OpenFlow Enabling Innovation in Campus Network以及中文翻译

附录A 外文原文

OpenFlow: Enabling Innovation in Campus Networks

Nick McKeown Stanford University Guru Parulkar Stanford University

Tom Anderson

University of Washington

Larry Peterson

Princeton University

Hari Balakrishnan

MIT

Jennifer Rexford

Princeton University

Scott Shenker University of California,

Berkeley

Jonathan Turner Washington University in

St. Louis

This article is an editorial note submitted to CCR. It has NOT been peer reviewed.Authors take full responsibility for this article’s technical https://www.sodocs.net/doc/7d8601038.html,ments can be posted through CCR Online.

ABSTRACT

This whitepaper proposes OpenFlow: a way for researchers to run experimental protocols in the networks they use every day. OpenFlow is based on an Ethernet switch, with an internal ?ow-table, and a standardized interface to add and remove ?ow entries. Our goal is to encourage networking vendors to add OpenFlow to their switch products for deployment in college campus backbones and wiring closets. We believe that OpenFlow is a pragmatic compromise: on one hand, it allows researchers to run experiments on heterogeneous switches in a uniform way at line-rate and with high

port-density; while on the other hand, vendors do not need to expose the internal workings of their switches. In addition to allowing researchers to evaluate their ideas in real-world traffic settings, OpenFlow could serve as a useful campus component in proposed large-scale testbeds like GENI. Two

buildings at Stanford University will soon run OpenFlow networks, using commercial Ethernet switches and routers. We will work to encourage deployment at other schools; and we encourage you to consider deploying OpenFlow in your university network too.

Categories and Subject Descriptors

C.2 [Internetworking]: Routers

General Terms

Experimentation, Design

Keywords

Ethernet switch, virtualization, flow-based

1. THE NEED FOR PROGRAMMABLE NETWORKS

Networks have become part of the critical infrastructure of our businesses, homes and schools. This success has been both a blessing and a curse for networking researchers; their work is more relevant, but their chance of making an impact is more remote. The reduction in real-world impact of any given network innovation is because the enormous installed base of equipment and protocols, and the reluctance to experiment with production traffic, which have created an exceedingly high barrier to entry for new ideas. Today, there is almost no practical way to experiment with new network protocols (e.g., new routing protocols, or alternatives to IP) in sufficiently realistic settings (e.g., at scale carrying real traffi c) to gain the con?dence needed for their widespread deployment. The result is that most new ideas from the networking research community go untried and untested; hence the commonly held belief that the network infrastructure has ―ossi?ed‖.

Having recognized the problem, the networking community is hard at work developing programmable networks, such as GENI [1] a proposed nationwide research facility for experimenting with new network architectures and distributed systems. These programmable networks call for programmable switches and routers that (using virtualization) can process packets for multiple isolated experimental networks simultaneously. For example, in GENI it is envisaged that a researcher will be allocated a slice of resources across the whole network, consisting of a portion of network links, packet processing elements (e.g. routers) and end-hosts; researchers program their slices to behave as they wish. A slice could extend across the backbone, into access networks, into college campuses, industrial research labs, and include wiring closets, wireless networks, and sensor networks.

Virtualized programmable networks could lower the barrier to entry for new ideas, increasing the rate of innovation in the network infrastructure. But the plans for nationwide facilities are ambitious (and costly), and it will take years for them to be deployed.

This whitepaper focuses on a shorter-term question closer to home: As researchers, how can we run experiments in our campus networks? If we can ?gure out how, we can start soon and extend the technique to other campuses to bene?t the whole community.

To meet this challenge, several questions need answering, including: In the early days, how will college network administrators get comfortable putting experimental equipment (switches, routers, access points, etc.) into their network? How will researchers control a portion of their local network in a way that does not disrupt others who depend on it? And exactly what

functionality is needed in network switches to enable experiments? Our goal here is to propose a new switch feature that can help extend programmability into the wiring closet of college campuses.

One approach -that we do not take -is to persuade commercial ―name-brand‖ equipment vendors to provide an open, programmable, virtualized platform on their switches and routers so that researchers can deploy new protocols, while network administrators can take comfort that the equipment is well supported. This outcome is very unlikely in the short-term. Commercial switches and routers do not typically provide an open software platform, let alone provide a means to virtualize either their hardware or software. The practice of commercial networking is that the standardized external interfaces are narrow (i.e., just packet forward ing), and all of the switch’s internal ?exibility is hidden. The internals differ from vendor to vendor, with no standard platform for researchers to experiment with new ideas. Further, network equipment vendors are understandably nervous about opening up interfaces inside their boxes: they have spent years deploying and tuning fragile distributed protocols and algorithms, and they fear that new experiments will bring networks crashing down. And, of course, open platforms lower the barrier-to-entry for new competitors.

A few open software platforms already exist, but do not have the performance or port-density we need. The simplest example is a PC with several network interfaces and an operating system. All well-known operating systems support routing of packets between interfaces, and open-source implementations of routing protocols exist (e.g., as part of the Linux distribution, or from XORP [2]); and in most cases it is possible to modify the

operating system to process packets in almost any manner (e.g., using Click [3]). The problem, of course, is performance: A PC can neither support the number of ports needed for a college wiring closet (a fan out of 100+ ports is needed per box), nor the packet-processing performance (wiring closet switches process over 100Gbits/s of data, whereas a typical PC struggles to exceed 1Gbit/s; and the gap between the two is widening).

