This sets how many UDP/RTP packets pass between full, uncompressed IP/UDP/RTP header refreshes, for the modem's first defined RTP compression context. Because header compression relies on both ends staying in sync on a shared compression context, periodically sending a full header rather than the compressed delta recovers that sync if a packet carrying context updates was lost over the satellite link; a shorter refresh rate here trades some bandwidth savings for faster recovery from packet loss. Setting this to 100 means every 100th RTP packet in that first compression flow is sent with a full header instead of the compressed form, limiting how long a lost-sync condition from a dropped packet can persist before it self-corrects.