- Casey
FiberMall
Answered on 8:47 am
Selecting the right 400G transceiver for multimode fiber involves many factors. Here are some of the key considerations:
Distance: The range of operations for each type of transceiver varies. Before choosing a transceiver, you should know the exact distance between the systems you plan to connect. Short-range transceivers are typically used for distances up to 70m, while long-range variants can cover distances above 2km.
Power Consumption: Power usage can vary substantially from one transceiver type to another. Higher capacity transceivers often use more power. Ideally, you should aim for a transceiver that offers the required data rate at the lowest possible power consumption.
Cost: Pricing can vary significantly between different transceivers. The overall cost should be evaluated in the context of your specific networking needs and budgetary constraints.
Compatibility: Not all transceivers will be compatible with your switches, routers, or other network devices. Be sure to confirm that the transceiver you choose works with your existing hardware.
Interconnection: Consider how different transceivers suit your interconnection environments. Transceivers come in different form factors such as QSFP-DD, OSFP, CFP2, CFP8, or COBO, and each has its own specifications for things like power consumption, size, and interface.
Reliability and Durability: The lifespan and durability of the transceivers also come into play. High-quality transceivers are built to last, reducing the need for replacements and maintenance.
The key features and common applications of each of these transceivers are described below.
1.The OSFP-400G-SR8 / SR8-C and QDD-400G-SR8 / SR8-C
The 400G-SR8 was the first 400G MMF transceiver available and has been deployed for point-to-point 400GE applications, such as leaf-to-spine connectivity, illustrated below.
While the 400G-SR8 provides cost-effective 400GE connectivity over MMF, it requires 16 fibers per transceiver and uses an MPO-16 APC fiber connector. Most 40G and 100G parallel MMF optics (such as the 40G-SR4 and 100G-SR4) use MPO-12 UPC fiber connectors. MPO-16 to 2x MPO-12 patch cables are required to use a 400G-SR8/SR8-C transceiver over an MPO-12 UPC-based fiber plant.
Another key application for 400G-SR8 transceivers is optical breakout into 2x 200G-SR4 links, enabling TOR-to-host connectivity where 200G to the host is required, as illustrated below.
The 400G-SR8-C transceiver has the same features as the 400G-SR8, with the added ability to breakout into 8x 50G-SR or 8x 25G-SR optical links. It can therefore be used in applications that require high-density 50G or 25G breakouts – as illustrated below.
- The OSFP-400G-SRBD and QDD-400G-SRBD, or “400G-BIDI”transceivers.
400G-BIDI transceivers use the widely deployed MPO-12 UPC connector for parallel multimode fiber. This allows existing 40G or 100G links that use 40G-SR4 or 100G-SR4 QSFP optics to be upgraded to 400GE with no change to the fiber plant, as illustrated below:
When configured for 400GE operation, the 400G-BIDI transceiver is compliant with the IEEE 400GBASESR4.2 specification for 400GE over 4 pairs of MMF.
Arista’s 400G-BIDI transceivers are also capable of breaking out into 4x 100GE links and can be configured (via EOS) to interoperate either with the widely deployed base of 100G-BIDI (100G-SRBD) transceivers, or newer 100G-SR1.2 transceivers, as indicated below.
In summary, Arista’s 400G-BIDI transceiver is software configurable to operate in any one of three operating modes:
i) 400G-SR4.2 for point-to-point 400GE links
ii) 4x 100G-BIDI for breakout and interop with 4x 100G-BIDI (100G-SRBD) transceivers
iii) 4x 100G-SR1.2 for breakout and interop with 4x 100G-SR1.2 transceivers
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