Existing platforms with specialized hardware for line-rate processing are not quite suitable for college wiring closets either. For example, an ATCA-based virtualized programmable router called the Supercharged Planet Lab Platform [4] is under development at Washington University, and can use network processors to process packets from many interfaces simultaneously at line-rate. This approach is promising in the long-term, but for the time being is targeted at large switching centers and is too expensive for widespread deployment in college wiring closets. At the other extreme is NetFPGA [5] targeted for use in teaching and research labs. NetFPGA is a low-cost PCI card with a

user-programmable FPGA for processing packets, and 4 ports of Gigabit Ethernet. NetFPGA is limited to just four network interfaces—insufficient for use in a wiring closet.

Thus, the commercial solutio ns are too closed and in?ex ible and the research solutions either have insufficient performance or fan out, or are too expensive. It seems unlikely that the research solutions, with their complete generality, can overcome their performance or cost limitations. A more promising approach is to compromise on generality and to seek a degree of switch flexibility that is:

Figure 1 Idealized OpenFlow Switch. The Flow Table is controlled by a remote controller

via the Secure Channel.

?Amenable to high-performance and low-cost implementations.

?Capable of supporting a broad range of research.

?Assured to isolate experimental traffic from production traffic. ?Consistent with vendors’ need for closed platforms.

This paper describes the OpenFlow Switch—a specification that is an initial attempt to meet these four goals.

2. THE OPENFLOW SWITCH

The basic idea is simple: we exploit the fact that most modern Ethernet switches and routers contain ?ow-tables (typically built from TCAMs) that run at line-rate to im plement ?rewalls, NAT, QoS, and to collect statistics. While each vendor’s ?ow-table is di?erent, we’ve identi?ed an interesting common set of functions that run in many switches and routers. OpenFlow exploits this common set of functions.

OpenFlow provides an open protocol to program the ?ow-table in di?erent switches and routers. A network administrator can partition tra?c into production and research ?ows. Researchers can control their own ?ows -by choosing the routes their packets follow and the processing they receive. In

this way, researchers can try new routing protocols, security models, addressing schemes, and even alternatives to IP. On the same network, the production tra?c is isolated and processed in the same way as today.

The datapath of an OpenFlow Switch consists of a Flow Table, and an action associated with each ?ow entry. The set of actions supported by an OpenFlow Switch is extensible, but below we describe a minimum requirement for all switches. For high-performance and low-cost the data-path must have a carefully prescribed degree of ?exibility. This means forgoing the ability to specify arbitrary handling of each packet and seeking a more limited, but still useful, range of actions. Therefore, later in the pape r, de?ne a basic required set of actions for all OpenFlow switches.

An OpenFlow Switch consists of at least three parts: (1) A Flow Table, with an action associated with each ?ow entry, to tell the switch how to process the ?ow, (2) A Secure Channel that connects the switch to a remote control process (called the controller), allowing commands and packets to be sent between a controller and the switch using (3) The OpenFlow Protocol, which provides an open and standard way for a controller to communicate with a switch. By specifying a standard interface (the OpenFlow Protocol) through which entries in the Flow Table can be de?ned externally, the OpenFlow Switch avoids the need for researchers to program the switch.

It is useful to categorize switches into dedicated OpenFlow switches that do not support normal Layer 2 and Layer 3 processing, and OpenFlow-enabled general purpose commercial Ethernet switches and routers, to which the Open-Flow Protocol and interfaces have been added as a new feature.

Dedicated OpenFlow switches. A dedicated OpenFlow Switch is a dumb datapath element that forwards packets between ports, as de?ned b y a remote control process. Figure 1 shows an example of an OpenFlow Switch.

In this context, ?ows are broadly de?ned, and are limit ed only by the capabilities of the particular implementation of the Flow Table. For example, a ?ow could be a TCP con nection, or all packets from a particular MAC address or IP address, or all packets with the same VLAN tag, or all packets from the same switch port. For experiments involving non-IPv4 packets, a ?ow could be de?ned as all packets matching a speci?c (but non-standard) header.

Each ?ow-entry has a simple action associated with it; the three basic ones (that all dedicated OpenFlow switches must support) are:

1 Forward this ?ow’s packets to a given port (or ports). This allows packets to be routed through the network. In most switches this is expected to take place at line-rate.

2 Encapsulate and forw ard this ?ow’s packets to a con troller. Packet is delivered to Secure Channel, where it is encapsulated and sent to a controller. Typically used for the ?rst packet in a new ?ow, so a controller can decide if the ?ow should be added to the Flow Table. Or in some experiments, it could be used to forward all packets to a controller for processing.

3 Drop this ?ow’s packets. Can be used for security, to curb denial of service attacks, or to reduce spurious broadcast discovery traffic from

end-hosts.

An entry in the Flow-Table has three ?elds: (1) A packet header that de?nes the ?ow, (2) The action, which de?nes how the packets should be processed, and (3) Statistics, which keep track of the number of packets and bytes for

each ?ow, and the time since the last packet matched the ?ow (to help with the removal of inactive ?ows).

In the ?rst generation ―Type 0‖ switches, the ?ow header is a 10-tuple shown in T able 1. A TCP ?ow could be speci?ed by all ten ?elds, whereas an IP ?ow might not include the transport ports in its de?nition. Each header ?eld can be a wildcard to allow for aggregation of ?ows, such as ?ows in which only the VLAN ID is de?ned would apply to all tra?c on a particular VLAN.

Table 1 The header ?elds matched in a “Type 0” OpenFlow switch.

The detailed requirements of an OpenFlow Switch are defined by the OpenFlow Switch Specification [6].

