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What is the maximum length of an IP packet?
65,535 bytes
This 16-bit field defines the entire packet size in bytes, including header and data. The minimum size is 20 bytes (header without data) and the maximum is 65,535 bytes.
What is the maximum packet size for UDP?
The minimum length is 8 bytes, the length of the header. The field size sets a theoretical limit of 65,535 bytes (8-byte header + 65,527 bytes of data) for a UDP datagram.
Why the maximum size of UDP datagram is 65507 bytes?
Some have answered that the actual maximum is (65535 – IPHL – UDPHL = 65507). The mistake, is that the Message Length field in the UDP Header includes all payload (Layers 5-7), plus the length of the UDP Header (8 Bytes).
Does UDP use MTU?
UDP doesn’t know anything about MTU. UDP packets can have any size from 8 to 65535 bytes. The protocol layers below UDP either can send a packet of a specific size or will reject to send that packet with an error if too big. The layer below UDP is usually IP, either IPv4 or IPv6.
Is there a limit to the size of a UDP packet?
There’s no fixed limit in TCP, because it’s a stream protocol, not a datagram protocol. In UDP over IPv4, the limit is 65,507 bytes. From Wikipedia: This field specifies the length in bytes of the UDP header and UDP data.
What’s the maximum length of an IP packet?
maximum of an IP packet is about 65535 bytes. maximum of a UDP packet is 65515 bytes But when I made a test and watch Wireshark, I get a different answer. I try to send some big data with TCP protocol.
When to set UDP length field to zero?
RFC 2675 specifies that the length field is set to zero if the length of the UDP header plus UDP data is greater than 65,535. Note that using extremely large UDP datagrams can be problematic. Few network links have such large MTUs, so the datagram will likely be fragmented.
What’s the difference between a TCP and a UDP?
For TCP, you typically use recv, not recvfrom to read incoming data from a connected socket. Many will point out, TCP is a stream protocol, not a message/packet protocol like UDP. As such recv will give you back a non-deterministic amount of bytes between 1 and the size of the buffer being passed in to the recv call itself.