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• 广播延时 – 这与网络传播距离有关, 数据跨网络到达目的地,  和信号通过的中介地. 延时范围从本地网络(LAN)的纳秒到微秒延时, 到卫星通信系统的0.25秒延时.
• 传输延时 – 这些延时是发送所有数据包的比特流到链接网络层所需要的时间, 这是一个包长度和链接层速率的问题. 例如, 为了传输一个10 Mb 文件跨 1 Mbps 链接层将需要10秒中, 而跨 100 Mbps 链接层只需要 0.1 秒.
• 处理延时 – 这个延时是处理包头, 检查比特级错误, 确定包的发送目的地的所花时间. 在高速路由环境处理延时基本是最小的. 然而, 对于网络处理复杂加密或深度包检测, 处理延时还是比较大的. 另外, 处理 NAT 的路由器也有高于正常处理的延时, 因为这些路由器都需要检查, 和修改输入和输出包.
• 队列延时 – 这些延时都是路由队列所消耗的时间. 网络设计的实际情况是一些队列延时将出现. 有效的队列管理技术是关键的, 可以保障高优先级的流量体验.

最佳实践

It should be noted that latency, not bandwidth, is the most common performance bottleneck for network dependent systems like websites. Therefore, one of the key design goals in architecting a Geode solution is to minimize network latency. Best practices for achieving this goal include:

本文将主要关注延时, 而不是带宽, 对于依赖网络的系统来说, 这是最普遍的性能瓶颈. 因此架构Geode解决方案的关键设计之一就是最小化网络延时. 达到这一目标的最佳实践如下:

• 保持 Geode 服务器和客户端在同一个局域网内, 最好是在同一个网段内. 目标是放所有的Geode 集群成员和客户端尽可能临近, 以减少互相通信的网络延时. 这不仅减少了广播延时, 也减少了路由和流量管理的延时. Geode 成员在一致的通信环境中, 甚至网络延时相对变化较少,能够大幅放大整体的性能.
• 慎重使用网络流量加密, Geode 将产生大量网络流量, 包括一定量的系统管理流量. 在 Geode 集群成员之间加密网络流量将增加处理延时, 甚至流量并不包含敏感数据.  可以考虑仅仅在敏感数据上进行加密. 或者, 如果是必要的限制 Geode 成员之间的数据访问, 考虑将 Geode 集群放在一个隔离的网络安全域内, 与其他的系统进行隔离.
• 使用最快的网络链路, 虽然带宽并不能单独决定吞吐量 - 所有事情都是平等的, 一个高速链路将比低速链路传输更多的数据, 在相同的时间下. 分布式系统如 Geode 透过网络传输高通量数据得益于高速的网络链路. 而一些对网络性能要求比较高通常使用 InfiniBand 网络技术, 达到 40Gbps, 10GbE 对于大多数应用是足够的, 在生产/测试环境下基本满足需求
• Keep Geode members and clients on the same LAN Keep all members of a Geode distributed system and their clients on the same LAN and preferably on the same LAN segment. The goal is to place all Geode cluster members and clients in close proximity to each other on the network. This not only minimizes propagation delays, it also serves to minimize other delays resulting from routing and traffic management. Geode members are in constant communication and so even relatively small changes in network delays can multiply, impacting overall performance.
• Use network traffic encryption prudently Distributed systems like Geode generate high volumes of network traffic, including a fair amount of system management traffic. Encrypting network traffic between the members of a Geode cluster will add processing delays even when the traffic contains no sensitive data. As an alternative, consider encrypting only the sensitive data itself. Or, if it is necessary to restrict access to data on the wire between Geode members, consider placing the Geode members in a separate network security zone that cordons off the Geode cluster from other systems.
• Use the fastest link possible Although bandwidth alone does not determine throughput - all things being equal, a higher speed link will transmit more data in the same amount of time than a slower one. Distributed systems like Geode move high volumes of traffic through the network and can benefit from having the highest speed link available. While some Geode customers with exacting performance requirements make use of InfiniBand network technology that is capable of link speeds up to 40Gbps, 10GbE is sufficient for most applications and is generally recommended for production and performance/system testing environments. For development environments and less critical applications, 1GbE is often sufficient.

高吞吐量

另外对于低延时来讲, Geode 系统的网络需要有高吞吐量. ISPs 和 FCC 经常使用术语'带宽'和'速度', 虽然它们并不是一回事. 事实上, 带宽只是众多影响因素之一. 因此, 更准确地说

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