Understanding GTP IP Fragmentation
A GPRS tunneling protocol (GTP) packet consists of the message body and three headers: GTP, UDP, and IP. If the resulting IP packet is larger than the maximum transmission unit (MTU) on the transferring link, the sending Serving GPRS Support Node (SGSN) or gateway GPRS support node (GGSN) performs an IP fragmentation.
By default, the device buffers IP fragments until it receives a complete GTP message, and then inspects the GTP message.
Related Topics
JUNOS Software Feature Support Reference for SRX Series and J Series Devices