Network Virtualization Solutions

Transcription

1 Network Virtualization Solutions An Analysis of Solutions, Use Cases and Vendor and Product Profiles October 2013 The Independent Community and #1 Resource for SDN and NFV

2 Tables of Contents Introduction 1 What is network virtualization? 2 What business problems does network virtualization solve? 2 What is the relationship between SDN and network virtualization? 3 What is an overlay? 4 Benefits of network virtualization 5 What are the main approaches to network virtualization in the market today? 5 What are the main use cases for network virtualization? 7 What are key primary and extended attributes of a network virtualization solution? 7 What should businesses consider when looking at a network virtualization solution? 8 Who are the leading vendors providing network virtualization solutions? 12 Big Switch Networks 16 Cisco Systems 21 ConteXtream 27 Dell 33 HP 40 IBM 45 Juniper Networks 51 Midokura 58 NEC 62 Nuage Networks 67 PLUMgrid 72 VMware/Nicira 79 Glossary of Terms SDNCentral. All Rights Reserved. Page ii

3 Introduction Until recently, virtualization in the data center primarily focused on compute and storage. But the continued pressure of more data and more access methods (mobile, tablets, desktops) anytime, anywhere has led to an explosion of web applications and business requirements for increased agility. To better handle this onslaught of demand, the network now is going virtual as well to achieve similar benefits that virtualization provided compute. Debate continues whether network virtualization (NV) and software-defined networking (SDN) are orthogonal or related, but most vendors in the network space (perhaps with the exception of some at VMware) are blurring the lines between the two and treat them as overlapping. For the purposes of this report, we will treat SDN as one of the paths to achieve network virtualization and argue that network virtualization deployed with SDN can be more valuable to the end user. Note that this report does not explicitly deal with NFV (network functions virtualisation), an initiative driven by ETSI (European Telecommunications Standards Institute) to encourage the use of commodity servers and virtualization to improve the agility and scalability of service provider infrastructure. NFV is highly complementary to both SDN and network virtualization, but it is an orthogonal topic. This report is targeted at CIOs, directors of infrastructure, network architects and network engineers looking to understand the market landscape in terms of the vendors and their product offerings. Given the nascent nature of the overall network virtualization market, few vendors have significant production deployments. As such, this report focuses on providing the reader with a high-level framework to evaluate the different offering and offers an opinion on each of the different vendors. As the NV market matures, SDNCentral will continue to expand our coverage and provide deeper analysis of solutions, technology and use cases on our website and in future reports. In this report, SDNCentral s research team answers the following key questions: What is network virtualization? What business problems does network virtualization solve? What is the relationship between SDN and network virtualization? What are the benefits of a network virtualization solution? What are the main approaches to network virtualization in the market today? What are key primary and extended attributes of a network virtualization solution? How would a network virtualization solution be deployed? What considerations are there in looking at a network virtualization solution? Who are the leading vendors providing network virtualization solutions? What problems are they best at solving? For further details or information about the right network virtualization solution to solve specific business and technical challenges, we recommend having a conversation with either the vendors listed in this report or knowledgeable independent consultants such as our affiliated sister company, Wiretap Ventures ( SDNCentral. All Rights Reserved. Page 1

4 What is network virtualization? Network virtualization is a framework that decouples and isolates virtual networks from the underlying physical network hardware. It has been compared to the way server virtualization works, isolating virtual machines from the underlying physical server hardware. While this analogy is mostly valid, there are subtle differences. A virtualized network abstracted from physical hardware generally still provides similar features and guarantees of a physical network, only with greater agility and flexibility than before, including superior operational efficiency and hardware independence. Historically, elements of network virtualization were present in 802.1Q VLANs (virtual LANs), a capability almost all switches today provide. VLANs provided certain abstractions, allowing multiple LANs to share a physical link with isolation between each of the LANs. However, the 12-bit VLAN identifier capped the number of VLANs in the network to around 4,000. This is a large number for a legacy enterprise network, but not quite enough for cloud environments whether within enterprise private clouds today or at cloud service providers. Similarly, other approaches like IPsec/SSL VPNs, and VPLS and MPLS within carrier environments have provided elements of network virtualization. Today, most discussion around network virtualization focuses on the data center. In particular, network virtualization generally is looked upon as the solution to provisioning private virtual networks for application workloads and any associated security, acceleration, and external connectivity services. In some situations, these private networks sit within a rack of servers or across multiple racks at a data center. In rare situations, they sit across geographically distributed data centers. Discussions exist about network virtualization in the WAN, or perhaps the next generation of it beyond MPLS/VPLS networks, but use cases for the data center are much better defined. What business problems does network virtualization solve? Private and public data centers are migrating toward new cloud architectures, creating new requirements and demands on the network to meet growing business needs. Driven by the web, social, and mobile trends, businesses today are expected to deliver scalable web and mobile applications to large numbers of users quickly. The rise of mobile apps, web-based applications, and highly-unpredictable demand dynamics particularly in consumer applications dictate highly scalable applications with quick development turnaround times to serve highly demanding users. Mobile applications like DrawSomething, which had to scale from almost nothing to 35M downloads in three weeks, and Mailbox, which went from zero to 1M users with hundreds of millions of messages in six weeks, are now the new normal in successful mobile and web applications. Likewise, businesses marketing to other businesses have been quick to adopt cloud development models, using them as business differentiators to capture more market share, increase revenues, and reduce cost. When agility is the new business goal, valued over the traditional goals of cheap and better, IT turns to cloud frameworks, Agile development methods, and web development talent as the solution SDNCentral. All Rights Reserved. Page 2

