What is the maximum size of data that the application layer can pass on to the…

Answer: Any Size

Explanation:

• TCP is a stream-oriented protocol. The application layer can provide arbitrarily large amounts of data; TCP will divide that stream into multiple segments and transmit them.

• There is no fixed maximum size on the total data an application can hand to TCP in one call or over a connection; practical limits depend on system resources (buffers, memory) and implementation.

• Limits for a single TCP segment are imposed by lower layers:

  • IP total-length field is 16 bits, so a single IP packet (including IP and TCP headers) cannot exceed 65535 bytes. That yields a theoretical maximum TCP payload in one IP packet of 65535 − (minimum IP header 20) − (minimum TCP header 20) = 65495 bytes.

  • On typical Ethernet networks with MTU 1500 bytes, an unfragmented IP packet carries up to 1500 bytes of IP payload, so a common TCP payload per packet is about 1500 − 20 − 20 = 1460 bytes.

• Common incorrect interpretations:

  • Statements that the maximum is 2^16 bytes confuse the IP/UDP 16-bit length field (per-packet limit) with a limit on application data.

  • Statements that the maximum is 1500 bytes confuse the Ethernet MTU (a per-packet link-size) with the total amount an application may send; TCP will split larger data across multiple packets.