TEN ESSENTIAL NETWORK VIRTUALIZATION DEFINITIONS

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1 E-Guide TEN ESSENTIAL NETWORK VIRTUALIZATION DEFINITIONS SearchSDN

2 T here is some confusion surrounding as there is no one definition. In this exclusive guide, you ll find ten to help you better understand the basics and build the best software-defined possible. PAGE 2 OF 11

3 TEN ESSENTIAL NETWORK VIRTUALIZATION DEFINITIONS Michelle McNickle The emergence of software-defined ing has also sparked discourse among IT pros about the need for. Yet in many ways, a singular definition has yet to emerge. In a recent interview with VMWare s Martin Casado, we learned SDN and differ -- Casado likened SDN to a mechanism, while is an application. SDN is relevant to system builders: I liken it to a way to build an engine, Casado said. Someone building a car would use a new way of building an engine to build the car, but customers don t buy engines, they buy cars. Here we ve rounded up 10 key to better explain the basics of. Network. Network is a method of providing virtual instances of physical s by separating bandwidth into independent channels. Each channel can be assigned or reassigned to a specific server or device in real time and is independently secured. With these combined PAGE 3 OF 11

4 resources, distinct tunnels or segments can be provisioned, each with unique routing and management policies. Network is intended to improve productivity and efficiency by performing tasks automatically, allowing files, images and programs to be centrally managed from a single physical site. Storage media, like hard drives and tape drivers, for example, can be easily added or reassigned, and storage space can be shared or reallocated among the servers as well. Network is said to be particularly effective in s that experience sudden and unforeseen data surges and capacityhungry applications. Virtual switch. A virtual switch (vswitch) is a software instance of a physical switch that allows virtual machines (VM) to communicate with one another. Essentially, vswitches manage and route traffic in a virtual environment. Each virtual host must connect to a vswitch in the same way a physical host must be connected to a physical switch. Similar to a physical Ethernet switch, a vswitch not only forwards data packets, it intelligently directs communication on the by inspecting packets before forwarding. A vswitch can be included in a server s hardware as part of its firmware, but some vendors have embedded vswitches directly into their hypervisors. Virtual switching has not traditionally been designed to present visibility of the virtual PAGE 4 OF 11

5 to engineers, but third-party tools, such as the Cisco Nexus 1000v, aim to change that. Additionally, as virtual switching comes under control of SDN environments, pros will have more direct visibility and management capability. Overlay. An overlay is a software construct that lives on the edges of a physical and consists of virtual switches that reside on the virtualized servers. These switches are used to create an abstracted, virtual on top of the underlying physical infrastructure. An overlay relies on a control plane to handle virtual switching on the server hosts, similar to a physical. These control planes can either use traditional protocols or they can rely on a software-defined ing controller. One example of an SDN overlay is Big Switch s Big Virtual Switch, which uses OpenFlow-enabled virtual switches at the server access layer of a to create a virtual on top of an existing physical. Then the overlay tunnels make it possible to build a software-defined on top of physical infrastructure that doesn t explicitly support SDN. Network hypervisor. A hypervisor is a tool that provides an abstraction layer of a, allowing engineers to provision virtual components and tenants or paths that are completely independent of the PAGE 5 OF 11

6 underlying physical. The hypervisor should do for what a server hypervisor does for server -- enable guest applications and operating systems regardless of changes in the underlying infrastructure. With this abstraction layer intact, the hypervisor should also provide visibility and manageability of virtual resources to support dynamic provisioning of virtual s and related virtual machine migration. As solutions grow, many are looking to incorporate them into an overall software-defined ing (SDN) architecture. Using SDN, and incorporating a hypervisor into an SDN architecture, will help make the both flexible and manageable enough for Infrastructure as a Service (IaaS) and virtual resource provisioning. VXLAN. A Virtual Extensible LAN (VXLAN)is a proposed encapsulation or tunneling protocol for running an overlay on existing Layer 3 infrastructure. VXLAN is said to make it easier for engineers to scale out a cloud computing environment while isolating cloud apps and tenants. Traditionally, engineers have used virtual LANs (VLANs) to isolate apps and tenants in a cloud computing environment, but VLAN specifications only allows for up to 4,096 IDs to be assigned at any given time. The primary goal of VXLAN is to extend the virtual LAN (VLAN) address space by PAGE 6 OF 11

