Between ToR & Leaf Connectivity Options

Optics Type: 400G-AOC

Description: Up to 30m over multiple MM fiber pairs. AOCs provide a complete solution, that includes two optics modules connected using multiple fiber pairs. They come in different fiber lengths to cater to different customer requirements.
Fiber Type & fiber connector: Usually MM fiber
Use Case: It is a cost-effective optical connectivity option for short reach (up to 30m).

1-400G QSFP-DD to 400G QSFP-DD, 400GE/200GE/HDR, 850nm 

2-400G QSFP-DD to 4x 100G QSFP56 Breakout AOC 

3-400G QSFP-DD to 2x 200G QSFP56 Breakout AOC 

4-400G QSFP-DD to 8x 50G SFP56 Breakout AOC

Optics Type: 400G-SR8
Description: Up to 100m over 8 MM fiber pairs, using 50G PAM4 optical signals. Modules use cost-effective VCSEL technology.
Fiber Type & fiber connector: Multi-mode fiber, MPO-16 connector
Use Cases:

1.Cost-optimized 400G solution for up to 100m. 

2.It can also fanout or breakout to 50/100/200G links. 400G to 8x 50G-SR or 4x 100G-SR2 

3.Breakout to 2x200G-SR4.

Optics Type: 400G-DR4
Description: Up to 500m over 4 SM fiber pairs, using 100G PAM4 optical signals on each fiber pair. 400G-DR4+/XDR4 modules support the extended reach of up to 2km.
Fiber Type & fiber connector: Single-mode fiber, MPO-12 connector
Use Case: A cost-optimized solution for up to 500m. Customers can use it for 400G to 400G connectivity as well as breakout 400G to 4x100G connectivity.

The breakout option is often used for Leaf to ToR, in conjunction with 100G DR1 (100G DR1 is a new QSFP28 single lambda module used to plug into legacy 100G switches with NRZ electrical signals).

Optics Type: 400G-DR4+/XDR4
Description: 400G-DR4+/XDR4 modules support the extended reach of up to 2km over 4 SM fiber pairs, using 100G PAM4 optical signals on each fiber pair.
Fiber Type & fiber connector: Single-mode fiber, MPO-12 connector
Use Case: A cost-optimized solution for up to 2km. Customers can use it for 400G to 400G connectivity as well as breakout 400G to 4x100G connectivity. 

The breakout option is often used for Leaf to ToR, in conjunction with 100G FR1.

Migrating to 400G? Choosing the Right Option (Part 2)

Migrating to 400G? Choosing the Right Option (Part 4)