Welcome!

SDN Journal Authors: Tom Leyden, Michael Bushong, Lori MacVittie, Torben Andersen, Elizabeth White

Related Topics: Virtualization, .NET, Cloud Expo, SDN Journal

Virtualization: Blog Post

Attention: Overlay Tunnel Construction Ahead

It's good to see folks from VMWare and Microsoft try and come together to create a single tunnel mechanism

A while ago I wrote a few articles describing the various tunnel protocols used for network virtualization between vSwitches on servers, and between vSwitches and physical network gateways. These are the mechanisms that construct overlay networks on top of a physical network. VMWare uses STT as the tunneling mechanism between vSwitches on servers and VXLAN to communicate with gateways to the non virtualized world. NVGRE is used mostly by Microsoft, and is an extension to GRE tunneling that has been around for a while.

Each one of these mechanisms have their pros and cons. They are all pretty much standard, or at least published by a standards organization, and multiple implementations exist of most of them. Outside of my complaint about the stream like nature of STT, the biggest problem with all of them is the fact that they are fixed in their definition. The header definition is fixed, the fields are fixed, the sizes of the headers are fixed.

The 24 bits used for a Virtual Network Identifier providing for 16 million different virtual network may seem like an amount we can live with for a long time to go. But creative minds will find ways to use those 24 bits to signal all sorts of meta information between the tunnel endpoints, or to intermediate switches and other services forwarding these tunneled packets. Additional summarized information about the content of a packet is extremely useful for any device or service that makes intelligent decisions on this packet.

And once you start that thought process, those 24 bits will disappear really quickly. And when 24 bits are not enough, it requires an update to the protocols and their implementations, and those are extremely painful, especially if portions of those protocols are handled in hardware.

Enter GENEVE, an Internet Draft published on Valentine’s day this year, which looks to take a more holistic view of tunneling. GENEVE takes its queue from many other protocols that have shown themselves to have a long life. Protocols like BGP, LLDP, ISIS and many others have been around for multiple decades and are still as popular as they have ever been. And the reason is simple, they are extendable. They evolve over time with new capabilities, not by revising the base protocols, but by adding new optional capabilities.

All of these protocols have a set of fixed headers, parameters and values, but then leave room for non-defined optional fields. New fields can be added to the protocol by simply defining and publishing them. The protocol is created in such a way that implementations know there may be optional fields that they may or may not understand.

Think of my favorite BGP. When its 4th version was created in the mid 90s, it had no ability to carry IPv6 (which wasn’t even called IPv6 at the time). It had no ability to carry multicast routes, Communities, ORFs or act as a Route Reflector. BGP has many optional attributes that have been added over the years and as a result is the most powerful routing protocol in existence. It is the result of a solid protocol design practice: we don’t know everything we may want to use this for at the moment we create it, so we design in the ability to simply add new capabilities.

GENEVE Header

Like VXLAN, GENEVE runs on top of UDP. It adds its own header, which is only 8 bytes of fixed header, containing that same 24 bit Virtual Network Identifier and a 16 bit Protocol Type as the main fields. After that, the initial definition is remarkably empty, every else is left open as options that follow a specific format if and when they get defined.

And that is the beauty of an extensible protocol, only those implementations that care about some specific option will have it implemented and acted upon. Everyone else has to quietly accept and ignore these options. Backward compatibility by design.

Along the way, a few more recommended practices are articulated, including one I complained about in my description of STT. While the language could be a bit stronger, it is recommended that each GENEVE encapsulated packet includes the entire header, which means I can actually reconstruct fragmented packets if I need to during debugging, each packet on the network has the entire original packet and the added GENEVE encapsulation.

Whether you like overlays, tunnels and everything that comes along with it or not, it is good to see folks from VMWare and Microsoft try and come together to create a single tunnel mechanism that is sensible and extensible. It seems to have all the right bits and pieces to have a long life and certainly provides mechanisms that allow for much better orchestration and cooperation between the overlay and physical network.

Of course it will take a while before it becomes a complete definition, with real implementations and hardware support. But when it does, we will have a better toolkit as a result.

[Today's fun fact: The city of Geneva (which is French of course is spelled Geneve) has the shortest commute time of any major city in the world. How appropriate.]

The post Attention: overlay tunnel construction ahead appeared first on Plexxi.

Read the original blog entry...

More Stories By Marten Terpstra

Marten Terpstra is a Product Management Director at Plexxi Inc. Marten has extensive knowledge of the architecture, design, deployment and management of enterprise and carrier networks.

@CloudExpo Stories
The BPM world is going through some evolution or changes where traditional business process management solutions really have nowhere to go in terms of development of the road map. In this demo at 15th Cloud Expo, Kyle Hansen, Director of Professional Services at AgilePoint, shows AgilePoint’s unique approach to dealing with this market circumstance by developing a rapid application composition or development framework.
SYS-CON Events announced today Isomorphic Software, the global leader in high-end, web-based business applications, will exhibit at SYS-CON's DevOps Summit 2015 New York, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Isomorphic Software is the global leader in high-end, web-based business applications. We develop, market, and support the SmartClient & Smart GWT HTML5/Ajax platform, combining the productivity and performance of traditional desktop software ...

