manual Vega Gateway

Version 2.1 16 March 2006 Page 9 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.
This configuration can form a good starting point for migrating to VoIP without immediately losing
the existing telecoms infrastructure.
The Vega can be configured to either route specific telephone numbers to the SIP proxy – where
only a small set of numbers is to be handled by the VoIP system, or all calls can be forwarded to
the Proxy for it to decide how all calls should be routed.
Use of a Proxy can also assist in NAT and firewall traversal.
If a significant proportion of the company’s calls are made between sites then it is possible that
further cost savings can be made by reducing the number of channels connected to the PSTN.
Telephony Network
- For PBXs
•
E1 Euro ISDN signalling is supported by Vega 400 and Vega 100
•
T1 NI1 & NI2 signalling is supported by Vega 400 and Vega 100
• T1 Loop start, Ground start and Wink start CAS signalling is supported by Vega 400 and
Vega 100
•
BRI Euro ISDN signalling is supported by Vega 50 BRI
•
Analog connection is possible, but is not preferred (for details on analog connectivity see
later section)
- For home-workers
• Analog FXS gateway to connect to analog phone
• Optional FXO port to allow local connection to PSTN
•
IP handset or soft phones may also be used
IP Network
• Recommend – private IP network between sites
• Can be any reliable IP connection, including leased line, line of site laser / wireless
connection and satellite
•
QOS should be implemented to ensure that VoIP packets pass through the network in a
consistent and timely manner and are not discarded by congested routers
• Consider VPN between sites as this:
- removes any issues with firewalls / NAT
- encrypts audio and management data
• For inter-site operation the Internet can be used, but contention and available bandwidth
must be considered
•
A VPN can be used from the home user to the company LAN. This is important for
securing data access to the company site, and for VoIP it gets around NAT traversal issues
User experience
- For PBX users that are not routed via the Proxy
• By grooming the traffic on the PSTN side of the PBX all user PBX functions will continue to
operate. This system will operate in exactly the same way as the phone system worked
before the gateways were installed, for example, even existing shortcode dialling will
continue to work (as the PBX will expand this to a full number before presenting it to the
PSTN).
VoIPon Solutions www.voipon.co.uk [e-mail] Tel: [phone]