Howto:Handle overlapping or partial Extensions: Difference between revisions
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<!-- Keywords: different length of DID DDI PSTN extensions migration numbering plan --> | <!-- Keywords: different length of DID DDI PSTN extensions migration numbering plan --> | ||
==More Information== | ==More Information== | ||
When customers migrate their PBX numbering plan from shorter to longer extension (say, from 3 to 4-digit extensions), there is a need to map the old shorter extension to the corresponding new longer extensions. As the PBX does not allow to create objects with overlapping ''Number'' properties (e.g. two objects with ''Number''s <code>200</code> and <code>2009</code>, this must be done in the gateway layer of the corresponding trunk access. | |||
In this article we will assume that the PBX uses 4 digit extension, while 3-digit extension should also be dial-able from the PSTN. However any other digit-length combination can be used. | |||
===Problem Details=== | ===Problem Details=== | ||
Since you cannot have overlapping numbers in the PBX | Since you cannot have overlapping numbers in the PBX, you will have to use different numbers (e.g. instead of 200 we use 2009) in the PBX and map the numbers correctly using the Relay (200 -> 2009). | ||
Unfortunately, the obvious idea to have an incoming map matching the 4 digit extensions (<code>....-></code>) and following that one for the 3 digit extensions (<code>...->9</code>), will not work. This is because a 3-digit caller will hang in the first map forever, as the gateway waits for following digits, which will never come. | |||
Also, swapping the order of the routing table entries will not help either, as then the first map will also match if the caller wants to dial 2001, sending the call to the PBX with the wrong CDPN. | |||
===Resolution=== | ===Resolution=== | ||
We will route calls from the PSTN to the PBX and try to find a matching extension. | We will route calls from the PSTN to the PBX and try to find a matching extension. Short 3 digit extensions, will trigger an 'Incomplete' - Timeout at the ''Trunk Line'' object, which we will use to reroute such calls back to the ''Gateway'' level. Here we arrange for the call to be disconnected with a so-called ''rerouting cause'' (see [[Reference:Rerouting_Causes]]). Because of this, the disconnected call will fall back to the PBX and from there back to the ''Gateway'' level (that is, to the first route sending the call from your trunk interface to the PBX). In this route, we provide an additional map that adds the extension digit <code>9</code> to the CDPN (<code>->9</code>) and routes it to the PBX again. | ||
Here are the individual configuration steps: | Here are the individual configuration steps: | ||
* In your PBX, create a Gateway object without number and register a Relay-GWx(e.g. GW1) interface at it | * In your PBX, create a ''Gateway'' object without number and register a Relay-GWx (e.g. <code>GW1</code>) interface at it | ||
* In your PBX, configure the newly created Gateway object as ''Incomplete'' destination of your | * In your PBX, configure the newly created ''Gateway' object as ''Incomplete'' destination of your standard ''Trunk line'' object | ||
* In the Gateway Routing | * In the ''Gateway/Routing'' table, create a route from your GWx (e.g. <code>GW1</code>) to <code>DISC</code> and use a re-routing cause code (e.g. 44) when disconnecting the call | ||
* In the Gateway Routing | * In the ''Gateway/Routing'' table, add an additional map to the original ''trunk-to-PBX'' route that adds the extension digit and routes the call to the PBX again | ||
== Related Articles == | |||
* [[Reference:Rerouting_Causes]] | |||
[[Category:Howto|{{PAGENAME}}]] | [[Category:Howto|{{PAGENAME}}]] | ||
Revision as of 13:25, 30 March 2016
Applies To
This information applies to
- all gateways, Firmware V8 or later
More Information
When customers migrate their PBX numbering plan from shorter to longer extension (say, from 3 to 4-digit extensions), there is a need to map the old shorter extension to the corresponding new longer extensions. As the PBX does not allow to create objects with overlapping Number properties (e.g. two objects with Numbers 200 and 2009, this must be done in the gateway layer of the corresponding trunk access.
In this article we will assume that the PBX uses 4 digit extension, while 3-digit extension should also be dial-able from the PSTN. However any other digit-length combination can be used.
Problem Details
Since you cannot have overlapping numbers in the PBX, you will have to use different numbers (e.g. instead of 200 we use 2009) in the PBX and map the numbers correctly using the Relay (200 -> 2009).
Unfortunately, the obvious idea to have an incoming map matching the 4 digit extensions (....->) and following that one for the 3 digit extensions (...->9), will not work. This is because a 3-digit caller will hang in the first map forever, as the gateway waits for following digits, which will never come.
Also, swapping the order of the routing table entries will not help either, as then the first map will also match if the caller wants to dial 2001, sending the call to the PBX with the wrong CDPN.
Resolution
We will route calls from the PSTN to the PBX and try to find a matching extension. Short 3 digit extensions, will trigger an 'Incomplete' - Timeout at the Trunk Line object, which we will use to reroute such calls back to the Gateway level. Here we arrange for the call to be disconnected with a so-called rerouting cause (see Reference:Rerouting_Causes). Because of this, the disconnected call will fall back to the PBX and from there back to the Gateway level (that is, to the first route sending the call from your trunk interface to the PBX). In this route, we provide an additional map that adds the extension digit 9 to the CDPN (->9) and routes it to the PBX again.
Here are the individual configuration steps:
- In your PBX, create a Gateway object without number and register a Relay-GWx (e.g.
GW1) interface at it - In your PBX, configure the newly created Gateway' object as Incomplete destination of your standard Trunk line object
- In the Gateway/Routing table, create a route from your GWx (e.g.
GW1) toDISCand use a re-routing cause code (e.g. 44) when disconnecting the call - In the Gateway/Routing table, add an additional map to the original trunk-to-PBX route that adds the extension digit and routes the call to the PBX again