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QSDN能否完全取代传统网络架构？
ANot totally, but mostly. Just like that modem is still used in many area even it only supports very low transaction speed. SDN can be popular and widely deployed in the networking environments. The legacy network architecture would still be there until its due day.
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QSDN在路由器方面是如何具体应用的？
AOpenFlow is a new method of control for flows in the network. To date, networking has always focussed on managing frames and packets with routing protocols, but applications don’t use single packets to deliver services. Rather, they exchange data between server and client, they create a stream of packets from a source to destination that is commonly known as flow. OpenFlow defines a standard for sending flow rules to network devices so that the Control Plane can add them to the forwarding table for the Data Plane. These flow rules contains fields for elements such as source & destination MAC, Source & destination IP, source and destination TCP, VLAN, QoS and MPLS tags and more. The flow rules are then added to the existing forwarding table in the network device. The forwarding table is what all routers and switches use to dispatch frame and packets to their egress ports. Therefore, OpenFlow is neither routing or switching, it’s about forwarding.
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Q两种SDN Application分别有什么advantage？
ADo you means fog computing and network virtualization? They have different features and benefits. Fog Computing is a paradigm that extends Cloud computing and services to the edge of the network. Similar to Cloud, Fog provides data, compute, storage, and application services to end-users. The distinguishing Fog characteristics are its proximity to end-users, its dense geographical distribution, and its support for mobility. Services are hosted at the network edge or even end devices such as set-top-boxes or access points. By doing so, Fog reduces service latency, and improves QoS, resulting in superior user-experience. Fog Computing supports emerging Internet of Everything (IoE) applications that demand real-time/predictable latency (industrial automation, transportation, networks of sensors and actuators). Network virtualization is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to the software containers on a single system. Whether virtualization is internal or external depends on the implementation provided by vendors that support the technology.
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QSDN设备都是靠Controller静态配置的吗？
A The configuration can be issued by the controller anytime, not just at the initial stage.
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QSDN只适用于交换机？
A SDN is a new type of networks which include many different types of equipments, like switches, gateway, router, firewall and controller, Switches are parts of them.
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QLayerscape和QorIQ有什么关系？
ALayerscape is the next generation of QorIQ product family. The key difference is Layperscape is core agnostic, that mean you can run DSP, Power Core, or ARM core. v.s. QorIQ which only has Power Architecture core (e500mc, e5500, e6500, etc).
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Q网络虚拟化是SDN的实现方式之一？
ANo. Network virtualization and SDN are two different things and somewhat incomparable. SDN is a mechanism and network virtualization is a solution. SDN is relevant to system builders
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Q如何在linux下实现SDN的应用？
AThe key element in SDN is OPENFLOW. There are some open source OPENFLOW stacks on the internet. You can check the site out, http://yuba.stanford.edu/~casado/of-sw.html.
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Q在保障大量IP流量安全方面飞思卡尔都有哪些方案？
AFreescale QorIQ product family has Data Path Acceleration Architecture (DPAA) to manage IP packets for scheduling and congestion control to gaurantee through put.
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Q目前，SDN实施面临哪些挑战？
A1. Some companies thought some parts of the networks don’t need to be updated with SDN technology, such as the core network which is adequately provisioned already for near-term increases in traffic. Both the carrier edge and data center networks, however, need to be redesigned for improved flexibility, given the lack of visibility into the future mix of applications or the growth in workloads. Scalability remains a significant challenge. 2. A few companies state network virtualization is applied to equipment beyond switches and that they expect carriers to focus on monetize the network first, before thinking about SDN implementations 3. There were many discussions about all the overlay networks that are emerging to resolve scalability issues both at Layer 2 and Layer 3, such as PCE, Openflow, VXLAN, STT, NVGRE etc. protocols.
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Q软件定义网络还有哪些技术难点待突破？
AWhile SDN will create the kind of network programmability that is expected to improve security in the long term, for now just the fact that the technology is so immature means it is "probably full of software vulnerabilities. One glaring downside of SDN is that when you make changes at the control level, they are reapplied throughout the network. SDN also presents many operational challenges, such as training existing employees [who are] well-versed in traditional network management and provisioning mechanisms.
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Q飞思卡尔的解决方案有什么特点？
AFreescale QorIQ series have many features, like low power consumption, high CPU MIPS performance, security offload(IPsec, SSL) or pattern match accelerator engine. Freescale also provide software development kit to speed up software development. Besides, Freescale also provides product longevity program which makes a broad range of devices available for a minimum period of 10 years.
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Qsingle core 和 multiple cores平台有什么区别？
ASingle core has dedicated access to peripheral devices/controller, performance is more predictable. Mutli core share resources more efficiently, the draw back is performance is less deterministic due to sharing.
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QMiddleware Libraries有什么作用，为开发带来哪些方便？
AIt is beneficial for SOC vendor to take charge of middleware libraries. First, the SOC vendor owns the IP of a hardware moduel and his engineers are the best candidates to implement the libraries for a module. Comparing a library to a whole software system pack, it is easier for an SOC vendor to take good care of a library, instead of an OS or an high level application. So SOC vendor providing middle libraries can bring users prompt library update and utmost functions of the hardware module.
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QSDN及时性管理的原理是什么？
A SDN方面可以应用在运营商网络中的很多应用场景。在无线网络中，运营商在网络中部署了一些业务节点如防火墙、深度包检测、病毒检测等以提供不同的服务。对于来自于不同用户或不同应用的流量，需要经过特定的业务链，而这种业务链可能会依据网络状况和用户的应用动态调整。但目前的技术只能静态配置业务链或扩展性有限制，造成网络节点的低效以及扩展性难题。 SDN控制器可以灵活动态地配置业务流所走的路径。 为实现这种动态以及灵活及时地根据网络节点状况作出反应, 必须建立一些新的机制,使得控制器依据这些机制提供的信息及策略调度网络流量。比如为了根据不同的应用决定业务流路径, 需要DPI设备将检测到的业务类型汇报给控制器, 控制器为这个业务流选择最佳的路径。
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Q目前有很多厂商是被动发展SDN相关技术的，您如何看待这种现象？
AThat depends on the decisions of each companies. Some companies are quite aggressive on SDN/Data center markets, some are not. All of them have their reasons for their decision. Freescale respects and supports all kinds of strategies by each companies.
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Q在SDN领域也像手机一样，从单核向多核发展，核数会增加到多少？
AThat depends on which functions are for the equipments. For top-of-rack switches, most of vendors use four cores. But for some computing nodes, 16/32 cores with multi-threads are popular at present.
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Qmultiple cores平台有哪些优点？
AMultiple cores make shareing easy, you can run multiple applications in the same system. Base on your need, you can also partition the mutliple cores to run AMP or/and SMP mode for greater flexibility.
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QSDN走向虚拟化有什么好处？
A SDN can easily move virtual resources throughout the network, create private virtual networks that meet specific performance and security needs, and a host of other high-value applications.
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Q虚拟化设备有什么好处？
AVirtualization help datacenter and network vendors dynamically run service (virtual machine) as needed to address demand surge. There will be less idle CPU and more efficient power management.
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