What is the minimum number of TCP sessions needed to complete a H.323 call between two H.323 gateways using slow start?

What is the minimum number of TCP sessions needed to complete a H.323 call between two H.323 gateways using slow start?
A . 0
B . 1
C . 2
D . 3
E . 4

Answer: C

Explanation:

H.323 has two modes of operation: slow start and fast start. The initiation of a call may proceed in a slow start or fast start in H.323. In a slow start, H.323 signaling consists of Setup, Call Proceeding, Alerting, and Connect steps. After these steps, the H.245 media negotiation is performed. When a call is initiated in H.323 fast start, the H.245 media negotiation is performed within the initial Setup message. With slow start, multiple TCP connections are needed for an H.323 call, such as one H.225 signaling channel and one H.245 signaling channel if required (minimum of these two).