|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.
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 how hardware commoditization, the ubiquitous nature of connectivity, and the emergence of Big Data a...
May. 4, 2015 10:00 AM EDT Reads: 5,434
SYS-CON Events announced today the IoT Bootcamp – Jumpstart Your IoT Strategy, being held June 9–10, 2015, in conjunction with 16th Cloud Expo and Internet of @ThingsExpo at the Javits Center in New York City. This is your chance to jumpstart your IoT strategy. Combined with real-world scenarios and use cases, the IoT Bootcamp is not just based on presentations but includes hands-on demos and walkthroughs. We will introduce you to a variety of Do-It-Yourself IoT platforms including Arduino, Raspberry Pi, BeagleBone, Spark and Intel Edison. You will also get an overview of cloud technologies s...
May. 4, 2015 10:00 AM EDT Reads: 3,837
SYS-CON Media announced today that @WebRTCSummit Blog, the largest WebRTC resource in the world, has been launched. @WebRTCSummit Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @WebRTCSummit Blog can be bookmarked ▸ Here @WebRTCSummit conference site can be bookmarked ▸ Here
May. 4, 2015 09:45 AM EDT Reads: 3,298
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.
May. 4, 2015 09:45 AM EDT Reads: 5,756
Avnet, Inc. has announced that it ranked No. 4 on the InformationWeek Elite 100 – a list of the top business technology innovators in the U.S. Avnet was recognized for the development of an innovative cloud-based training system that serves as the foundation for Avnet Academy – the company’s education and training organization focused on technical training around top IT vendor technologies. The development of this system allowed Avnet to quickly expand its IT-related training capabilities around the world, while creating a new service that Avnet and its IT solution providers can offer to their...
May. 4, 2015 09:19 AM EDT Reads: 201
The WebRTC Summit 2015 New York, to be held June 9-11, 2015, at the Javits Center in New York, NY, announces that its Call for Papers is open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 16th International Cloud Expo, @ThingsExpo, Big Data Expo, and DevOps Summit.
May. 4, 2015 09:15 AM EDT Reads: 3,082
Chuck Piluso will present a study of cloud adoption trends and the power and flexibility of IBM Power and Pureflex cloud solutions. Speaker Bio: Prior to Data Storage Corporation (DSC), Mr. Piluso founded North American Telecommunication Corporation, a facilities-based Competitive Local Exchange Carrier licensed by the Public Service Commission in 10 states, serving as the company's chairman and president from 1997 to 2000. Between 1990 and 1997, Mr. Piluso served as chairman & founder of International Telecommunications Corporation, a facilities-based international carrier licensed by t...
May. 4, 2015 09:00 AM EDT Reads: 755
There are lots of challenges in IoT around secure, scalable and business friendly infrastructure for enterprises. For large corporations, IoT implementations are one of the top priorities of the decade. All industries are seeing a competitive need to sustain by investing in IoT initiatives. The value addition comes from improved customer service, innovative product and additional revenue streams. The data from these IP-connected devices can be leveraged for a variety of business applications as well as responsive action controls. The various architectural building blocks of an IoT ...
May. 4, 2015 09:00 AM EDT Reads: 1,096
Recent technology advances in miniaturization has positioned the wearables as the pinnacle of technology convergence with the human body. We inquire if wearables are mere standard miniaturized devices extended with the connectivity and present our views on considerations like design, applications, performance, efficiency, interoperability, usage scenarios, human device interaction and consequent trade-offs enabling wearables to impart optimal value.
May. 4, 2015 08:00 AM EDT Reads: 1,714
In this session we look at creating interactive communications via the web by adding messaging, file transfer, and group communication (group chat and audio/video conferencing) into the web experience. We will also discuss potential applications of this technology in areas including B2B, B2C, P2P, and gaming. Peter is Technical Director at Acision. He graduated from The University of Edinburgh in 2000 with a BSc (Hons) in Computer Science. After graduation Peter worked on a PSTN switch developing signalling stacks for SS7, ISDN and similar protocols and creating advanced routing and serv...
