manual Vega Gateway

Version 2.1 16 March 2006 Page 7 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.
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.
USPs
•
Vega dial planner capability provides powerful routing decision making. For example, calls
can be routed based on dialled number prefixes, full numbers, and even on who is making
the call.
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?
• Consider NAT traversal for home worker
•
Emergency calls should be routed directly to the PSTN, not over the VoIP link
•
Program in fixed number length dial plans where possible to avoid the DTMF timeout
delays incurred when routing calls to variable length numbers
• Call transfer from PBX to PBX will only work if call transfer PBX to PBX worked across the
PSTN (the PBX may block this).
• If extension number dialling of the far end PBX or home-workers is to be used (rather than
just grooming off the full dialled destination number), remember the extension number will
have to be prefixed with the PBX’s ‘connect to PSTN’ digit; usually 9 in UK, but can be 0 in
Europe.
•
If IP connectivity fails, calls can be programmed to be routed over the PSTN instead; there
may, however, be a bit of delay in deciding that the IP connection is down.
• Ensure that only authorised home-worker / remote office users can make outbound calls to
the PSTN – avoid just anyone with SIP connectivity to the internet being able to make calls
through the Vega and to the PSTN
Future extensions
• Addition of a Proxy to support additional features for IP users
•
If advanced PBX functionality is required, consider the use of analog long line extensions
• Extend the “on net” group to a group of companies who regularly call each other so all
calls between these companies are free
• Connection to an ITSP for cheaper off-net calls – and possibly for more flexible ingress of
national, international or non-geographic numbers.
•
If PSTN connectivity is not reliable at any site then VoIP can be used as a backup to route
outbound calls via a different site.
• More than 2 sites to be interconnected
3
rd
party product choices
• For NAT traversal between sites, consider SNOM NAT filter, SIParator or Alcatel T610
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