This blog provides the list of Mandatory and Optional Architectural elements to support IP PSTN SIP Trunking in Enterprise network and at the Service provider end.
Enterprise Network Elements
Enterprise network includes the following Network Elements
- Enterprise OSS Elements
- Enterprise Call control and Routing Elements
- Enterprise Centralized Services Call processing element
- Enterprise security FW
- Enterprise Border Element SBC
- Enterprise Security (outside FW)
- Enterprise IP Network Element (CPE)
Service Provider Elements
Service Provider network includes the following
- Voice SIP Service Provider IP Network (PE)
- Voice SIP Service Provider Border Element SBC
- Voice Call control Softswitch
- Voice SIP NMS/OSS
IP PSTN Network Architecture
This diagram includes the list of Mandatory and optional Architectural elements to support IP PSTN SIP Trunking in Enterprise network and at the Service provider end.
*Mandatory elements are highlighted in blue and Optional are highlighted in orange.
Mandatory Enterprise Customer Elements:
- Enterprise NMS / OSS Elements
Provide Monitoring, Alerting, Troubleshooting, Provisioning, Billing and Emergency Services Support.
ie Cisco Prime Collaboration etc
- Call Control and Routing Elements
Provide End User Device registration and call control, UC and Voice Services, internal and external call routing (Dial-plan Management).
100% Geographic redundancy and availability recommended.
ie CUCM
- Enterprise Border Element (SBC)
Provide normalisation of CUCM SIP Trunk supporting (SIP interworking), demarcation point [‘inside’ / ‘outside’] and topology hiding, call admission control, L5 L7 SIP validation. (2nd layer of enterprise security)
100% Geographic redundancy and availability, recommended minimum one per data-centre to support the required scalability and performance.
ie CUBE
- Enterprise Security Element (Outside Firewall)
Provide L2 L3 inspection and filtering providing: DoS protection, Privacy, Identity. (1st Layer of enterprise security).
100% Geographic redundancy and availability, recommended minimum one per data-centre to support the required scalability and performance.
ie Cisco ASA
- Enterprise IP Network Element (CPE)
Provide dedicated high availability dual IP connectivity to the SIP Trunk Service Provider service. (Trusted)
100% Geographic redundancy and availability, recommended minimum one per data-centre to support the required scalability and performance.
ie Cisco ISR Router
- Enterprise Centralized Services Call Processing Element [ This is optional]
Provide centralized aggregation for core services, for example centralized voicemail or centralized IP PSTN access.
100% Geographic redundancy and availability recommended.
ie Soft switch
- Enterprise Load Sharing & Proxy Functional Element [ optional]
Provide SIP Proxy (CUSP) and load-sharing for multiple SIP trunk environments, for example deployments with multiple SBE (CUBE) elements due to scalability or redundancy requirements.
100% Geographic redundancy and availability recommended. Minimum one element per data-centre for redundancy, additional elements may be required to support scalability or performance requirements.
ie CUSP
- Enterprise Security Element (Inside Firewall) [ optional]
Provide L2 L3 inspection and filtering providing: DoS protection, Privacy, Identity. (3rd Layer of enterprise security: Outside FW + CUBE SBC + Inside FW)
This provides an additional – optional - layer of security. I.e: typical DMZ approach.
Possibly required when the SIP Trunk IP Interface is shared with either WAN or Internet data traffic, where the SP Trunk is not trusted to be ‘clean’.
100% Geographic redundancy and availability, recommended minimum one per data-centre, scaled according to performance requirements.
ie Cisco ASA
Service Provider include the following Network Elements
- Service Provider Network Element (PE)
Provide dedicated high availability dual IP connectivity to the Enterprise customer network (Trusted).
Redundancy and availability should be handled by the SP.
- SP Border Element ie SBC
Provide normalisation of SIP Trunk supporting (SIP interworking), demarcation point [‘inside’ / ‘outside’] and topology hiding, call admission control, L5 L7 SIP validation.
Redundancy and availability should be handled by the SP.
ie CUBE
- SP Call Control Element - Softswitch
Call-control element and interconnect point to other SP networks (i.e VoIP and TDM)
Redundancy and availability should be handled by the SP.
- SP NMS / OSS Elements
Provide Monitoring, Alerting, Troubleshooting, Provisioning, Billing and Emergency Services Support to the SP.
- SP Security Element (Outside Firewall) [ optional]
Provide L2 L3 inspection and filtering providing: DoS protection, Privacy, Identity.
Redundancy and availability should be handled by the SP.
11 Comments
