1. Rosenberg, J. et al., SIP: Session Initiation Protocol RFC 3261, IETF, June 2002.
2. Calhoun, P. et al., Diameter Base Protocol RFC 3588, IETF, September 2003.
3. 3GPP, Network architecture, TS 23.002 (V12.4.0), March 2014.
4. 3GPP, Policy and charging control architecture, TS 23.203 (V12.4.0), March 2014.
5. ITU-T Recommendation Y.1531, 2007. SIP-based Call Processing Performance.