Welcome!

AJAX & REA Authors: Rajesh Lain, Sebastian Kruk, RealWire News Distribution, Harald Zeitlhofer

Blog Feed Post

MLAG: An Example of Complexity that should not be

In Monday’s blog post, Derick explained the network engineering cycle, traversal in the referential space and the need to provide solutions that enable the network engineer to do his or her job better, more accurate, easier, simpler, more complete. We cannot automate or encapsulate a network engineer’s job and we should not try. We must however encapsulate and automate specific tasks and workflows.

Multichassis Link Aggregation (MLAG) is one of those features that should be so straightforward, but isn’t. MLAG allows a single device to be connected to 2 ethernet switches using a single Link Aggregation Group (LAG). The device is configured with a single LAG with ports that are connected to two switches, rather than a single switch. The two switches coordinate between each other and make it appear to the device as if they are single device.

This part is actually straightforward, it really comes down to using a single LACP system-id across both links from both switches. The end device is blind to the fact there are different switches at the end of each link.

MLAG is Complicated

The hardest part of MLAG is the packet forwarding coordination and behavior between the two switches. For instance, if the end device sends a broadcast packet onto one of the links of the LAG towards switch 1 of the MLAG, the solution must ensure that switch 2 does not send that same broadcast packet back to the end device. Because the two switches together create a LAG, the basic rule that a packet received on a LAG can never be send back out that same LAG must be observed. Sounds simple, but if that broadcast packet gets to switch 2, how does it know it came from the device at the other end of the LAG to begin with? Sounds trivial, just look at the source MAC address, but ethernet forwarding usually does not do anything with a source MAC address.

If a broadcast packet comes in the rest of the network and arrives at switch 1 and 2, who will forward this packet? Only one of them can, again to avoid duplication of packets. Similarly for multicast. In multicast rich environments, would you always pick the same switch to forward this onto the LAG, or would you share that responsibility. And if you share, how do you inform the rest of the network that it is this switch for this specific group that is responsible for distribution?

When one of then links in the LAG fails, what does that switch do with packets towards the end device? How does it get that packet to its MLAG peer so that it is delivered? If you have configured MLAG on any popular platform out there, you have now discovered the reason for the private interconnect between two MLAG peers.

They’re all the same, but different

Whether you call it MLAG, SMLT, VSS, vPC, vLAG or anything else, they all implement the same concept. And there is no question that MLAG is a rather complicated feature to implement and get all the data forwarding possibilities right. There are many failure scenarios to consider to ensure that traffic is not lost, looped, or duplicated.

There is however no reason to expose any of this complexity to you as the user. Why do I have to create a port group between two switches, then explain to each that they are MLAG peers on a special VLAN, then stick IP addresses on this VLAN, create an MLAG peering session, verify it is up and running, then create actual MLAG ports that are mapped to some unique identifier I need to track that needs to match up with the one used on the peer? I counted 24 individual configuration steps just to get the MLAG peering configured.

Why so Complicated?

This is a perfect example of exposing the gory details of the scaffolding required for something that as a user really should be as simple as “I want this port on this and that port on that switch to be part of the same LAG”. Because really that is what you want. Sure, for debugging purposes you may need to understand what is communicated between switches and who has taken responsibility for what, but why did you the user have to manually create all this plumbing between the two systems? That should be encapsulated by us, the vendor, so that you can focus on automating the actual provisioning of ports in an MLAG.

And I completely understand the implementation reasons for having 2 switches matched up to become MLAG peers and MLAGs can only exist between those two peers. But it’s one of those limitations imposed on you that should not be, there is absolutely no reason you could not have 3 MLAG peers. Or 4. Or any combination of 2 switches, different for each MLAG. For us there is no difference between a LAG and an MLAG. That is, there most certainly is a difference, but as far as provisioning one goes, they are identical. You simply configure a LAG. And you have a choice to add ports from other switches to that LAG. And that’s it. All that took was a desire to remove these constraints to make your job easier and more accurate.

