title UAS PRACK Flows http://www.websequencediagrams.com/#

opt
note over UAC, UAS: Flow 1
UAC->UAS: INVITE (NoOffer)
UAS->UAC: 18x (Offer)
UAC->UAS: PRACK (Answer)
UAS->UAC: 200/Prack
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Flow 2
UAC->UAS: INVITE (Offer)
UAS->UAC: 18x (Answer)
UAC->UAS: PRACK 
UAS->UAC: 200/Prack
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Flow 3
UAC->UAS: INVITE (Offer)
UAS->UAC: 18x (Answer)
UAC->UAS: PRACK (Offer)
UAS->UAC: 200/Prack (Answer)
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Flow 4
UAC->UAS: INVITE (Offer)
UAS->UAC: 18x
UAC->UAS: PRACK 
UAS->UAC: 200/Prack
UAS->UAC: 18x (Answer)
UAC->UAS: PRACK 
UAS->UAC: 200/Prack
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Flow 5
UAC->UAS: INVITE (Offer)
UAS->UAC: 18x
UAC->UAS: PRACK 
UAS->UAC: 200/Prack
UAS->UAC: 18x (Answer)
UAC->UAS: PRACK (Offer)
UAS->UAC: 200/Prack (Answer)
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Flow 6
UAC->UAS: INVITE (Offer)
UAS->UAC: 18x (unreliable)
UAS->UAC: 18x (reliable)
UAC->UAS: PRACK 
UAS->UAC: 200/Prack
UAS->UAC: 18x (Answer)
UAC->UAS: PRACK (Offer)
UAS->UAC: 200/Prack (Answer)
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Flow 7
UAC->UAS: INVITE (Offer)
UAS->UAC: 200/Invite (Answer)
UAC->UAS: ACK
end

opt
note over UAC, UAS: Negotiated Reliable Flow 1
UAS->UAC: 18x
UAC->UAS: PRACK (Offer)
UAS->UAC: 200/Prack (Answer)
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Negotiated Reliable Flow 2
UAS->UAC: 18x
UAC->UAS: PRACK
UAS->UAC: 200/Prack
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Negotiated Reliable Flow 3
UAS->UAC: UPDATE (Offer)
UAC->UAS: 200/Update (Answer)
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Negotiated Reliable Flow 4
UAC->UAS: UPDATE (Offer)
UAS->UAC: 200/Update (Answer)
note over UAC, UAS: Negotiated Reliable
end

opt
note over UAC, UAS: Negotiated Reliable Flow 5
UAS->UAC: 200/Invite
UAC->UAS: ACK
end

