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Marcelo Gornstein edited this page Feb 9, 2014 · 31 revisions

Routing workflow

This is done by the switch_route module module.

How it works

Here's a brief description of the first steps in a call lifecycle. The term trunk is used intensively here, so you might want to also read the Trunks wiki entry.

Trunk recognition

  • New call in a trunk.
  • The name of the trunk is used to find a trunk in the system.
  • If none is found, the call ends with error unknown_incoming_trunk.
  • If the trunk does not belong to an organization, the call ends with error trunk_without_organization.
  • If the trunk belongs to a disabled carrier, the call ends with error carrier_disabled (since #79).

Number translation

  • If found, the incoming dialrules of the trunk (ani) are used to translate the ani to E164.
  • If the ani can't be translated to E164, the call ends with error cant_translate_incoming_ani
  • If found, the incomig dialrules of the trunk (dnis) are used to translate the dnis to E164.
  • If the dnis can't be translated to E164, the call ends with error cant_translate_incoming_dnis

Client identification

  • If the trunk belongs to a client, the ani in e164 format is used to search for a did in the system:
  • The call ends with error client_using_unknown_did if none is found.
  • If a did is found, but it's owned by a different subscriber, the call ends with ani_in_wrong_trunk.
  • If the trunk belongs to a client, the numbering plan dial rules are used to translate the dnis into E164.
  • If the dnis can't be translated to E164, the call ends with error cant_translate_dnis_by_numplan.
  • For on net calls, the plan assigned to the target dnis will be checked to know if it allows incoming calls, if not, the call ends with incoming_calls_not_allowed_for_client.
  • For on net calls, when an incoming call should be charged but there's no tariff for that specific combination of ani/dnis, the call ends with unknown_tariff_for_incoming_call.

Further checks

  • All off net calls from trunks that don't belong to a subscriber or an internal trunk, are denied with the error unknown_source_for_offnet_call.
  • All calls where the subscriber can't be identified correctly, ends with error unknown_source_for_offnet_call.
  • If the call is on net, but the destination did is not assigned to a trunk, the call ends with cant_route_to_local_unallocated_did.
  • For off net calls, routes are selected based on the routing plan of the originating did. See [Below](#selecting routes) for the details.

See Whitelists and Blacklists

Error-To-Hangup-Causes

See Hangup Causes.

Selecting Routes

The Routing Plan

Every DID is assigned a routing plan. A routing plan is just a sorted collection of route categories. Route categories are basically tags, used to group routes. A route plan usually looks like this

premium - normal - low

Meaning that routes will be searched for, and tried in that particular order (i.e: first, all the available premium routes, then, all the normal ones, and then the ones in the low category).

For every one of those categories, all available routes are selected (just 1 per trunk carrier (since #117), the one that best matches the destination), and then sorted by LCR.

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