Focusing on the user experience of the network takes time, it takes determination, it requires a completely different view on delivering capabilities. Read Derick’s blog post from this past Monday and you will get a sense of our beliefs and approach.

 

[Today's fun fact: Sauerkraut is also a member of the cabbage family and should not be considered an insult (ref: yesterday's fun fact). It is fat free, low in calories, provides about a third of daily needs of vitamin C in a single cup and contains iron, calcium, potassium, thiamin, riboflavin, niacin and 8 grams of fiber. Americans consume 387 million pounds a year, that is more per capita than Germany. And it was first created in the Alsace in France, not Germany.]

The post MLAG: An Example of Complexity that should not be 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.

Cloud Expo Latest Stories
With the explosion of the cloud, more businesses are transitioning to a recurring revenue model to generate reliable sales, grow profits, and open new markets. This opportunity requires businesses to get to market quickly with the pricing and packaging options customers want. In addition, you will want to take advantage of the ensuing tidal wave of data to more effectively upsell, cross-sell and manage your customers. All of this is possible, but only with the right approach. At 15th Cloud Expo, Brendan O'Brien, Co-founder at Aria Systems and the inventor of cloud billing panelists, will lead a panel discussion on what it takes to launch and manage a successful recurring revenue business. The panelists will offer their insights about what each department will need to consider, from financial management to line of business and IT. The panelists will also offer examples from their success in recurring revenue with companies such as Audi, Constant Contact, Experian, Pitney-Bowes, Teleko...
Planning scalable environments isn't terribly difficult, but it does require a change of perspective. In his session at 15th Cloud Expo, Phil Jackson, Development Community Advocate for SoftLayer, will broaden your views to think on an Internet scale by dissecting a video publishing application built with The SoftLayer Platform, Message Queuing, Object Storage, and Drupal. By examining a scalable modular application build that can handle unpredictable traffic, attendees will able to grow your development arsenal and pick up a few strategies to apply to your own projects.
Come learn about what you need to consider when moving your data to the cloud. In her session at 15th Cloud Expo, Skyla Loomis, a Program Director of Cloudant Development at Cloudant, will discuss the security, performance, and operational implications of keeping your data on premise, moving it to the cloud, or taking a hybrid approach. She will use real customer examples to illustrate the tradeoffs, key decision points, and how to be successful with a cloud or hybrid cloud solution.
The cloud provides an easy onramp to building and deploying Big Data solutions. Transitioning from initial deployment to large-scale, highly performant operations may not be as easy. In his session at 15th Cloud Expo, Harold Hannon, Sr. Software Architect at SoftLayer, will discuss the benefits, weaknesses, and performance characteristics of public and bare metal cloud deployments that can help you make the right decisions.
Over the last few years the healthcare ecosystem has revolved around innovations in Electronic Health Record (HER) based systems. This evolution has helped us achieve much desired interoperability. Now the focus is shifting to other equally important aspects – scalability and performance. While applying cloud computing environments to the EHR systems, a special consideration needs to be given to the cloud enablement of Veterans Health Information Systems and Technology Architecture (VistA), i.e., the largest single medical system in the United States.
Cloud and Big Data present unique dilemmas: embracing the benefits of these new technologies while maintaining the security of your organization’s assets. When an outside party owns, controls and manages your infrastructure and computational resources, how can you be assured that sensitive data remains private and secure? How do you best protect data in mixed use cloud and big data infrastructure sets? Can you still satisfy the full range of reporting, compliance and regulatory requirements? In his session at 15th Cloud Expo, Derek Tumulak, Vice President of Product Management at Vormetric, will discuss how to address data security in cloud and Big Data environments so that your organization isn’t next week’s data breach headline.
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using the URL as a basic building block, we open this up and get the same resilience that the web enjoys.
