User A
LE A
LE B
TE
User B
Initial address message
(IAM)
ISUP message IAM is sent to transit exchange.
Transit exchange analyzes B number and determines that call should be
routed to local exchange of user B (LE B).
IAM message is sent to LE B.
Within all exchanges, the path is cut through (circuit switched path
between user A and LE B).
Signalling
sequence 2 (call setup)