Carrier Grade Virtualization (CGV) may be defined as virtualization services that fulfill some or all expected properties existing in carrier grade solutions. Let’s examine these properties and the requirements it imposes on Carrier Grade Virtualization. The list is not an exhaustive definition, but is comprehensive enough to provide an overview of Carrier Grade Virtualization.

 

 

• Availability: Virtualization can increase overall availability of carrier grade systems, so that the 5 to 7 nines expected and provided by existing systems be preserved, or even enhanced (through lengthened MTTF or shortened MTTR).
• High-Performance scaling: Carrier Grade Virtualization must contribute to scalability, both through high efficiency with minimum overhead, and by enabling capabilities of new hardware, especially multicore processors.
• Small error recovery domains: Virtualization by itself isolates virtual machines and their guest Operating Systems (OSes) from each other; failure of a VM or a guest OS does not impact other collocated VMs. Carrier Grade Virtualization leverages this “natural” characteristic and extends it by dedicating VMs to specific functions such as providing device access.
• Real-time behavior: Since software components used in carrier grade systems do have real-time requirements, Carrier Grade Virtualization must be able to support real-time workloads and systems and so needs to offer real-time and deterministic properties.
• Upgrade capabilities: Virtualization changes the way software components (OSes, middleware, applications) are instantiated on a hardware platform. Carrier Grade Virtualization must ease software upgrades of such components, and must also support self upgrade.
• Configurable security: Virtualization isolates virtual machines and their workloads from one another. Carrier Grade Virtualization predicates more than “one size fits all” approach to security. CGV must offer capabilities to define and apply appropriate security policies among virtual machines and to control access by VMs to physical resources (CPU, memory, devices…).
• Efficient and Uniform Management Interfaces: Virtualization introduces new objects (virtual machines) which must be managed. Carrier Grade Virtualization must provide efficient and uniform management interfaces.

 

Much like the well defined Carrier Grade OS (CGOS) and Carrier Grade Linux (CGL) specifications, CGV focuses on seven central themes listed below. CGOS and CGL specifications are outside the scope of this document and can be found on the SCOPE Alliance and Linux-Foundation portals.

 

Technical

On the technical side, CGV can positively impact fault granularity, detection and resolution, as well as overall security.

 

Scope and Impact of Faults

Purpose-built carrier-class systems take pains to minimize the granularity of failure so as to optimize fault detection, isolation, and resolution. Carrier Grade Virtualization offers at least as fine-grained fault resolution as purpose-built / integrated systems, and can actually go a step further.

 

Flexible Redundancy Models

This change in resolution and capability streamlines failover by decoupling the redundancy of software fault domains and the redundancy hardware domains. It also provides more choices for overall system architecture with more flexible sparing typology.

 

Real-time Support

Carrier Grade Virtualization must support legacy applications and OSes, many of which offer Quality of Service and real-time scheduling properties.

 

Enhanced Scalability

Carrier Grade Virtualization can address a greater range of applications than purpose-built HA systems by targeting a wider range of embedded hardware, enabling legacy OSes and workloads to run with scaling performance on multicore platforms without having to modify or tune them for that purpose. The modular architecture design supports varying degrees of application integration with HA infrastructure to avoid force-fit of overkill technology.

 

Improved Security

While specifications like Carrier Grade Linux specify a range of security mechanisms required by carrier class systems, they do so in a vacuum without consideration for viable system architecture context. Carrier Grade Virtualization offers a mix of implicit and explicit security improvements over most software deployed in purpose-built fault-resilient systems.

 

Financial

Financial benefits that derive from CGV are many and varied, and span the gamut from acquisition (capital expenditure) to streamlined performance and availability (operational expense):

 

CAPEX – Capital Expenditure

Compared to both legacy fault tolerant systems and hardware-intensive highly available COTS hardware, Carrier Grade Virtualization offers OEMs, integrators and service providers’ significant returns through reuse by running on both commodity blades and custom embedded hardware. Furthermore, its ability to provision with virtual spares improves hardware utilization and lowers the cost of most configurations.

 

OPEX – Operational Expenditure

Telecommunications and networking infrastructure systems are notoriously expensive to maintain and update. By designing with and deploying CGV, end-deployers optimize operational expenses through the use of smaller TCBs resulting in improved up-time to meet stringent Service Level Agreements (SLA), lower power consumption from having a fewer active nodes and more flexible hosting resulting in cost-effective upgrade options.

 

Time-To-Market

Carrier Grade Virtualization’s ability to enable the reuse of legacy software and hardware offers system vendors substantial time savings that would otherwise be spent in costly re-validation engineering cycles. These savings manifest themselves in condensed development and quality assurance phases and therefore contributing directly to a faster pace into market entry.

 

Improved Quality as a Competitive Advantage

The extended availability of Carrier Grade Virtualization systems coupled with the reuse of tested and tried software and hardware results in a lower number of new product variables. Thus, the quality of the product continues to evolve, adding to its differentiation without sacrificing feature desirability, cost nor time to market.