Converged Networks with Interoperable SPI-4.2 and CSIX-L1 Interfaces

Abstract

Next generation networks for handling OC-192 POS and 10 GbE traffic are employing new physical layer devices based on the OIF SPI-4.2 interface standard. This has created a migration issue for the network equipment provider needing to incorporate the newer SPI-4.2 technology into an existing platform currently operating under an earlier standard, such as the NPF CSIX-L1 which was commonly used for OC-48/ 2.5 Gbps applications. We describe, here, a "tunneling" strategy to achieve protocol interoperability, in which special tagging information is inserted into the packet flows through the CSIX-L1 interface to align with the SPI-4.2 data structure. The tunneling strategy has been applied to a common switch fabric prototype system. Performance measurements have been made and are presented showing the capability that such an interoperable packet switching system can achieve.Standards-based switch fabric devices have been replacing proprietary ASICs and older switch technology to provide high quality of service (QoS) non-blocked switching in the latest platforms being developed for converged network applications. Deployed as chip sets, these devices began use in switching and routing applications of OC-48 / 2.5 Gbps line rate devices and have now migrated to service OC-192 /10 GbE ports. In this migration the specification for the fabric interface has moved from the NPF CSIX-L1 standard, to the OIF SPI-4.2 standard for supporting 10 Gbps physical devices.