Verizon Teams with Leading Companies to Develop A-IMS
Verizon, together with Cisco, Lucent Technologies, Motorola, Nortel, and Qualcomm Team, reveal a vision for the advancement of next-gen network architecture for wireless mobile telecommunications networks. Executive Vice President and Chief Technical Officer at Verizon Wireless, Dick Lynch, announces the company has been working for nearly a year with a task force of the industry's "best and brightest" network engineers and strategists from Cisco, Lucent Technologies, Motorola, Nortel and Qualcomm. Their aim has been to develop enhancements to a well known, emerging architecture, known as IP Multimedia Subsystem.
The team has generically termed this architecture A-IMS - for Advances to IMS - in order to reflect its evolution from work done earlier in technology standards bodies. The A-IMS architecture developed by the task force provides solutions to implement next-generation services in current networks, as well as creates a foundation for the efficient roll-out of both SIP- and non-SIP-based services in future networks. IMS is generally accepted as a core component of virtually all next-generation, IP-based communications networks for SIP-based applications, and is designed to assure standardization of multi-media services across all of these interconnected networks. The current outputs of the task force are a concept document and an architecture document that are being provided to industry leaders. From these documents, the task force companies plan to make necessary standards contributions in the immediate future.
The A-IMS standard is built on some key architectural principles, including:
* Comprehensive Security: Security is more than authentication, and involves all components in the network, including the devices. Indeed, security agents run on the network devices, providing reverse-firewalls to protect the network from the device and to aid in posture assessment during logon. Comprehensive security also requires the Security Manager to monitor the network at all times, determine baseline traffic patterns, and then use those to detect and respond to anomalies. To respond, the Security Manager can change server configurations, install firewall rules or modify Intrusion Detection Services behaviors.
* Uniform Treatment of SIP and non-SIP Applications: To the greatest degree possible, A-IMS allows the service provider to manage and control both SIP and non-SIP applications in a uniform way. This is done primarily by usage of the Policy Manager, that allows the service provider to manage the usage of network resources on behalf of both types of applications. Key network functions, including mobility, roaming and packet accounting are also defined in ways that allow them to support both types uniformly.
* Dual Anchoring: A-IMS provides a mobile terminal with two IP addresses - one anchored in a Bearer Manager in the visited network, and one in a BM in the home network. Service provider policy controls which address is used for which applications. This allows for latency sensitive applications to use the visited anchor, whereas applications that require greater levels of service provider control can use the home anchor.
* Three-Layer Peering: When connecting to roaming partners, peering occurs at three layers: security peering, used for access authentication, IP peering, used for transport of bearer traffic, and policy peering, used for control of bearer services. Policy server peering involves the usage of a policy server in both the home and visited networks. Usage of two allows for the home provider policies to apply even while roaming, yet allows them to be tempered by visited network policies on usage of the network.
* Multi-Tiered Service Interaction Management: Feature interaction management across SIP-based applications, and between SIP and non-SIP applications is provided. Feature interaction management is linked with network policies, allowing for application interaction decisions to take into account the state of the network. The architecture also allows for extensibility to new interaction resolution mechanisms through the addition of service interaction application servers.
Highlights of the A-IMS plan clearly define several "pillars" as essential to the architecture:
* Bearer Manager: Allocates resources and manages bearer traffic to meet customer's service quality requirements. The primary functions include policy enforcement, mobility management, security, accounting, and access control.
* Policy Manager: A primary policy decision point for network policies, deciding the ways that the underlying network supports applications on behalf of subscribers and visitors to the network.
* Application Manager: The SIP services platform in the network that authorizes access to SIP services, provides SIP registration and authentication functions, and is responsible for the invocation and management of SIP-based features.
* Security Manager: Responsible for monitoring the network for security threats and responding to them in real time, making decisions on what devices are allowed access to the network based on their posture - a measure of the safety of the device based on the freshness of its software patches and security features.
* Services Data Manager: The main repository of subscriber and network control data and collects and stores charging data for the network.
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