Exploring The Difference Between InfiniBand EDR vs. 100Gb Ethernet

Date 04/30/2025

InfiniBand EDR is a network interconnection technology designed for high-performance computing environments. The performance and architectural differences between InfiniBand EDR and 100Gb Ethernet are described in this article, along with the technical characteristics and RDMA implementations of both solutions, and application scenarios.

With the continuous expansion of high-performance computing and artificial intelligence scenarios, data centers' requirements for network bandwidth, latency, and efficiency continue to rise. 100G InfiniBand and 100G Ethernet, as two mainstream technologies, show obvious differences in performance and architectural concepts, and have been the focus of many enterprises' difficult choices when deploying networks. Here we will analyze the technical characteristics, RDMA implementation, performance and application scenarios of these two solutions to help you clear your mind and make the right technology choice for your business.

The Infrastructure and Design Concept of InfiniBand and Ethernet

What Is InfiniBand EDR?

InfiniBand EDR (Enhanced Data Rate) is a network interconnection technology designed for high-performance computing environments. Its most important feature is its highly customizable architecture, which supports hardware-level zero-copy data transmission, kernel bypass communication, and end-to-end flow control mechanisms, resulting in microsecond or even sub-microsecond latency performance and extremely high bandwidth utilization.

InfiniBand's network architecture adopts a dedicated switching chip working in tandem with host channel adapters (HCAs), which has a lossless transmission mechanism and adaptive routing functions, making it ideal for supercomputing clusters. InfiniBand's network architecture utilizes a dedicated switching chip working with host channel adapters (HCAs) with lossless transport mechanisms and adaptive routing, making it ideal for supercomputing clusters, AI training nodes, and other environments with extremely sensitive performance requirements.

What Is Ethernet?

On the other hand, 100G Ethernet uses a more standard network design, relying on well-known Ethernet standards and having a variety of protocols to make it compatible, easy to use and cheap. Its advantage is that it can be quickly integrated into existing enterprise and cloud computing infrastructures, supporting large-scale distributed deployments and multi-tenant scenarios, making it one of the most widely used solutions in data centers and commercial networks.

RDMA Protocol Implementation Comparison Between InfiniBand EDR vs. 100G Ethernet

Remote Direct Memory Access (RDMA) technology is a key enabler for efficient data transfers, bypassing kernel processing, reducing latency and easing the burden on the CPU. InfiniBand and Ethernet take different technology paths in this regard.

the difference between InfiniBand EDR vs. 100G Ethernet

InfiniBand supports RDMA natively and was designed around this technology, supporting mechanisms such as zero-copy, kernel bypass, and lossless transfers through hardware-level flow control and virtual channels. Its HCAs (Host Channel Adapters) and switching chips are optimized for this type of high-performance transmission, forming a closed but efficient technology system.

Ethernet, on the other hand, utilizes RoCE (RDMA over Converged Ethernet) and iWARP to achieve RDMA capability. RoCEv2, the mainstream solution, operates on top of the UDP layer, solving the problem of lack of scalability in large-scale deployments of earlier versions, but requires higher losslessness of the underlying network, such as the need to enable mechanisms such as Priority Flow Control (PFC). iWARP, on the other hand, relies more on the TCP stack, which, although less demanding on the network structure, imposes higher latency and CPU overheads.

Performance Comparison Between InfiniBand EDR vs. 100G Ethernet

From the publicly available benchmark data, the difference in latency and bandwidth performance between the two network solutions is also more obvious. In tests using OpenMPI and the OSU Micro-Benchmarks tool, InfiniBand EDR delivers small packets about 10% faster than RoCEv2, with average latency in the microseconds or lower. Standard Ethernet latency is typically higher than 10 microseconds due to limitations in the software stack and buffering mechanisms.

In terms of bandwidth, InfiniBand achieves 99% link utilization at almost full load, thanks to its adaptive routing and congestion control mechanisms. While RoCEv2's performance can also reach about 90-95%, but only if the network environment has been optimized for in-depth flow control, otherwise it is prone to performance fluctuations due to packet loss.

Parameters	InfiniBand	RoCEv2
End-to-end Delay	Offers ultra-low latency, typically around 2 microseconds	Slightly higher latency, usually around 5 microseconds
Switch Delay	Approximately 100–150 nanoseconds for a single switch hop; three hops add up to around 2.5 microseconds	About 500 nanoseconds per hop; total around 4.6 microseconds for three hops
Compatibility	Requires dedicated InfiniBand components for deployment	Operates over standard Ethernet infrastructure
Scale	Can scale efficiently to support tens of thousands of nodes	Suitable for scaling up to a few thousand servers
Flow control	Uses a built-in credit-based flow control system with no additional setup	Requires manual configuration of PFC (Priority-based Flow Control) and ECN
Congestion control	Leverages ECN-based mechanisms	Also relies on ECN for managing congestion
Multi-path routing	Supports dynamic, adaptive multi-path routing for optimal traffic distribution	Implements ECMP (Equal-Cost Multi-Path), where each session follows a single path
Cost and Vendor Ecosystem	Primarily supplied by a single vendor, often resulting in higher pricing	Widely available from multiple vendors, leading to more cost-effective options

Application Scenario Differences Between InfiniBand EDR vs. 100G Ethernet

In high-performance computing (HPC), InfiniBand is the mainstream choice, especially for tasks requiring MPI communication, where low latency and stable bandwidth are irreplaceable advantages. Artificial intelligence scenarios, especially large-scale distributed training, also rely heavily on its extreme efficiency in synchronization between nodes.

In cloud data center, enterprise storage and virtualization scenarios, RoCEv2's advantages are gradually emerging. It is compatible with existing Ethernet architectures, adapts to SDN and NFV frameworks, and is able to provide RDMA capability close to that of InfiniBand without adding additional hardware costs. Meanwhile, with iSER (RDMA-based iSCSI Extension) support, enterprises can build efficient NAS/SAN systems without having to completely migrate to InfiniBand architecture.

High-frequency trading systems in the financial industry still tend to use InfiniBand to guarantee nanosecond latency, while for mixed-load environments, such as in virtualized clusters where AI inference coexists with regular data analytics, RoCE and iWARP offer more cost-effective options.

Conclusion

InfiniBand remains an unassailable choice when extreme performance is sought and budgets are tight. However, in more enterprise scenarios where scalability and deployment flexibility are sought, 100G Ethernet with RDMA technology offers a worthwhile compromise. The final decision depends not only on technical specifications, but also on the evolution direction of your current network architecture and business load characteristics.

Whichever path you choose, reliable optical modules are equally critical. 100G modules such as those provided by QSFPTEK, with strong compatibility and field-proven, can help you easily complete network upgrades and guarantee stable and efficient transmission capacity under different technology systems.