Welcome!

IoT User Interface Authors: Elizabeth White, John Basso, Liz McMillan, AppDynamics Blog, Yakov Fain

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.

@CloudExpo Stories
"Avere Systems is a hybrid cloud solution provider. We have customers that want to use cloud storage and we have customers that want to take advantage of cloud compute," explained Rebecca Thompson, VP of Marketing at Avere Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
"We formed Formation several years ago to really address the need for bring complete modernization and software-defined storage to the more classic private cloud marketplace," stated Mark Lewis, Chairman and CEO of Formation Data Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
When it comes to cloud computing, the ability to turn massive amounts of compute cores on and off on demand sounds attractive to IT staff, who need to manage peaks and valleys in user activity. With cloud bursting, the majority of the data can stay on premises while tapping into compute from public cloud providers, reducing risk and minimizing need to move large files. In his session at 18th Cloud Expo, Scott Jeschonek, Director of Product Management at Avere Systems, discussed the IT and busin...
There will be new vendors providing applications, middleware, and connected devices to support the thriving IoT ecosystem. This essentially means that electronic device manufacturers will also be in the software business. Many will be new to building embedded software or robust software. This creates an increased importance on software quality, particularly within the Industrial Internet of Things where business-critical applications are becoming dependent on products controlled by software. Qua...
As organizations shift towards IT-as-a-service models, the need for managing and protecting data residing across physical, virtual, and now cloud environments grows with it. Commvault can ensure protection, access and E-Discovery of your data – whether in a private cloud, a Service Provider delivered public cloud, or a hybrid cloud environment – across the heterogeneous enterprise. In his general session at 18th Cloud Expo, Randy De Meno, Chief Technologist - Windows Products and Microsoft Part...
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...
Large scale deployments present unique planning challenges, system commissioning hurdles between IT and OT and demand careful system hand-off orchestration. In his session at @ThingsExpo, Jeff Smith, Senior Director and a founding member of Incenergy, will discuss some of the key tactics to ensure delivery success based on his experience of the last two years deploying Industrial IoT systems across four continents.
Most organizations prioritize data security only after their data has already been compromised. Proactive prevention is important, but how can you accomplish that on a small budget? Learn how the cloud, combined with a defense and in-depth approach, creates efficiencies by transferring and assigning risk. Security requires a multi-defense approach, and an in-house team may only be able to cherry pick from the essential components. In his session at 19th Cloud Expo, Vlad Friedman, CEO/Founder o...
"We host and fully manage cloud data services, whether we store, the data, move the data, or run analytics on the data," stated Kamal Shannak, Senior Development Manager, Cloud Data Services, IBM, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
CenturyLink has announced that application server solutions from GENBAND are now available as part of CenturyLink’s Networx contracts. The General Services Administration (GSA)’s Networx program includes the largest telecommunications contract vehicles ever awarded by the federal government. CenturyLink recently secured an extension through spring 2020 of its offerings available to federal government agencies via GSA’s Networx Universal and Enterprise contracts. GENBAND’s EXPERiUS™ Application...
With the proliferation of both SQL and NoSQL databases, organizations can now target specific fit-for-purpose database tools for their different application needs regarding scalability, ease of use, ACID support, etc. Platform as a Service offerings make this even easier now, enabling developers to roll out their own database infrastructure in minutes with minimal management overhead. However, this same amount of flexibility also comes with the challenges of picking the right tool, on the right ...
"We view the cloud not really as a specific technology but as a way of doing business and that way of doing business is transforming the way software, infrastructure and services are being delivered to business," explained Matthew Rosen, CEO and Director at Fusion, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develo...
DevOps at Cloud Expo – being held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA – announces that its Call for Papers is open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the world's largest enterprises – and delivering real results. Am...
SYS-CON Events announced today that MangoApps will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. MangoApps provides modern company intranets and team collaboration software, allowing workers to stay connected and productive from anywhere in the world and from any device.
“We're a global managed hosting provider. Our core customer set is a U.S.-based customer that is looking to go global,” explained Adam Rogers, Managing Director at ANEXIA, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
"This week we're really focusing on scalability, asset preservation and how do you back up to the cloud and in the cloud with object storage, which is really a new way of attacking dealing with your file, your blocked data, where you put it and how you access it," stated Jeff Greenwald, Senior Director of Market Development at HGST, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices 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 opportuni...
In today's uber-connected, consumer-centric, cloud-enabled, insights-driven, multi-device, global world, the focus of solutions has shifted from the product that is sold to the person who is buying the product or service. Enterprises have rebranded their business around the consumers of their products. The buyer is the person and the focus is not on the offering. The person is connected through multiple devices, wearables, at home, on the road, and in multiple locations, sometimes simultaneously...
Keeping pace with advancements in software delivery processes and tooling is taxing even for the most proficient organizations. Point tools, platforms, open source and the increasing adoption of private and public cloud services requires strong engineering rigor – all in the face of developer demands to use the tools of choice. As Agile has settled in as a mainstream practice, now DevOps has emerged as the next wave to improve software delivery speed and output. To make DevOps work, organization...