QoS considerations for Carrier Grade Clouds: location, location, location.

A Carrier-Grade Cloud (CGC) is a cloud platform suitable for deployment, with stringent Availability, Reliability, QoS and Security requirements which are fundamental for Real-Time applications in many domains such as Telecoms, Automotive, Banking (Trading) sector.

In our previous post we looked at the security requirements paramount to the design of such systems. Now lets see how Network Equipment Providers (NEP) and mobile operators can differentiate their offering and meet the CGC stringent Quality of Service (QoS) demands.

The challenge with QoS in the cloud:

Qos is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance. The technical problems behind guaranteeing QoS are non-trivial for all but the most basic “best-effort” guarantees. Resource capacity planning is Non-deterministic Polynomial-time hard.

QoS requirements can’t be met with SLA’s and contractual enforcement alone, but must be a “hard” requirement within the technical design of such systems. These QoS constraints should be more than best-effort and formerly drafted into an SLA using templates such as the Web Services Agreement and made discoverable by the applications.

Network traffic represents the bulk of the operators cost, therefore maintaining a cloud infrastructure in one central location would be unsustainable. The way forward is a distributed location aware cloud infrastructure. Here operators are best positioned since they own the pipes and datacenters and can rely on their physically distributed network infrastructure to minimize routing costs and latency.

Traditional cloud computing is location-agnostic. But to meet QoS demands in a CGC a balance must be found between:

  1. reducing the cost of computation and storage (which comes at the expense of the network), and
  2. reducing the cost of networking (which increases requirements for local storage and processing)

The key differentiator to all other off-the-shelf services for QoS, is to provide ways for managing locality and fine grained control of where data is placed. Data should be stored where it is used coupled with intelligent caching and replication to meet the applications requirement towards network performance. Fetching data from the network should be avoided and instead allow computation to take place where the data is and by making computation power available at strategic locations.

Carrier-Grade CLoud Orchestration must therefore take a holistic approach, not only considering the management of storage and computation, but also the network.

That said, cloud security requirements prevent us from exposing the network-management or location to the upper application layer. Internal routing or priority of scheduling must be kept encapsulated within the PaaS/IaaS to avoid exposure of the internal topology to applications.

QoS parameter encapsulation:

For QoS we need an abstraction offered to upper application layers. A policy of constraints which allows the application (user of the service) to specify which type of priority it should receive, including:

  • VM-bandwidth, latency, redundancy
  • Co-Location proximity of VM’s (how close the location of a fail-over node should be placed)
  • Location of data. Possibly an intelligent mechanism to predict where data will be needed based on historical usage.
  • A management interface to model future usage scenarios and costs and what-if scenarios.

This is currently more of a research subject and also new territory for the cloud vendors. The good news is that Telcos have a head-start in this area because:

  1. QoS and Real-Time has always been their core business. since the early days of circuit switched routing to today’s packet-switched networks.
  2. Telcos are big enough to build their own internal offering instead of having to rely on reselling leased cloud services. This gives them better control and allows them to guarantee QoS levels and open up new revenue streams.
  3. Telcos control the network pipes and routing policy, hence are best positioned to build additional features and services and open the cloud to areas which previously had no use for it.

As a pioneer in next generation cloud architecture Valbonne Consulting has the bandwidth, knowledge and right experts to provide these features tailored to your requirements. Call us today to find out how we can  help: +33 (0) 4 92 944 799

Conclusion:

Telcos can leverage their experience in billing metered services and further differentiate by billing based on the QoS constraints and resources actually used.

Network, location and QoS are major concern for CGC. Standards such as SDN/NFV will bring the network management to the cloud and enable the required fine-grained control over where data is processed, cached and stored within a Carrier Grade Cloud.

Further work is needed from standardization groups defining capacity-planning and resource scheduling in the cloud.

Deep Reading:

  1. A QoS aware service mashup model for cloud computing applications [pdf]
  2. Managing Performance Interference Effects for QoS-Aware Clouds [pdf]
  3. NEC’s Carrier Grade Cloud Platform [pdf] (focus mainly on NFV)