How to plan a software-defined data-center network

Architectures for software-defined data centers can address the need for flexibility and agility, but implementing them is difficult and calls for coordinating a host of complex features including containers, security, provisioning, scaling and migration to hybrid cloud.

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The data-center network is a critical component of enterprise IT’s strategy to create private and hybrid-cloud architectures. It is software that must deliver improved automation, agility, security and analytics to the data center network. It should allow for the seamless integration of enterprise-owned applications with public cloud services. Over time, leading edge software will enable the migration to intent-based data-center networks with full automation and rapid remediation of application-performance issues.

This article evaluates the data-center networking requirements for private enterprises that manage their own internal IT resources. It excludes the data centers of hyperscale cloud providers, as their requirements and resources are radically different that those of typical IT organizations.

Changing Data Center Requirements

The popularity of SaaS and public cloud creates pressure on IT to modernize internal enterprise data-center operations. The enterprise data center needs to support multi-tenancy, be operationally efficient and cost effective. The data center needs to support a wide range of physical and virtual workloads and adapt to the new style of application development, including support for containers. Because security breaches can take months to discover, software in the data center should alert operators to suspicious traffic flows and recommend corrective action. IT leaders need the ability to link the internal applications and internal resources including private-cloud with public-cloud resources to create hybrid cloud architectures. 

What is the Software Defined Data Center Network (SDDCN)?

The abstraction of networking hardware from networking software (software-based networking) enables significant changes in how networks are built and operated. The two places in the network most impacted are the wide area network – the software-defined WAN - and data-center network software. The SDDCN combines with compute resources (virtual machines and containers) and storage (disk and flash) to deliver specified performance for private-cloud applications. Via software abstraction, data-center resources can be easily reallocated to address changing application requirements without changing the underlying physical compute, storage or network elements.

SDDCN Requirements

Internal IT operations now compete for internal resources with SaaS applications and public cloud platforms. Internal data centers must rapidly provision new services, be agile in their ability to deliver the required performance for mission critical applications, be secure and be able to quickly fix any data-center operational challenges. The SDDCN is a key enabler of successful private cloud operations. It enables IT to quickly provision and manage large numbers of high-speed (25GB to 100GB)  physical network links. The short list of SDDCN requirements includes:

  • Network performance at scale
  • Ease of provisioning of networking, compute and storage resources for new applications
  • Ability to rapidly scale bandwidth up and down by application
  • Work-load migration between internal data centers and public cloud
  • Providing application isolation to enhance security and support multi-tenancy

Data-center network-software architecture will also enable customization via open APIs, programmability and must easily integrate with third-party applications, including security, application acceleration and performance management.

SDDCN Architecture

The abstraction of network software from network hardware in the data center enables the rapid adaptability of the network. The software must work with network hardware to handle the massive increases in data flows created by new applications such as Big Data and micro-services architectures. The network software needs to scale its performance to handle rapid east-west traffic flows and to easily provision virtual network switches (vSwitches) and virtual LANs (vLANs).

The SDDCN must be able monitor and analyze traffic flows to provide its quality of service (QoS) guarantees to critical applications. This includes support for time of day scheduling, low-latency traffic (video and VoIP) and traffic bursting, such as storage replication. Network analytics provides the clues to remediate any application-performance issues or slowdowns. The SDDCN must track traffic flows and enable application communications across physical servers, to remote data centers and to public-cloud resources as in a hybrid cloud. Distributed organizations require high-speed connections to multiple data centers in geographically separate locations. The SDDCN should be able to “stretch” applications across data centers, provide for business continuity and disaster recovery via active/active network links.

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