http://trafficserver.apache.org/downloads
当从 5.x 升级至 6.0 版本时，需要重新编译用户编写的插件。如果从 3.2.0+ 版本升级至 v6.0.0，清闲保存好缓存，详细升级指导请看：https://cwiki.apache.org/confluence/display/TS/Upgrading+to+v6.0
这是第二个支持 HTTP/2 的版本，现在已经趋于稳定。此版本不再支持 RHEL5。
主要改进如下：
日志记录组件
应用协议 (HTTP/2, HTTP/1, SPDY/3.1), with %
Milestones/state times of a transactions to get a better understanding of where time for responses is spent.
SSL session 攻击或者丢失
连接复用或者请求新连接
Wiretracing TLS
Ability to wire trace and log TLS connections. See "New Configuration Options" below.
PCRE Jit
Added support for PCRE Jit for regex_map. Automatically used when compiled on a system that supports it. There is a speed improvement over normal PCRE matching.
将废弃的特性
traffic_line command line program will be removed in the 7.0.0 release and is replaced by the command line program traffic_ctl
SPDY support will be removed in the 7.0.0 release and is replaced by only supporting HTTP/2
新配置选项
proxy.config.cop.init_sleep_time
proxy.config.http.websocket.max_number_of_connections
proxy.config.net.max_connections_active_in
proxy.config.http.max_post_size
proxy.config.http.cache.generation
proxy.config.http.cache.open_write_fail_action
proxy.config.net.inactivity_check_frequency
proxy.config.net.event_period
proxy.config.net.accept_period
proxy.config.net.retry_delay
proxy.config.net.throttle_delay
proxy.config.cache.read_while_writer.max_retries
proxy.config.cache.read_while_writer_retry.delay
proxy.config.log.periodic_tasks_interval
proxy.config.ssl.handshake_timeout_in
proxy.config.ssl.wire_trace_enabled
proxy.config.ssl.wire_trace_addrproxy.config.ssl.wire_trace_percentage
proxy.config.ssl.wire_trace_server_name
proxy.config.http2.accept_no_activity_timeout
proxy.config.http2.no_activity_timeout_in
proxy.config.allocator.hugepages
新指标
HTTP/2 Metrics
proxy.process.http2.total_client_streams
proxy.process.http2.total_transactions_time
proxy.process.http2.total_client_connections
proxy.process.http2.connection_errors
proxy.process.http2.stream_errors
proxy.process.http2.current_client_sessions
proxy.process.http2.current_client_streams
新插件（实验性）
stream_editor - Plugins for modifying the content of a response using a string or regular expression substitution
mp4 - Allows for starting at the offset of a mp4 video stream
cache_promote - Give better granularity on when an object is allowed to be written into the cache.
更多改进内容请看：https://cwiki.apache.org/confluence/display/TS/What%27s+New+in+v6.0.x
JIRAs：https://issues.apache.org/jira/secure/ReleaseNote.jspa?version=12324897&styleName=&projectId=12310963
Traffic Server 是一套快速、模块化的兼容 HTTP/1.1 的反向代理服务器，与 Nginx 和 Squid 类似，目前该项目已经转到 Apache 基金会。
Traffic Server设计的思想是将一个大系统划分为若干个小的子系统，每个子系统负责专门的任务或应用。比如，Event子系统负责提供任务调度服务，Net子系统负责提供网络服务。每个子系统抽象为一个Processor，这种高内聚低耦合的设计原则使系统具有更好的重用性，维护性和扩展性。例如，如果hostDBProcessor需要进行DNS解析，可以直接调用dnsProcessor的相关函数，而无需关注DNS解析的细 节；dnsProcessor也只需封装DNS请求和解析DNS应答，和网络相关的功能可以调用netProcessor来完成。
来自:开源中国社区