A satellite terminal product required that a PPPoE stack be installed on the MIPS AU1100 (main satellite protocol (GAN/BGAN) control card) to perform PPPoE over a satellite link. A proprietary PPPoE stack existed on another platform whose main function was to control communications between the GAN/BGAN card and peripherals that existed at the satellite terminal site. This stack was ported.
Challenges
The RTOS on both systems was different (MQX on one and Nucleus on the other). Required modification of COTS Nucleus RTOS device drivers to siphon off PPPoE packets.
The Discovery and LCP packets had to bridge more peers to the ISP than in the original version so the original stack needed adjustments. Latencies from the added peers compounded by the satellite link delay and the slow transmission rate offered by the service created "timeout" issues not handled by the ISP's stack. Designed feature to spoof the ISP into resetting its timers.