Header
Date
Diversion
Error-Info
Event
Expires
From
In-Reply-To
Max-Forwards
Min-Expires
Min-SE
MIME-Version
Organization
P-Asserted-Identity
P-Preferred-Identity
Priority
Privacy
Proxy-Authenticate
Proxy-Authorization
Proxy-Require
RAck
Record-Route
Refer-To
Referred-By
Referred-To
Remote-Party-ID
Replaces
Reply-To
Requested-By
Require
Response-Key
Supported
Notes
No
Yes
No
Yes
Yes
Yes
No
Yes
No
Yes
No
No
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Yes
No
Session Initiation Protocol (SIP)
B - 5