Two-way communications (ask or tell)?

Question

akka documentation for java says

http://doc.akka.io/docs/akka/2.4/java/camel.html#Consumer_timeout

Two-way communications between a Camel endpoint and an actor are initiated by sending the request message to the actor with the ask pattern and the actor replies to the endpoint when the response is ready.

And then

http://doc.akka.io/docs/akka/2.4/java/camel.html#Asynchronous_routing

A consumer endpoint sends request messages to its consumer actor using the tell method and the actor returns responses with getSender().tell once they are ready.

Which of both statements is true? Does it depend on the Camel component?

If tell method is used, how does the endpoint know to which client respond?

Thanks.