OpenFlow-enabled switches. Some commercial switches, routers and access points will be enhanced with the OpenFlow feature by adding the Flow Table, Secure Channel and OpenFlow Protocol (we list some examples in Section 5). Typically, the Flow Table will re-use existing hardware, such as a TCAM; the Secure Channel and Proto col will be ported to run on the switch’s operating system. Figure 2 shows a network of OpenFlow-enabled commercial switches and access points. In this example, all the Flow Tables are managed by the same controller; the OpenFlow Protocol allows a switch to be controlled by two or more controllers for increased performance or robustness. Our goal is to enable experiments to take place in an existing production network alongside regular tra?c and applications. Therefore, to win the

con?dence of network administrators, OpenFlow-enabled switches must isolate experimental tra?c (processed by the Flow Table) from production

tra?c that is to be processed by the normal Layer 2 and Layer 3 pipeline of the switch. There are two ways to achieve this separation. One is to add a fourth action:

4. Forward this ?ow’s packets through the switch’s nor mal processing pipeline.

The other is to de?ne separat e sets of VLANs for experimental and production tra?c. Both approaches allow normal production tra?c that isn’t part of an experiment to be processed in the usual way by the switch. All OpenFlow-enabled switches are required to support one approach or the other; some will support both.

Additional features. If a switch supports the header formats and the four basic actions mentioned above (and detailed in the OpenFlow Switch

Speci?cation), then we call it a ―Type 0‖ switch. We expect that many switches will support additional actions, for example to rewrite portions of the packet header (e.g., for NAT, or to obfuscate addresses on intermediate links), and to map packets to a priority class. Likewise, some Flow Tables will be able to match on arbitrary ?elds in the packet header, enabling experiments with new non-IP protocols. As a particular set of features emerges, we will

de?ne a ―Type 1‖ switch.

Controllers. A controller a dds and removes ?ow-entries from the Flow Table on behalf of experiments. For example, a static controller might be a simple application running on a PC to statically establish ?ows to interconnect a set of test computers for the duration of an experiment. In this case the ?ows resemble VLANs in current networks— providing a simple mechanism to

isolate experimental tra?c from the production network. Viewed this way, OpenFlow is a generalization of VLANs.

One can also imagine more sophisticated controllers that dynamically

add/remove ?ows as an experiment progresses. In one usage model, a researcher might control the complete network of OpenFlow Switches and be free to decide how all ?ows are processed.

Figure 2 Example of a network of OpenFlow-enabled commercial switches and routers.

A more sophisticated controller might support multiple researchers, each with di?erent accounts and permissions, enabling them to run multiple independent experiments on di?erent sets of ?ows. Flows identi?ed as under the control of a particular researcher (e.g., by a policy table running in a controller) could be delivered to a researcher’s user-level control program which then decides if a new ?ow-entry should be added to the network of switches.

3. USING OPENFLOW

As a simple example of how an OpenFlow Switch might be used imagine that Amy (a researcher) invented Amy-OSPF as a new routing protocol to

replace OSPF. She wants to try her protocol in a network of OpenFlow Switches, without changing any end-host software. Amy-OSPF will run in a controller; each time a new application ?ow starts Amy-OSPF picks a route through a series of OpenFlow Switches, and adds a ?ow-entry in each switch along the path. In her experiment, Amy decides to use Amy-OSPF for the

tra?c entering the OpenFlow network from her own desktop PC— so she doesn’t disrupt the network for others. To do this, she de?nes one ?ow to be all the tra?c entering the Open-Flow switch through the switch port her PC is connected to, and adds a ?ow-entry with the action ―Enca psulate and forward all packets to a controller‖. When her packets reach a controller, her new protocol chooses a route and adds a new ?ow-entry (for the application ?ow) to every switch along the chosen path. When subsequent packets arrive at a switch, they are processed quickly (and at line-rate) by the Flow Table. There are legitimate questions to ask about the performance, reliability and scalability of a controller that dynam ically adds and removes ?ows as an experiment progresses: Can such a centralized controller be fast enough to process new ?ows and program the Flow Switches? What happens when a controller fails? To some extent these questions were addressed in the context of the Ethane prototype, which used simple ?ow sw itches and a central controller [7]. Preliminary results suggested that an Ethane controller based on a low-cost desktop PC could process over 10,000 new ?ows per second —enough for a large college campus. Of course, the rate at which ne w ?ows can be processed will depend on the complexity of the processing required by the re searcher’s experiment. But it gives us con?dence that mean ingful experiments can be run. Scalability and redundancy are possible by making a

controller (and the experiments) stateless, allowing simple load-balancing over multiple separate devices.

3.1 Experiments in a Production Network

Chances are, Amy is testing her new protocol in a network used by lots of other people. We therefore want the network to have two additional properties:

1 Packets belonging to users other than Amy should be routed using a standard and tested routing protocol running in the switch or router from a

―name-brand‖ vendor.

2 Amy should only be able to add ?ow entries for her tra?c, or for any tra?c her network administrator has allowed her to control.

Property 1 is achieved by OpenFlow-enabled switches. In Amy’s experiment, the default action for all packets that don’t come from Amy’s PC could be to forward them through the normal processing pipeline. Amy’s o wn packets would be forwarded directly to the outgoing port, without being processed by the normal pipeline.

Property 2 depends on the controller. The controller should be seen as a platform that enables researchers to implement various experiments, and the restrictions of Property 2 can be achieved with the appropriate use of permissions or other ways to limit the powers of individual researchers to control ?ow entries. The exact nature of these permission-like mechanisms

will depend on how the controller is implemented. We expect that a variety of controllers will emerge. As an example of a concrete realization of a controller, some of the authors are working on a controller called NOX as a follow-on to the Ethane work [8]. A quite di?erent controller might emerge by extending the GENI management software to OpenFlow networks.

