%% You should probably cite rfc6223 instead of this I-D. @techreport{ietf-sipcore-keep-12, number = {draft-ietf-sipcore-keep-12}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-ietf-sipcore-keep/12/}, author = {Christer Holmberg}, title = {{Indication of Support for Keep-Alive}}, pagetotal = 18, year = 2011, month = jan, day = 20, abstract = {This specification defines a new Session Initiation Protocol (SIP) Via header field parameter, "keep", which allows adjacent SIP entities to explicitly negotiate usage of the Network Address Translation (NAT) keep-alive mechanisms defined in SIP Outbound, in cases where SIP Outbound is not supported, cannot be applied, or where usage of keep-alives is not implicitly negotiated as part of the SIP Outbound negotiation. {[}STANDARDS-TRACK{]}}, }