TMS zl Management and Configuration Guide ST.1.0.090213

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Firewall
IP Reassembly
IP Reassembly
The maximum transmission unit (MTU) determines the size of the largest
packet that can pass through the Data-Link Layer (Layer 2) of a connection.
If a packet is larger than the MTU for that device, it will be broken into
fragments. Fragments from one intermediate device may be further frag-
mented by another intermediate device. The device that fragments the packets
sends the fragmented packets in order, but they may not all be routed the same
way, which means that they may not arrive at the TMS zl Module in order.
Figure 4-81. Packet Fragmentation
The TMS zl Module will put all the packets back together in the right order.
All of the packets must be received before the TMS zl Module can reassemble
them, so it keeps packets in a memory buffer until all of the packets have been
received.