HTTP
Hypertext Transfer Protocol
HTTP (Wikipedia)
HTTP (Mozilla Developer Network)
RFC 2616 HTTP v1.1
RFC 7540 HTTP v2
HTTP List of status codes (Wikipedia)
SIP
Session Initiation Protocol
SIP (Wikipedia)
RFC 3261
SIP response codes (Wikipedia)
TCP
TRANSMISSION CONTROL PROTOCOL
RFC 793
SCTP
Stream Control Transmission Protocol
RFC 4960
DIAMETER protocol
Diameter protocol is the successor of the RADIUS protocol.
It uses TCP or SCTP as transport protocol.
RFC 6733
Wireshark entry about DIAMETER protocol