On several recent occasions, in discussions with my customers, colleagues and industry peers, the importance of the network, as it relates to Cloud Computing and Data Centers, has been challenged. I am surprised that such a topic is even up for debate ! In my opinion, the underlying network infrastructure of any given Data Center is the architectural foundation for service and application strategy; be it Cloud Computing, Virtual Desktops, Video or even Hosting services.
If we look at a broader scale, no one can argue the complexity and at the same time, the intelligence the modern Internet brings to it’s consumers. How would enterprises and service providers alike, offer converged services like voice, video and data without any network intelligence ? Not to mention, security, application scaling and other managed services. Networks are no longer the traditional packet switching platforms, it’s the heart and soul of intelligence which integrates with other intelligent applications to differentiate the multitude of services that can be enabled over a common medium. As application requirements are increasingly becoming complex, the need for equally smarter transport is critical.
Virtualization is bringing a whole new perspective to this discussion. It’s true you can account for network, compute and storage virtualization within a given solution; virtual switch, virtual machine, virtual firewall, virtual load-balancer, etc.; but how far can we abstract the network ? One can absolutely argue, Cloud Computing is server/compute resource centric, however for most enterprises, when you combine this compute structure with application workload requirements from business, technology and operations perspectives, suddenly the foundation architecture plays a crucial role -- i.e. the network and it’s interconnects.
Ok, going back to the importance of the network in Cloud Computing. In my Data Center conversations and implementation work with my customers I am seeing a rising trend (as we also see in the industry) to create on-demand service offerings that take advantage of product demands, market timings and business goals. This also increase profitability and productivity in a time efficient manner, which are also important to a business. What it leads to is a complete “end-to-end” packaging of a service in an automated, orchestrated manner where there is little to no manual intervention. In this process, there could be many different combinations of workloads identified and orchestrated. The point I am making here is, whether you offer a consumption model that is IaaS, PaaS, SaaS or any such combination, the underlying foundation network capabilities and dependencies must be accounted for from all perspectives, thus establishing a need for a solid infrastructure foundation architecture, thus the value of the network.
What role does network play in a Data Center ?
Data Centers are usually where business critical applications reside and where business critical logic happens, for both internal and external consumers. There are many levels of communications that need to happen internally and externally to the Data Centers. Ensuring that these communications happens seamlessly, efficiently and in a secure manner is a critical role of the network that ties all these components together.
Let’s take a look at the simplified figure below. Each block has a dependency with multiple blocks which establishes the workload patterns that the network has to carry. This dependencies across the modules perform specific business functions. These business functions could be carrying different workloads like:
1. Running complex business critical applications across multiple tiers and locations
2. Load sharing and clustering of applications across geographies
3. Cloud Computing -- Automation & Orchestration workloads
4. Disaster Recovery and Business Continuance (DR/BC) -- availability workloads
5. Data replication and backup workloads
6. Security and compliance enforcement
7. Development and testing workloads
8. Day-to-day maintenance
9. Management workloads
One thing in common across all these functions is the network and it’s ability to bind these components together !
It is critical now than ever to have an intelligent, reliable and functional network that provides next generation innovations for enterprises to evolve from a traditional network to a “Cloud enabled” network. What is a “Cloud enabled” network ? A network that is VM-aware, a network that can grow and shrink based on consumption demands, a network that can re-calculate paths dynamically during failures, a network that can guarantee different classes of service based on predefined parameters and postures, a network that ensures no blocked paths, a network that can track shifting workloads and react accordingly (VM mobility), we can go on and on. Bottom line, networks are becoming programmable (APIs) and flexible to accommodate the shifting applications paradigm which are demanded in various Cloud models.
There are many network based innovations that have been widely discussed in Cisco and other forums, like Virtual Port-Channels (vPC), Overlay Transport Virtualization (OTV), Locator/ID Separation Protocol (LISP), FabricPath, FibreChannel-over-Ethernet (FCoE), Virtual Security Gateway (VSG), etc. These innovations with next generation HW/SW combinations like Cisco Nexus series products help create a path towards unified fabric, network and compute approach to Cloud Computing. This is further proof that we are trying to address business and technical challenges with smarter networking tools. I am not saying that this level of intelligent networking is required in every scenario, but based on the business and technology requirements, next generation Data Center networks are making application decisions that it never had to make before !
For any given Data Center, it’s capabilities are finite. So, right away, we have an exhaustible resource to start with, typically it would the facilities -- power, rack-space, available ports, etc. Or it could be other physical assets within the Data Center like network, compute or storage. Since we are talking about networks, let’s agree that even network resources are finite from various perspectives, for example, scale; number of MAC addresses, VLANs, Layer 3 peers, throughput, over-subscription ratios to name a few. I will cover some of these aspects of the network in a future topic when I will discuss Data Center consolidation and migration planning.
For now, next time someone claims that the networks do not play an important role in Cloud Computing, you will have something to say about it !