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Diameter Session Mobility draft-liu-aaa-diameter-session-mobility-00.txt IETF56 San Francisco, March 19 th 2003. Liu Qing, Le Yanqun, Forsberg Dan Nokia Research Center. Diameter Session Management in Diameter Application Protocols.
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Diameter Session Mobilitydraft-liu-aaa-diameter-session-mobility-00.txtIETF56 San Francisco, March 19th 2003. Liu Qing, Le Yanqun, Forsberg Dan Nokia Research Center
Diameter Session Management in Diameter Application Protocols • Diameter session consists of one or more AAA transactions related to a user, but the current Diameter Base Protocol can only handle static users -> There is no session mobility. • In Diameter Mobile IPv4 Application, a new Diameter Session is suggested to be set up when the user changes his access router. But this is not so effective, in the sense of the round-trip of AAA messages and scalability. REQUIREMENT: A generic Diameter Session Mobility Mechanism that enable users to change their access router without affections to their home servers.
AAAL AAAH ? Context transfer Router Router AR “Case Study”: Handoff • When MN has changed the AR • How to Abort session? How to forward unsolicited requests from AAAH? HA? AR Foreign Domain Home Domain MN
nAAAL aAAAL oAAAL AAAH AR AR AR AR AR Diameter Nodes in Session Mobility • aAAAL, oAAAL and nAAAL are roles for an AAAL. An AAAL can have multiple roles. Home Domain Foreign Domain aAAAL = Anchor AAAL oAAAL = Old AAAL nAAAL = New AAAL MN MN
Requirements • Each AR (AAA Client) knows its local AAA server. • More info to the routing table? • The values of oAAAL and aAAAL MUST be available for the nAAAL after handover (for example via Context Transfer between ARs, or carried by MN). • The request from the AAAH SHOULD always go through the aAAAL. • An AAAL MUST maintain the downstream node for an active session, for example: [Session-Id, Downstream-Node, Session-Timeout, …]. • Any other user AAA information maintained in AAAL can be transferred to the nAAAL(like ”Context Transfer” between AAALs).
Handover Inside One AAAL • SessionID: foo • Downstream: • y.bj.nokia.com • Other AAA info AAAH ibm.com aAAAL bj.nokia.com SUR/SUA AR y.bj.nokia.com AR x.bj.nokia.com MN SUR = Session-Update-Request SUA = Session-Update-Answer
Between two AAALs (1/2) • SessionID: foo • Downstream: • x.hsk.nokia.com • Other AAA info • SessionID: foo • Downstream: • hsk.nokia.com AAAH ibm.com AAAL hsk.nokia.com aAAAL bj.nokia.com SUR/SUA AR x.hsk.nokia.com AR x.bj.nokia.com MN
Between Two AAALs (2/2) • SessionID: foo • Downstream: • x.boston.nokia.com • Other AAA info • SessionID: foo • Downstream: • boston.nokia.com AAAH ibm.com nAAAL boston.nokia.com aAAAL bj.nokia.com oAAAL hsk.nokia.com SUR/SUA AR x.boston.nokia.com AR x.bj.nokia.com AR x.hsk.nokia.com MN MN
Request/Answer from AAAH • SessionID: foo • Downstream: • x.boston.nokia.com • Other AAA info • SessionID: foo • Downstream: • boston.nokia.com ASR/ASA or RAR/RAA AAAH ibm.com (Serving)AAAL boston.nokia.com aAAAL bj.nokia.com AAAL hsk.nokia.com STR/STA or Auth-Request/Answer AR x.boston.nokia.com AR x.bj.nokia.com MN
New AVPs • Anchor-AAA-Server AVP (DiameterIdentity). • Contains the identity of the Anchor AAA Server. • Serving-AAA-Server AVP (DiameterIdentity). • Contains the identity of the client’s current AR’s AAA Server. • Session-Update-Vector AVP (Unsigned32). • Contains a passed-by flag set by aAAAL and AAAH. • Session-Info AVP (Grouped). • Possible AVP values TBD (for session data transfer between AAALs).
Session-Update-Request <SUR> ::= < Diameter Header: XXX, REQ, PXY > < Session-Id > { Origin-Host } { Origin-Realm } { Destination-Host} { Destination-Realm } { Auth-Application-Id } [ User-Name ] [ Anchor-AAA-Server ] [ Serving-AAA-Server ] [ Session-Update-Vector ] * [ Class ] [ Origin-State-Id ] * [ AVP ] * [ Proxy-Info ] * [ Route-Record ]
Session-Update-Answer <SUA> ::= < Diameter Header: XXX, PXY > < Session-Id > { Result-Code } { Origin-Host } { Origin-Realm } [ User-Name ] [ Session-Info] [ Serving-AAA-Server ] * [ Class ] [ Error-Message ] [ Error-Reporting-Host ] * [ Failed-AVP ] [ Origin-State-Id ] * [ Redirect-Host ] [ Redirect-Host-Usase ] [ Redirect-Max-Cache-Time ] * [ AVP ] * [ Proxy-Info ]
Open Issues • Security. • Performance and scalability. • AAA session update when handoff happens between two different foreign domains. • Relationship with mobility protocols. • Race condition requirements to the Diameter Base.
Next Steps • Further study of Diameter User Session Mobility co-work with Diameter Mobile IPv4 Application and other Diameter Applications. • Performance Study/Improvement. • Security Considerations.