The SIPP working group represents the evolution of three different IETF working groups focused on developing an IPng. The first was called IP Address Encapsulation (IPAE) and was chaired by Dave Crocker and Robert Hinden. It proposed extensions to IPv4 which would carry larger addresses. Much of its work was focused on developing transition mechanisms.
Somewhat later Steve Deering proposed a new protocol evolved from IPv4 called the Simple Internet Protocol (SIP). A working group was formed to work on this proposal which was chaired by Steve Deering and Christian Huitema. SIP had 64-bit addresses, a simplified header, and options in separate extension headers. After lengthly interaction between the two working groups and the realization that IPAE and SIP had a number of common elements and the transition mechanisms developed for IPAE would apply to SIP, the groups decided to merge and concentrate their efforts. The chairs of the new SIP working group were Steve Deering and Robert Hinden.
In parallel to SIP, Paul Francis (formerly Paul Tsuchiya) had founded a working group to develop the "P" Internet Protocol (Pip). Pip was a new internet protocol based on a new architecture. The motivation behind Pip was that the opportunity for introducing a new internet protocol does not come very often and given that opportunity important new features should be introduced. Pip supported variable length addressing in 16-bit units, separation of addresses from identifiers, support for provider selection, mobility, and efficient forwarding. It included a transition scheme similar to IPAE.
After considerable discussion among the leaders of the Pip and SIP working groups, they came to realize that the advanced features in Pip could be accomplished in SIP without changing the base SIP protocol as well as keeping the IPAE transition mechanisms. In essence it was possible to keep the best features of each protocol. Based on this the groups decided to merge their efforts. The new protocol was called Simple Internet Protocol Plus (SIPP). The chairs of the merged working group are Steve Deering, Paul Francis, and Robert Hinden.