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Registration Revocation in Mobile IP. draft-glass-mobileip-reg-revok-00.txt (soon to be -01!) Steven M. Glass - Sun Microsystems Steven.Glass@Sun.com. Why the Need?. RFC2002, etc. was designed when access was the issue. Mobile IP's focus was on functionality.
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Registration Revocationin Mobile IP draft-glass-mobileip-reg-revok-00.txt (soon to be -01!) Steven M. Glass - Sun Microsystems Steven.Glass@Sun.com
Why the Need? • RFC2002, etc. was designed when access was the issue. Mobile IP's focus was on functionality. • No real-world example existed to revok a registration. At the time, short registration lifetimes were sufficient for WG consensus. • Now, AAA is [one of] the "killer apps" here. • AAA requires the possibility that a registration can be immediately terminated, and Mobile IP services suspended for a particular mobile node.
Problem Space • Terminations must be able to be originated by either side - home or foreign domains. • Currently there is no "signaling" message to do this. • Terminations must be [able to be] relayed to the revoked MN (policy issue). • It MUST be understood by ALL mobile nodes, not just those "enhanced" based on this draft. • => This must be a server-only solution! • Termination messages must be Authenticated! • SAs MUST exist between HA and FA. (AAA)
An Easy Solution? • 2002: MN notification mechanism already exists! • Compliant MNs understand FA becon sequence number reset means current registration is gone! • Already provide for unicast becons to MNs. Today, triggered from Agent Solicitation messages, however: • Mobile Nodes MUST support Agent Solicitations • Mobile Nodes MUST process received Agent Advertisements • Not prohibited by RFC1256 (router discovery) • Already used by [an]other MIP draft, but let's not split hairs... • If revok-becon isn't from current FA it will be ignored, so no increased risk for denial-of-service attack.
Mobility Agent Solution • FA MAY unicast becon with sequence number 0 to MN indicating registration is gone (mipv4). • Need to add a deRegistration message that can be sent between HA and CoA (MIPv4/v6). • MUST be authenticated, and "unreplayable" • Authentication/replay failure means silently ignore. • Would be nice to specify either "unconditionally revoke" or "allow reregistration" (renegotiate).
Details... • New Registration type - Revocation "Request". • Not really a "request", more like a "notification". • MUST be sent only HA to CoA, or FA to HA. • MN's "revocation request" is the deregistration (lifetime = 0, etc)! • If Revocation Request has been accepted, Revocation Reply MAY be sent, but if not, clearly registration has still been revoked.
Network View – Foreign Domain Foreign Domain Triggered Revocation: (MIPv4-centric) MN FA HA |<--Becon(0)---| |-RevReq(FA-HA)->| |<-RevRep(HA-FA)-| Revoke = e.g. AAA to FA (not shown) Becon(0) = Agent Adv w/seq#=0 RevReq = "Request" with auth, etc. RevRep = optional, wit auth, etc.
Network View – Home Domain Home Domain Triggered Revocation MN FA/CoA HA |<---RevReq----| |<--Becon(0)---| |----RevRep--->| revoke = e.g.AAA to HA (not shown) RevReq = "Request" with auth, etc. Becon(0) = Agent Advert w/seq#=0 RevRep = optional, with auth, etc.
Revocation Message Format 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Code | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Agent Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |... (other extensions, e.g. HA-FA authenticator) ... Type: (TBD) Code: Indicates "unconditionally revoke" or "allow rereg". Lifetime: The lifetime of this deRegistration. Home Address: registered address of the MN. Agent Address: address of the agent sending the revocation. * Identifier: used for replay protection (same in req and rep).
Observations • MN will almost certainly attempt to reregister: • FA MUST NOT silently ignore! => MNconfusion! • FA MAY reply with "administratively prohibited", or FA MAY forward to HA to respond. • Different reasons for revocation lead to different reregistration actions. "unconditional" vs. "renegotiate" • MN may then attempt to reregister with different FA, but HA will handle this. • Changes to FA, and HA (obviously), but also to MNs that will colocate to understand HA revoke!
Pitfalls? • Comments from the audience???
Final Thoughts • Multiple Bindings: • HA may revoke any of multiple bindings. • If one of multiple-binding FAs revokes a registration, HA may revoke other of multiple-bindings. • The "R" bit (another use?): • An FA may set the R-bit to be able to inform MNs of other service revocations resulting in MIP revocation.