SDN: The Solution for More Intelligent Distributed Cloud Data Centers
By Sam Tang, Data Center Product Management Dept, Huawei IT Product Line
Challenges of Multiple Data Centers
Enterprise IT applications are growing in complexity and are usually scattered across multiple data centers. To reduce costs and improve efficiency, enterprises use cloud computing to build data center infrastructure, which poses three challenges for enterprise Chief Information Officers (CIOs).
● Challenge 1: How can CIOs fulfill the Service Level Agreement (SLA) for applications deployed across data centers?
CIOs of large enterprises tend to have the following concerns: What is the best way to improve the availability and end-user experience of enterprise application systems? How can CIOs find the most suitable resources for deploying enterprise applications over hundreds of data centers housing hundreds of thousands of servers on interwoven networks? How can enterprises launch Virtual Private Network (VPN) services as quickly as possible? What is the best way to quickly add or remove devices while ensuring consistent service performance during peak hours?
● Challenge 2: How can CIOs manage virtual data centers?
As cloud-enabled internal data center resources are presented in matrix form, virtual data centers are showing up. How can CIOs best manage these virtual data centers?
● Challenge 3: What resources are needed for data centers to effectively support a cloud-computing platform architecture?
Gartner reported that over 50% of data center servers have been migrated to the cloud. On the large-scale cloud platform, dynamic Virtual Machine (VM) migration will occur frequently and on a larger scale across multiple data centers. What network solution can CIOs use to ensure high migration speed while avoiding service interruption? How can CIOs meet the requirement for large numbers of VLANs in multi-tenant scenarios?
SDN as the Best Option for Network Virtualization
There are two solutions in the industry for supporting cloud-computing platforms, but both are somewhat unsatisfactory.
First is the CT solution using TRansparent Inter-connection of Lots of Links (TRILL) or Shortest Path Bridging (SPB), which is implemented by hardware. TRILL and SPB protocols change the control plane of switches and expand Layer 2 networks, allowing for large-scale migrations. However, this solution may be inapplicable for interoperability between multi-vendor devices. This solution usually applies to newly built data centers.
Second is the IT solution that uses software overlays to implement a Virtual eXtensible Local Area Network (VXLAN), which encapsulates Layer 2 networks into Layer 3. This solution supports flexible VM migrations and as many as 16,000,000 VLANs, but adds forwarding performance problems.
To fulfill the SLA for applications across multiple data centers and to manage virtual data centers effectively, an open and flexible network solution must be available to configure networks dynamically and rapidly, pool computing and storage resources, enhance application performance and the user experience, and manage resources flexibly.
SDN offers the best solution by separating the control plane from the data plane on traditional network devices. With all control functions on a central controller, SDN configures and manages various network devices through standardized interfaces. SDN is receiving much attention throughout the industry lately from carriers, Internet Service Providers (ISPs), and information technology, chip, and device vendors as well as startups, standards organizations, and consulting institutes. SDN is also being well received by users.
More Intelligent Distributed Cloud Data Centers
Traditional data centers, with predesigned network architecture and devices, have high costs and low flexibility. In contrast, SDN-based distributed data centers can provide intelligent network services that are efficient and flexible, which enhances the SLA for upper-layer services in data centers.
● On-demand dynamic network configuration provides rapid service platform deployment and shortened service launch time
Before deploying new services on traditional data centers, network planning must begin several months ahead of time. The data center must be statically preconfigured, and all devices configured sequentially. With this slow process, it takes about a month for a VPN service to finally be launched. In contrast, SDN-based data centers are able to provide on-demand network services. As requested by customers, the system can dynamically re-configure the network as needed. As a result, SDN reduces the amount of time it takes to launch a VPN service from a month to less than an hour. With SDN, deploying enterprise applications in distributed data centers takes only days or hours rather than months.
● Dynamic Layer 3 network connectivity and intelligent detection of VM migration across data centers
In traditional data centers, VM migration requires manual reconfiguration of VM, Internet Protocol (IP), and Media Access Control (MAC) addresses, which causes service interruption, greatly affecting enterprises as well as customers. Here, SDN-based distributed data centers offer a big advantage. Before VMs are migrated across data centers, VXLANs are dynamically configured. After VMs are migrated, VM locations can be automatically detected and topologies automatically generated.
