Data integrity – the maintenance and assurance of the accuracy and consistency of data over its entire life cycle – is a critical part of any system that stores, processes or retrieves data. Gen-Z memory-semantic fabric ensures data integrity in several ways.
Gen-Z provides packet data integrity capable of detecting random, single- and double-burst errors, and all Gen-Z packets contain two Cyclic Redundancy Checks (CRCs). If a physical layer implementation requires Decision Feedback Equalization (DFE), then an encoding layer is transparently inserted, providing an additional layer of protection.
The Gen-Z PHY Specification also specifies a lower raw bit error ratio (BER) in order to deliver a superior solution-level BER. Preluded CRC (PCRC) protects against errors that could cause the packet virtual circuit and length to be incorrectly interpreted.
Furthermore, all Gen-Z packets contain a 24-bit End-to-end CRC (ECRC) field, which protects the entire packet. Unlike the PCRC validation, a packet can be relayed despite having a bad ECRC. For example, if cut‐through packet relay is supported, then packet transmission through the egress interface can occur prior to the receipt of the ECRC field at the ingress interface. If an ERC error is detected, then the component stomps the ECRC field to ensure the next component knows the packet is bad.
To detect random burst errors, Gen-Z specifies a Phit encoding layer that can be inserted into implementations that use DFE. Each Phit can contain a single packet, partial packet, or multiple packets depending on the packet sizes. If an error is detected, this is handled as a transient ECRC error.
Finally, a transient error threshold is set on each interface to facilitate a predictive hardware failure report. If this threshold is exceeded within the specified time, then the interface automatically initiates physical layer retraining.
Ensuring data integrity is just one of the many benefits provided by Gen-Z technology. To learn more about Gen-Z data integrity, view the entire presentation here. To learn about this and many other topics, please review our educational materials.