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Version 2.1 

16 March 2006 

Page 24 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.

 

9.b Analog breakout to the PSTN – e.g. for a company or for a PSTN toll bypass 

 

 

A Vega FXO can be connected directly to PSTN lines. 
 
Calls from VoIP into the PSTN specify the desired destination number by sending DTMF tones 
into the PSTN. 
 

Considerations 

• 

Disconnect supervision is only supported by physical signalling – line current reversal or 
loop current disconnect; no voice or tone detect can be configured on the Vega to indicate 
end of call 

• 

Answer supervision is only supported by physical signalling – line current reversal 

• 

Calls received on the telephony interface arrive with no dialled number information as 
analog signalling just uses a ringing voltage to indicate the call arrival. 

• 

Different impedances are required for ‘approved’ connection in different countries.  Europe 
should have the Vega FXO interface configured for CTR21 impedance; the US should have 
the interface configured for 600R operation.  900R impedance is also available. 

 

 
 
 
 
 
 
 
 

VoIPon Solutions  www.voipon.co.uk  [email protected]  Tel: +44 (0) 1245 600560

Summary of Contents for Vega Gateway

Page 1: ...d below 1 VoIP between sites 2 VoIP between sites and home worker remote office 3 VoIP between sites and home worker remote office using a proxy 4 Analog long line extensions 5 IP Telephony 6 PSTN toll bypass 7 TDM to from VoIP converter 8 Leased line eliminator for QSIG connections between sites 9 Analog connections Analog Applications a Vega FXS for analog telephones b Analog breakout to the PST...

Page 2: ...ork All other calls from the PBX continue to be routed to the PSTN All calls from the PSTN are routed to the PBX The source Vega gateway will direct the VoIP calls to specific destination gateways based on the telephone number dialled single numbers or number ranges can be groomed off to specific destinations On receiving a VoIP call a destination gateway can use the dialled number to decide wheth...

Page 3: ...me 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 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 ca...

Page 4: ... 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 3rd party product cho...

Page 5: ...propriate tariffs for outbound calls based on those negotiated by the company with their chosen carrier By inserting a Vega gateway between the PSTN and the PBX the Vega gateway can groom calls that are destined for other site s onto the IP network All other calls from the PBX continue to be routed to the PSTN All calls from the PSTN are routed to the PBX The source Vega gateway will direct the Vo...

Page 6: ...d but contention and available bandwidth must be considered Recommend a VPN should 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 By grooming the traffic on the PSTN side of the PBX all user PBX functions will continue to operate This system will operate in e...

Page 7: ...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...

Page 8: ...nserting a Vega gateway between the PSTN and the PBX the Vega can consider how to handle every call between the PSTN and the PBX either routing the call over IP routing the call to the PBX or routing the call to the PSTN With the addition of a Proxy Media server to the system advanced processing of calls can be accomplished This functionality is Proxy dependent but often includes for example Forke...

Page 9: ...ble 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 Q...

Page 10: ...his 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 shou...

Page 11: ...here 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 Where a media server is used consider placing it close to where the media is going to be used this minimises the...

Page 12: ...any benefits including extension number dialling to all personnel voice mail on a single site common functionality for all phone users people can move offices and do not have to learn a new phone system By using data connections to join remote users back to the main site PBX this concept can be extended to home users using the Internet as the data network Now home workers have all the PBX function...

Page 13: ...connected directly to the PBX pick the handset up and you dial tone from the PBX this may be stuttered by the PBX to indicate voice mail hookflash recall will allow the phone to access advanced features of the PBX like call transfer follow me camp on busy conferencing There might be a slightly longer delay needed between clearing down from 1 call to getting dial tone ready to make the next call US...

Page 14: ... need conversion to from traditional protocols and this is achieved using Vega trunking gateways Many ACD solutions are also moving to VoIP infrastructures The use of VoIP makes it easy to distribute agents across multiple sites and out to home workers By addressing calls and screen pops to IP addresses it is up to the IP data infrastructure to deliver the messages to the correct destinations whet...

Page 15: ...company site and for VoIP it gets around NAT traversal issues User experience The user experience will be completely controlled by the SIP proxy H 323 gatekeeper Choice of the correct application server device will be key to successful delivery of service USPs Vega gateways are very good at interoperating with 3rd party VoIP devices Features available that are not available on traditional telephon...

Page 16: ...ction IP Network Recommend private IP network between sites Can be any reliable IP connection including leased line satellite and the internet QOS should be implemented if possible to ensure that VoIP packets pass through the network in a consistent and timely manner and are not discarded by congested routers The Internet is often used for carrying the VoIP traffic contention and available bandwid...

Page 17: ...es and increased call hold times compared to other manufacturers gateways due to the quality of the connected call Considerations Use of analog gateways to break into break out of the PSTN may have timing issues over start and end of calls unless line current reversal analog signalling is used Future extensions Expansion to a wider range of destination countries and cities through use of ITSP conn...

Page 18: ...can receive calls and convert them to SIP or H 323 the Vega gateway can also receive SIP or H 323 calls and convert them to E1 T1 or BRI calls Telephony Network E1 Euro ISDN signalling and QSIG 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 BR...

