ATM offers two kinds of connection

the Permanent Virtual Circuit and the Switched Virtual Circuit. The latter has an advantage over the former. But

to a great extent

whether the SVC can be accepted by users

is determined by whether the SVC signaling is efficient

flexible and reliable. The paper describes the point to point SVC signaling protocol Q. 2931 and the point to multipoint SVC signaling protocol Q. 2971 at the user network interface. Then

it lays the author’s finger on the limitation of the SVC signaling today.