Figure 171 Business Secure Router Sip Alg - Nortel 222 User Manual

Figure 171 Business Secure Router SIP ALG

Signaling session
over UDP port 5060
SIP ALG and NAT
The Business Secure Router dynamically creates an implicit port forwarding rule
for SIP traffic from the WAN to the LAN.
The SIP ALG on the Business Secure Router supports all NAT mapping types,
including One to One, Many to One, Many to Many Overload and Many One
to One.
SIP ALG and firewall
The Business Secure Router creates an implicit temporary firewall rule for the
dynamic RTP port on the WAN to the SIP client device on the LAN. The firewall
rule is created for both directions to allow voice packets. The firewall rule is
deleted when the call is terminated.
SIP ALG and Multiple WAN
When the Business Secure Router has two WAN ports and uses the second
highest priority WAN port as a back up, it drops SIP connections when the
primary WAN port connection fails. The Business Secure Router does not
automatically change the SIP connection to the secondary WAN port.
Audio session using RTP
Nortel Business Secure Router 222 Configuration — Advanced
Appendix M SIP 343