differences.txt

SSD8的练习一答案

Caching

It did not allow either origin servers or clients to give full and explicit instructions to caches; therefore, it depended on a body of heuristics that were not well-specified. This led to two problems: incorrect caching of some responses that should not have been cached, and failure to cache some responses that could have been cached. The former causes semantic problems; the latter causes performance problems In order to make caching requirements more explicit, HTTP/1.1 adds the new Cache-Control header, allowing an extensible set of cache-control directives to be transmitted in both requests and responses. The set defined by HTTP/1.1 is quite large, so we concentrate on several notable members

Bandwidth optimization

HTTP/1.0 wastes bandwidth in several ways that HTTP/1.1 addresses. A typical example is a server's sending an entire (large) resource when the client only needs a small part of it. There was no way in HTTP/1.0 to request partial objects. HTTP/1.1 range requests allow a client to request portions of a resource

Persistent Connections

HTTP/1.0, in its documented form, made no provision for persistent connections. Some HTTP/1.0 implementations, however, use a Keep-Alive header to request that a connection persist. This design did not interoperate with intermediate proxies 。 HTTP/1.1 specifies a more general solution. In recognition of their desirable properties, HTTP/1.1 makes persistent connections the default.HTTP/1.1 clients, servers, and proxies assume that a connection will be kept open after the transmission of a request and its response. The protocol does allow an implementation to close a connection at any time, in order to manage its resources, although it is best to do so only after the end of a response. 

In my code ,I will give more information to the users and add more options to make sure the users feel more comfortable.