Outbound Routes

The Outbound Routes feature allows service providers to create routing rules based on the LRN of the called number. Outbound Routes can be applied based on the prefix of the requested called number if the number has not been ported. If the requested called number has been ported, the Outbound Route prefix field must refer to the LRN of the requested called number.

The Outbound Routes table is searched after the Inbound Routes table.

Setup

When adding new Outbound routes, it is important to consider the following aspects of the Outbound Routes page.

Jurisdiction

Outbound routes can be restricted to calls within a certain jurisdiction:

• International - No restriction. Choosing this allows the route to apply to all calls to include this jurisdiction and all lower jurisdictions.
• Domestic - Route only applies to calls where the calling number and called number are based in same country.
• Intrastate - Route only applies to calls where the calling number and called number are based in same US state or Canadian territory.
• Local - Can be configured to be defined as Intra LATA or Intra Rate Center in the SBCs page.

LATA

This is the LATA of the LRN of the called number. This must match the Called LRN LATA field in the SIP Messages page.

SPID

This is the porting-corrected OCN of the called number. This must match the Called LRN SPID field in the SIP Messages page.

Prefix

A route can be matched to a prefix for a Translated Called Number, or the prefix field can be left blank for the route to apply to any called number. For Outbound Routes, the prefix refers to the translated called number regardless of whether the number has been ported.

In the SIP Messages page, the Ported Called Number column can be checked to determine whether a number has been ported. If the Ported Called Number field is set to Yes, the Called LRN NPANXX column shows the NPANXX of the ported number LRN. For a ported number, the Called LRN NPANXX value should be used for the Outbound Route Prefix field. The Outbound Route rule applies to all numbers associated with that LRN NPANXX and not just the individual phone number.

If the Ported Called Number is set to No, the Translated Called Number value should be used for the Outbound Route Prefix field.

Route Destinations

Routes are created by configuring groups of destinations. A destination must be either an IP address or a hostname followed by an optional port and optional tags. A destination may also refer to a specific trunk ID to route through a specific trunk group. Users can configure destinations based on priority (primary, secondary, tertiary, quaternary, quinary) in case of failover. For outbound routing, the Primary Route Destinations may be destinations belonging to a preferred provider while the Secondary Route Destinations may be destinations belonging to a backup provider.

Within each destination priority level, multiple possible destinations can be listed separated by a comma to evenly distribute traffic.

Route Prefix

For each destination priority level, a prefix can be configured to be added in front of the phone number in the Contact header. This can be useful if different phone number prefixes are required by different providers. As shown below, entering a prefix of ‘abc’ would enable ClearIP to prepend this value in the SIP 302 Contact header phone number.

SIP/2.0 302 Moved Temporarily
Via: SIP/2.0/TCP sip.clearip.com:5060
From: <sip:+14045266060@transnexus.com:5060>
To: <sip:+18554742536@sip.clearip.com:5060>
Call-ID: 123456
CSeq: 1 INVITE
Contact: <sip:abc18554742536@1.0.0.3>;q=0.99
Reason: SIP;cause=302;text="Moved Temporarily"
Content-Length: 0

Destinations per Route

The Destinations per Route number can be configured to control the route failover order. The Destinations per Route number tells ClearIP how many routes from each route destination priority level to return in the Contact header.

If the Destinations per Route is 1, ClearIP returns one destination from the Primary Route Destinations, one destination from the Secondary Route Destinations, one destination from the Tertiary Route Destinations, one destination from the Quaternary Route Destinations, and one destination from the Quinary Route Destinations. ClearIP returns 5 routes in the Contact header in the order described. For outbound routing, this means that after the first routing failure at the preferred provider, the route should failover to the backup provider.

If the Destinations per Route is 2, then ClearIP returns two destinations from the Primary Route Destinations, two destinations from the Secondary Route Destinations, two destinations from the Tertiary Route Destinations, two destinations from the Quaternary Route Destinations and two destinations from the Quinary Route Destinations. Within each Route Destination, the destinations are selected randomly, and ordered randomly, for load balancing. ClearIP returns up to 10 routes in the Contact header in the order described.

If the Destinations per Route value is equal to or greater than the number of destinations in any particular destination priority level, then all listed destinations for that destination priority level are returned in the Contact header.

