The best replacement for protocol is procedure.

The best alternatives to protocol are rated as following:
★★★★★  procedure
★★★  policy
★★★  guideline
★★  interface
★★  api
★★  routing protocol
★★  protocol
★  standing order
★  montreal protocol
★  internet protocol
★  delegate
★  intent to treat
★  routed protocol
★  voip
★  protocols
★  kyoto protocol
★  ftp
★  cesium chloride protocol
★  point to point protocol
★  standard operating procedure
★  port number
  agenda 21
  stop and wait protocol
  short protocol
  distance vector protocol
  file transfer protocol
  etiquette
  http
  non protocol
  itt
  h 323
  modified bruce protocol
  algorithm
  ssl protocol
  cap and trade systems

Your alternative for protocol is not listed? Suggest!
Speaking about protocol, one probably shouldn't forget about port number.

Other search terms related to protocol and their ratings are:
★★★★★ port number
★★★ lupron
trizol
You have in mind a companion for protocol and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of protocol in all years. Click on graph for more.
protocol
procedure
policy