manual Vega Gateway

Version 2.1 16 March 2006 Page 10 of 33
Vega Gateway Scenarios. ©2005-2006 VegaStream Ltd.
Examples are given in best faith – ensure that you check the capabilities of systems before
deploying them, especially the functionality of devices not designed and delivered by VegaStream.
- For home users who are routed via the proxy
•
Home-workers will be able to dial extension numbers of any of the PBXs (as the proxy will
resolve the phone number and route the call to the appropriate Vega gateway). Calls made
to users on a PBX will appear to the PBX to come from the PSTN and so will not provide
the advanced functionality to the home-worker that an extension user would have (e.g.
voice mail, call transfer, conferencing). The advanced features available to the home-
worker will be those available from the SIP proxy.
The home-worker will be able to dial PSTN numbers. If the company sites are in different
areas, and especially if the sites are in different countries the SIP proxy can provide least
cost routing functionality to route the call to the most appropriate Vega to deliver the call to
the PSTN.
• For incoming calls to the home-worker, it is best that the home-worker is given one of the
DDI numbers available in the ISDN trunk. When the Vega receives a call from the PSTN to
that phone number it will groom the call off and forward it to the home-user.
Colleagues on the PBX will have to dial the home-worker’s full number (not just the
extension number) so that the call is routed by the PBX towards the PSTN. When the Vega
receives a call from the PBX to that phone number it will groom the call off and forward it to
the home-user.
- For users who have their calls routed via the proxy
• This enables users to have dual ringing – or multiple parallel ringing, for instance having
your desk phone (connected to the PBX) and your home-office VoIP phone both ringing
whenever you receive an incoming call.
• Users can have VoIP pre-processing features of their calls, features like the ability to
decide which order your phones are called in, and which callers are allowed to disturb you
and which should be routed through to voice mail.
- Proxy initiated calls
•
Proxy initiated functionality will be available, e.g. where the user can use a web browser to
access the proxy and drag and drop user icons to initiate, for example a conference
• Calls that were connected using the Proxy will retain the capability to be controlled by the
proxy, for instance call transfer could be initiated by the user on the web interface to the
proxy if the original call was routed via the proxy
USPs
• VegaStream have a wide range of VoIP gateways to provide connections for both home
and office based workers.
Considerations
•
Check the numbers that are presented to the PSTN consider for example:
- does the PBX present both National format and local format numbers to the PBX?
- does the PBX insert any “carrier select prefix” to the dialled number?
- can “block caller ID” or other prefixes be used in dialled numbers?
• Be careful of interactions between PBX functionality and Proxy functionality, e.g. if Voice-
mail is enabled on both the PBX and the VoIP system, when does each get the voice-mail,
and is it acceptable that users may have to check two places to collect their voice-mail?
• Consider NAT traversal for home worker
•
The maximum number of parallel ringing calls into the PBX may be limited by the maximum
number of SIP registrations that the Vega can make.
• Emergency calls should be routed directly to the PSTN, not over the VoIP link
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