Examples

Route Toll-free Calls through Preferred Provider

ClearIP can be used to route all outbound toll-free calls through a preferred provider. For each 8YY area code, an Outbound Route can be created with the destinations set for the preferred provider. The route must be restricted to outbound calls only.

Route Calls to an LRN to an Ordered List of IP Addresses

ClearIP can be used to route calls to a static, ordered list of destination IP addresses.

The number 14045266060 has been ported, which can be confirmed in the SIP Messages page under the Ported Called Number field, and the Called LRN NPANXX which is 1675949 gives us the NPANXX of the LRN to which the number has been ported.

An Outbound Route can be created that applies to either the Called LRN NPANXX or the Called LRN field by entering the same value into the Prefix field of the Outbound Route. This Outbound Route is configured to direct the SBC to send the call first to a preferred destination with IP address 1.1.1.1. If that destination is not available, then the SBC should try to send the call to the next destination 2.2.2.2. If that is not available, then the SBC would try to send the call to the next destination 3.3.3.3.

This Outbound Route applies to all calls to called numbers that have been ported to an LRN with the same NPANXX. To create a static route that only applies to a single phone number that has been ported and not the entire LRN, a route should be created in the Inbound Routes page instead.

This Outbound Route returns the following SIP 302 response:

SIP/2.0 302 Moved Temporarily
Via: SIP/2.0/TCP sip.clearip.com:5060
From: <sip:+14045266060@transnexus.com:5060>
To: <sip:+18554742536@sip.clearip.com:5060>
Call-ID: 123456
CSeq: 1 INVITE
Contact: <sip:+18554742536@1.1.1.1>;q=0.99, <sip:+18554742536@2.2.2.2>;q=0.98, <sip:+18554742536@3.3.3.3>;q=0.97
Reason: SIP;cause=302;text="Moved Temporarily"
Content-Length: 0

Route Calls to an LRN to Load Balance between IP Addresses

In this Outbound Route, there is a comma separated list without spaces of 3 IP addresses entered in the Primary Route Destinations field with Destinations Per Route set to 3.

ClearIP returns a SIP 302 response with a list of all 3 IP addresses listed in a random order with the order varying for each SIP 302 response.

SIP/2.0 302 Moved Temporarily
Via: SIP/2.0/TCP sip.clearip.com:5060
From: <sip:+14045266060@transnexus.com:5060>
To: <sip:+18554742536@sip.clearip.com:5060>
Call-ID: 123456
CSeq: 1 INVITE
Contact: <sip:+18554742536@1.0.0.3>;q=0.99, <sip:+18554742536@1.0.0.1>;q=0.98, <sip:+18554742536@1.0.0.2>;q=0.97
Reason: SIP;cause=302;text="Moved Temporarily"
Content-Length: 0

How ClearIP Processes Calls in Outbound Routing

Exact order of Priority of Outbound Routing Rules

As ClearIP processes calls, it will look for an Outbound Route. If only one route matches, it will use that one. If there are multiple routing rules that match, it will use all matching rules, sorted in order of priority.

On the Outbound Routes page, there are several columns to the right of the Comment column. The columns to the right define the outbound route’s limiters. The priority of the limiters is as follows, from highest priority to lowest:

1. Calling Number
2. Calling Country
3. User
4. Group
5. Service Provider
6. SBC

There are also several columns to the left of the Comment column. These can be thought of as filters. The Jurisdiction filter, going from most restrictive to least restrictive, plus LATA, SPID, and Prefix filters will be used to select the rules. Instead of looking at one of these, ClearIP will use all three filters in different combinations; the combination with the most restrictive jurisdiction and longest prefix available takes priority. The priority of the filter combinations is as follows, from highest priority to lowest:

1. Local LATA, SPID, and Prefix
2. Local SPID and Prefix
3. Local LATA and Prefix
4. Local Prefix
5. Intrastate LATA, SPID, and Prefix
6. Intrastate SPID and Prefix
7. Intrastate LATA and Prefix
8. Intrastate Prefix
9. Domestic LATA, SPID, and Prefix
10. Domestic SPID and Prefix
11. Domestic LATA and Prefix
12. Domestic Prefix
13. International LATA, SPID, and Prefix
14. International SPID and Prefix
15. International LATA and Prefix
16. International Prefix

The highest priority limiter and the longest, most specific set of filters with the most restrictive jurisdiction will be used to sort the Outbound Routes by highest priority. This is illustrated in the below table: