|By Marten Terpstra||
|May 16, 2014 12:45 PM EDT||
IP Multicast is one of those technologies that most everyone loves to hate. It’s almost the perfect example of how complicated we have made networking. Getting IP Multicast to run depends on several protocols that are all somewhat intertwined or dependent on each, their relationship sometimes explicit, sometimes implicit.
Even trying to describe the basic operation is complicated.
When an application or service provides information using IP multicast, it simply starts sending it onto a specific multicast group. The multicast router for the subnet of the sender sees the incoming multicast packet and will initially have no forwarding information for that stream in its forwarding hardware. The packet is passed onto the CPU of that router, which will encapsulate this packet and send it towards a special multicast router designated the Rendez-vous Point (RP). When the RP has installed the multicast routes for this group, it will tell the multicast router on the sender’s segment to stop sending. When it does, this router installs its own multicast routes for the source tree (the tree specific to this sender) and the shared tree (the one towards the RP) without any outgoing interfaces, and the traffic is dropped at this first router. But, the network (well at least the part between the sender and the RP) is now aware of this multicast stream. And who is sending.
Now when we want to join this IP Multicast group, the first action is send an IGMP join out on the subnet you are attached to. The IP Multicast router that serves this subnet sees the join and determines where RP can be found. It takes the client join, and sends it towards the RP, using the unicast routing table as its guide. Every multicast router along the way registers that there is a listener on the interface this join came in on and passes it along towards the IP. All along this path, the unicast routing entry for the RP is used to create the tree towards the listener.
Once received by the RP, the shared tree and the source tree towards the sender have been joined. We have an end to end path between sender and receiver, with the RP in the middle of it all. All that is left is to send a join from the RP towards the router on the sender’s subnet to essentially tell it to start passing the actual multicast along the path towards the RP (the source tree), where the RP will then push it out onto the shared tree towards the destination. Voila, it’s as simple as that.
But wait, we are not done. Once the packets start to flow from source to destination, the multicast router closest to the destination will send another join message for this group, but this time towards the sender. It is only now that it can do this because those first few data packets actually indicate who the sender is. That join is passed router to router to router towards the router on the sender’s subnet, and once arrived, that router will now also start sending the multicast data along that path towards the receiver. The receiving subnet router sees that stream appearing and will now send a prune message onto the shared tree towards the RP, indicating it no longer needs the multicast stream through the RP.
If you are not familiar with IP Multicast and after reading the above are not confused, congratulations, your brain is very well wired for complex networking.
If you step away from how IGMP and PIM implement this today as above, the most fundamental of IP multicast topologies is that you need to build a forwarding tree that is rooted in the source, with the destinations as its leaves. At each intermediate node in the tree, the packets are replicated to its branches, therefore creating the least amount of duplication. And by using a tree, it is loop free, packets won’t swirl around the network bringing it to its knees.
The challenging part though is that the tree is based on the unicast forwarding topology. From a leaf on this tree towards the sender, each step is identical to how a unicast IP packet would be forwarded. The forwarding topologies are connected and dependent on each other. IP Multicast is built on top of a unicast routed infrastructure, and unicast routing changes can have dramatic impacts to the multicast forwarding topologies.
I mentioned here before that I once spent a wonderful 2 weeks in Delhi working on a network where surveillance cameras created an aggregate 8Gbit/sec worth of multicast data, with a requirement that any unicast change would have limited impact to these streams. Believe me, it is extremely hard to engineer and tune, and we had the luxury of hijacking a really large network night after night to simulate failures.
SDN based architectures have the opportunity to change all this. Multicast forwarding was designed the way it was designed to work on arbitrary network topologies, with random senders and receivers coming and going. It builds trees on the fly and on demand. For many networks, topologies are not arbitrary, and those applications that consume/produce lots of multicast do not have randomly placed senders and receivers that come and go as they please. Many of them are well known or placed in fairly static and fixed topologies.
A controller with a global view of the network can create multicast topologies ahead of time. It knows all possible replication points and can create distribution trees among them. It can create different distribution trees for different multicast groups. It can create them independent of the unicast forwarding. It can calculate backup topologies in case portions of the tree fail. And it can do all of that guaranteeing there are no loops and optimal replication. When applications indicate their participation in specific multicast streams as senders or listeners to this controller, it can optimize very specifically based on those participants. The possibilities are endless.
We had a customer visit us yesterday that has very significant multicast needs and we walked him through some of these possibilities. He left with a huge smile on his face. And that smile on his face was not because he really liked what we built (even though he did), but it was because we showed him that if you remove legacy network thinking and constraints, networking can yet again be extremely exciting and creates solutions that he did not think were possible, in a fairly simple and straightforward way. And that, in turn, is truly exciting to us.
Samsung VP Jacopo Lenzi, who headed the company's recent SmartThings acquisition under the auspices of Samsung's Open Innovaction Center (OIC), answered a few questions we had about the deal. This interview was in conjunction with our interview with SmartThings CEO Alex Hawkinson. IoT Journal: SmartThings was developed in an open, standards-agnostic platform, and will now be part of Samsung's Open Innovation Center. Can you elaborate on your commitment to keep the platform open? Jacopo Lenzi: S...
Oct. 26, 2014 01:00 AM EDT Reads: 2,699
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, moderated by Ashar Baig, Research ...
Oct. 25, 2014 11:45 AM EDT Reads: 1,851
In her General Session at 15th Cloud Expo, Anne Plese, Senior Consultant, Cloud Product Marketing, at Verizon Enterprise, will focus on finding the right mix of renting vs. buying Oracle capacity to scale to meet business demands, and offer validated Oracle database TCO models for Oracle development and testing environments. Anne Plese is a marketing and technology enthusiast/realist with over 19+ years in high tech. At Verizon Enterprise, she focuses on driving growth for the Verizon Cloud pla...
Oct. 25, 2014 10:00 AM EDT Reads: 1,727
StackIQ offers a comprehensive software suite that automates the deployment, provisioning, and management of Big Infrastructure. With StackIQ’s software, you can spin up fully configured big data clusters, quickly and consistently — from bare-metal up to the applications layer — and manage them efficiently. Our software’s modular architecture allows customers to integrate nearly any application with the StackIQ software stack.
Oct. 25, 2014 10:00 AM EDT Reads: 1,789
As Platform as a Service (PaaS) matures as a category, developers should have the ability to use the programming language of their choice to build applications and have access to a wide array of services. Bluemix is IBM's open cloud development platform that enables users to easily build cloud-based, creative mobile and web applications without having to spend large amounts of time and resources on configuring infrastructure and multiple software licenses. In this track, you will learn about the...
Oct. 25, 2014 08:00 AM EDT Reads: 1,795
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at Internet of @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, will discuss how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money! Speaker Bio: ...
Oct. 24, 2014 09:30 PM EDT Reads: 1,444
Compute virtualization has been transformational, yet security policy implementation and enforcement has lagged behind in agility and automation. There are a number of key considerations when implementing policy in private and hybrid clouds. In his session at 15th Cloud Expo, Holland Barry, VP of Technology at Catbird, will discuss the impact of this new paradigm and what organizations can do today to safely move to software-defined network and compute architectures, including: How normal ope...
Oct. 24, 2014 07:00 PM EDT Reads: 1,548
How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic • Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff hap...
Oct. 23, 2014 07:45 PM EDT Reads: 1,728
SYS-CON Events announced today that SOA Software, an API management leader, 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. SOA Software is a leading provider of API Management and SOA Governance products that equip business to deliver APIs and SOA together to drive their company to meet its business strategy quickly and effectively. SOA Software’s technology helps businesses to accel...
Oct. 23, 2014 06:15 PM EDT Reads: 1,753
SYS-CON Events announced today that Utimaco 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. Utimaco is a leading manufacturer of hardware based security solutions that provide the root of trust to keep cryptographic keys safe, secure critical digital infrastructures and protect high value data assets. Only Utimaco delivers a general-purpose hardware security module (HSM) as a customiz...
Oct. 23, 2014 05:45 PM EDT Reads: 1,654
Almost everyone sees the potential of Internet of Things but how can businesses truly unlock that potential. The key will be in the ability to discover business insight in the midst of an ocean of Big Data generated from billions of embedded devices via Systems of Discover. Businesses will also need to ensure that they can sustain that insight by leveraging the cloud for global reach, scale and elasticity.
