Chapter 13 VoIP Trunking
13.9.4 Call ProgressionThe call is initiated by the manager dialing into the headquarter’s ZyXEL Device via PSTN. In this scenario a VoIP link is established between headquarters and the branch office and then the call is forwarded to Sales1 using PSTN.
Table 77 PSTN to PSTN: VoIP Trunking Call Progression
MANAGER | HEADQUARTERS | BRANCH OFFICE | SALES1 |
The manager dials the PSTN number of the headquarters’ |
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ZyXEL Device. |
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The ZyXEL Device receives the call and sends a ringback |
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alert tone to indicate to the caller that VoIP trunking is |
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enabled. |
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The manager dials the PSTN number of Sales1 |
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1234). |
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The ZyXEL Device prompts the manager to enter the PIN in |
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order to allow VoIP trunking. |
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The manager dials the PIN (12345). |
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| The ZyXEL Device confirms the password and allows for VoIP trunking. |
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| The ZyXEL Device inspects the phone number against call rules. Since the number |
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| starts with the pattern (5555), it uses the account (CityB) associated with this pattern to |
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| connect the call to the remote peer device at the branch office. |
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| The remote peer device inspects the number and requests authentication in order to |
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| forward the call. |
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| The ZyXEL Device at A sends outgoing authentication to the remote peer device. |
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| The remote peer device confirms that the username and password match an account in |
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| its incoming authentication list. |
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| The remote peer device forwards the call to Sales1. | |
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Sales1 picks up and the call commences. |
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