3.2 More Examples

As with any experimental platform, the set of experiments will exceed those we can think of up-front — most experiments in OpenFlow networks are yet

to be thought of. Here, for illustration, we o?er some examples of how OpenFlow-enabled networks could be used to experiment with new network applications and architectures.

Example 1: Network Management and Access Con trol. We’ll use Ethane as our ?rst example [7] as it was the research that inspired OpenFlow. In fact, an OpenFlow Switch can be thought of as a generalization of Ethane’s datapath switch. Ethane used a speci?c implementation of a controller, suited for network management and control, that manages the admittance and routing of ?ows. The basic idea of Ethane is to allow network managers to de?ne a network-wide policy in the central controller, which is enforced directly by making admission control decisions for each new ?ow. A controller checks a new ?ow against a set of rules, such as ―Guests can communicate using HTTP, but only via a web proxy‖ or ―VoIP phones are not allowed to communicate with laptops.‖ A controller associates pack ets with their senders by managing all the bindings between names and addresses — it essentially takes over DNS, DHCP and authenticates all users when they join, keeping track of which switch port (or access point) they are connected to. One could envisage an extension to Ethane in which a policy dictates that particular ?ows a re sent to a user’s process in a controller, hence allowing researcher-speci?c processing to be performed in the network.

Example 2: VLANs. OpenFlow can easily provide users with their own isolated network, just as VLANs do. The simplest approach is to statically declare a set of ?ows which specify the ports accessible by tra?c on a given

VLAN ID. Tra?c identi?ed as coming from a single user (for example, originating from speci?c switch ports or MAC addresses) is tagged by the switches (via an action) with the appropriate VLAN ID.

A more dynamic approach might use a controller to manage authentication of users and use the knowledge of the users’ locations for tagging tra?c at runtime.

Example 3: Mobile wireless VOIP clients. For this example consider an experiment of a new call-hando? mechanism for WiFi-enabled phones. In the experiment VOIP clients establish a new connection over the

OpenFlow-enabled network. A controller is implemented to track the location of clients, re-routing connections — by reprogramming the Flow Tables — as users move through the network, allowing seamless hando? from one access point to another.

Example 4: A non-IP network. So far, our examples have assumed an IP network, but OpenFlow doesn’t require packets to be of any one format — so long as the Flow Table is able to match on the packet header. This would allow experiments using new naming, addressing and routing schemes. There are several ways an OpenFlow-enabled switch can support non-IP tra?c. For example, ?ows could be identi?ed using their Ethernet header (MAC src and dst addresses), a new EtherType value, or at the IP level, by a new IP Version number. More generally, we hope that future switches will allow a controller to create a generic mask (o?set + value + mask), allowing packets to be processed in a researcher-speci?ed way.

Example 5: Processing packets rather than ?ows.

The examples above are for experiments involving ?ows — where a controller makes dec isions when the ?ow starts. There are, of course, interesting experiments to be performed that require every packet to be processed. For example, an intrusion detection system that inspects every packet, an explicit congestion control mechanism, or when modifying the contents of packets, such as when converting packets from one protocol format to another.

Figure 3: Example of processing packets through anexternal line-rate

packet-processing device, such as a programmable NetFPGA router.

There are two basic ways to process packets in an OpenFlow-enabled network. First, and simplest, is to force all of a ?ow’s packets to pass through a controller. To do this, a controller doesn’t add a new ?ow entry into the Flow Switch — it just allows the switch to default to forwarding every packet to a controller. This has the advantage of ?exibility, at the cost of performance. It might provide a useful way to test the functionality of a new protocol, but is unlikely to be of much interest for deployment in a large network.

The second way to process packets is to route them to a programmable switch that does packet processing — for example, a NetFPGA-based programmable router. The advantage is that the packets can be processed at line-rate in a user-de?nable way; Figure 3 shows an example of how this could be done, in which the OpenFlow-enabled switch operates essentially as a patch-panel to allow the packets to reach the NetFPGA. In some cases, the NetFPGA board (a PCI board that plugs into a Linux PC) might be placed in the wiring closet alongside the OpenFlow-enabled switch, or (more likely) in a laboratory.

4. THE OPENFLOW CONSORTIUM

The OpenFlow Consortium aims to popularize OpenFlow and maintain the OpenFl ow Switch Speci?cation. The Con sortium is a group of researchers and network administrators at universities and colleges who believe their research mission will be enhanced if OpenFlow-enabled switches are installed in their network.

Membership is open and free for anyone at a school, college, university, or government agency worldwide. The OpenFlow Consortium welcomes individual members who are not employed by companies that manufacture or sell Ethernet switches, routers or wireless access points (because we want to keep the consortium free of vendor in?uence). To join, send email to

join@https://www.sodocs.net/doc/7d8601038.html,.

The Consortium web-site contains the OpenFlow Switch Speci?cation, a list of consortium members, and reference implementations of OpenFlow switches.

Licensing Model: The OpenFlow Switch Speci?cation is free for all commercial and non-commercial use. (The exact wording is on the web-site.) Commercial switches and routers claiming to be ―OpenFlow-enabled‖ must conform to the requirements of an OpenFlow Type 0 Switch, as de?ned in the OpenFlow Switch Speci?cation. OpenFlow is a trademark of Stanford University, and will be protected on behalf of the Consortium.

5. DEPLOYING OPENFLOW SWITCHES

We believe there is an interesting market opportunity for network equipment vendors to sell OpenFlow-enabled switches to the research community. Every building in thousands of colleges and universities contains wiring closets with Ethernet switches and routers, and with wireless access points spread across campus.

