System Design and Verification Blogs

Draft 1.0 of 802.3ck, also known as 100G per lane, was finally published by IEEE in Dec 2019.  This draft provided the standardization of higher lane speed support for backplane systems, including 3 speed mode variations: 100G, 200G, and 400G. Backplane Ethernet speed is increasing, evolving from 10G, 25G, 50G, to current 100G on a single SerDes lane within less than 10 years, offering unprecedented capacity for the datacenter and cloud infrastructure.

The challenges for most of Ethernet SoC or IP vendors are not only concerned with design complexity, but its verification productivity and efficiency as well. Design companies are preferring commercial verification IP (VIP) to reduce SoC/IP verification cycle, leveraging its full compliance to the specification and fine-grained stimulus generation.

Cadence Ethernet VIP supports the latest 802.3ck draft 1.1 and will continuously support along with the standard getting into finalization. 802.3ck feature in Ethernet VIP was meticulously designed with 3 major advantages that help tackle down verification challenges.

1. Compliance to the Specification: 100G per lane is not simply scaling up of 50G or 25G, though the Spec is largely leveraging the previous standards. There are quite a lot of additional but unique requirements in the standard that needs to be conscientiously covered by verification. For instance, the link training coefficient changes compared with 802.3cd.
2. Observability and Controllability: One of the biggest challenges in verification is the debug efficiency in terms of observability and controllability. Ethernet PHY is typical stacked model with several sublayers like PCS, FEC, PMA, and PMD. A verification engineer needs a good way to probe the data in between the layers or inside a certain layer, in order to verify the data integrity. A more advanced test involves the error injections that require a fine control within a sublayer to introduce the intentional faults, so that the verification engineer can understand if DUT is working expectedly in certain extreme cases.
3. Consistency: Cadence Ethernet VIP provides consistent user experience across the different interfaces and speed mode. It means that once a user is familiar with the usage of one interface, the rest of the other interfaces is very similar usage. Specifically, for 802.3ck feature in Cadence VIP, we do not invent new API but organically reuse existing transaction fields, configurations, and callbacks which provide a unified solution. Hence it shrinks the required learning curve for engineers and offers a great user experience.

All these are the crucial points one should take into consideration when choosing Ethernet VIP for project. Cadence VIP supports far more interfaces, speed modes, and features which are beyond the scope of this blog. For further details and demo of Cadence Ethernet VIP, please drop an Email to support@cadence.com or contact your local Cadence representative to get more details.