1. Home
    2. /
  2. Manuals
    3. /
  3. Linksys
    4. /
  4. SPA-841
    5. /
  5. 11
Page 51 / 286 Scroll up to view Page 46 - 50
Configuring Your System for ITSP Interoperability
Network Address Translation (NAT) and Voice over IP (VoIP)
SPA9000 Voice System Administration Guide
49
3
Network Address Translation (NAT) and Voice over IP (VoIP)
NAT is a function that allows multiple devices to share the same public, routable, IP
address to establish connections over the Internet. NAT is present in many
broadband access devices to translate public and private IP addresses. To enable
VoIP to co-exist with NAT, some form of NAT traversal is required.
Some ITSPs provide NAT traversal, but some do not. If your ITSP does not provide
NAT traversal, you have several options.
•
“NAT Mapping with Session Border Controller,” on page 49
•
“NAT Mapping with SIP-ALG Router,” on page 49
•
“Configuring NAT Mapping with a Static IP Address,” on page 49
•
“Configuring NAT Mapping with STUN,” on page 51
NAT Mapping with Session Border Controller
It is strongly recommended that you choose an ITSP that supports NAT mapping
through a Session Border Controller. With NAT mapping provided by the ITSP, you
have more choices in selecting a router.
NAT Mapping with SIP-ALG Router
If the ITSP network does not provide a Session Border Controller functionality, you
can achieve NAT mapping by using a router that has a SIP ALG (Application Layer
Gateway). The WRV200 router is recommended for this purpose, although any
router with a SIP-ALG can be used. By using a SIP-ALG router, you have more
choices in selecting an ITSP.
Configuring NAT Mapping with a Static IP Address
If the ITSP network does not provide a Session Border Controller functionality, and
if other requirements are met, you can configure NAT mapping to ensure
interoperability with the ITSP.
Downloaded from
www.Manualslib.com
manuals search engine
Page 52 / 286
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).
Downloaded from
www.Manualslib.com
manuals search engine
Page 53 / 286
Configuring Your System for ITSP Interoperability
Network Address Translation (NAT) and Voice over IP (VoIP)
SPA9000 Voice System Administration Guide
51
3
Voice tab > Line N > NAT Settings
STEP 6
Click
Submit All Changes
.
NOTE
You also need to configure the firewall settings on your router to allow SIP
traffic. See
“Firewalls and SIP,” on page 54
.
Configuring NAT Mapping with STUN
If the ITSP network does not provide a Session Border Controller functionality, and
if other requirements are met, it is possible to use STUN as a mechanism to
discover the NAT mapping. This option is considered a practice of last resort and
should be used only if the other methods are unavailable.
Requirements:
•
STUN is a viable option only if your router uses asymmetric NAT. See
“Determining Whether the Router Uses Symmetric or Asymmetric NAT,” on
page 53
.
•
You must have a computer running STUN server software.
•
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
.
Downloaded from
www.Manualslib.com
manuals search engine
Page 54 / 286
Configuring Your System for ITSP Interoperability
Network Address Translation (NAT) and Voice over IP (VoIP)
SPA9000 Voice System Administration Guide
52
3
STEP 3
Scroll down to the
NAT Support Parameters
section, and then enter the following
settings to enable and support the STUN server settings:
•
Handle VIA received:
yes
•
Handle VIA rport:
yes
•
Insert VIA received:
yes
•
Insert VIA rport:
yes
•
Substitute VIA Addr:
yes
•
Send Resp To Src Port:
yes
•
STUN Enable
: Choose
yes
.
•
STUN Server:
Enter the IP address for your STUN server.
Voice tab > SIP > NAT Support Parameters
STEP 4
Click
Voice tab > Line
N
, where N is the number of the line interface.
STEP 5
Scroll down to the
NAT Settings
section.
•
NAT Mapping Enable:
Choose
yes
.
•
NAT Keep Alive Enable:
Choose
yes
(optional).
Voice tab > Line N > NAT Settings
NOTE
Your ITSP may require the SPA device to send NAT keep alive messages to
keep the NAT ports open permanently. Check with your ITSP to determine
the requirements.
Downloaded from
www.Manualslib.com
manuals search engine
Page 55 / 286
Configuring Your System for ITSP Interoperability
Network Address Translation (NAT) and Voice over IP (VoIP)
SPA9000 Voice System Administration Guide
53
3
STEP 6
Click
Submit All Changes
.
NOTE
You also need to configure the firewall settings on your router to allow SIP
traffic. See
“Firewalls and SIP,” on page 54
.
Determining Whether the Router Uses Symmetric or
Asymmetric NAT
STUN does not work on routers with symmetric NAT. With symmetric NAT, IP
addresses are mapped from one internal IP address and port to one external,
routable destination IP address and port. If another packet is sent from the same
source IP address and port to a different destination, then a different IP address
and port number combination is used. This method is restrictive because an
external host can send a packet to a particular port on the internal host
only if
the
internal host first sent a packet from that port to the external host.
NOTE
This procedure assumes that a syslog server is configured and is ready to receive
syslog messages.
STEP 1
Make sure you do not have firewall running on your PC that could block the syslog
port (port 514 by default).
STEP 2
Connect to the administration web server, and choose Admin access with
Advanced settings.
STEP 3
To enable debugging, complete the following tasks:
a.
Click
Voice tab > System
.
b.
In the
Debug Server
field, enter the IP address of your syslog server. This
address and port number must be reachable from the SPA9000.
c.
From the
Debug level
drop-down list, choose
3
.
Downloaded from
www.Manualslib.com
manuals search engine

Rate

3.5 / 5 based on 2 votes.

Popular Linksys Models

Famous Router IPs
Famous Router Companies
Bookmark Our Site

Press Ctrl + D to add this site to your favorites!

Share
Top