We are actively working with several switch and router manufacturers who are adding the OpenFlow feature to their products by implementing a Flow Table in existing hardware; i.e. no hardware change is needed. The switches run the Secure Channel software on their existing processor.

We have found network equipment vendors to be very open to the idea of adding the OpenFlow feature. Most vendors would like to support the research community without having to expose the internal workings of their products. We are deploying large OpenFlow networks in the Computer Science and Electrical Engineering departments at Stanford University. The networks in two buildings will be replaced by switches running OpenFlow. Eventually, all tra?c will run over the OpenFlow network, with production tra?c and experimental tra?c being isolated on different VLANs under the control of

network administrators. Researchers will control their own tra?c, and be able to add/remove ?ow-entries.

We also expect many di?erent OpenFlow Switches to be developed by the research community. The OpenFlow web-site contains ―Type 0‖ reference designs for several di?erent platforms: Linux (software), OpenWRT (software, for access points), and NetFPGA (hardware, 4-ports of 1GE). As more reference designs are created by the community we will post them. We encourage developers to test their switches against the reference designs.

All reference implementations of OpenFlow switches posted on the web site will be open-source and free for commercial and non-commercial use.

6. CONCLUSION

We believe that OpenFlow is a pragmatic compromise that allows researchers to run experiments on heterogeneous switches and routers in a uniform way, without the need for vendors to expose the internal workings of their products, or researchers to write vendor-speci?c control software.

If we are successful in deploying OpenFlow networks in our campuses, we hope that OpenFlow will gradually catch-on in other universities, increasing the number of networks that support experiments. We hope that a new generation of control software emerges, allowing researchers to re-use controllers and experiments, and build on the work of others. And over time, we hope that the islands of OpenFlow networks at di?erent universities will be interconnected by tunnels and overlay networks, and perhaps by new

Open-Flow networks running in the backbone networks that connect universities to each other.

7. REFERENCES

[1] Global Environment for Network Innovations. Web site https://www.sodocs.net/doc/7d8601038.html,.

[2] Mark Handley Orion Hodson Eddie Kohler. ―XORP: An Open Platform for Network Research,‖ ACM SIGCOMM Hot Topics in Networking, 2002. [3] Eddie Kohler, Robert Morris, Benjie Chen, John Jannotti, and M. Frans Kaashoek. ―The Click modular router,‖ ACM Transactions on Computer Systems 18(3), August 2000, pages 263-297.

[4] J. Turner, P. Crowley, J. Dehart, A. Freestone, B. Heller, F. Kuhms, S. Kumar, J. Lockwood, J. Lu, M.Wilson, C. Wiseman, D. Zar. ―Supercharging PlanetLab -High Performance, Multi-Application, Overlay Network Platform,‖ ACM SIGCOM M ’07, August 2007, Kyoto, Japan.

[5] NetFPGA: Programmable Networking Hardware. Web site

https://www.sodocs.net/doc/7d8601038.html,.

[6] The OpenFlow Switch Speci?cation. Available at

https://www.sodocs.net/doc/7d8601038.html,.

[7] Martin Casado, Michael J. Freedman, Justin Pettit, Jianying Luo, Nick McKeown, Scott Shenker. ―Ethane: Taking Control of the Enterprise,‖ ACM SIGCOMM ’07, August 2007, Kyoto, Japan.

[8] Natasha Gude, Teemu Koponen, Justin Pettit, Ben Pfa?, Martin Casadao, Nick McKeown, Scott Shenker, ―NOX: Towards an Operating Syst em for Networks,‖

In submission. Also:

https://www.sodocs.net/doc/7d8601038.html,/docs/nox-nodis.pdf.

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创新 Innovation

Topic of PresentationTitle of Presentation 八个关于在中国创新的迷思 8 innovation myths in China 马祺 尼尔森大中华区总裁 Mitch Barns The Nielsen Company

八个关于在中国创新的迷思 8 innovation myths in China 1) 中国≠创新1) China ≠Innovation 2) 在中国创新= 成功的保证2) Innovation in China = success guaranteed 3) 中国≠其他国家3) China ≠Other countries 4) 创新者> 追随者4) Innovator > Follower 5) 跨国企业= 创新者 5) Multinational company = Innovator 6) 本土企业= 追随者6) Local company = Follower 7) 本土品牌= 低端品牌7) Local brand = Mass 8) R&D研发花费= 成功8) R&D Spending = Success

迷思一：中国缺乏创新 Myth #1: China is not an innovator 2) 在中国创新= 成功的保证2) Innovation in China = success guaranteed 3) 中国≠其他国家3) China ≠Other countries 4) 创新者> 追随者4) Innovator > Follower 5) 跨国企业= 创新者5) Multinational company = Innovator 6) 本土企业= 追随 者 6) Local company = Follower 7) 本土品牌= 低端品牌7) Local brand = Mass 8) R&D研发花费= 成功8) R&D Spending = Success 1) 中国≠创新1) China ≠Innovation

(完整版)Innovation关于创新的英语6级作文

Innovation With the development of social economy, innovation has received more and more attention as to the obbligato role of innovation in social development. Why do so many people think that innovation is important? Later on, I will demonstrate this problem from three aspects. First of all, for individuals, innovative thinking has a significant impact on the future of human beings. People make progress by way of innovation day by day. Furthermore, for enterprises, innovation is the basis of the survival and development. Innovation can improve production efficiency and competitiveness of enterprises. Last but not least, for countries, innovation is the soul of national prosperity and national progress. Without innovation, countries couldn't survive in the world. So how do we promote innovation? As far as I am concerned, both individuals and governments should take an active part. For individuals, we should enhance the innovative thinking and improve the ability of innovation. In addition, we should actively participate in innovation activities. For governments, they should encourage social innovation, providing preferential policies and favorable conditions. Merely in this way, can we create a social environment conducive to innovation virtually. By the way, what do you think of this topic?

