SPI-4 Phase 2 is an interface defined for packet or cell transfer between physical layer device and link layer device, for aggregate bandwidth of OC- 192 ATM, Packet over SONET/SDH, and 10 Gbps Ethernet applications.

GDA's SPI4P2 Interface controller is a highly configurable and efficient implementation, fully compliant to Optical Internet working forum's OIFSPI4- 02.0, System packet level interface Level 4 Phase 2 implementation agreement. SPI4P2 is a fully digital, multi-module design created to provide complete solution in variety of application scenarios: from dynamic alignment through protocol and FIFO management.