GRE was previously not supported on SRX branch devices in a Chassis Cluster. This article covers the code versions where it is supported.
In 11.1 and previous Junos versions, GRE is not supported on SRX branch devices in a Chassis Cluster. Beginning with Junos 11.2R3 and 11.4R1 and all newer software versions, GRE is supported on SRX branch devices in a Chassis C luster. This feature has been available on the SRX High-End platform since Junos 11.2R1.