多项选择题
An RSVP session is maintained with the periodic exchange of which two message types?（） (Choose two.)
A.path B.resv C.session D.keepalive
单项选择题 How is an RSVP resv message sent back to the ingress router?（）
单项选择题 The traffic engineering extensions to RSVP provide what functionality?（）
单项选择题 What is the purpose of the RSVP hello interval?（）
