Create Tests then Implement

Test-driven development (TDD) can help to build software better and faster. Following this the next steps are to product a simple tool to view PGM packets on the network. Conveniently tcpdump already includes a level of PGM support and its packet parsing concept can be leveraged to speed up development. tcpdump can be also used to verify operation of the new tool pgmdump.

Now we need to generate some packets, easiest is to generate a simple original data (ODATA) packet and fill the payload with a basic string: basic_send. For a variation of packet SPMs can be generated on a timer, in effect implementing the ambient SPM function of the PGM protocol: spm_idle.

A PGM packet sent by basic_send can be received and decoded by pgmdump and tcpdump simultaneously.