I've been building IPsec VPNs for years but to be honest I've never fully grasped the technical difference between IKE and ISAKMP. I often see the two terms used interchangeably (probably incorrectly).
I understand the two basic phases of IPsec and that ISAKMP seems to deal primarily with phase one. For instance, the IOS command "show crypto isakmp sa" displays IPsec phase one information. But there's no equivalent command for IKE.