Prefix To Domain Name Conversion - Matrix Telecom SARVAM UMG System Manual

Prefix to Domain Name Conversion

Prefix to Domain Name Conversion is used when a user sets Call Forward or makes a Blind Transfer on SIP. This
feature is applicable only when the destination port is SIP.
SARVAM UMG supports multiple SIP Trunks and FXS Ports. When the FXS Port user dials a SIP number,
SARVAM UMG routes the call to the IP network using the SIP Trunk determined by the routing mechanism. The
FXS Port user can dial only numbers, not domain names. Therefore, it becomes necessary to assign Prefix codes
to domain names, which the FXS user can dial.
Now, it is necessary that the number string dialed by SARVAM UMG is understood by the ITSP through which the
call is routed. So, an appropriate Prefix Code is assigned to the Domain of the ITSP through which the calls are to
be routed.
However, when the FXS Port user sets Call Forward or Blind Transfer, the Prefix Code and the number are sent to
the calling party in the redirect message, without the domain name. So the calling party will not be able to reach the
FXS user at the forwarded/transfer destination. The 'Prefix to Domain Name Conversion' feature resolves this.
Let us understand this feature with the help of an example:
• Assume that SARVAM UMG is configured to route calls made to the domain 'abc.com' from the FXS Port,
through the SIP Trunk subscribed with the ITSP 'Pulver.com'.
• Since the FXS Port user cannot dial the domain name, a prefix code must be assigned to the domain
name.
• The Prefix code, *234 is assigned to the domain 'abc.com'.
• When the FXS Port user wants to dial the SIP ID 9874@abc.com, the user must dial *234 followed by
9874.
• SARVAM UMG determines that the called party is the subscriber of abc.com and converts *2349874 to
9874@abc.com and routes the call to the desired destination through 'Pulver.com'.
• Now, given the above scenario, assume that the FXS Port user sets Call Forward to *2349874 (that is,
9874@abc.com).
• When an external caller calls the FXS Port user, the caller will receive *2349874 in the Redirect message.
• However, to reach the FXS user at the forwarded destination, the caller must have a domain name in the
contact address. Since the caller will not recognize *234 (the prefix code assigned to abc.com), the caller
will not be able to reach the FXS user at the forwarded destination address.
• With Prefix to Domain Name Conversion, SARVAM UMG converts this prefix code to the domain name
abc.com (9874@abc.com), and sends it in the Redirect message to the external caller informing the caller
of the new contact address.
• On receiving this information in the Redirect message, the external caller can call the new contact number,
9874@abc.com, and talk to the FXS user.
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