Oct. 22, 2014 09:00 PM EDT Reads: 1,585
SYS-CON Events announced today that ElasticBox is holding a Hackathon at DevOps Summit, November 6 from 12 pm -4 pm at the Santa Clara Convention Center in Santa Clara, CA. You can enter as an individual or team of up to 10 developers. A New Star Is Born Every Month! All completed ElasticBoxes will then be sent to a judging panel - 12 winners will be featured on the ElasticBox website in 2015. All entrants will receive five full enterprise licenses for one year + ElasticBox headphones + Elasti...
Oct. 22, 2014 01:00 PM EDT Reads: 1,601
Once the decision has been made to move part or all of a workload to the cloud, a methodology for selecting that workload needs to be established. How do you move to the cloud? What does the discovery, assessment and planning look like? What workloads make sense? Which cloud model makes sense for each workload? What are the considerations for how to select the right cloud model? And how does that fit in with the overall IT tranformation? In his session at 15th Cloud Expo, John Hatem, head of V...
Oct. 22, 2014 12:00 PM EDT Reads: 1,599
Cloud services are the newest tool in the arsenal of IT products in the market today. These cloud services integrate process and tools. In order to use these products effectively, organizations must have a good understanding of themselves and their business requirements. In his session at 15th Cloud Expo, Brian Lewis, Principal Architect at Verizon Cloud, will outline key areas of organizational focus, and how to formalize an actionable plan when migrating applications and internal services to...
Oct. 22, 2014 11:45 AM EDT Reads: 1,645
SAP is delivering break-through innovation combined with fantastic user experience powered by the market-leading in-memory technology, SAP HANA. In his General Session at 15th Cloud Expo, Thorsten Leiduck, VP ISVs & Digital Commerce, SAP, will discuss how SAP and partners provide cloud and hybrid cloud solutions as well as real-time Big Data offerings that help companies of all sizes and industries run better. SAP launched an application challenge to award the most innovative SAP HANA and SAP ...
Oct. 22, 2014 07:00 AM EDT Reads: 1,755
Ixia develops amazing products so its customers can connect the world. Ixia helps its customers provide an always-on user experience through fast, secure delivery of dynamic connected technologies and services. Through actionable insights that accelerate and secure application and service delivery, Ixia's customers benefit from faster time to market, optimized application performance and higher-quality deployments.
Oct. 21, 2014 09:00 PM EDT Reads: 1,569
SYS-CON Events announced today that Calm.io has been named “Bronze Sponsor” of DevOps Summit Silicon Valley, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Calm.io is a cloud orchestration platform for AWS, vCenter, OpenStack, or bare metal, that runs your CL tools puppet, Chef, shell, git, Jenkins, nagios, and will soon support New Relic and Docker. It can run hosted, or on premise and provides VM automation / expiry, self-service portals,...
Oct. 21, 2014 08:45 PM EDT Reads: 1,534
SYS-CON Events announced today that Aria Systems, the recurring revenue expert, 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. Aria Systems helps leading businesses connect their customers with the products and services they love. Industry leaders like Pitney Bowes, Experian, AAA NCNU, VMware, HootSuite and many others choose Aria to power their recurring revenue bu...
Oct. 21, 2014 06:00 PM EDT Reads: 1,629
The Internet of Things (IoT) is going to require a new way of thinking and of developing software for speed, security and innovation. This requires IT leaders to balance business as usual while anticipating for the next market and technology trends. Cloud provides the right IT asset portfolio to help today’s IT leaders manage the old and prepare for the new. Today the cloud conversation is evolving from private and public to hybrid. This session will provide use cases and insights to reinforce t...
Oct. 21, 2014 05:15 PM EDT Reads: 1,727
Blue Box has closed a $10 million Series B financing. The round was led by a strategic investor and included participation from prior investors including Voyager Capital and Founders Collective, as well as the Blue Box executive team. This round follows a $4.3 million Series A closed in December of 2012 and led by Voyager Capital. In May of this year, the company announced general availability of its private cloud as a service offering, Blue Box Cloud. Since that release, the company has dem...
Oct. 21, 2014 01:45 PM EDT Reads: 1,668