What are the Benefits of Breakout Deployment?
Boost Port Density & Save Rack Space
A 24-port 40G QSFP+ patch panel provides 96 10G SFP+ ports, and a 48-port QSFP+ patch panel provides 192 10G SFP+ ports. However, a 24 or 48-port 10G SFP+ patch panel can only support up to 24 or 48 10G SFP+ ports. The 24-port fiber panel with full 40G QSFP+ supports four times the ports against the panel with 10G SFP+, therefore 96 ports require 4 24-port 10G SFP+ fiber panels. Four panels will waste rack space both in horizontal and vertical directions.
Cut Power Consumption
Splitting a QSFP+ port into 4 SFP+ ports saves more than 60% power compared to using 4 separate SFP+ ports.
Realize Spine-to-Leaf Architecture & Downlink to Lower-Speed Access
Breakouts enable connectivity with different data rates at two ends. Given that 10G and 1G ports dominate the access layer switches and end devices, connecting the legacy 10G port to the spine layer 40G/100g servers and switches are necessary.
Adapt to Future Upgrade
QSFP+ and QSFP28 connectors are highly compatible with 200G/400G/800G networks, such as 200G QSFP-DD, QSFP-56, 400G, and 800G QSFP-DD. Investing in 40G, and 100G breakout optics at one end of the link grants you the flexibility to smoothly upgrade to a higher speed in the future.
What are the Breakout Capable Optics?
Optics that support breakout mode often form factors with the multichannel interface, that is QSFP+, QSFP28, QSFP56, and QSFP-DD. These channelized connectors are implemented on transceiver modules and high-speed direct attach cables to offer breakout capability.
Breakout transceivers and cables are listed in the table below, including 40G QSFP+, 100G QSFP28, 200G QSFP56, 200G/400G/800G QSFP-DD transceivers and 40G QSFP+ breakout cables, 100G QSFP28 breakout cables.
Breakout Transceivers
Breakout DAC & AOC Cables
In the following part, the most popular breakout capable optics will be introduced with connectivity solution.
In the following part, the most popular breakout-capable optics will be introduced with connectivity solutions.
40G to 10G Breakout Connectivity
Deployment Case: The demand is to link the 10G leaf switch to the high-speed 40G switch in the spine. The distance between the two switches is short, within 10 meters.
Solution 1: Using the QSFP+ module
To connect a 40G QSFP+ switch port to 4 10G SFP+ ports within 10m, prepare the following products:
1. a multimode (MM) 40G QSFP+ transceiver
2. four MM 10G SFP+ transceivers
3. an OM3 or OM4 breakout MMF
Solution 2: Using QSFP+ to SFP+ breakout cable
A more cost-effective and simple solution is to use a 40G to 10G breakout direct attach cable, which has twisted a QSFP+ connector at one end and 4 SFP+ connectors at the other end of the cable. You don’t need to buy extra transceivers.
For short-distance interconnection, using cheaper direct attach copper cable (DAC) with 40G QSFP+ to SFP+ connectors can save cost.
If you need over 10m link within racks or adjacent racks, pick an active optical cable (AOC) with 40G QSFP+ to SFP+ connectors.
100G to 25G Breakout Connectivity
Deployment Case: The demand is to link the 25G switch to the 100G switch. The distance between the two switches is short, within 10 meters.
Solution 1: Using the QSFP28 module
To connect a 100G QSFP28 switch port to 4 25G SFP+ ports within 10m, prepare the following products:
1. a multimode (MM) 100G QSFP28 transceiver
2. four MM 25G SFP28 transceivers
3. an OM3 or OM4 breakout MMF
Solution 2: Using QSFP28 to the SFP28 breakout cable
Use 100G breakout cable for easy and plug and play connection.
QSFP28 to SFP28 DAC cable
QSFP28 to SFP28 AOC cable
Final Words
Breakout mode transceivers and cables endow the capability to connect the higher speed end to lower speed multiple ends. Typically from 40G to 10G, 100G to 25G, 400G to 100G and etc. The benefits of breakouts are — lower-speed ports access, an increase per RU port density and total bandwidth, saving in system costs.
Sole multichannel transceivers with corresponding fiber patch cables and direct attach cables are two options for breakout connectivity. The decision of which breakout solution to choose is based on your existing architectures, application scenario, budget, etc. For short-distance interconnection in racks or between racks, using a direct attach cable is cheaper and easier than separate modules with fiber patch cables. And for within 10m transmission copper DAC saves extra costs than fiber AOC. But for the short link over 10 meters, one should pick AOC for longer reach.
QSFPTEK provides both copper and fiber breakout cable, and multilane transceivers with breakout capability. Choose one option to get a quote.
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