Supporting network virtualization over the WAN is no easy feat. Extending virtual networks over different WAN services presents different benefits and drawbacks. Depending on the type of service, it can affect the amount of control the enterprise has over the IP infrastructure, the dependency on the service provider and the ease of encryption, among other factors that enterprises need to take into consideration.
Chapter 7, “Extending the Virtualized Enterprise over the WAN,” from the book Network Virtualization, provides an in-depth analysis on this topic, helping IT professionals understand the options and technology behind extending virtual networks over the WAN. See an excerpt from the chapter below, or download the complete free PDF download here: Extending the virtualized enterprise over the WAN.
Extending the virtualized enterprise over the WAN
Because of the variety of technology alternatives available from service providers, the WAN is an interesting part of the enterprise network. Depending on the services offered by the provider, the enterprise will have different levels of control over the WAN. In many cases, the enterprise will require the use of overlay logical networks to fulfill its WAN connectivity requirements. These logical overlays become more sophisticated when they must support multiple virtual networks (VNs). This chapter analyzes the different WAN scenarios the enterprise faces and discusses the technology alternatives and best practices for maintaining multiple VNs over the different WAN offerings.
The most common WAN services currently offered by providers are as follows:
- IP services—Layer 3 virtual private networks (VPNs) or the Internet.
- Layer 2 circuits—Traditional Frame Relay, ATM or Ethernet Layer 2 circuits.
In addition, it is common for an enterprise to deploy overlay networks on top of these services. Some of the most widely used overlays are as follows:
- Point-to-point generic routing encapsulation (p2p GRE)
- Hub-and-spoke multipoint GRE (mGRE)
- Dynamic multipoint VPN (DMVPN)
→ To continue reading about network virtualization over different WAN services and overlays, download the PDF of Extending the virtualized enterprise over the WAN.
About this book: Network Virtualization offers an abundance of information about virtualized enterprise networks and enables network architects to make technological decisions in accordance with varying business requirements. This book begins with the basic principles of enterprise network design and then delves into a range of topics including infrastructure segmentation architectures, extending the virtualized enterprise over different WAN services, traffic steering and quality of service, all while providing real-world case studies.
About the authors: Victor Moreno works as a technical marketing engineer at Cisco Systems with over 10 years of experience in the industry. Moreno also has experience with enterprise campus network virtualization, having been involved with it since 2001. Kumar Reddy, also working at Cisco Systems, is a senior manager of technical marketing engineering with more than 15 years of experience. Reddy has experience in multiple areas, having worked with broadband DSL, LAN switching and designing end-to-end systems.
This was first published in August 2011