The Next Internet? Inside PARC’s Vision of Content Centric Networking
The Internet may be hurtling toward collapse under the strain of too much traffic. But PARC research fellow Van Jacobson thinks he knows how to fix it.
He’s done it before. Back in the mid-1980s, when the Internet was seeing its first modest surge in usage, Jacobson noticed that data packets were piling up on the message routers of the day, like cars waiting for cross-traffic to clear before entering an intersection. Working with fellow Berkeley computer science instructor Mike Karels, he came up with a small change to the Transmission Control Protocol (TCP) that, in essence, allowed packets to ease into the intersections gradually, curing the congestion. Later, Jacobson also came up with a way to compress the “headers” or address sections of Internet Protocol (IP) packets from 40 bytes down to about 3 or 4 bytes, which made a big difference at a time when so many packets were still squeezing through narrow telephone lines.
But the challenges the Internet is facing today are very different, and call for a much broader solution, Jacobson believes. He argues that the global computing network was never designed to carry exabytes of video, voice, and image data to consumers’ homes and mobile devices, as it’s now doing, and that it will never be possible to increase wireless or land-line bandwidth fast enough to keep up with demand. In fact, he thinks the Internet has outgrown its original underpinnings as a network built on physical addresses, and that it’s time to put aside TCP/IP and start over with a completely novel approach to naming, storing, and moving data.
Jacobson’s alternative is called Content Centric Networking, or CCN, and it’s grown into the single biggest internal project at PARC, the Xerox-owned research center that’s famous as the birthplace of graphical computing, laser printing, and the Ethernet standard. If the ideas behind CCN were broadly adopted, PARC researchers believe, it would speed the delivery of content and vastly reduce the load on the networking equipment at the Internet’s core.
It would also pose a challenge to the model of utility-style storage and processing that’s come to be known as cloud computing. And that might undermine many current business models in the software and digital content industries—while at the same time creating new ones. In other words, it’s just the kind of revolutionary idea that has remade Silicon Valley at least four times since the 1960s. And this time, PARC doesn’t want to miss out on the rewards.
“When there is widespread adoption of CCN there will be lots of opportunities to build valuable businesses on top of it that are really impossible to foresee today,” says Teresa Lunt, vice president of PARC’s Computing Science Laboratory. “The main reason we’re investing is because we’re in love with the technology, and we want CCN to make it out into the world…[but] we know that PARC will be able to participate in the upside as well.”
Replacing “Where Is It?” with “Who Wants It?”
To understand why Content Centric Networking is so different, you have to start by looking at today’s Internet, which was designed back in the days when there were only a handful of machines that needed to talk to each other, and the network was used mainly for short bursts of point-to-point communication. In this established scheme, every piece of content has a name, but to find it you have to know in advance where it’s stored—which means the whole system is built around host identifiers and file hierarchies like www.xconomy.com/san-francisco/2012/08/07/the-next-internet/. (The first part of that URL gets translated into the IP address 220.127.116.11, which leads to the server at St. Louis, MO-based Contegix where Xconomy’s content database is hosted. The rest refers to the sub-sub-sub-folder on that server where WordPress, our content management system, stored this page.)
The fundamental idea behind Content Centric Networking is that to retrieve a piece of data, you should only have to care about what you want, not where it’s stored. Rather than transmitting a request for a specific file on a specific server, a CCN-based browser or device would simply broadcast its interest in that file, and the nearest machine with an authentic copy would respond. File names in a CCN world look superficially similar to URLs (for example, /parc.com/van/can/417.vcf/v3/s0/Ox3fdc96a4…) but the data in a name is used to establish the file’s authenticity and provenance, not to indicate location.
It’s easy to see how much sense this makes compared to the current client-server model. Say I’m using my Apple TV box to browse my Flickr photo collection on my big-screen TV. To get each photo, the Apple TV has to connect to Flickr, which is hosted on some remote data center owned by Yahoo—it could be in Utah or North Carolina, for all I know. The request has to travel from the Apple TV over my Wi-Fi network, into Comcast’s servers, then across the Internet core, and finally to Yahoo. Then the photos, which amount to several megabytes each, have to travel all the way back through the network to my TV.
But the photos on Flickr are just copies of the originals, which are stored on my camera and on my laptop, about 15 feet away from my TV. It would be much smarter and more economical if the Apple TV could simply ask for each photo by name—that is, if it could broadcast its interest in the photo to the network. My laptop could respond, and I could keep browsing without the requests or the data ever leaving my apartment. (In Jacobson’s scheme, file names can include encrypted sections that bar users without the proper keys from retrieving them, meaning that security and rights management are built into the address system from the start.)
