Note 1、 本文只涉及User-Server-User过程[Request及Response请参考上图] 2、 有关站点加速及Cache请参考：http://longrujun.com/tags/SQUID/default.aspx 3、 有关大规模站点体系规划及性能优化请参考下图，不深入探讨

In the world of information technology, the concept of abstractions are particularly handy. Take, for example, the Services abstraction at the heart of SOA, which masks the complexity of the underlying technology implementation while presenting composable business Services to internal and external users. But every abstraction comes at a price, and the Services abstraction is no exception. Loose coupling, composability, agility, and the other benefits of SOA all introduce performance overhead. For limited sets of Services with small numbers of users, this performance hit may be minimal. For SOA implementations with large numbers of users, Services, or traffic, however, maintaining the necessary performance levels presents a substantial challenge, both to the architects who design the infrastructure as well as IT operations personnel who are responsible for keeping the lights on.

Squid反向代理N个后台WEB实现说明[小结文档]