2016年8月15日
By 托德•约翰逊总统 & collective Technology, Inc .董事会主席.
专题文章

并非所有的企业视频传输系统都是一样的

There is no shortage of delivery technologies intended to handle bandwidth-intensive traffic like video, 特别是, 视频直播. 面向企业IT专业人员, trying to meet expectations that all videos will be available at acceptable quality all the time across all platforms isn’t easy.

所以，什么对你的企业是最好的? 像大多数重要的问题一样，答案取决于你的需求. 适用于一个应用程序的东西可能不适用于另一个应用程序.

Three video delivery technologies have emerged over the years that offer the most potential for supporting various applications:

硬件缓存和流中继器
多播
Peer-assisted交付

硬件缓存和流中继器

These devices were initially intended to improve performance for web pages and lightweight transactions, 传送视频并不是它们的主要目的. Using hardware caches and stream repeaters involves deploying multiple hardware devices at judicious locations around the enterprise to cache on-demand video or repeat 视频直播 streams for end-users near the devices.

适合点播视频服务的缓存需要大量快速的本地存储空间. Video on demand (VOD) also requires repeaters capable of receiving and echoing a number of differing types of live streaming protocols. 这可能给全球性、异质企业带来挑战. Supporting both live and on-demand video requires devices capable of both or the installation of multiple devices at each location.

这也是一项昂贵的冒险. 在公司拥有许多不同规模和连接的地点的情况下，它的可扩展性很差, 或者用户群体正在发生变化, since the devices are sized and placed to match the needs of a location and are not readily changed or redeployed. Eventually you end up with smaller offices not being served—the irony is that the people in these offices need the communication the most.

多播

This technology uses devices already spread throughout an enterprise network as opposed to hardware caching that relies on deploying additional purpose-built devices: switches, 路由器, 和网关. Most of these have the built-in ability to forward a single incoming data stream to many downstream devices at once. 你可以把它想象成广播的方式.

类似于硬件缓存中使用的中继器, 多播避免将相同的流从源单独发送到每个最终用户. 这使得企业可以在共享链路上节省带宽.

这对这项技术来说是积极的. 多播 is an effective way to reduce bandwidth use when delivering high-quality 视频直播 to a large audience, 比如CEO全体员工广播, 同时大大减少了服务器和网络的负载.

但也有局限性. 事实证明，有许多方法可以配置多播. 在每个涉及的服务器上，整个配置必须是正确的和同步的, device, 和终端用户机器的组播成功.

然后是视频回放技术的问题. 每个终端用户机器必须能够接收多播流, and that usually takes the form of vendor-specific applications that may not be compatible or even available across all end-user devices.

因为它承诺要斋戒, 无处不在的, 为企业提供高效的视频传输, 很少有公司成功地采用多播作为视频传输技术. 多播 is not well-suited for environments looking to solve bandwidth problems related to video-on-demand.

Peer-Assisted交付

有点像多播, peer-assisted delivery makes use of existing infrastructure to provide efficient video delivery across the enterprise, recruiting available resources on end-user machines to build a distributed edge cache and stream-repeating server farm. 在终端用户机器上安装一个小型软件代理, 使他们能够参与到一个新兴的类似电网的输送网络中.

这种方法有几个有趣的优点. 只需要部署终端用户软件, 没有硬件, and this is generally substantially faster and cheaper than geographically-dispersed hardware deployments. 这也使得系统可以很容易地升级，以处理新的协议和其他不断变化的需求. 中央控制器通常由供应商托管和管理, 一些供应商提供私有云选项.

同侪辅助传送系统自然具有自缩放性. 终端用户想要观看的内容越多, 就会有更多的设备可以为他们提供内容. Some implementations take advantage of the fact that there is a smart agent on each user machine and provide additional delivery services such as content subscriptions with background delivery or distribution of other content types. Peer-assisted交付 technology enables the full range of diverse enterprise video use cases including one-to-many live broadcasting, 实时和按需人力百家乐软件培训, 数字标牌和360度视频等等.

