文档介绍：一概念
Totally-ordered multicast (5pt)
A multicast operation by which all messages are delivered in the same order to each receiver.
Scalability (5pt)
scalability is the ability of a system, network, or process to handle a growing amount of work in a capable manner or its ability to be enlarged to accommodate that growth.
Availability & Reliability (5pt)
Availability: Readiness for usage o说明系统已准备好，马上就可以使用。通常，它指在 任何给定的时刻，系统都可以正确地操作，可根据用户的行为来执行它的功能。换句 话说，高度可用的系统在任何给定的时刻都能及时地工作。
Reliability: Continuity of service delivery。指系统可以无故障地持续运行。与可用性相 反，可靠性是根据时间间隔而不是任何时刻来进行定义的。
Omission failures (5pt)
〃当服务器不能对请求进行响应时就发生遗漏性故障。
A component fails to respond to incoming requests.
Receive omission: Fails to receive incoming messages.
Send omission: Fails to send messages
Bully Algorithm (5pt) P451
The bullv alsorithm is a method in distributed computins for dvnamicallv electing a coordinator bv process ID number. The process with the highest process ID number is selected as the coordinator.
Piimary-back protocols (5pt)
Protocols that allow processes to perform read operations on a locally available copy ,but should forward write operations to a (fixed) primary copy.
CDN (Content Delivery Networks) (5pt)
A content delivery network or content distribution network (CDN) is a large distributed system of servers deployed in multiple data centers across thelntemet. CDNs serve a large fr