Page 19: ...hem especially the functionality of devices not designed and delivered by VegaStream Considerations Not all supplementary services supported in ISDN signalling directly map to VoIP protocols If supplementary service are needed it is important to check that they will map OK Future extensions 3rd party product choices VoIPon Solutions www voipon co uk sales voipon co uk Tel 44 0 1245 600560 ...

Page 20: ...faces then using the destination information in the QSIG header the Vega can select the correct far end Vega gateway to send the tunnelled QSIG data to The far end gateway unpacks the received tunnelled QSIG messages and presents them on its T1 or E1 interface The PBXs do not know that the QSIG connection was not a leased line Telephony Network E1 tunnelled QSIG signalling is supported by Vega 400...

Page 21: ...to point trunking1 rather than fully meshed2 connection of Vega gateways may be needed if the protocol is QSIG like and not fully QSIG compatible some manufacturers use QSIG as a basis for their inter PBX connectivity but retain certain proprietary elements PBXs send calls for specific destination PBXs to specific trunks QSIG from different manufacturers may have proprietary elements If QSIG PBXs ...

Page 22: ...l is being sent to it by detecting that a current line current is flowing This line current is triggered by the far end device going off hook FXS devices detect DTMF Dual Tone Multi Frequency tones which are used for dialling telephone numbers FXS devices typically detect hook flash also known as recall hook flash is used by PBXs and other telephony systems to alert them and trigger them to move i...

Page 23: ...nd often cheap analog telephones to be connected into a VoIP system This can be especially useful where Cat 5 cabling already runs analog phones to peoples desks the Vega can replace the PBX in the telecoms cabinet the Cat 5 telephone extensions terminate on the Vega FXS rather than on the old PBX A major benefit to users is that they see no change to their working environment and equipment Also i...

Page 24: ...sion is only supported by physical signalling line current reversal or loop current disconnect no voice or tone detect can be configured on the Vega to indicate end of call Answer supervision is only supported by physical signalling line current reversal Calls received on the telephony interface arrive with no dialled number information as analog signalling just uses a ringing voltage to indicate ...

Page 25: ...to Calls from the Vega to the PBX are like calls from the PSTN no dialled number is passed so typically the call will be routed to a receptionist or an auto attendant or the FXS gateway may just be used for outbound calls May not be able to receive transferred calls some PBXs will prevent calls being transferred to a trunk interface 9 d FXO connection to a PBX When making calls from VoIP to PBX th...

Page 26: ...siderations Call transfer from a PBX extension to the other PBX may not be blocked by the PBX if the local PBX does not allow call transfers to Trunk Interfaces Calls FXO to FXS To connect to the far end PBX call the local PBX extension number of a line connected to the FXO gateway The FXO gateway will route the call to the destination FXS gateway Considerations Calls presented PBX to FXO can only...

Page 27: ...es not allow call transfers to Trunk Interfaces Calls presented FXS to PBX can only provide ringing voltage to indicate call arrival Just as PSTN calls to analog trunk interfaces of a PBX have to be routed to an operator or auto attendant so do calls from the Vega FXS 9 g PBX to PBX connectivity using FXO only To connect to the far end PBX call the local PBX extension number of a line connected to...

Page 28: ...Stream 9 h Mass analog connection using a Vega 400 and a channel bank Where mass capacity of FXS and or FXO interfaces are required it can be cheaper to use a Vega 400 together with a channel bank Considerations Ensure that the channel bank supports the required functionality e g will it support hook flash call cleardown detection 9 i Analog long line extensions See 1 VoIP between sites above VoIP...

Page 29: ...oxy functionality no intelligence features Alceo ArelNet Softswitch Asterisk SIP proxy freeware free freeware proxy is continually being developed freeware if you use it you have to support it it does not come with a manufacturer s backing as a developer VoIP reseller it can prove to be a good base architectire on which to add your own tailored features when used with audio cards it runs out of pr...

Page 30: ...IP proxy far end NAT traversal Does not support far end NAT traversal with Sipura code only basic proxy functionality no intelligence features Interactive Intelligence ACD call queuing functionality cost IVR Technologies Talking SIP LignUp SIP Proxy Mitel Knowledge MKC proxy NetCentrex Gatekeeper NetSapiens V Box Standalone unit no hard disc Nortel CS1000 Nortel MCS5100 Nortel MCS5200 Nuera SSC Po...

Page 31: ... PCs Standalone version available Tangerine Inc SIP H 323 application server Teleware ACD functionality Session Border controllers For larger installations and ISP installations there are devices that sit in the Internet called session border controllers which amongst other things resolve NAT traversal issues These are typically high capacity and expensive They are manufactured by for example Jaso...

Page 32: ...e that you check the capabilities of systems before deploying them especially the functionality of devices not designed and delivered by VegaStream ITSPs and VoIP services Call UK Engin GossipTel Gradwell Hipcom Primus Pulver free world dial up Telic net VoIPon Solutions www voipon co uk sales voipon co uk Tel 44 0 1245 600560 ...

Page 33: ...idth required for the voice traffic ensure that they do not drop packets introduce too much latency or introduce too much jitter If it cannot consider using a specialist VoIP firewall for handling just the VoIP traffic Beware some VoIP aware firewalls get it wrong A VoIP aware firewall that mis translates things can be worse than a non VoIP aware firewall Check that the VoIP aware firewall works c...

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