Figure 5-2 Softswitch Network Topology - Alcatel-Lucent 7330 Product Information Manual

5 — VoIP overview
Server (s) DHCP,
application, FTP etc.,
IP phone
PSTN
gateway
PSTN
cloud
POTS
phone
Class 5 PSTN
switch
The ONT supports redundant softswitch servers. When operating in a redundant
configuration, the ONT contacts the secondary server if the primary server is lost.
Softswitch call flow
The call flow associated with a conventional softswitch for traffic originating from
the ONT is generally the same as specified in the IETF/ITU-T H.248/Megaco call
flow.
One fundamental difference between the gateway mode and the softswitch mode is
that, in the softswitch mode, the Megaco signaling protocol instructs the ONT in
terms of playing tones, and on-hook and off-hook event through out-of-band
signaling messages.
5-8

Figure 5-2 Softswitch network topology

Management channel
Softswitch
IP cloud
BRAS
L2
Ethernet
cloud
Note —
To implement redundant softswitch servers, you must use the
DHCP option 120 for a second softswitch IP address.
March 2011
ONT Product Information Guide Edition 01
Signaling
channel
ONT
OLT
Alcatel-Lucent 7330/7302 ISAM FTTN R04.02.42a
RJ11
POTS
phone
RJ45
IP
phone
18189
3FE 54199 AAAA TCZZA