[Synopsys IP Resources] Integrated MAC, PCS, and PHY IP for 400G/800G Ethernet

arui1999

[Synopsys IP Resources] Integrated MAC, PCS, and PHY IP for 400G/800G Ethernet [Copy link]

The bandwidth required to handle more complex data is increasing rapidly, driving the data rates of 800G and 1.6T. There are many factors that contribute to this, such as the increase in the number of users and the number of devices per user, the increase in access rates, the increase in access methods, and more diverse service requirements. It is expected that 800G and 1.6T will achieve a 2-fold and 4-fold growth respectively in 9 years, however, the application growth of different content streams will range from 7 to 55 times, see Table 1 in the IEEE 802.3 Ethernet Bandwidth Assessment Report for details.

As shown in Table 1, the application with the most obvious increase in bandwidth demand is data switching in the data center, which has reached 16.3 times in 8 years. The connection of the data center rack unit (RU) is mainly copper wire, and optical devices are used in other locations. In the RU, the speed of the switch will increase from 12.8T to 25.6T, 51.2T and 102.4T. The same speed change is also observed in pluggable and co-packaged optical devices, with speeds increasing from 400G to 800G to 1.6T and Super Ethernet. Previously, a 12.8T switch required the instantiation of 32 x8 50G SerDes. For the next generation of switches, 112G and the upcoming 224G SerDes will become indispensable. Higher-speed SerDes have the advantages of smaller area, lower cost, lower power consumption, and shorter time to market.

The IEEE 802.3 working group defined the 400G standard, and the Ethernet Alliance defined and released the higher-speed 800G standard. The IEEE 802.3 standard for 400G uses multi-lane distribution (MLD) technology to distribute data from a single media access control (MAC) channel to 16 physical coding sublayer (PCS) channels. The Ethernet Alliance's 800G standard uses a MAC extended to 800 Gb/s, and two 400G Gb/s PCS (modified) to drive 8x100G channels. The two PCSs have a total of 32 channels (2 x16 400G standard PCSs), both of which use the RS (544,514) forward error correction (FEC) technology supported by the 400G standard.

Some applications, such as cars or printers, require lower Ethernet data rates (ranging from 10M to 25G), but for automotive applications, the data must be of higher quality and reliability. At the other end of the Ethernet speed spectrum, AI, hyperscale data centers, and telecommunications applications have begun using 400G Ethernet systems and are looking for data rates up to 800G. The SoC design for many of these applications is complex enough without considering the need to integrate high-speed Ethernet. Moreover, many SoC designers do not have the core capabilities to integrate an integrated Ethernet IP subsystem.

This article explains the Ethernet MAC and PHY Layer and uses a case study to describe different Ethernet design configurations for 400G/800G links.

Read more...