ClearIP returns selected routes as configured in the routing services inside a Contact header and allows for flexibility in defining the routes and parameters within the Contact header.
Contact header structure
ClearIP creates contact headers for routing using a specific structure.
Contact: <sip:USER@HOST>
The USER section contains user information and optional tags and parameters in the Contact header. It consists of everything after “sip:” and before the “@”.
The HOST section contains the route destination and optional tags and parameters in the Contact header after the “@” character. List the IP addresses or domain names, including the destination, tags, and parameters into the Destination field when creating a route.
The examples below show how these sections can be used.
Example: Route with one destination
Contact: <sip:+18554742536@1.1.1.1;tag;parameter=1>;q=0.99
A single destination is added to a route by entering the exact URI that includes the IP address or domain name as the Primary Route Destination when creating the route. The Secondary and Tertiary Route Destinations are left blank. In this example, the Destination is “1.1.1.1;tag;parameter=1”. The single destination can have an unlimited number of tags and parameters as long as they are each separated by a semicolon with no spaces in between.
Example: Route with multiple destinations
Contact: <sip:+18554742536@1.1.1.1>;q=0.99, <sip:+18554742536@2.2.2.2>;q=0.98
Multiple destinations are added to a route by entering a list of single destinations such as “1.1.1.1,2.2.2.2” as the Route Destinations. Each single destination can have any number of tags and parameters, but the listed destinations must be separated by commas with no spaces in between. Multiple destinations are useful for load balancing and failover which is described further in the Inbound and Outbound Routes page.
Example: Route with Route Prefix
Contact: <sip:+18554742536@1.1.1.1>;q=0.99
In this example, the Route Prefix is “1”. The Route Prefix prepends an input to the user field in the Contact header. This can be useful for modifying phone numbers in the Contact header if required by certain carriers.
The Route Prefix is unrelated to the number translation process done in ClearIP. Number translation takes the called and calling number and translates them into E164 format without the plus for use only during ClearIP’s internal processing. After the processing is completed, ClearIP returns a SIP response with the called and calling number in the exact format they were given to ClearIP before number translation.
If the format of the phone number in the Contact header returned by ClearIP should be different than the format of the phone number given to ClearIP in the SIP Invite, then the Route Prefix can be used to give the number the correct format.
Trunk-based Routing for Metaswitch CFS, Oracle ACME, or Ribbon
If ClearIP should return a trunk group ID as the route destination to a Metaswitch CFS or Oracle ACME, add the route destination by entering “sip.clearip.com;dtg=XXXX” into the Route Destination fields where XXXX is the destination trunk group ID.
Contact: <sip:+18554742536@sip.clearip.com:5060;dtg=XXXX>;q=0.99
Trunk-based Routing for Sansay
If ClearIP should return a trunk group ID as the route destination to a Sansay, add the route destination by entering “127.0.0.1;tgrp=XXXX” into the Route Destination fields where XXXX is the destination trunk group ID.
Contact: <sip:+18554742536@127.0.0.1;tgrp=XXXX>;q=0.99
Routing for netsapiens
If ClearIP should return a route destination to a netsapiens, a specific route prefix must be added by entering “lcr” into all Route Prefix fields. This prepends lcr to the phone number in the Contact header and allows the netsapiens to route the call based on the route returned in the ClearIP SIP 302 Contact header.
Contact: <sip:lcr18554742536@1.1.1.1>;q=0.99