May. 4, 2015 08:00 AM EDT Reads: 1,837
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 configurable to any form factor or custom configuration. AIC leads the industry with nearly 20 years of ...
May. 4, 2015 03:45 AM EDT Reads: 5,760
SYS-CON Events announced today that Vicom Computer Services, Inc., a provider of technology and service 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. They are located at booth #427. Vicom Computer Services, Inc. is a progressive leader in the technology industry for over 30 years. Headquartered in the NY Metropolitan area. Vicom provides products and services based on today’s requirements around Unified Networks, Cloud Computing strategies, Virtualization around Software defined Data Ce...
May. 4, 2015 02:00 AM EDT Reads: 2,432
Enterprise IoT is an exciting and chaotic space with a lot of potential to transform how the enterprise resources are managed. In his session at @ThingsExpo, Hari Srinivasan, Sr Product Manager at Cisco, will describe the challenges in enabling mass adoption of IoT, and share perspectives and insights on architectures/standards/protocols that are necessary to build a healthy ecosystem and lay the foundation to for a wide variety of exciting IoT use cases in the years to come.
May. 3, 2015 03:00 PM EDT Reads: 1,151
SYS-CON Events announced today that B2Cloud, a provider of enterprise resource planning software, 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. B2cloud develops the software you need. They have the ideal tools to help you work with your clients. B2Cloud’s main solutions include AGIS – ERP, CLOHC, AGIS – Invoice, and IZUM
May. 3, 2015 12:00 PM EDT Reads: 4,370
Containers and microservices have become topics of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 16th Cloud Expo at the Javits Center in New York June 9-11 will find fresh new content in a new track called PaaS | Containers & Microservices Containers are not being considered for the first time by the cloud community, but a current era of re-consideration has pushed them to the top of the cloud agenda. With the launch of Docker's initial release in March of 2013, interest was revved up several notches. Then late last...
May. 3, 2015 12:00 PM EDT Reads: 3,756
There is no doubt that Big Data is here and getting bigger every day. Building a Big Data infrastructure today is no easy task. There are an enormous number of choices for database engines and technologies. To make things even more challenging, requirements are getting more sophisticated, and the standard paradigm of supporting historical analytics queries is often just one facet of what is needed. As Big Data growth continues, organizations are demanding real-time access to data, allowing immediate and actionable interpretation of events as they happen. Another aspect concerns how to deliver ...
May. 3, 2015 11:00 AM EDT Reads: 5,625
SYS-CON Events announced today that MangoApps 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., and the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. MangoApps provides private all-in-one social intranets allowing workers to securely collaborate from anywhere in the world and from any device. Social, mobile, and easy to use. MangoApps has been named a "Market Leader" by Ovum Research and a "Cool Vendor" by Gartner...
May. 3, 2015 11:00 AM EDT Reads: 4,303
The world's leading Cloud event, Cloud Expo has launched Microservices Journal on the SYS-CON.com portal, featuring over 19,000 original articles, news stories, features, and blog entries. DevOps Journal is focused on this critical enterprise IT topic in the world of cloud computing. Microservices Journal offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. Follow new article posts on Twitter at @MicroservicesE
May. 3, 2015 11:00 AM EDT Reads: 2,817
WebRTC defines no default signaling protocol, causing fragmentation between WebRTC silos. SIP and XMPP provide possibilities, but come with considerable complexity and are not designed for use in a web environment. In his session at @ThingsExpo, Matthew Hodgson, technical co-founder of the Matrix.org, discussed how Matrix is a new non-profit Open Source Project that defines both a new HTTP-based standard for VoIP & IM signaling and provides reference implementations.
May. 3, 2015 10:45 AM EDT Reads: 4,213
The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, and physical persons. In the IoT vision, every new "thing" - sensor, actuator, data source, data con...
May. 3, 2015 10:30 AM EDT Reads: 5,243