How Do I? | Part 2 Voice Over IP - Page 99 |
Step 5 - Configure VPN Line
The VPN Line Group ID is an absolute reference to VPN line. It is permissible for 2 VPN lines to share the same Line ID in case where redundancy is required.
VoIP Gateway Options
Call Routing - When an extension number dialled from one INDeX to another, the transmitted number is prefixed with the node number of the other INDeX. The VPN number is sent to the IPNC cassette via the trunk group containing the IPNC channels. The IPNC acts on the VPN number matched in its Shortcodes.
Silence Suppression
Further Bandwidth can be saved by enabling silence suppression on the link. This can reduce the required bandwidth by over 50% during period of silence but carries a QoS penalty in that the conversation can feel unnatural.
FAX support
Fax is supported (the configuration for FoIP transport).
Compression Types
The Following Compression types are supported
G711 – Offer the best quality speech but uses the highest bandwidth. G711 should be used on LAN or WAN links were bandwidth availability is not an issue.
G729 and 723 Ultra low voice compression allows optimum use of slow speed WAN links.
VPN line control
VPN Line is used to control the amount of concurrent calls that are allowed to occupy the link (see page 41).
VPN line Configuration
In order to demonstrate how the VPN line is used for call routing and control a simple VoIP example is shown below:
| Site 1 (Node 6002) |
| Site 1 (Node 6003) |
|
Extn 2000 - 2100 |
|
| Extn 3000 - 3100 | |
| Gateway 1 |
| Gateway 2 |
|
| IP | Link | INDeX and IPNC | Unit 2 |
| INDeX and IPNC |
|
| |
(emulating DPNSS) |
|
|
| |
LAN IP Address |
|
| LAN IP Address | |
192.168.200.10/24 |
| 192.168.50.1/24 | ||
SoftPhone | IP Network 1 |
| IP Network 2 |
|
(Extn 4321) |
|
|
|
|
INDeX IPNC Cassette Administration Manual | How Do I? - Page 99 |
38DHB0002UKDD – Issue 7 (22/11/02) | Part 2 Voice Over IP |