“The simplest explanation is that you replace the concept of the IP address as the defining entity in the network with the name of the content,” says Lunt. “Now all the talk in the network is about ‘Have you seen this content?’ and ‘Who needs this content?’ as opposed to ‘What is the routing path to particular terminus in the network?’ It’s a simple idea, but it makes a lot of things possible.”
For example, now that memory is so much cheaper than when the Internet was first built, it’s becoming more economical to cache popular content at many places throughout the network. This minimizes the distance content has to travel to reach end users, and hence the amount of bandwidth consumed. Lunt uses a real-world analogy. “It used to be that if you had a store and you needed a product, you called up the factory for delivery and they sent a truck,” she explains. “That model works for a small business in one town, but it doesn’t scale up to a nationwide or global network. So people have built warehouses where you can cache a lot of stuff, and then people order from the nearest warehouse. You can have a very efficient system without having to go back to the factory for each order.”
Similarly, in a content-centric network, if you want to watch a video, you don’t have to go all the way back to the source, Lunt says. “I only have to go as far as the nearest router that has cached the content, which might be somebody in the neighborhood or somebody near me on an airplane or maybe my husband’s iPad.”
Of course, caching data at different points in the network is exactly what content distribution networks (CDNs) like Akamai do for their high-end corporate clients, so that Internet videos will start playing faster, for example. But in a content-centric world, Lunt says, the whole Internet would be a CDN. “Caching becomes part of the model as opposed to something you have to glue onto the side.”
Tinkering with Applications
Computer scientists have been discussing the idea of name-based (as opposed to location-based) networking since the 1970s. But the proposal began to pick up steam in 2006. That’s when Jacobson, who’d done stints as head of the Network Research group at Lawrence Berkeley National Laboratory and as chief scientist at Cisco Systems and Packet Design, joined PARC to lead a new Content Centric Networking research program.
PARC had been operating as a contract R&D lab—independent of Xerox, but wholly owned by it—-since 2002. Its business model is to build internal intellectual property and expertise, often with the help of government funding and university collaborators, and then to get the technologies to market through spinoffs or commercialization agreements with industry partners. In 2006, for example, PARC licensed some of its natural language search technology to a spinoff called Powerset, which was acquired by Microsoft in 2008 for $100 million.
In 2009, after three years of design work, Jacobson’s team released CCNx, an open-source software implementation of the protocols needed to build research-stage content centric networks. The next year they released an Android version of CCNx, optimized to run on smartphones, and joined the Named Data Networking (NDN) initiative, a network of 11 university labs that won $8 million in National Science Foundation funding for further development of the CCN idea.
It’s unlikely any of that could have happened if Jacobson had tried to develop his ideas inside a company like Cisco or Packet Design. “Having worked at both large companies and startups, I came to PARC to make Content Centric Networking a reality,” Jacobson said in a 2010 statement. The lab “understands the importance of openness and collaboration to achieve success for new network architectures,” he said.
In that vein, PARC hosted the first meeting of the Emerging Networks Consortium this spring. It’s a group of big companies like Alcatel-Lucent, BT, France Telecom-Orange, Huawei, Panasonic, and Samsung who want to experiment with CCN technologies and have agreed to share what they’re learning. “That has been a good validation for us that it’s not just us or the academic sector” who are interested in CCN, says Jatinder Singh, PARC’s director of mobile innovation strategy. “A lot of these industries are actively tinkering with use cases they might want to implement.”
What might those cases be? To be clear, no one is talking yet about replacing the existing Internet with a content-centric system. That would be impractical, not to mention expensive. (And in practice, a new networking standard would probably be implemented as an “overlay” on the existing TCP/IP-based Internet, just as the Internet started out as an overlay on the telephone network.) Rather, Lunt and Singh say the CCN approach is likely to turn up first in specific applications on the edges of the network. Then, if it’s successful enough, it might filter back toward the center.
The world of wireless medical devices is one area PARC is eyeing. The traditional TCP/IP-based approach would be to equip these devices to connect to the Internet via Wi-Fi; collect their data on a centralized server; then retrieve the data from PCs or smartphones. But that comes with privacy and security hazards—and there are no common standards yet for formatting or exchanging medical data. “The medical device ecosystem is sort of fragmented,” says Singh. “You have vendors producing blood pressure monitors and scales and glucose meters, but so far there isn’t a clear mechanism for aggregating data across those devices.”
