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inet-framework / inet

INET Framework for the OMNeT++ discrete event simulator
https://inet.omnetpp.org
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Packet size/datagram size less than 65,535 bytes but still gets fragmented. Why? #970

Closed arahman33 closed 7 months ago

arahman33 commented 7 months ago

** Event #22 t=0.25 Backhaul.helio_666.ipv4.ip (Ipv4, id=205) on UDPData-0 (inet::Packet, id=266)

INFO: Received (inet::Packet)UDPData-0 (7893 B) (inet::SequenceChunk) length = 7893 B from upper layer. DETAIL: Sending datagram 'UDPData-0' with destination = 10.0.0.5 INFO: Routing (inet::Packet)UDPData-0 (7913 B) (inet::SequenceChunk) length = 7913 B with destination = 10.0.0.5, output interface = wlan0, next hop address = DETAIL: Breaking datagram into 2 fragments

The messageLength does not exceed 65,535 bytes. Then why is it getting fragmented?

attaching parts of the .ini file.

..wlan[0].typename = "AckingWirelessInterface" ..wlan[0].mac.useAck = false ..wlan[0].mac.fullDuplex = false ..wlan[0].radio.typename = "UnitDiskRadio" ..wlan[0].radio.analogModel.typename = "UnitDiskAnalogModel" .helio_666.app[0].typename = "UdpBasicApp" .helio_666.app[0].localPort = 666 *.helio_666.app[0].messageLength = 7885B

Update: I changed the MTU from AckingWireless and it no longer gets fragmented.

levy commented 7 months ago

Fragmentation depends on the MTU size specified on the network interface.