HTTP/2 connections are persistent. For best performance, it is expected that clients will not close connections until it is determined that no further communication with a server is necessary (for example, when a user navigates away from a particular web page) or until the server closes the connection.
HTTP/2连接是持久连接。为了获得最佳性能，人们期望客户端不要关闭连接，直到确定不需要再继续和服务端进行通信(例如，当用户离开一个特定的web页面时)，或者直到服务端关闭连接。
Clients SHOULD NOT open more than one HTTP/2 connection to a given host and port pair, where the host is derived from a URI, a selected alternative service [ALT-SVC], or a configured proxy.
对于给定的一对主机和端口，客户端应该只打开一个 HTTP/2 连接，其中主机或者来自于一个 URI ，一种选定的 可替换的服务 [ALT-SVC] ，或者来自于一个已配置的代理。
A client can create additional connections as replacements, either to replace connections that are near to exhausting the available stream identifier space (Section 5.1.1), to refresh the keying material for a TLS connection, or to replace connections that have encountered errors (Section 5.4.1).
客户端可以创建额外的连接作为替补，或者用来替换将要耗尽可用流标识符空间( 5.1.1节 )的连接，为一个 TLS 连接刷新关键资料，或者用来替换遇到错误( 5.4.1节 )的连接。
A client MAY open multiple connections to the same IP address and TCP port using different Server Name Indication [TLS-EXT] values or to provide different TLS client certificates but SHOULD avoid creating multiple connections with the same configuration.
客户端可以和相同的 IP 地址和 TCP 端口建立多个连接，这些地址和端口使用不同的服务器名称指示 [TLS-EXT] 值，或者提供不同的 TLS 客户端证书。但是应该避免使用相同的配置创建多个连接。
Servers are encouraged to maintain open connections for as long as possible but are permitted to terminate idle connections if necessary. When either endpoint chooses to close the transport-layer TCP connection, the terminating endpoint SHOULD first send a GOAWAY (Section 6.8) frame so that both endpoints can reliably determine whether previously sent frames have been processed and gracefully complete or terminate any necessary remaining tasks.
鼓励服务端尽可能长地维持打开的连接，但是准许服务端在必要时可以关闭空闲的连接。当任何一端选择关闭传输层 TCP 连接时，主动关闭的一端应该先发送一个 GOAWAY 帧( 6.8节 )，这样两端都可以确定地知道先前发送的帧是否已被处理，并且优雅地完成或者终结任何剩下的必要任务。