Networking.

Optical fiber capacity-distance demonstrations track the practical frontier of how much data can be transmitted how far through fiber — a moving target as multi-core fiber and better amplification push the record higher each year.

TCP source-port field width is 16 bits under the RFC 9293 TCP header.

TCP destination-port field width is 16 bits under the RFC 9293 TCP header.

TCP sequence-number field width is 32 bits under the RFC 9293 TCP header.

TCP acknowledgment-number field width is 32 bits under the RFC 9293 TCP header.

TCP receive-window field width is 16 bits under the unscaled RFC 9293 TCP header. The RFC 7323 Window Scale extension is excluded.

TCP checksum field width is 16 bits under the RFC 9293 TCP header.

TCP MSS value-field width is 16 bits under the mandatory four-byte RFC 9293 TCP MSS option.

Default TCP MSS for IPv4 is 536 bytes under RFC 9293 TCP over IPv4 when no MSS option is received. The value is derived as 576 minus 40 header bytes.

Default TCP MSS for IPv6 is 1220 bytes under RFC 9293 TCP over IPv6 when no MSS option is received. The value is derived as 1280 minus 60 header bytes.

QUIC minimum supported datagram size is 1200 bytes under a network path carrying QUIC version 1. This is UDP payload size, excluding IP and UDP headers.

QUIC variable-length integer maximum is 4611686018427387903 dimensionless under the QUIC version 1 variable-length integer format. Eight-byte encodings contain 62 usable value bits.

QUIC v1 connection-ID maximum length is 20 bytes under Source and Destination Connection IDs in a QUIC version 1 long header.

QUIC stateless-reset-token length is 16 bytes under a QUIC version 1 stateless reset token.

QUIC default maximum UDP payload is 65527 bytes under the omitted QUIC version 1 max_udp_payload_size transport parameter. This endpoint receive limit is not a path MTU, and values below 1,200 are invalid.

IPv6 minimum link MTU is 1280 bytes under RFC 8200 IPv6 links. Links unable to convey it in one piece must provide lower-layer fragmentation and reassembly.

Maximum ordinary UDP payload over IPv4 is 65507 bytes under UDP over IPv4 with a 20-byte IPv4 header and 8-byte UDP header. IPv4 options are excluded.

Maximum ordinary UDP payload over IPv6 is 65527 bytes under ordinary UDP over IPv6 with an 8-byte UDP header. IPv6 jumbograms and extension-header overhead are excluded.

IPv6 jumbo-payload length maximum is 4294967295 bytes under the RFC 2675 32-bit Jumbo Payload option. Jumbograms begin at 65,536 bytes.

DNS-over-UDP historical message-size limit is 512 bytes under original RFC 1035 DNS over UDP. The historical limit excludes IP and UDP headers and predates EDNS.

IPv4 total-length field maximum is 65535 bytes under the RFC 791 16-bit Total Length field. The value includes the IPv4 header and payload.

UDP length-field width is 16 bits under the RFC 768 UDP header. The encoded length includes the eight-byte UDP header.