发布网友 发布时间:2022-04-28 22:33
共1个回答
热心网友 时间:2022-06-24 06:50
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。
The requesting client SHOULD retry the request at the new address(es)
given by the Contact header field (Section 20.10). The Request-URI
of the new request uses the value of the Contact header field in the
response.
The ration of the validity of the Contact URI can be indicated
through an Expires (Section 20.19) header field or an expires
parameter in the Contact header field. Both proxies and UAs MAY
cache this URI for the ration 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The temporary URI may have become out-of-date sooner than the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(20.10)。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(20.19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。