@startuml
skinparam responseMessageBelowArrow true

actor "Administrator A" as AdministratorA
participant "Node A" as NodeA
participant "Node B" as NodeB
actor "Administrator B" as AdministratorB

AdministratorA->NodeA: Register federated node B.
AdministratorA-->AdministratorB: Send node URI.
note right of AdministratorA
Administrator A sends the node URI
to administrator B via a secure channel.
end note
...
AdministratorB->NodeB: Register federated node A.
note left of AdministratorB
Administrator B registers node A
using the node URI.
end note
@enduml