5 These new deployment best practices and application development models tend to favor a large number of private enclaves or mini-personal data centers in which developers develop, test, and debug new applications. Likewise, with the move toward running cloud instances in the web, cloud service providers have to offer similar on-demand mini-data centers for each of their clients. Virtualization of both compute and storage is key to many of these cloud architectures, as they provide quick provisioning, improved resource utilization, and operational efficiencies. Unfortunately, the network has lagged. While compute and storage resources could be rapidly provisioned in minutes, network changes such as adding and removing VLANs, or adding and deleting firewall rules, tended to run closer to weeks due to the highly inefficient approach of processing change order queues using manual configuration and reconfiguration. Network virtualization is considered the solution to closing the virtualization gap between networking and compute and storage. Network virtualization helps complete the picture and allows data centers to provide the full suite of cloud capabilities, from on-demand self-service and rapid elasticity, to flexible billing and department chargebacks all across compute, storage, and finally, networking. What is the relationship between SDN and network virtualization? The relationship between SDN and network virtualization can be confusing and sometimes even contentious. Some vendors take the view that network virtualization is completely separate from SDN and that SDN is not needed for network virtualization. For the purposes of this report and most deployments, SDN and network virtualization will tend to go hand in hand. To understand how SDN and network virtualization are related, we start by defining SDN. Various vendors define SDN in different ways, ranging from SDN being any OpenFlow-enabled infrastructure to SDN simply being automation and orchestration. At its most basic, SDN is an approach to networking that centralizes control of the network by separating the control plane from the data forwarding plane and moving control logic to off-device compute. SDN also exposes programmable control APIs to allow applications to orchestrate and automate network services. SDN can be used to achieve network virtualization through direct fabric programming or creating direct paths through the network fabric (virtual and physical) to effectively achieve isolation of private networks from each other. However, this form of network virtualization has been less popular than network virtualization using overlays, in which traffic from virtual machine endpoints are simply encapsulated and tunneled through existing physical networks. Pure overlay networks can provide network virtualization without the use of programmatic flow controls. Certainly a centralized, separated control plane is not always needed. However, given that most network virtualization solutions involve chaining of Layer 4-7 services and composition of multi-tiered networks, there always will be a programmatic element and hence a link to SDN SDNCentral. All Rights Reserved. Page 3

6 What is an overlay? An overlay (sometimes called a network virtualization overlay) essentially is a virtual network that sits on top of a physical network, often with the physical network not being aware of the existence of the virtual one. Overlays are created by encapsulating data packets and using external headers to mask what s inside. The external headers allow the packets to traverse regular Layer 2 or Layer 3 networks. When encapsulated packets reach the final gateway, they are unpacked (or de-encapsulated) before being forwarded to the correct target host. These final gateways can be virtual switches attached to VM hosts, or they can be external gateways that act as bridges between a virtual network and an existing physical network. Overlays provide agility and location flexibility without having to upgrade or modify existing physical equipment at the core of the network. By pushing intelligence to the edge, overlays can provide additional features and capabilities more rapidly, without requiring forklift upgrades of physical equipment. Popular encapsulation formats include VXLAN (proposed by Cisco and VMware, and supported by many other vendors today including Arista Networks, Dell, HP, Juniper, Nuage, PLUMgrid, F5, etc.), NVGRE (Microsoft primarily), and STT (originally created by Nicira to improve performance of tunneled traffic but will be deprecated over time as VXLAN comes to dominate). Other encapsulations include MPLS (GRE/ UDP), OTV, NVO3, straight GRE, and even IPsec. Overlay networks usually depend on external Layer 3 headers to guide the packets to the appropriate location. In any overlay deployment, dealing with broadcast, unknown unicast (where the sending party doesn t know where the target host is), or multicast tends to require special handling. Particularly with VXLAN, which depends heavily on IP multicast to provide this capability, there tend to be scale limitations. Most VXLAN-based network virtualization vendors have come up with their own solutions for dealing with this problem, often relying on a registration and lookup service, which provides global visibility into endpoints. Furthermore, because multicast and broadcast can be complicated and expensive operations in an overlay, many overlay solutions also provide special handling for well-known multicast and broadcast-dependent services, such as DHCP and ARP. More advanced overlay solutions also provide intelligent multicast systems, and they appropriately forward packets only when necessary instead of flooding all endpoints on the virtual network with packets. While physical networks aren t necessarily aware of overlays, overlays ultimately depend on physical networks for end-to-end connectivity, available bandwidth to provide quality of service, and recovery in the case of link failure. As SLAs (service level agreements) for overlays become more business critical, intelligent coupling between the overlays and the physical underlay network will become an asset. TO LEARN MORE To read the rest of the 90 page report, you can buy it at We invite you to also visit SDNCentral as a resource for Software-Defined Networking, Network Functions Virtualization and Network Virtualization. If you have any questions, we can be reached at 2013 SDNCentral. All Rights Reserved. Page 4

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