IMG 1010 - Fully Qualified Domain Name Support

Overview:

This feature allows the IMG to support SDP connection (c=) line with a Fully Qualified Domain Name (FQDN) instead of an IP address on the outgoing leg. If the outgoing Fully Qualified Domain Name (FQDN) is configured and then enabled in the SIP SGP Profile pane, the SIP Signaling and/or VoIP module IP addresses of the IMG will be replaced with the FQDN in the outgoing request and/or outgoing SIP response messages. Follow the procedure below to configure FQDN on IMG.

Benefit:

This feature allows for the management of IMG IP Addresses via DNS. This type of management has greater flexibility and more security than the hard-coded alternatives in SDP and SIP.

Configuration Procedures:

Incoming support is always enabled and can not be changed. If the IMG receives an incoming INVITE with a Fully Qualified Domain Name (FQDN) in the SIP URI, the IMG will initiate a DNS query. On the Outgoing side, the Fully Qualified Domain Name must be configured for the Feature to initiate a DNS query. See configuration below.

Create Network Interface (Data).  - Prerequisite -

• The procedure assumes a logical and physical IMG have already been created. See IMG 1010 - Logical IMG and IMG 1010 - Physical IMG for more information on these panes in ClientView.

• Configure the Data Network Interface and IP Bearer. See the IMG 1010 - Configuring VoIP link for more information on accomplishing these two objects.

Create a DNS Server and DNS Client:

The next step is to create a DNS Server and DNS Client object. See Below

• Right Click on IMG EMS object and select New External Network Element. See IMG 1010 - External Network Elements for more information on configuring this object.

• Right Click on External Network Elements object and select New DNS Servers. See IMG 1010 - DNS Servers for more information on configuring this object.

• Right Click on DNS Servers object and select New DNS Server. Enter IP Address of this DNS server. See IMG 1010 - DNS Server for more information.

• Right Click on IMG Name (Physical IMG) and select New DNS Client. The IP address will default to the IP address of the IMG Ctrl Port. Select from drop down menu in the Primary DNS Server field the DNS Server just created. See IMG 1010 - DNS Client for more information

Create SIP Profile (SGP)

• Create a SIP Profile. Right Click on Dialogic IMG EMS and select New Profiles.

• Right Click on the Profiles object just created and select SIP SGP. Change the SIP Profile ID to something other than 0. This will allow other fields in this object to be changed.hostho Select from drop down menu when the Fully Qualified Domain Name servers will be displayed. See screen capture below
    

  Open

  

Create SIP Signaling:

• Right Click on IMG Name: and select New Signaling.  See IMG 1010 - Signaling Object link for more information on this object.

• Right Click on the Signaling object created and select New SIP. See IMG 1010 - SIP Signaling Object link for more information on this object.

  • Enter a FQDN in the Fully Qualified Domain Name (FQDN) field. See screen capture below.
    
    

    Open

    

Create Remote Gateway

Through ClientView create external network element. To associate the SIP profile created with a remote SIP gateway, an external network element must be created. Follow procedure below to communicate with a remote gateway.

• Right Click on Dialogic IMG EMS and select New External Network Elements. See IMG 1010 - External Network Elements for more information.

• Right Click on External Network Elements and select New External Gateways. See IMG 1010 - External Gateways for more information.

• Right Click on External Gateways and select New External Gateway. Select SIP as the Gateway Signaling Protocol and select the profile created for FQDN. See IMG 1010 - External Gateway for more information.

• Once the External Network Elements are created, they can be associated with Channel Groups etc through IP Network Elements.

SIP Virtual Address (Optional):

When configuring a SIP Virtual Address that will be utilizing the Fully Qualified Domain Name feature the Network Interface Object created for this SIP Virtual Address must have Gratuitous ARP and ARP Responses set to Disable. Below is procedure describing what would need to be accomplished if a SIP Virtual Address was being configured with a fully qualified domain name server. See IMG 1010 - SIP Virtual Address .

• Right Click on IP Network and select IP Address. In the Physical Interface field select CPU from drop down menu. Enter 'IP Address' for this interface and also enter 'Default Gateway' ip address. See IMG 1010 - IP Network (Interface) link for more information.

• In the Gratuitous ARP and ARP responses field select Disable from the drop down menu.

• Right Click on SIP Signaling object created earlier and select New SIP Virtual Address. The SIP Virtual IP Address field will be automatically populated with the address of the interface just created.

• Enter FQDN in the Fully Qualified Domain Name (FQDN) field. See Below!SC_FQDN_SIP_Virt_Address.png|title=!

• See IMG 1010 - SIP Virtual Address for more information

FQDN enabled but No FQDN Configured

If Outgoing FQDN options are enabled but no FQDN hostname is entered through ClientView, then IMG will send out a WARNING and process the call normally with IP's. Below is the warning displayed and some scenarios that would generate this warning.

• Signaling ONLY option is enabled but NO IMG Signaling FQDN
  Local IMG Signaling IP of the IMG will be shown

• SDP C Equal Line ONLY option is enabled but NO VoIP module FQDN
  Local VoIP module IP of the IMG will be shown  

• Both option is enabled but NO IMG Signaling FQDN
  Local Signaling IP of the IMG will be shown
  FQDN of VoIP module (NOT IP) will be shown at SDP C equal line  

• Both option is enabled but NO VoIP module FQDN
  FQDN of the local IMG Signaling will be shown
  Local VoIP module IP of the IMG will be shown

Call Trace - FQDN failure message:

If DNS is not configured or not configured properly, the call will fail responding with a 488 "Not Acceptable Here"

RADIUS

VSAs

The following Dialogic VSA's support the Fully Qualified Domain Name feature.

• dialogic-voip-src-sig-fqdn

• dialogic-voip-src-rtp-fqdn

• dialogic-voip-dst-rtp-fqdn

See IMG 1010 - RADIUS - Dialogic VSA's for more information.

Dictionary File

The radius dictionary file has been updated to support this feature. Customers using RADIUS should update the dictionary.dialogic file they are using with the latest one located in the GCEMS install under

 /opt/dialogic/common/radius (Software 10.5.1)

/opt/cantata/common/radius (Software 10.3.3 to 10.5.0)

On a freeRADIUS server this file should be copied into ‘/usr/share/freeradius’ directory.

Call Flows

Outgoing with FQDN Enabled

The following call flow shows an SS7 to SIP call flow where FQDNs is enabled.

Incoming FQDN DNS Query

The following call flow shows the case where an incoming INVITE includes an SDP c line w/ FQDN to perform a DNS query before the call is established.

Example INVITE Messages

Outgoing FQDN option = Signaling ONLY

When the Outgoing FQDN option is set to Signaling Only, the FQDN of the local IMG signaling IP address only is inserted in the outgoing SIP messages. Relevant lines are in bold..

Outgoing FQDN option = SDP c equal line ONLY

When the Outgoing FQDN option is set to SDP c=line ONLY, the FQDN of the local IMG VoIP IP address only is inserted in the outgoing SIP messages. Relevant lines are in bold.

Outgoing FQDN option =Both

The following shows a SIP INVITE message when the Outgoing FQDN option is set to Both. Relevant lines are in bold.