Nat Mapping With Session Border Controller; Nat Mapping With Sip-Alg Router; Nat Mapping With A Static Ip Address - Cisco 521SG - Unified IP Phone VoIP Administration Manual

Configuring SIP, SPCP, and NAT
Managing NAT Transversal with Cisco IP Phones
STEP 1
STEP 2
STEP 3
STEP 4
STEP 5
Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide

NAT Mapping with Session Border Controller

We recommend that you choose an service provider that supports NAT mapping
through a Session Border Controller. With NAT mapping provided by the service
provider, you have more choices in selecting a router.

NAT Mapping with SIP-ALG Router

NAT mapping can be achieved by using a router that has a SIP Application Layer
Gateway (ALG). By using a SIP-ALG router, you have more choices in selecting an
service provider.

NAT Mapping with a Static IP Address

You can configure NAT mapping on the phone to ensure interoperability with the
service provider.
• You must have an external (public) IP address that is static.
• The NAT mechanism used in the router must be symmetric. See
Whether the Router Uses Symmetric or Asymmetric
Use NAT mapping only if the service provider network does not provide a Session
Border Controller functionality. To configure NAT mapping on the phone:
Click Voice > SIP and navigate to NAT Support Parameters.
Set the following parameters to yes:
• Handle VIA received
• Insert VIA received,
• Substitute VIA Addr
• Handle VIA rport
• Insert VIA rport
• Send Resp To Src Port
Enter the public IP address for your router EXT IP field.
Click the Ext_n tab and navigate to NAT Settings.
Set NAT Mapping Enable to yes.
4
Determining
NAT.
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