Just to illustrate the problems of making SLA part of IKEv2 let me point out to
an argument against using EAP in the context of SLA that was given in a
previous message. It was claimed that adding EAP to SLA would
require all implementations of IKE to implement EAP. But then why should ALL
implementation of IKE be required to implement all the remote-access
and legacy-authentication payloads and the sepcial authentication mode??
If, in contrast, SLA implementation would be required only for
those providing remote user access, then implementing EAP would be
a natural thing to require given that EAP is today's most general
IETF-standarized mechanissm for transporting user (and legacy) authentication
information.
Bottom line: I suggest to (a) separate SLA to another document; (b) develop IKEv2 and SLA at the same time (i.e. now); (c) advance the separate documents for standardization concurrently; (d) do NOT make SLA a mandatory mode of IKEv2.