SIP Authentication Challenge
When the Oracle Communications Core Session Manager receives a response from the HSS including the hash value for the user, it sends a SIP authentication challenge to the endpoint, if the endpoint did not provide any authentication headers in its initial contact the with Oracle Communications Core Session Manager. If the endpoint is registering, the Oracle Communications Core Session Manager replies with a 401 Unauthorized message with the following WWW-Authenticate header:
WWW-Authenticate: Digest realm="atlanta.com", domain="sip:boxesbybob.com", qop="auth", nonce="f84f1cec41e6cbe5aea9c8e88d359", opaque="", stale=FALSE, algorithm=MD5
If the endpoint initiates any other request to the Oracle Communications Core Session Manager besides REGISTER, the Oracle Communications Core Session Manager replies with a 407 Proxy Authentication Required message with the following Proxy-Authenticate header:
Proxy-Authenticate: Digest realm="atlanta.com", qop="auth", nonce="f84f1cec41e6cbe5aea9c8e88d359", opaque="", stale=FALSE, algorithm=MD5