To the extent SIP was industry driven, it was due to the fuzzy standards themselves which left a lot of room for vendor specific handling especially used to max

To the extent SIP was industry driven, it was due to the fuzzy standards themselves which left a lot of room for vendor specific handling especially used to max out their own device to device performance often supported by proprietary enhancements. The biggest trade show was called Interop for a reason. At this point SIP might have served its purpose, but the basic approach of separating a control signaling plane from media paths has stood the test of time.