3Com CoreBuilder 9000, Руководство пользователя

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360 C
HAPTER
13: E
STABLISHING
ATM C
HANNELS
Figure 18 Signaling Message Sequence for a Point-to-Point Connection
Point-to-Multipoint Connection
Figure 19 shows the sequence of signaling messages for setting up a
point-to-multipoint external link (connection) between a root station and
a set of destinations (leaves) by signaling.
From the Calling Party to The Enterprise ATM Switch: The calling edge
device initiates the establishment of a connection to the first destination
leaf by sending a SETUP message that contains the connection
characteristics except for VPI/VCI. The SETUP message also contains a
point-to-multipoint flag. The connection to the first leaf proceeds as in a
point-to-point connection.
The connection to the second destination leaf is initiated by an ADD
PARTY message. The switch then establishes the connection with the
second leaf as if it were a point-to-point connection. When the
connection is complete, the switch sends an ADD ACKNOWLEDGE
message to the root station.