Computer Networks · TEE · practice

UDP and TCP arithmetic

Extra mathematical models

TEE · Complete six-unit quick reference · current syllabus 702AI0C023

L_{UDP}=8+L_{data}

UDP length includes its own eight-byte header, not the IP header.

H_{TCP}=4\times\mathrm{data\ offset}

Offset counts 32-bit words; minimum 20-byte TCP header.

ACK=\mathrm{first\ byte\ sequence}+L

After receiving all L consecutive data bytes, acknowledge the next expected byte. SYN and FIN each add one.

W_{new}=\max(0,\min(rwnd,cwnd)-F)

Supporting simplified sending allowance; F bytes in flight, all quantities in the same units.