ARMONK, N.Y., Nov. 20, 2014 /PRNewswire/ --  IBM (NYSE: IBM) today announced that it is bringing a greater level of control, security and flexibility to cloud-based application development and delivery with a single-tenant version of Bluemix, IBM's

"BSQUARE is in the business of selling software solutions for smart connected devices. It's obvious that IoT has moved from being a technology to being a fundamental part of business, and in the last 18 months people have said let's figure out how to do it and let's put some focus on it, " explained Dave Wagstaff, VP & Chief Architect, at BSQUARE Corporation, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com...
"Our premise is Docker is not enough. That's not a bad thing - we actually love Docker. At ActiveState all our products are based on open source technology and Docker is an up-and-coming piece of open source technology," explained Bart Copeland, President & CEO of ActiveState Software, in this SYS-CON.tv interview at DevOps Summit at Cloud Expo®, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The Internet of Things is not new. Historically, smart businesses have used its basic concept of leveraging data to drive better decision making and have capitalized on those insights to realize additional revenue opportunities. So, what has changed to make the Internet of Things one of the hottest topics in tech? In his session at @ThingsExpo, Chris Gray, Director, Embedded and Internet of Things, discussed the underlying factors that are driving the economics of intelligent systems. Discover ...
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, p...
The move in recent years to cloud computing services and architectures has added significant pace to the application development and deployment environment. When enterprise IT can spin up large computing instances in just minutes, developers can also design and deploy in small time frames that were unimaginable a few years ago. The consequent move toward lean, agile, and fast development leads to the need for the development and operations sides to work very closely together. Thus, DevOps become...
Verizon Enterprise Solutions is simplifying the cloud-purchasing experience for its clients, with the launch of Verizon Cloud Marketplace, a key foundational component of the company's robust ecosystem of enterprise-class technologies. The online storefront will initially feature pre-built cloud-based services from AppDynamics, Hitachi Data Systems, Juniper Networks, PfSense and Tervela. Available globally to enterprises using Verizon Cloud, Verizon Cloud Marketplace provides a one-stop shop fo...
AppZero has announced that its award-winning application migration software is now fully qualified within the Microsoft Azure Certified program. AppZero has undergone extensive technical evaluation with Microsoft Corp., earning its designation as Microsoft Azure Certified. As a result of AppZero's work with Microsoft, customers are able to easily find, purchase and deploy AppZero from the Azure Marketplace. With just a few clicks, users have an Azure-based solution for moving applications to the...
“In the past year we've seen a lot of stabilization of WebRTC. You can now use it in production with a far greater degree of certainty. A lot of the real developments in the past year have been in things like the data channel, which will enable a whole new type of application," explained Peter Dunkley, Technical Director at Acision, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
SYS-CON Events announced today that IDenticard will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. IDenticard™ is the security division of Brady Corp (NYSE: BRC), a $1.5 billion manufacturer of identification products. We have small-company values with the strength and stability of a major corporation. IDenticard offers local sales, support and service to our customers across the United States and Canada...
SYS-CON Events announced today that AIC, a leading provider of OEM/ODM server and storage solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. AIC is a leading provider of both standard OTS, off-the-shelf, and OEM/ODM server and storage solutions. With expert in-house design capabilities, validation, manufacturing and production, AIC's broad selection of products are highly flexible and are conf...
Leysin American School is an exclusive, private boarding school located in Leysin, Switzerland. Leysin selected an OpenStack-powered, private cloud as a service to manage multiple applications and provide development environments for students across the institution. Seeking to meet rigid data sovereignty and data integrity requirements while offering flexible, on-demand cloud resources to users, Leysin identified OpenStack as the clear choice to round out the school's cloud strategy. Additional...
The cloud is becoming the de-facto way for enterprises to leverage common infrastructure while innovating and one of the biggest obstacles facing public cloud computing is security. In his session at 15th Cloud Expo, Jeff Aliber, a global marketing executive at Verizon, discussed how the best place for web security is in the cloud. Benefits include: Functions as the first layer of defense Easy operation –CNAME change Implement an integrated solution Best architecture for addressing network-l...
“We help people build clusters, in the classical sense of the cluster. We help people put a full stack on top of every single one of those machines. We do the full bare metal install," explained Greg Bruno, Vice President of Engineering and co-founder of StackIQ, in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
DevOps Summit 2015 New York, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that it is now accepting Keynote Proposals. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete...
“DevOps is really about the business. The business is under pressure today, competitively in the marketplace to respond to the expectations of the customer. The business is driving IT and the problem is that IT isn't responding fast enough," explained Mark Levy, Senior Product Marketing Manager at Serena Software, in this SYS-CON.tv interview at DevOps Summit, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Mobile commerce traffic is surpassing desktop, yet less than 20% of sales in the U.S. are mobile commerce sales. In his session at 15th Cloud Expo, Dan Franklin, Segment Manager, Commerce, at Verizon Digital Media Services, defined mobile devices and discussed how next generation means simplification. It means taking your digital content and turning it into instantly gratifying experiences.