Innovation 创新 英语作文

I n n o v a t i o n With the economic globalization becoming increasingly intensive, innovation has become one of central topic around the world. Many countries see it as the key to develop their economy. Innovation is an inexhaustible source of motive power for the development of a nation, and a necessary quality for the growth of a man. What can we benefit from it? Innovation can enhance overall national economy, which is important to heighten our nation status in the world. Israel is about the size of China’s B eijing, yet Israel is the most advanced economics in the Middle East because of its strong innovation supported by advanced education. Although over half of land is in state of drought, Israel has the most advanced irrigation technologies. Some well-known products were invented there, such as router, Povos, Intel Core processor and so on. Always following others’ footsteps, you will never surpass him. Being yourself and dare to innovate will be your best choice. Without innovation, Steve Jobs would not have built up Apple which got where it is today. Each new design product of Apple, conceptual unit as a whole or endless after part, is able to bring you surprise and brighten your eyes. That Apple created smartphone, which have a giant influence on peoples’ lives, also makes one of the most highly valued companies in the world. Additionally, if factories have the abilities in innovation, the factories will be booming. As a result, they can provide our people with more jobs and it will make our nation more stable. What is more, a majority of new products may be available through innovation. Therefore, it is also significant factor for improving our living standards. Owing to such benefits, no wonder more and more countries focus on innovation today. Recognizing its importance is only the first step to advocate innovation, and some effective measures should be taken for it. There is no doubt in saying that without innovation, we will lack the competence we need to have a foothold in society. Therefore, only through innovation can we make ourselves competent and competitive. It is high time that we set our mind free and stride forward to make ourselves join the stream of innovation. Our country should continue to enlarge the recruit of graduate. For another, the conditions of scientists and skilled workers should be further improved. Only in this way, our nation has a brighter future.

新题型 作文 The Importance of Innovation

The Importance of Innovation 2011年12月17日四六级写作,之前2011年12月17日的四六级作文，有如下特点： 1、全英文给题，无中文提纲 2、文章给出一句名人名言或是俗语谚语，对其进行评论 3、文章主题与“人生哲理、优秀品质”相关，不再是以往的校园、学习或社会热点。四六级作文如果同时满足以上三条特点，那么以下的5篇练习题的针对性是很强的。 学习建议：建议同学们参照范文进行比较，看看文章思路、遣词造句方面有没有可以改进的地方；然后进行范文背诵，找到套路，让你的考场作文大放异彩。Directions: For this part, you are allowed 30 minutes to write a short essay entitled The Importance of Innovation by commenting on Rosabeth Moss Kanter’s famous remark ““Mindless habitual behavior is the enemy of innovation.”You should write at least 150 words but no more than 200 words. The Importance of Innovation “Mindless habitual behavior is the enemy of innovation. ” I assume that you are familiar with Rosabeth Moss Kanter’s famous remark. It is o bvious that a man who always stick to habit and experience can hardly create new things . Rosabeth Moss Kanter’s remark aims at informing us of the significance of innovation. Why does innovation play an indispensable role in our life ? innovation can promote the advancement of both individuals and society as a whole. Only those who are innovative can make continuous progress and maintain a competitive edge. Quite a few examples can be given to prove the importance of it, and I can think of no better illustration than the following one: how could Steve Jobs, a genius who changed the way of modern communication, recreation and even our life, launch so many powerful electronic products constantly without creative spirit？ We should always bear in mind t hat the consciousness of innovation is of great significance to us all. Hence, we need to develop a habit of discovering new things，using new methods and applying new thoughts in our work, study or simply everyday life. “Innovation is the spirit of human being’s progress.” A philosopher once said. (202 words) “不用心思的习惯性行为是创新的敌人”我觉得你对Rosabeth Moss Kanter的这句名言很熟悉。很明显，一个总是遵循习惯和经验的人是很难创造出新事物的。 Rosabeth Moss Kanter 的这句名言目的在于告诉我们创新的重要性。为什么创新在我们的生活中扮演如此重要的角色呢？创新可以促进个人和整个社会的进步。只有那些创新的人才能去的持续的进步并且保持竞争优势。相当多的例子可以用来证明创新的重要性，我想不出比一下这个例子更好的了：斯蒂夫.乔布斯，这个改变了我们的通讯方式、娱乐方式甚至是生活方式的天才，如果没有创新精神，他怎么可能持续地发布功能强大的电子产品呢？ 我们应该牢记在心，创新对于我们每个人都非常重要。因此，在我们的工作、学习甚至是生活中，我们要养成发现新事物、使用新方法、运用新思维习惯。“创新是人类进步的灵魂”一位哲学家也曾这么说过。 Unity breeds success

Innovation-in-practice-创新-实践-BCG-matrix-波士顿矩阵

A very impressive interview, thank you, Pouline, Chloe and Lynn. Now let’s come to the conclusion part. In this part, I’ll talk from two aspects. One is key to success. That’s why Nokia Lumia 800 can successful got the gold award in Innovation competition. The second part is predicting the future. We will predict the future of Nokia from its current position. IDSA gave the gold award to Nokia Lumia800 and provided reasons like: it established Windows phone; combined hardware with the Windows Phone user interface and the principle of the design team. I think the primary reason for Nokia to win the award is design thinking. The IDEO’s CEO Tin Brown gave a definition of “design thinking” like this, “Design thinking is a human-centered approach to innovation that draws from the designer's toolkit to integrate the needs of people,

