use 768 instead of 512 for DAGMAXRANKINCREASE.
#define MAXDAGRANK 0xffff
#define DEFAULTDAGRANK MAXDAGRANK
#define MINHOPRANKINCREASE 256 // default value in RPL and Minimal 6TiSCH draft
-#define DAGMAXRANKINCREASE 512 // per RFC6550 https://tools.ietf.org/html/rfc6550#section-8.2.2.4 point 3
+#define DAGMAXRANKINCREASE 768 // per RFC6550 https://tools.ietf.org/html/rfc6550#section-8.2.2.4 point 3
#define DEFAULTJOINPRIORITY 0xff
