sip错误302 moved temporarily是什么意思

SIP中3XX的响应码一般表示的是和重定向有关的响应，详情请参考RFC3261。

2133 302 Moved Temporarily

The requesting client SHOULD retry the request at the new address(es)

   given by the Contact header field (Section 2010)  The Request-URI

   of the new request uses the value of the Contact header field in the

   response

The duration of the validity of the Contact URI can be indicated

   through an Expires (Section 2019) header field or an expires

   parameter in the Contact header field  Both proxies and UAs MAY

   cache this URI for the duration of the expiration time  If there is

   no explicit expiration time, the address is only valid once for

   recursing, and MUST NOT be cached for future transactions

   If the URI cached from the Contact header field fails, the Request-

   URI from the redirected request MAY be tried again a single time

      The temporary URI may have become out-of-date sooner than the

      expiration time, and a new temporary URI may be available

302响应表示请求方应当把请求重新发到这个Contact头域所指出的新地址(2010)。新请求的Request-URI应当用这个应答的Contact头域所指出的值。

在应答中的Expires(2019节)或者Contact头域的expires参数定义了这个Contact URI的生存周期。UA或者proxy在这个生存周期内cache这个URI。如果没有严格的有效时见，那么这个地址仅仅本次有效，并且不能在以后的事务中保存。

如果cache的Contact头域的值失败了，那么被转发请求的Request-URI应当再次尝试一次。临时URI可以比超时时间更快的失效，并且可以有一个新的临时URI。

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