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URI dialing
A URI address typically takes the form name@example.com, where
URI dialing can make use of DNS to enable endpoints registered with different systems to locate and call each other. Without DNS,
the endpoints would need to be registered to the same or neighbored systems in order to locate each other.
URI dialing without DNS
Without the use of DNS, calls made by a locally registered endpoint using URI dialing will be placed only if the destination endpoint is
also locally registered, or is accessible via a neighbor system. This is because these endpoints can be located using the
process, rather than a DNS query.
If you wish to use URI dialing from your network without the use of DNS, you would need to ensure that all the systems in your network
were connected to each other by neighbor relationships - either directly or indirectly. This would ensure that any one system could
locate an endpoint registered to itself or any another system, by searching for the endpoint's URI. This does not scale well as the
number of systems grows. It is also not particularly practical, as it means that endpoints within your network will not be able to dial
endpoints registered to systems outside your network (for example when placing calls to another company) if there is not already a
neighbor relationship between the two systems.
If a DNS zone and a DNS server have not been configured on the local VCS, calls to endpoints that are not registered locally or
to a neighbor system could still be placed if the local VCS is neighbored (either directly or indirectly) with another VCS that has
been configured for URI dialing via DNS. In this case, any URI-dialed calls that match the neighbor zone will go via that
neighbor, which will perform the DNS lookup. This configuration is useful if you want all URI dialing to be made via one particular
system, e.g. a VCS Expressway.
If you do not wish to use DNS as part of URI dialing within your network, then no special configuration is required. Endpoints will
register with an alias in the form of a URI, and when calls are placed to that URI the VCS will query its local zone and neighbors for
that URI.
If the VCS does not have DNS configured and your network includes H.323 endpoints, then in order for these endpoints to be
reachable using URI dialing either:
•
the H.323 endpoints should register with the VCS using an address in the format of a URI
•
an appropriate transform should be written to convert URIs into the format used by the H.323 registrations. An example would be
a deployment where H.323 endpoints register with an alias, and incoming calls are made to alias@domain.com. A local transform
is then configured to strip the @domain, and the search is made locally for alias. See the section
H.323 numbers
for an example of how to do this.
SIP endpoints always register with an AOR in the form of a URI, so no special configuration is required.
URI dialing via DNS
By using DNS as part of URI dialing, it is possible to find an endpoint even though it may be registered to an unknown system. The
VCS uses a DNS lookup to locate the domain in the URI address and then queries that domain for the alias.
The remainder of this section describes how to configure the VCS to support URI dialing via DNS.
Overview and
Introduction
Getting started
status
D14049.05
February 2009
Overview
name
is the alias and
example.com
System
VCS
Zones and
configuration
configuration
neighbors
is the domain.
zone search
Stripping @domain for dialing to
Call
Bandwidth
processing
control
107
TANDBERG
VIDEO COMMUNICATIONS SERVER
Enabling URI dialing via DNS
URI dialing via DNS is enabled separately for outgoing and
incoming calls.
Outgoing calls
To enable your VCS to locate endpoints using URI dialing via
DNS, you must:
•
configure at least one DNS zon
e, and
•
configure at least one DNS serve
r.
This is described in the section
Configuring URI dialing via DNS
for outgoing
calls.
Incoming calls
To enable endpoints registered to your VCS to receive calls from
non-locally registered endpoints using URI dialing via DNS, you
must:
•
ensure all endpoints are registered with an AOR (SIP) or
H.323 ID in the form of a URI
•
configure appropriate DNS records, depending on the
protocols and transport types you wish to use.
This is described in the section
Configuring URI dialing via DNS
for Incoming
calls.
Firewall traversal calls
To configure your system so that you can place and receive calls
using URI dialing through a firewall, see the section
and firewall
traversal.
Firewall
Applications
Maintenance
traversal
ADMINISTRATOR GUIDE
URI Dialing
Appendices
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