Is your organization struggling to deal with skyrocketing volumes of digital assets? The amount of data is growing exponentially and organizations are having a hard time managing this growth. In his session at 15th Cloud Expo, Amar Kapadia, Senior Director of Open Cloud Strategy at Seagate, will walk through the essential considerations when developing a cloud storage strategy. In this discussion, you will understand the challenges IT is facing, why companies need to move to cloud, and how the right cloud model can help your business economically overcome the data struggle.
If cloud computing benefits are so clear, why have so few enterprises migrated their mission-critical apps? The answer is often inertia and FUD. No one ever got fired for not moving to the cloud – not yet. In his session at 15th Cloud Expo, Michael Hoch, SVP, Cloud Advisory Service at Virtustream, will discuss the six key steps to justify and execute your MCA cloud migration.
The 16th International Cloud Expo announces that its Call for Papers is now open. 16th International Cloud Expo, to be held June 9–11, 2015, at the Javits Center in New York City brings together Cloud Computing, APM, APIs, Security, Big Data, Internet of Things, DevOps and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal today!
Most of today’s hardware manufacturers are building servers with at least one SATA Port, but not every systems engineer utilizes them. This is considered a loss in the game of maximizing potential storage space in a fixed unit. The SATADOM Series was created by Innodisk as a high-performance, small form factor boot drive with low power consumption to be plugged into the unused SATA port on your server board as an alternative to hard drive or USB boot-up. Built for 1U systems, this powerful device is smaller than a one dollar coin, and frees up otherwise dead space on your motherboard. To meet the requirements of tomorrow’s cloud hardware, Innodisk invested internal R&D resources to develop our SATA III series of products. The SATA III SATADOM boasts 500/180MBs R/W Speeds respectively, or double R/W Speed of SATA II products.
In today's application economy, enterprise organizations realize that it's their applications that are the heart and soul of their business. If their application users have a bad experience, their revenue and reputation are at stake. In his session at 15th Cloud Expo, Anand Akela, Senior Director of Product Marketing for Application Performance Management at CA Technologies, will discuss how a user-centric Application Performance Management solution can help inspire your users with every application transaction.
SYS-CON Events announced today that Gridstore™, the leader in software-defined storage (SDS) purpose-built for Windows Servers and Hyper-V, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Gridstore™ is the leader in software-defined storage purpose built for virtualization that is designed to accelerate applications in virtualized environments. Using its patented Server-Side Virtual Controller™ Technology (SVCT) to eliminate the I/O blender effect and accelerate applications Gridstore delivers vmOptimized™ Storage that self-optimizes to each application or VM across both virtual and physical environments. Leveraging a grid architecture, Gridstore delivers the first end-to-end storage QoS to ensure the most important App or VM performance is never compromised. The storage grid, that uses Gridstore’s performance optimized nodes or capacity optimized nodes, starts with as few a...
SYS-CON Events announced today that Cloudian, Inc., the leading provider of hybrid cloud storage solutions, has been named “Bronze Sponsor” of SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Cloudian is a Foster City, Calif.-based software company specializing in cloud storage. Cloudian HyperStore® is an S3-compatible cloud object storage platform that enables service providers and enterprises to build reliable, affordable and scalable hybrid cloud storage solutions. Cloudian actively partners with leading cloud computing environments including Amazon Web Services, Citrix Cloud Platform, Apache CloudStack, OpenStack and the vast ecosystem of S3 compatible tools and applications. Cloudian's customers include Vodafone, Nextel, NTT, Nifty, and LunaCloud. The company has additional offices in China and Japan.
SYS-CON Events announced today that TechXtend (formerly Programmer’s Paradise), a leading value-added provider of server and storage virtualization, and r-evolution will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. TechXtend (formerly Programmer’s Paradise) is a leading value-added provider of software, systems and solutions for corporations, government organizations, and academic institutions across the United States and Canada. TechXtend is the Exclusive Reseller in the United States for r-evolution