1. IP-Centrex – First phase
Max 2000 calls
IX78 ADSL SIP FW
CDR (MOS) QoS
QoS being so important for good quality and the MOS score giving a valuable assessment of the quality, some ITSPs standardise and always install an Ingate or an IX78 as CPE.
SIP Carrier 2
SIP Carrier 1
Avaya Environment
Internet
PC Softphone
Ingate SIParator
CDR (MOS) QoS
Simple NAT/FW
PC Softphone
Legacy Firewall
The Ingate SBC Firewall, centrally located at the ITSP, will provide protection of the network, routing and interoperability with carriers and IP-PBX as well Far End NAT Traversal (FENT).
Avaya Environment
The Ingate SBC Firewall, centrally located at the ITSP, will provide protection of the network, routing and interoperability with carriers and IP-PBX as well Far End NAT Traversal (FENT).
Potential customers of an IP-Centrex Service Provider will usually have networks protected NAT/simple firewalls. The FENT function will take care of NAT issues.
Some might have advanced firewalls.
=> An Ingate SIParator will then be required for SIP-based communication to traverse the firewall.
=> QoS being so important for good quality and the MOS score giving a valuable assessment of the quality, some ITSPs standardise and always install an Ingate or an IX78 as CPE.
Some customers might have advanced firewalls. An Ingate SIParator will then be required for SIP-based communication to traverse the firewall.
FENT CDR (MOS)
Ingate SBC Firewall
ITSP
Servers
Avaya CM
Billing / User db

2. IP-Centrex – Next phase
Max 3x2000 calls (in this example)
IX78 ADSL SIP FW
CDR (MOS) QoS
SIP Carrier 1
SIP Carrier 2
Avaya Environment
Avaya Environment
Internet
PC Softphone
Simple NAT/FW
PC Softphone
Ingate SIParator
Legacy Firewall
CDR (MOS) QoS
As the number of customers grow, capacity requirement increases. A battery of Ingates can be built with load balancing between them achieved on basis of DNS SRV.
Servers
DNS SRV load balancing
As the number of customers grow, capacity requirement increases. A battery of Ingates can be built with load balancing between them achieved on basis of DNS SRV.
Avaya CM
CDR (MOS)
ITSP
Ingate SBC Firewall
Billing / User db

3. Reference Case
GCM - A Service Provider offering Hosted VoIP services, with Ingate and Avaya equipment