Cisco Systems SPA9000 IP Phone User Manual


 
Configuring Your System for ITSP Interoperability
Network Address Translation (NAT) and Voice over IP (VoIP)
SPA9000 Voice System Administration Guide 50
3
Requirements:
You must have an external (public) IP address that is static.
The NAT mechanism used in the router must be symmetric. See “Determining
Whether the Router Uses Symmetric or Asymmetric NAT,” on page 53.
The LAN switch must be configured to enable Spanning Tree Protocol and Port
Fast on the ports to which the SPA devices are connected.
NOTE Use NAT mapping only if the ITSP network does not provide a Session Border
Controller functionality.
STEP 1 Connect to the administration web server, and choose Admin access with
Advanced settings.
STEP 2 Click Voice tab > SIP.
STEP 3 Scroll down to the NAT Support Parameters section, and then enter the following
settings to support static mapping to your public IP address:
Handle VIA received, Insert VIA received, Substitute VIA Addr: yes
Handle VIA rport, Insert VIA rport, Send Resp To Src Port: yes
EXT IP: Enter the public IP address for your router.
Voice tab > SIP: NAT Support Parameters
STEP 4
Click Voice tab > Line
N
, where N represents the line interface number.
STEP 5 Scroll down to the NAT Settings section.
NAT Mapping Enable: Choose YES.
NAT Keep Alive Enable: Choose YES (optional).