@startuml
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participant Initiator
participant Responder

== preparation ==

Initiator <- Responder : [s]

== interactive ==

Initiator -> Responder : [e, es, s, ss], INFO..., HALT...
Initiator <- Responder : [e, ee, se], INFO..., HALT...
Initiator -> Responder : INFO..., FREQ..., DONE...
Initiator <- Responder : INFO..., FREQ..., DONE...
Initiator -> Responder : FILE..., INFO..., DONE..., PING
Initiator <- Responder : FILE..., INFO..., DONE..., PING

@enduml