The next-gen cabling PCIe connections
PCIe Express through cables, just faster than OCuLink.
Although it may seem that OCuLink technology is gaining popularity, it is no longer developed, and the OCuLink Work Group ceased work in 2021. However, PCI-SIG did not unveil anything that would replace these cables, which were primarily designed for data centers but are now commonly used for consumer external GPUs and storage.
Today, PCI-SIG has unveiled the specs for CopperLink, the next-generation cabling based on PCI Express. These cables will enable new connection types for modern storage, data centers, and AI systems, including external and internal connections. It is not aimed at consumers, but nothing should stop companies from using it for such purposes.
Source: PCI-SIG
Within PCI-SIG, there are three workgroups: the Electrical Work Group (EWG), the Cabling Work Group (CWG), and the Optical Work Group (OWG). The latter’s work is not yet finished, but the idea is to create optical cabling for even faster systems later.
The newest CopperLink specs are for PCIe 5.0 and 6.0 technology with signaling at 32 or 64 GT/s respectively. These standards will evolve, and future bandwidth is said to increase. The workgroup is already working on PCIe 7.0 specs with 128 GT/s speed.
CopprLink Internal Cable Specification
- Supports PCIe 5.0 and 6.0 technology signaling at 32.0 and 64.0 GT/s
- Includes the SNIA SFF-TA-1016 connector form factor
- Maximum of 1m reach within a single system
- Example implementations include motherboard-to-add-in-card, motherboard-to-backplane, chip-to-chip and add-in-card-to-backplane in a self- contained server platform node
- Target applications include storage and data center compute nodes
CopprLink External Cable Specification
- Supports PCIe 5.0 and 6.0 technology signaling at 32.0 and 64.0 GT/s
- Includes the SNIA SFF-TA-1032 connector form factor
- Maximum of up to 2m reach in rack-to-rack connections
- Example implementations include CPU-to-storage, CPU-to-memory, CPU-to-accelerator, and accelerator fabrics in disaggregated server platform nodes
- Target applications include storage and data center AI/ML use cases
There are two types of cables: the internal one using the SNIA SFF-TA-1016 connector and the external version with the SNIA SFF-TA-1032 connector. The former is an unshielded cable that will enable motherboard to add-in-card, motherboard to backplate, or chip-to-chip connections. The external cables are designed for storage and data-center connections where cables longer than 1 meter are needed. Officially, the CopperLink external cable will support up to 2m in length and enable connections between CPUs, storage, memory, and accelerators.
It took many years for OCuLink to find its purpose outside server rooms, but given the popularity of storage systems and external GPUs (either for gaming or AI acceleration), the adoption of CopprLink could reach the consumer market even faster. Worth noting that once available, Thunderbolt 5 will pose a strong competition given its simple USB Type-C connection and bandwidth up to 120 Gbps.
Source: PCISIG