7 assigning a 24-bit segment ID and increasing the number of available IDs to 16 million. VXLAN can potentially allow engineers to migrate virtual machines across long distances and play an important role in software-defined ing (SDN). To implement SDN using VXLAN, administrators can use existing hardware and software -- a feature that makes the technology financially valuable. OpenStack Quantam API. OpenStack Quantum is a cloud ing controller and Networking as a Service project within the OpenStack cloud computing initiative. It includes a set of application program interfaces (APIs), plug-ins and authentication/authorization control software that enable interoperability and orchestration of devices and technologies within IaaS environments. The core Quantum API includes support for Layer 2 ing and IP address management, as well as an extension for a Layer 3 router construct that enables routing between Layer 2 s and gateways to external s. Quantum includes a growing list of plug-ins that enable interoperability with various commercial and open source technologies. Multi-tenant s. Multi-tenant architecture allows the physical to be divided into smaller, isolated logical s. Like PAGE 7 OF 11

8 tenants in an apartment complex, multi-tenant s share the physical ing gear but operate using their own distinct management and security policy, preventing spillover or visibility between the segments. While the capability to separate s into logical units has been available for some time through the use of VLANs, virtualized data centers and cloud computing concepts have brought multi-tenancy back to the attention of administrators. There are a few approaches to isolating traffic in a multi-tenant, including defining virtual switches, like Cisco s Nexus 1000v or the open source Open vswitch for each application. VMs connect to the physical by linking to virtual Ethernet adapters and virtual switches. Then, these connect to physical Ethernet adapters and switches. Virtual switches manage the movement of VMs and also aid in the provisioning and management of VLANs in the data center. Network architects create segments or tenants musing these switches and in some cases using a centralized SDN controller. Multi-tenancy is often used within cloud s so that s can be created for specific sets of data and/or applications. Network functions. Network functions, or NFV, is an initiative to virtualize functions that were previously carried out by proprietary, dedicated hardware. The concept is still being PAGE 8 OF 11

9 developed by the ETSI Industry Specification Group (ISG) for Network Functions Virtualization and was first presented by a group of service providers at the SDN and OpenFlow World Congress in October The goal of NFV is to decrease the amount of proprietary hardware that is needed to launch and operate services -- functions previously done by routers, firewalls, load balancers and other hardware would instead be hosted on VMs. If it s successfully developed and implemented, NFV will revolutionize how s are built, managed and used to create services. It s unlikely that virtual hosts will totally displace equipment, but the high-value portion of services could be made into a series of interoperating, cloud-hosted components. NVGRE. Network Virtualization using Generic Routing Encapsulation, or NVGRE, is an overlay or tunnelling protocol for. Using the encapsulation protocol, engineers can create a large amount of virtual LANs for subnets that extend across dispersed data centers on Layers 2 and 3. Its purpose is to enable multi-tenant and load-balanced s to be shared across on-premises and cloud environments. The NVGRE specification was proposed by Microsoft, Intel, HP, and Dell, and it competes with another encapsulation method, VXLAN. Key capabilities of NVGRE include identifying PAGE 9 OF 11

10 a 24-bit Tenant Network Identifier (TNI) to address problems associated with the multi-tenant. It also uses a Generic Routing Encapsulation (GRE) to create an isolated virtual Layer 2 that could be confined to a single physical Layer 2 or extend across subnet boundaries. Nexus 1000v. The Cisco Nexus 1000v is a Cisco Nexus Operating System (NX-OS) switch that s rendered fully in software and provides visibility and management inside the virtual stack, enabling distinct tenants composed of physical and virtual ing resources. The switch enables a team to monitor, manage and troubleshoot both the physical and virtual s with Cisco commands and tools. The switch is programmable and is based on IEEE 802.1Q switching technology. It used a control-path API to communicate with the data plane. This allows administrators who use non- Cisco physical components to use the 1000v to handle virtual management. PAGE 10 OF 11

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