* commit '967648121d3857b808941848203dfa44229781d7': cherrypick Change-Id: I3c2a7ea731d2fc3c0e2372e2f1a06ed659a6539f docs: move the SIP guide into guide/network/
* commit '967648121d3857b808941848203dfa44229781d7': cherrypick Change-Id: I3c2a7ea731d2fc3c0e2372e2f1a06ed659a6539f docs: move the SIP guide into guide/network/