Carrier Hosted Enterprise

Market and Requirement

Carrier to Enterprise VoIP and Multimedia services can be separated into two main areas:

1. Carrier hosted IP Centrex services, where carriers provide the complete communication service to the corporate using a centrally located Softswitch and providing line gateways or IP telephones at the corporate site. In essence the complete communication service is outsourced to the carrier.
2. IP PBX connectivity. This service allows the corporate to break traffic out to the PSTN using the carrier Softswitch infrastructure. Carriers additionally may route on-net calls and interwork with legacy PBXs. Finally, some carriers offer a complete PBX remote management service to remove the burden of reconfiguration and maintenance from the corporate.

Session border controllers enable the service provider to access corporate users across NAT and firewall devices whilst maintaining Quality of Service, core network security and regulatory compliance.

Critically, in the corporate market place there is an expectation of high service availability with consistent Quality of Service levels. This requirement flows through into equipment design where resilience and redundancy must be part of product design from day one; as is the case with the Newport Networks 1460. A network diagram is shown below:

The following will be key when deploying session border control solutions if a carrier's investment return is to be maximised when used in the corporate sector.

• Session border controllers must be able to scale flexibly and to a large capacity.
• They must allow the use of overlapping IP address spaces. Each corporate is likely to have a private IP address space.
• They must be able to differentiate between Corporate Centrex customers, PBXs, and residential customers, and perform Session Admission Control accordingly to ensure Corporate Service Level Agreements are met.
• They must provide security for the operator's and the corporate's networks, whilst also preventing service theft
• They must be capable of being deployed in a flexible manner. Signalling and media resource must be physically separable to meet the deployment scenarios of some operators.
• They must provide regulatory service such as Emergency Call Handling and Lawful Intercept which is now being mandated as broadband telephony and multimedia mature.
• They must be capable of evolving to TISPAN and IMS architectures to ensure investment reuse as the carrier's network moves towards the converged network architecture space.

The Newport Networks 1460 is the only product that is capable of providing the required level of feature function today, and also providing the level of flexibility required to deal with a rapidly expanding user-base and uncertain network evolution requirements.

Key Newport Networks 1460 Carrier Hosted Enterprise Capabilities

Future Proof Investment

• The 1460 can be deployed as a traditional session border controller, or it can be physically separated into a MediaProxy and SignallingProxy providing deployment flexibility.
• Multiple MediaProxies can be controlled from one SignallingProxy if required.
• Common hardware is used in combined session border control deployments and separated signalling and media deployments.

Both combined session border control deployments and separated signalling and media deployments can be upgraded for IMS and converged network use as required by the network operator ensuring maximum investment reuse.

Resilience

• The 1460 has no single point of failure providing in excess of 99.999% availability
• All system modules are 1 + 1 resilient including power distribution units, fans and disks.
• Physical link aggregation (802.3-2002) provides link resilience and load balancing.

Access Reach

• Secure traversal of NAT and firewall devices whether deployed at the customer premise or in the core network.
• VLAN support provides capability to host multiple overlapping IP address spaces.
• Intelligent filtering of SIP re-registrations to minimise signalling load on Softswitches/Proxies.
• Scaling from 5,000 to 100,000 simultaneous bi-directional calls on a single chassis.
• Support for up to 1 million concurrent registered subscribers.

Quality of Service

• Session Admission Control applied to physical interfaces, VLANs and corporate address groupings/PBXs, ensuring that corporate Service Level Agreements are met.
  
• Session Admission Control for Corporate Centrex additionally allows Session Admission Control based on number of internal sessions (media kept within corporate) and number of external sessions (media and signalling sent to carrier), see 'Media release' feature.
• Bandwidth Policing on a per-session basis to ensure sessions do not exceed negotiated rate
• Media release allows media to stay within the corporate for calls within a routable IP address space saving significant access bandwidth costs in a corporate application.
• Type of Service (ToS) and DiffServe Code Point (DSCP) remapping on a per-user and per-session basis ensuring that users do not exceed negotiated/specified quality.
  
• Load balancing across multiple core network Softswitches/Proxies.

Security

• Network Address and Port Translation (NAPT) provides Topology Hiding for core network.
• Malformed or 'illegal' SIP signalling discarded.
• Rate limiting of Registration messages to protect core network Softswitches/Proxies.
• All media traffic from non registered IP addresses discarded at line rate.
• Policing of signalling traffic, media traffic and quality monitoring (RTCP) stream. This prevents inappropriate use (fraud).

Regulatory

• Lawful Intercept for CALEA and ETSI.
• Supported national variants including, but not limited to: USA, Canada, UK, Germany, Italy.
• Emergency Call Handling Facilities allowing Session Admission Control to be suspended for emergency calls and calls to be passed to designated Emergency Call Handling Proxies