Innovation翻译

创新，创业和金融市场周期 虽然硬盘的数据不难发现，金融危机的出现有实质性的负面投资者愿意资助创新创业的影响。特别是这种资金匮乏令人担忧的广泛认可创新企业所谓的“绿芽”需要- 在全球范围内的经济衰退后，重新点燃经济增长。越来越多的证据表明一个强大创业，开拓创新，经济增长之间的关系。本文件首先回顾了关于创新和之间的关系的证据创业。然后将这些活动了解市场周期的后果。我们顺便看看，金融因素影响创新投资决策和创新 特别是创业型企业。然后我又到当前的经济危机的影响。突出四个关键观察： ?当前全球经济危机的创新融资的一个戏剧性的效果，无论是通过风险投资，首次公开发行（IPO），或企业风险投资。 ?这是不是第一次这样的危机，在创业融资。这些模式反映的事实，出现财政拮据限制高潜力企业家。 ?这些资金周期是严重的，因为高潜力企业的重要性创新。 我讨论的影响，越来越多的政府计划，寻求结束鼓励企业家和风险资本融资。过于频繁，这些努力都忽略了上面所讨论的关系。 1.简介：金融危机和创新 1.A.危机的简短摘要 当前的经济危机一直是显着的，它的强度和广度。国家统计局经济研究所（NBER 2008）宣布美国经济已经进入衰退期为12月然而，经济条件已经一直处于下降通道，在许多发达国家世界[两个概述，看到福斯特和马格多夫（2009）和希尔森拉特和所罗门（2009）]经济衰退以来，美国房地产泡沫有着千丝万缕的联系。当联邦储备降低利率以刺激经济在2001年科技泡沫之后9/11，低利率敞开了大门宽松的信贷中的住房市场。从2002年到2004年，作为利息率仍然低，次级贷款成为家常便饭。消费者趁着有利获得抵押贷款和金融机构的信贷条件，推广新的贷款产品和金融仪器。例如，借款人能够获得住房贷款批准几乎没有首付，而贷款人可以放弃时，他们通过他们自己的既得利益，贷款质量向机构投资者。的需求和房屋价值攀升到2006年，但2007年中期，一个信贷危机爆发。杂乱无章的借贷行为的后果和监管不力的系统迅速赶上全球金融市场。2008年的秋天，当投资银行，如贝尔斯登和雷曼兄弟塌陷的压力下，贬值的抵押贷款支持证券，信贷紧缩迫在眉睫。越来越多的房主拖欠贷款或被迫取消抵押品赎回权的时候，例如，他们不能增加按揭付款。贷款人发现自己抵押贷款支持证券，旁边没有什么值得。破灭的房地产泡沫和烦恼大型机构举行他们引发流动性危机，借贷几乎陷于停顿，信用体系完全抓住。2009年9月18日，美国。政府出面用USD700亿美元纾困计划，希望能拯救金融系统的总崩溃的边缘结束“有毒”资产，注入足够的资金进入银行迅速启动信贷市场的周期。该政府接管房利美（Fannie Mae）和房地美（Freddie Mac）的救助了美国国际集团（AIG）在9月和有效对超过价值5万亿美元的债务时，结合其他银行的债务担保。在其他国家发生类似的纾困陷入困境的银行，最主要的是瑞士和美国 英国。在过去的一年中，政府的干预，以刺激经济已成为常规，几乎预期，但许多发达国家的经济仍然脆弱。巨额债务织机，股票市场依然动荡，并担忧失业，通货膨胀的危险，挥舞基本行业继续削弱消费者的信心。虽然在某些市场有复苏的迹象，关键如住房部门仍然依赖于政府的支持。 1.B.创业和创新的影响轶事 虽然硬盘的数据不难发现，金融危机的出现有实质性的负面投资者愿意资助创新创业的影响。特别是这种资金匮乏令人担忧的光的广泛认可需要创新企业- 所谓的“绿芽”- 重新点燃经济增长之后，全球性的经济衰退。以介绍方式，可以被看作是一个高潜力的企业家融资景观谱，更先进的企业获得大量资金从不同的逐渐变大

以创新为主题的英语作文.doc

以创新为主题的英语作文 1、How to Be Creative Being creative is to have the skill and ability to produce something new . To be honest creative is of immune significance which advances the development of economy and thus gives people pleasure and enjoyment . Do you want to be creative ?if yes here are some suggestion . First of all you should be brave . You should dare break the traditional thoughts without hesitation .You should rid yourself of the idea that what others have put forward is the best and try to doubt it .In other words seeing a good thing or idea you should try your best to creat better rather than only speaking highly of it . In addition you should be confident As the old saying goes "opportunity only knock on the door of a pepared and confident mind ."Or rather the person who are hesitant about anything can't grasp the chance for the reason that creation will flash away if not written down timely .Only when you are confident about yourself can you grasp the idea passing through your mind.

Innovation创新-英语演讲稿

What we cannot afford to lose We cannot lose innovation There is a wonderful word which expresses the most original motions and desires among human-beings. With solving any kind of imperfections, our world has moved ahead. This is the word “innovation” tha t we cannot afford to lose. We chicaned every detail of the innovation. Thousands years before, we created fire when we took a stone to knock another one. Since Han Dynasty, four great inventions had been created and it is one of the greatest signs that China become to the ancient civilized country. And nowadays, thousands of software, products, architectures and public facilities have upgraded more than that about 100 years ago. So how did these happen? What will you do if you are not satisfied with your tools anymore? What will you do if old mode cannot afford to develop in a company? There is no doubt that we should innovate no matter where we are and what we do. Not because of the design itself, but actually for its intended purpose. If there was no Apple, everyone could not imagine how to contact others easily and enjoy a better Internet surfing.

