200G HDR Optics Products Application Scenarios - NADDOD Blog

200G HDR Optics Products Application Scenarios

NADDOD Abel InfiniBand Expert Dec 21, 2022

From the client’s demand, EDR is gradually withdrawing from the market, NDR rate is too high and only head customers try to use it at present, HDR is widely used with the flexibility of HDR 100G and HDR 200G. Here, we provide an introduction for the application scenarios of HDR products.


HDR Products

Introduction to IB networking

The increasingly large scale of computing, the traditional tree network can not meet the demand, an improved tree network began to appear, it is the Fat-Tree architecture. The basic idea of Fat-Tree architecture is to use a large number of low-performance switches to build a large-scale non-blocking network, for any communication mode, there is always a path for their communication bandwidth to reach the NIC bandwidth. After the Fat-Tree architecture was introduced into the data center, the data center became a traditional three-tier structure. Since the traditional three-tier structure has the disadvantages of wasted resources, large failure domain, and huge changes in traffic direction development, the Spine-Leaf network architecture was created. Currently InfiniBand networking uses the spine-leaf architecture, which is widely used in data centers, high performance computing, and artificial intelligence (as shown in the figure below).The cables and optical modules provided by NADDOD are mainly used to connect Spine switches to Leaf switches and Leaf switches to servers under this architecture, and depending on the equipment different transceivers are selected depending on the transmission distance between them.


InfiniBand networking - 2 layer fat tree structure

200G HDR Transceiver Application Scenarios

Switch to switch interconnection

Leaf layer switches, aggregating traffic from servers, and Spine switches interconnecting all Leaf switches in a full-grid topology. Generally Leaf switches and Spine switches are interconnected, mainly using direct DAC cables or direct AOC cables. Because both AOC and DAC are hot-swappable, easy to install and replace, and can achieve higher port bandwidth, density and configurability at a lower cost, it can reduce the power demand of data centers. However, for long transmission distances and the need for cross-cabinet cabling, HDR SR4 or HDR FR4 is generally used.

Leaf-Spine

No Products Category Distance Cost
1 Q56-200G-CU1H DAC ≤3m Low
2 Q56-200G-A3H AOC 3≤distance≤30m Medium
3 Q56-200G-SR4H Optical Transceiver 30≤distance≤100m Medium
4 Q56-200G-FR4H Optical Transceiver distance≤2km High

Interconnection between switches and NICs

For data centers, high-speed cables are often used for ToR (Top of Rack) interconnections between ToR switches and servers. This DAC high-speed cable solution is ideal for short distance server-to-switch connections because the 200G HDR DAC breakout cable supports links up to 3m, while offering low power consumption, low latency, high bandwidth and low cost. The breakout cable can also split a 200G HDR (4x 50G-PAM4) switch port into two 100G HDR100 (2x 50G-PAM4) ends, enabling a 40-port QM8700 InfiniBand switch to support an 80-port 100G HDR100, improving port utilization. As shown in the figure below.

TOR switch to connect to the server

No Products Category Distance Cost
1 Q2Q56-200G-CU1H DAC ≤3m Low
2 Q2Q56-200G-A1H AOC 1≤distance≤30m High

Summary

InfiniBand network architecture is simple, but there are a variety of solutions to choose from. 100G rate has both 100G EDR solution and 100G HDR solution, and 200G rate has both HDR and 200G NDR options. NADDOD can provide suitable optical connectivity products according to the specific needs of different customers.