Tls exiration value

hi, i noticed on the asterisk console that when an endpoint gets created, like this:

Added contact ‘sips:[email protected]:56997;transport=TLS’ to AOR ‘123’ with expiration of 3600 seconds

an expiration of 3600 seconds is set. I understand this to mean that the session renegotiates every hour? if this is so, is the timeout setable and where?

i am using
pjsip endpoints