On top of that, it’s overkill to send health data up to cloud servers if it’s only needed within the confines of a single home or clinic. Imagine, instead, that your CCN-equipped smartphone is constantly polling your scale, your sleep monitor, and all your other home health devices for new data. Then when you visit your doctor, the office network pulls the stored data directly from your phone. “Using smartphones as hubs, we are looking at how CCN can allow data to be gathered, contextualized, and shared in a secure fashion,” says Singh.
Members of the Emerging Network Consortium also have some very different applications in mind, including using CCN-based networks to ease the burden on cellular networks. That could work either by using CCN-based networks for “backhaul” of data between wireless towers, or by offloading mobile data from 3G and 4G networks onto CCN-based Wi-Fi networks. “Voice over CCN” is another possibility, as are lighting and environmental control systems for buildings and home media sharing—pairing TVs, PCs, tablets, and smartphones with one another without the need for a central Wi-Fi hub.
Twitter Without Twitter, Facebook Without Facebook
If it all sounds very speculative, that’s because it is. At this stage, companies like Samsung may be investigating CCN mainly as a hedge against uncertainty. “The technology industry is so fast-paced that they know that whatever their cash cow is this year, in five to 10 years it’s going to be something else,” says Lunt. “They have to be constantly looking for the next big thing … Samsung makes equipment for carriers, they make handsets, they make consumer devices. CCN could mean a whole new set of businesses for them.”
But Content Centric Networking could also mean a whole new set of challenges for companies in the content business. Apple, Amazon, Microsoft, Facebook, Google, Twitter, Netflix, and their ilk have spent hundreds of billions of dollars building siloed, centralized, proprietary storage and distribution infrastructures, designed wholly around the client-server model and often reachable only via tollbooths like the iTunes Store or Xbox Live. (See my colleague Greg Huang’s recent take on the Four Horsemen of the Consumer Apocalypse.)
In a CCN world, consumers would probably still have to look at ads and pay for movies, music, books, apps, and the like, but they might not be so dependent upon a few giant cloud operators.
“One of the things that’s intriguing about not having to go to the source is that you could start to think about implementing applications differently,” Lunt says. “You could build apps that don’t have any notion of a server at all. So you could have Twitter without Twitter or Facebook without Facebook—that is, without having to have a major investment in hosting content, because the network is caching it all over the place.”
Such architectures might give users more control over privacy and security of their data, and let them share their own data across devices without having to go through proprietary services like Apple’s iCloud, PARC executives say.
“What Apple is trying to do with iCloud is to say: You shouldn’t have to care which device you got an app on, or which device you took a photo on, whether it was your iPad or iPhone or MacBook Air. You just want your content to be on the other devices when you want it,” says Steve Hoover, CEO of PARC. “That validates our vision. But the way they are solving that puts more load on the network than it needs to, and it requires consumer lock-in. So Apple may be a user of this [CCN] technology one day, because it will make it easier. On the other hand, they could also hate it, because it will make it a lot easier for other people to provide that capability of getting the content whenever you want.”
Already, there’s at least one startup, Cambridge, MA- and New York-based Silver Lining Systems, that says it’s using concepts from Content Centric Networking to solve performance problems in data centers and virtualized computing environments. (The company includes former Verizon, Netezza, and Endeca executives, according to the Boston Globe. It isn’t working directly with PARC.) The CCN initiative could eventually lead to PARC spinoffs as well, though nothing formal is in the works. “There could be a B2C play, an Akamai for consumers,” Hoover speculates. “Right now, for example, I have photos on Photobucket, Shutterfly, and Flickr, and I have to think about where those photos are before I can go get them. Somebody could build a CCN layer that interfaces with every photo-sharing service out there, and every time you upload a photo, they manage that for you.”
How much might consumers be willing to pay for such a service? It’s hard to know until someone builds it. Hoover says PARC’s job is to help companies move in that direction.
“When Bob Metcalfe sat in this building and drew Ethernet on a paper napkin, there wasn’t even an Internet, so nobody could have predicted that the business model [for the Internet] was going to be Google search and advertising,” Hoover says. “We can sit here and speculate about where the tollbooths will go, but to me, it’s more about whether there are pockets of money out there ready to address problems that people have now. The tollbooths will go where they need to be.”