Talkswitch 24-CA - Manual (Page 190)

1 7 8 T A L K S W I T C H US E R G U I D E • N O R T H A M E R I C A
When you first set up your VoIP device (TalkSwitch 48-CVA unit, gateway or
phone), it will register itself with the TalkSwitch 48-CVA that is configured
as the IP server so that calls can be directed to your location.
When you initiate a VoIP call, your device (TalkSwitch 48-CVA unit, gateway
or phone) will contact the TalkSwitch 48-CVA that is configured as the IP
server to obtain the contact information for the destination you are trying
to reach. Once the information is received, the call is established directly
between your location and the destination. The IP server is no longer
involved in
the call.
If the location of the IP proxy and registrar has a dynamic IP address, you
have to use the dynamic DNS since the IP server location becomes
unreachable as soon as the IP address changes.
What is Dynamic DNS?
Dynamic DNS is a Domain Name Service used with dynamic IP addresses. DNS
is used to allow devices to find other devices on the Internet by name rather
than by IP address. Dynamic DNS allows you to use a Fully Qualified Domain
Name (FQDN) to locate a device with a dynamic IP address. The FQDN does
not change. There are companies on the Internet who can provide you with
a DNS address, even if your IP address changes. Such companies are
www.dyndns.org, hn.org or www.no-ip.com. Please consult with them how
to use their service. The basic idea is that you will receive an address like
myname.homeip.net which points to your IP address (i.e. 209.210.230.140).
This is important for locations where the IP server resides and where the
public IP address is dynamic. All other locations will point to this IP server’s
domain instead of an IP address.
What is the drawback of using dynamic DNS?
When DNS records are updated, they have to be sent all over the world so
that everyone will be aware of the changes. Basically, one DNS server
connects to another and swaps information. In many cases, the DNS servers
are updated very quickly. Updates should not take longer than 15 minutes
to propagate throughout the DNS system. It is possible that propagation
could take longer due to unforeseen traffic but it shouldn’t take much more
than an hour at the most.
How often will my public IP address change?
This depends on the policies of your Internet Service Provider (ISP, the
company that provides your Internet access). It can be a matter of days,
weeks or even months before your IP address changes. A power loss or
reboot to your cable or DSL modem usually results in the assignment of a
new IP address.