ZTE IMS Virtualization

Background

Internet applications and IT technology have severely eroded the high profit margins of telecom carriers. Instead of trying to block internet applications such as Skype and Viber, more and more carriers are seeking to cooperate with or learn from them. With the success of Amazon cloud services, carriers have been focusing on how to adopt cloud computing in telecommunications. Some have already built their own cloud data centers and are thinking how best to profit from those technologies. The key technology is virtualization.

IMS is the standardized all-IP architecture for services such as VoLTE, RCS-e, and HD video conferencing. It supports both fixed and mobile access for all terminal types. The elements of IMS are logically independent, and IMS can run on a virtualization platform. Some tier-1 telecom carriers have already started researching how to introduce virtualization into IMS and how to optimize cost, performance, and deployment of telecom equipment.

The marriage of IMS and virtualization benefits carriers in the following ways:

●   Virtualization decouples software from hardware. It allows an IMS element to be organized in horizontal layers, such as hardware layer, virtual machine layer, and application layer. You can purchase hardware from manufacturer A, virtual machines from manufacturer B, and upper-layer IMS applications from manufacturer C. This breaks the traditional binding procurement of hardware and software, which provides greater flexibility and lowers cost.

●    Virtualization machines (VMs) allow carriers to move applications that are scattered in multiple, rarely-used physical servers into one physical server, regardless of the operating system. This makes resource utilization more efficient. With an elastic virtualization platform, carriers can easily deploy a new element or increase the capacity of an existing element.

 ●   Virtualization is applicable in scenarios such as IMS hosting and IMS-in-a-box where establishment costs and difficulty are high. A carrier can have many VMs for its operating companies (OpCos) or resellers, and earns revenue from both OpCos/resellers and end users. This is especially useful for a carrier with an unbalanced number of users across multiple OpCos. An OpCo with a smaller number of users can be hosted by the OpCo with a larger number of users, and the former need only manage the VM, to save investment on equipment.

●    A VM offers different categories of cloud computing services based on the layers of an IMS cloud. For example, carriers can offer infrastructure-as-a-service (IaaS) for OpCos and resellers to rent. OpCos and resellers can offer platform-as-a-service (PaaS) for government and enterprise, and software-as-a-service (SaaS) for end users.

ZTE IMS Virtualization Scenarios

ZTE is fully aware of the impact of virtualization on the telecom industry and has developed a virtual management platform called TULIP elastic computing system (TECS). TECS supports hypervisors such as Citrix Xen and VMware vSphere. The use of VMs in TECS makes IMS/CS product deployment more flexible. In addition to ATCA and general-purpose server platforms, VMs can also be deployed in other hardware platforms. However, the ATCA platform is preferable for carrier-grade applications, and a general-purpose server platform is preferable for enterprise-level applications.

Fig. 1 shows the use of VMs in IMS. The TECS divides the operating system of IMS hardware platform into multiple VMs for multiple service systems to run on. The virtualization of CPU, memory, and storage allows multiple service systems to share the hardware platform in order to improve resource utilization, reduce costs, and protect investment.

The TECS has following features:

●    multiplatform, multi-OS capabilities

●    support for computing, network virtualization, and related virtualization resource management

●    support for scalability and independent upgrade of IMS elements and applications.

With a TECS, applications that run on different middleware/operating systems can share the same hardware in different deployment scenarios. The following scenarios show how virtualization in TECS brings flexibility and scalability to meet the requirements of IMS deployment.

IMS Hosting

Virtualization allows multiple IMS instances to run on the same hardware (a blade or server). A multinational carrier can deploy an IMS system at their headquarters. Multiple instances of the same IMS element, for example, CSCF, run on the IMS hardware to serve multiple OpCos. Each OpCo manages its own instance. IMS hosting is suitable for a multinational carrier with an unbalanced number of users across OpCos and with a need of deploying IMS rapidly for each OpCo. It is also suitable for resellers of wholesale IMS services.

IMS-in-a-Box

Virtualization allows IMS elements and TECS to run on an ATCA blade or commercial server instead of on multiple shelves. This improves the integration of IMS elements. IMS-in-a-box is suitable for a carrier or a medium-to-large sized enterprise to deploy a small-capacity IMS without the need for scalability.

Smooth Migration from CS to IMS

Virtualization allows IMS and CS elements such as MSCS, MGCF, and CSCF to run on an ATCA blade or a commercial server. If there is a reduction in the number of CS users, the carrier can move the VM resources from MSCS to CSCF to avoid resource waste and smoothly migrate from CS to IMS.

Impact of IMS Virtualization

Virtualization is a metaphor for “the IT world,” and IMS is an evolved architecture based on telecommunication networks. Virtualization in IMS has following characteristics:

●    With optimization technology such as VT-x, the most recent data shows that the performance of a VM-based IMS system is comparable with that of non-VM-based IMS system.

●    It is still difficult to move some traditional network elements, such as an E1 card of MGW, to IP-based VMs.

●    The software and hardware of a telecommunication network are managed by NMS in a unified manner. However, virtualization technology eliminates the dependencies between software and hardware, which can be managed by different entities. This is a change to the vendor’s network management system.

Future Development

It may take a long time to standardize cloud computing, if indeed it ever is standardized. The existing methods for interoperation between clouds rely on testing and certification.

Migrating IMS services to cloud makes network development more flexible for carriers and introduces a variety of services, such as video conferencing, to enterprise customers, end users, and resellers. Also, voice and video services become a kind of cloud computing service provided by the carrier and can be accessed anytime and anywhere through terminals.