Long-header packets are intended to be introduced in a future version of the UniPro specification, so their format is undefined (except for one bit) in the current UniPro v1.14 specification. However, UniPro v1.14 defines a hook that allows long-header packets to be received or transmitted by a UniPro v1.14 conformant-device assuming the latter can be upgraded via software. The "long-header trap" mechanism of UniPro v1.14 simply passes the payload of a received L2 data frame (being the L3 packet with its header and payload) to the L3 extension (e.g. software) for processing. The mechanism can also accept L2 frame payload from softwarethe L3 extension for transmission. This mechanism aims to allow UniPro v1.14 devices to be able to be upgraded in order to support protocols that require the as-yet undefined long-header packets.