Innovation 创新 英语作文

Innovation With the economic globalization becoming increasingly intensive, innovation has become one of central topic around the world. Many countries see it as the key to develop their economy. Innovation is an inexhaustible source of motive power for the development of a nation, and a necessary quality for the growth of a man. Whatcan we benefitfrom it? Innovation can enhance overall national economy, which is important to heighten our nation status in the world.Israel is about the size of China’s Be ijing, yet Israel is the most advanced economics in the Middle East because of its strong innovation supported by advanced education. Although over half of land is in state of drought, Israel has the most advanced irrigation technologies. Some well-known products were invented there, such as router, Povos, Intel Core processor and so on.Always following others’ footsteps, you will never surpass him. Being yourself and dare to innovate will be your best choice. Without innovation, Steve Jobs would not have built up Apple which got where it is today. Each new design product of Apple, conceptual unit as a whole or endless after part, is able to bring you surprise and brighten your eyes.That Apple created smartphone, which have a giant influence on peoples’ lives, also makes one of the most highly valued companies in the world. Additionally, if factories have the abilities in innovation, the factories will be booming. As a result, they can provide our people with more jobs and it will make our nation more stable. What is more, a majority of new products may be available through innovation. Therefore, it is also significant factor for improving our living standards. Owing to such benefits, no wonder more and more countries focus on innovation today. Recognizing its importance is only the first step to advocate innovation, and some effective measures should be taken for it. There is no doubt in saying that without innovation, we will lack the competence we need to have a foothold in society.Therefore, only through innovation can we make ourselves competent and competitive. It is high time that we set our mind free and stride forward to make ourselves join the stream of innovation. Our country should continue to enlarge the recruit of graduate. For another, the conditions of scientists and skilled workers should be further improved. Only in this way, our nation has a brighter future.

Innovation创新英语作文

I n n o v a t i o n创新英语 作文 集团标准化工作小组 #Q8QGGQT-GX8G08Q8-GNQGJ8-MHHGN#

I n n o v a t i o n With the economic globalization becoming increasingly intensive, innovation has become one of central topic around the world. Many countries see it as the key to develop their economy. Innovation is an inexhaustible source of motive power for the development of a nation, and a necessary quality for the growth of a man. What can we benefit from it Innovation can enhance overall national economy, which is important to heighten our nation status in the world. Israel is about the size of China’s Be ijing, yet Israel is the most advanced economics in the Middle East because of its strong innovation supported by advanced education. Although over half of land is in state of drought, Israel has the most advanced irrigation technologies. Some well-known products were invented there, such as router, Povos, Intel Core processor and so on. Always following others’ footsteps, you will never surpass him. Being yourself and dare to innovate will be your best choice. Without innovation, Steve Jobs would not have built up Apple which got where it is today. Each new design product of Apple, conceptual unit as a whole or endless after part, is able to bring you surprise and brighten your eyes. That Apple created smartphone, which have a giant influence on peoples’ lives, also makes one of the most highly valued companies in the world. Additionally, if factories have the abilities in innovation, the factories will be booming. As a result, they can provide our people with more jobs and it will make our nation more stable. What is more, a majority of new products may be available through innovation. Therefore, it is also significant factor for improving our living standards. Owing to such benefits, no wonder more and more countries focus on innovation today. Recognizing its importance is only the first step to advocate innovation, and some effective measures should be taken for it. There is no doubt in saying that without innovation, we will lack the competence we need to have a foothold in society. Therefore, only through innovation can we make ourselves competent and competitive. It is high time that we set our mind free and stride forward to make ourselves join the stream of innovation. Our country should continue to enlarge the recruit of graduate. For another, the conditions of scientists and skilled workers should be further improved. Only in this way, our nation has a brighter future.

英语演讲 传统和创新(tradition and innovation )

Tradition and Innovation Good morning, my fellow students and dear teachers. The stories of our fathers and mothers lie in the long tradition, while the future script of our children will be written by innovation. One nation would not be itself any more if it does not inherit their tradition, which is one of the most important ingredients for the culture of a nation. The influence of tradition on the main stream thoughts is still dominant, but there were good ones as well as bad ones. Tradition is the result of our ancestors’ adaption to environment. Part of tradition still suits nowadays, such as the solar term is the guide of weather. But somehow, tradition will make people shut down their will to take a step forward which may stop the development of the economy. So, our attitude towards tradition should be dialectical, take the essence to its dregs to keep its positive energy. Innovation is an important power that will help us improve the society in many aspects. First, innovation is the way that people use their intelligence to create new things by breaking the old. Thus, innovation can activate our economy by creating new growth point and new jobs. Second, politics should suit the economy if one country wants to keep its economic growth. Politics should change along with the economy, if politics remain the same, it will have negative effects on the economy, and thus, innovation in politics is needed. Third, I want to talk about my major, Industrial Design, because a lot of things occur to at the first sight of the word “innovation”. Innovation is also needed in improving our daily life. A great example is the Apple Company and its brilliant products. Design is to produce something new and new means in some way. Einstein said: “Everything should be made as simple as possible, but not simpler.”And apple is one of those who make their products as simple, cheap and functional as they can. You know you’ve achieved perfection in design, not when you have nothing more to add, but when you have nothing more to take away. Tradition is the innovation of the past, and innovation is the new tradition. Innovation is the blast that will bring new towards old. Innovation is the best way for our nation to invest in the future.