新兴的趋势

未来几年，企业网络可能会发生重大变化, 其中许多将对视频交付服务产生直接影响. 它们包括以下内容:

Wi-Fi
WebRTC
云端的服务
软件定义网络(SDN)
软件定义的企业内容交付网络(SD ECDN)

Wi-Fi

An ever-increasing number of end-user devices in the enterprise connect into the company's network over Wi-Fi. This follows naturally from the increased power of mobile devices and laptops and the increased mobility of the workforce. 然而, 这一趋势伴随着复杂的因素, 特别是在无线网络上分配和共享带宽的方式.

Technologies such as multicast that may help with applications such as video can be severely constrained in typical Wi-Fi deployments. 一些软件定义的对等辅助方法可以减轻这些担忧, 很大程度上是因为它们的分布式适应性.

WebRTC

网络实时通信背后的思想, 或者简单地, WebRTC是实现实时的, 点对点通信会话，包括来自本地web浏览器的语音和视频, 不需要插件.

WebRTC仍然是新的，在生产中的实际应用很少. 目前，只有有限数量的浏览器支持WebRTC. 值得注意的是，有两款浏览器没有:ie浏览器 & Safari. 这些浏览器主导着企业部署, 即便如此，由于标准仍在不断成熟，兼容性问题仍然存在.

WebRTC的承诺是在个人用户之间进行实时会话. 在公司的联络中心, 例如, an agent may be able to establish an audio or video session with a customer who is visiting its support site for a video chat. 但在这个阶段，它是严格一对一的, 不是一对多, 并且只适用于实时会话, 比如视频会议. There’s no support for video on demand or bandwidth management features to deal with performance issues.

Some vendors are exploring attempts at one-to-many applications built on WebRTC that rely on sparsely supported features, 但这些方法的可行性尚未得到证实.

而WebRTC无疑是一项值得关注的技术, 它还不是一个适用于所有大规模企业视频用例的可行解决方案.

云端的服务

More and more solutions are being offered to the enterprise from services that are hosted on external clouds, 比如亚马逊的AWS和微软的Azure. 这是云服务惊人增长的自然结果, 提供经济, 主要是无摩擦的, 高度可扩展的托管基础设施.

所有这些外部托管服务都通过企业的互联网网关提供给最终用户. That means these alternatives can present wildly different traffic patterns for IT to manage and accommodate.

这也给一些视频传输方法带来了明显的挑战, 尤其是多播, increasing the complexity of establishing multicast networks across these gateways to almost unmanageable proportions.

SDN

SDN, 或者软件定义的网络, is hailed by many as a revolutionary approach to the way large networks are deployed and managed within an enterprise. SDN is a sensible move towards making all of the management and control of network infrastructure fully software-based.

SD ECDN

软件定义的企业内容交付网络被设计为高效工作, 企业网络中的经济内容交付系统.

软件定义的ecdn带来了一定程度的控制、灵活性和适应性. 该技术往往具有类似于SDN的架构, 中央控制器协调分布式和多样化的交付资产, 为完全可编程性提供通用API.

当前的SD ECDN实现是围绕一个对等辅助的交付核心构建的, capitalizing on its software-based nature and adaptability as well as its many clear advantages as a video delivery technology.

提供必要的安全保障, 最好的同侪协助系统是建立多层次的递送网络, 基于pki的安全框架，消除了攻击漏洞, 提供点对点和静态加密, validate signatures on data from arbitrary nodes and implement identity-based content access-control.

Further, having agents on all the end-user machines that are in touch with a central controller provides the basis for deep, 集中控制配送网络, SD系统的签名属性. This allows IT to put in place delivery and resource-utilization policies that match the performance and impact tradeoffs they wish to make and makes it easy to change and adapt these dynamically as needs dictate.

这些都是智能代理, 能够处理多种交付方式, 最大化现场活动的性能, 分散按需内容库的缓存负载, 并礼貌地吸收了后台订阅交付的空闲带宽.

IT部门处理各种令人眼花缭乱的视频传输技术已经够久了, 纠结于如何最好地服务于多样化的用户群. 虽然所有的系统都有积极的一面, SD ECDN模型是为企业视频环境带来健康的技术, 以及一个新的性能和控制水平，最终用户和IT都将欣赏.

这是一篇由供应商提供的文章. 流媒体 accepts 文章 contributed by vendors based solely on the value of insight and 信息 they offer to our readers.