IBM Boosts Mainframe Networking with Advanced Ethernet and DPU Integration

IBM is redefining its mainframe networking strategy to better integrate with modern enterprise infrastructures. The IBM Z mainframe now supports standard Ethernet and IP connectivity, along with advanced technologies like remote direct memory access (RDMA) for high-performance communications. This shift ensures that IBM Z is deeply embedded within hybrid cloud environments, enhancing bandwidth, latency, and I/O capacity.

One notable advancement is the integration of a Data Processing Unit (DPU) architecture, which offloads I/O processing from the main processor cores. This DPU, part of the IBM Telum II processor architecture, features four processing clusters and eight programmable microcontrollers per cluster, significantly improving performance, latency, and throughput. By moving I/O functions onto the chip, IBM can innovate more rapidly and reduce power consumption and hardware complexity.

IBM has also introduced a 100GB Ethernet adapter for its IBM Z and IBM LinuxONE systems, featuring two 100 GbE ports. This upgrade eliminates the need for external I/O drawers, streamlining network connectivity. The adapter is particularly beneficial for clients consolidating Linux virtual machines onto a single mainframe, such as Citibank, which reported improved performance, security, and sustainability by migrating to LinuxONE.

Additionally, IBM unveiled the Network Express converged adapter with the z17 family in 2025. This adapter combines OSA Ethernet and RDMA over converged Ethernet (RoCE/RDMA) onto a single physical adapter, supporting speeds from 10G to 25G. The adapter also includes Enhanced Queued Direct I/O (EQDIO) technology, which optimizes Ethernet traffic for higher throughput and lower latency.

Industry analysts, such as Steven Dickens of HyperFRAME Research, highlight these advancements as crucial for maintaining the mainframe’s relevance in modern IT environments. Dickens notes that security and network segmentation around the mainframe are becoming increasingly important, requiring more frequent penetration testing and patching.