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.

ISAKMP is part of IKE. (IKE has ISAKMP, SKEME and OAKLEY). IKE establishs the shared security policy and authenticated keys. ISAKMP is the protocol that specifies the mechanics of the key exchange.

The confusion, (for me,) is that in the Cisco IOS ISAKMP/IKE are used to refer to the same thing. By which I mean, my understanding is that Cisco's IKE only implements/uses ISAKMP. So one configures IKE, and then conceptually inside that, one configures ISAKMP.
