Technical Tip: DID (Direct Inward Dialing) number override by main number in SIP trunk for outgoing call

[Chong_Yoon_Fui_FTNT]

Description
This article describes that DID number is override by main number configured in SIP trunk when making an outbound call.

DID configuration.

# config dialplan did-mapping
  edit Incoming
    set incoming-trunk SIP_Trunk
    # config  from-callerid
    end
    set schedule any_time
    # config  mapping
      edit 23
        set option inbound outbound
        set did 65377345
        set extension 340
      next

SIP trunk configuration.

# config trunk sip-peer
  edit SIP_Trunk
    config  did
    end
    set caller-number 65362727
    set sip-setting sip_trunk_default
    set max-channel 5
    set max-outgoing-channels 5
  next
end

From the packet capture, the outbound call is using the main number instead of DID number (65377345).

Scope
For version 5.3 and onward.

Solution
To avoid DID to be override by main number, enable update-pai-header in the sip trunk configuration

# config trunk sip-peer
  edit SIP_Trunk
    config  did
    end
    set caller-number 65362727
    set update-pai-header enable
next