● Intelligent Routing, with Enhanced User Experience and Guaranteed SLA
Traditional data centers are not able to provide intelligent routing and dynamic bandwidth adjustment for services and therefore cannot satisfy user demands. SDN solutions, however, allow customers greater freedom to select bandwidth and routes with low delay, in compliance with SLA requirements.
● Flexible Networking Enables Rapid Virtual Data Center Build-Outs
SDN solutions allow for flexible networking, self-service applications for virtual data centers and on-demand virtual data center build-outs, making it possible for data center management to bond naturally with service and resource management. Service management is simplified as a result.
● Simple Network O&M for Higher Efficiency
The traditional data center network model requires expert planning and pre-configuration, and uses static topologies. In this model, all devices must be configured one after another, which is both time-consuming and tedious, in large part because devices from different vendors have different interfaces. In contrast, SDN only requires configuring the outer VLAN on switches; the SDN automatically handles all other configurations, reducing manual operations and minimizing errors.
Huawei Distributed Cloud Data Center () solution transforms traditional data centers that are dispersed, layered, and heterogeneous into distributed cloud data centers that are physically dispersed and logically centralized, with self-managed resources. This solution also allows data centers in different regions, at different phases of development, and different in scale to become virtualized into a single "logical resource pool" containing both physical and virtual resources from multiple data centers. The result is an SLA-guaranteed virtual data center with uniform management, presentation, and operations.
Huawei solution offers the following advantages:
• SLA-centered: Huawei solution offers computing, storage, networking, and security and fault tolerance services at different levels, meeting the SLA for priority services as well as common services.
• Infrastructure-as-a-Service (IaaS): With converged IT and CT infrastructures, virtual and physical resources as well as intra- and inter-DC networks are converged completely. Multi-tenant virtual data centers become available to provide services to users.
• Network-as-a-Service (NaaS): Huawei solution provides automated services on end-to-end networks and Quality of Service (QoS)-guaranteed network services through intra- and inter-DC connectivity, bandwidth, access, and isolation. These network services can be flexibly configured and dynamically adjusted as needed.
• Management-as-a-Service (MaaS): Unified architectures and processes are provided to manage physical and virtual infrastructure resources, irrespective of where they are located and how they are administered.
SDN is the key to implementing NaaS in Huawei by providing core control and scheduling over intelligent networks. With intra-DC and inter-DC controllers, Huawei provides overlay, elastic, and programmable SDN intelligent network pipes for upper layers, as well as highly agile, automated, and reliable distributed data centers.
Using self-service management services provided by ManageOne (Huawei's cross-DC resource management and scheduling software), end users can apply for virtual data center services at different SLA levels. Designed to satisfy customer demands, ManageOne automatically invokes intra- and inter-DC controllers through the intelligent policy-scheduling center to configure and deploy resources.
● Intra-DC Controller
With virtualization software and physical equipment integrated, and physical and virtual resources (e.g. computing, storage, and networks) orchestrated, the intra-DC controller provides a range of capabilities, including data center resource management, service monitoring, automated resource deployment (including networks) inside data centers, and flexible resource expansion. The intra-DC controller also manages and controls networks and is integrated with the SDN controller for both virtual and physical networks. It uses overlay networking with TRILL-based large Layer 2 networks and SDN + VXLAN. Additional support includes automatic delivery and configuration of virtual networks in cloud-computing scenarios, network automation for QoS control and security policy customization, auto-sensing of VM migrations, and large, software-based Layer 2 firewalls, load balancers, and Virtual Service Gateways (VSGs).
● Inter-DC Controller
The inter-DC controller provides a flexible and SLA-compliant interconnected network across data centers, including Multi-Protocol Label Switching (MPLS) networks and VPNs, and manages Wide Area Network (WAN) information such as reserved bandwidth, delay, and dynamic routing.
The new economics for IT environments increasingly require intelligent data center networks. When building new data centers or revamping existing ones, enterprises should adopt a distributed data center solution capable of providing SLA-guaranteed virtual data centers and managing multiple data centers in a unified manner. Our most successful enterprise customers are leveraging advanced SDN solutions to deliver intelligent and elastic network services.