802 Handoff A Technical Preview

1. 802 HandoffA Technical Preview David Johnston david.johnston@ieee.org dj.johnston@intel.com David Johnston, Intel

2. Purpose (of these slides) • To date, a lot has been said about scope, purpose, goals, interworking, liason, PARs and other such things • This presentation skips rapidly through that and gets to the meat of some technical aspects of 802 handoff that could become part of the standard David Johnston, Intel

3. Problem Statements • Three problem statements approved as findings of the group • #1 Detection of a useable attachment to a network is impacted by the ambiguous indicators of network attachment in certain 802 MACs. Thus there is a need to develop a standard that allows a mobile terminal to optimize detection of a useable attachment to a network above the LLC. • #2 The information necessary to make effective handoff decisions is lacking in part because 802 networks provide insufficient information to the upper layers. Thus there is a need to develop a standard that permits information exchange between mobile terminals and/or networks to enable mobile terminals and/or networks to make more effective handoff decisions. • #3 There is no standardized mechanism in 802 for information exchange between mobile terminals and network attachment points. This impacts the ability to make informed decisions to select between disparate network attachment points or to initiate handoffs between heterogeneous network types or between administrative domains within a single network type. Thus there is a need to develop a standard that permits mobile terminals and network attachment points to access information on which to base effective handoff decisions. David Johnston, Intel

4. Draft Scope • For the purposes of converging towards a consensus on purpose and scope, the group approved the following text as a working copy of the scope for discussion prior to the September interim • “The scope of this project is to develop a standard that shall define mechanisms that may be adopted into implementations so that handoff of handoff-capable upper layer entities, e.g. MobileIP sessions, can be optimized between homogeneous or heterogeneous media types both wired and wireless, where handoff is not otherwise defined. • Consideration will be made to ensure compatibility with the 802 architectural model. • Consideration will be made to ensure that compatibility is maintained with 802 security mechanisms including 802.1x. Neither security algorithms nor security protocols shall be defined in the specification.” David Johnston, Intel

5. Draft Purpose • For the purposes of converging towards a consensus on purpose and scope, the group approved the following text as a working copy of the purpose for discussion prior to the September interim • “The scope of this project is to develop a standard that shall define mechanisms that may be adopted into implementations so that handoff of handoff-capable upper layer entities, e.g. MobileIP sessions, can be optimized between homogeneous or heterogeneous media types both wired and wireless, where handoff is not otherwise defined. • Consideration will be made to ensure compatibility with the 802 architectural model. • Consideration will be made to ensure that compatibility is maintained with 802 security mechanisms including 802.1x. Neither security algorithms nor security protocols shall be defined in the specification.” David Johnston, Intel

6. Relevant Elements in Network David Johnston, Intel

7. Handoff Cases David Johnston, Intel

8. What Can We Do? • Easy: • Enable make before break handoffs • Reduce length of break before make handoffs • Prevent inappropriate attachment attempts • Improve scanning speed • Prevent unnecessary DHCP attempts • Hard: • Pre authenticate via backbone • Transfer QoS context • Remotely interrogate base stations • Media independent handoff decisions on network side • L2 end to end triggers David Johnston, Intel

9. How do we do it • Easy • Provide an information base with defined structure and semantics • Provide access via the top (API, MAC SAP messages, management interface (oids, ndis snmp) • Provide access via link (extended 802.1x model, encapsulation) • Hard • Define new media independent inter base protocols • Other (Left as exercise to the reader) David Johnston, Intel

10. L1,2 – L3 Triggers • Meets emerging requirements in IETF for fast mobile IP and for effective DNA (Detection of Network Attachment) • Maps elsewhere (non IP, handoff-able L3 nets) • Sends events upwards from L2 to L3 • Indicated specific states or state changes • Link Up, Handoff decision, etc • May contain per trigger metadata • Link ID, VLAN etc. David Johnston, Intel

11. The 802.1x Model David Johnston, Intel

12. Extending The 802.1x Model David Johnston, Intel

13. Extending the 802.1x model • 2 Handoff ethertypes, one for secure, one for insecure • Device on other end of link can interrogate the information bases using packets marked with the appropriate ethertypes • Packets passed are traditional MSDUs common to all 802 MACs • Thus information can be made available independent of media type David Johnston, Intel

14. Define Handoff Decision Data • Pre defined information to support handoff decisions • Network vendor • Auth types supported • L3 network media (internet/PSTN/ATM etc) • Etc • Make it extensible • Supports proprietary vendor codes/extensions • Supports playpen data types David Johnston, Intel

15. Transporting The Decision Data • It needs a coding and encapsulation for transmission • Ethertypes to map into extended 802.1x model • ASN.1 or XML or canonical S expressions • I prefer canonical S expressions due to opportunities for easy parsing, signing and stateless expression • XML canonicalisation needed for signing • VERY compute intensive David Johnston, Intel

16. Define Media Independent HO Decision Data Encapsulation EG: <base_descriptor> <media_type>802.11</media_type> <auth_required> <auth_vendors> ipass boingo </auth_vendors> <backbone_pre_auth> yes </backbone_pre_auth> <CS_descriptor> <type>mIPv6</type> <address>192.168.0.1</address> </CS_descriptor> <adjacent_bases> base1 base2 etc. </adjacent_bases> </base_descriptor> • Pick XML/ ASN.1/ Canonical S Expressions • Make it suitably extensible David Johnston, Intel

17. More ‘out there’ ideas • Make link signaling carry more elaborate semantics than ‘fetch’ • Get/Set, Forward, Remote Request • Enable end to end triggers through information conduit • Allows remote triggering, network side handoff commands to mobile part David Johnston, Intel