IEEE 802 Handoff ECSG L2 Triggers

1
IEEE 802 Handoff ECSGL2 Triggers

• David Johnston
• david.johnston_at_ieee.org
• dj.johnston_at_intel.com

2
Background..

• Fast Handoff for Mobile IP and Link Layer
  Triggers. Gang Wu Alper Yegin.
• Recommends
• Formal definition of 802 L2 triggers and
  associated APIs
• Align definitions between IETF and IEEE
• Architectural Elements of an 802 Handoff
  Solution, David Johnston
• Recommends
• L2 Triggers
• Flexibility/Extensibility in trigger definition
• draft-satish-l2-mobilereq-01.txt, Satish
  Jamadagni
• Ties L2 triggers to handover decision stages

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Potential Trigger Types

• Link_up(which link)
• Link_down(which_link, why)
• Link_going_up(which link, when)
• Link_going_down(which link, when)
• Domain_crossing(old subnet, new subnet)
• Etc.

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Trigger Trajectories - Local

• Upper Layer attaches to LSAP of LLC
• May register interest in particular triggers from
  a trigger source
• Triggers may therefore have multiple destinations
• Triggers may originate from PHY, or MAC

IP
Other
LLC
LLC
MAC
PHY
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Trigger Trajectories Link Traversing
IP
Other

• Trigger sent down the stack to appear at remote
  end of link
• Requires a transport
• Security Implicationsb
• Applies to AP-STA, SS-BS situations
• Upper layer needs a reason to use these triggers
• Could originate from upper layer

IP
Other
LLC
LLC
LLC
MAC
MAC
PHY
PHY
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Trigger Semantics

• Triggers should have well defined semantics
• Implementations or standards defined behavior
  (e.g. in dot11 or dot16) map semantics of trigger
  to internal events
• E.G.
• Link_up Full MSDU transport established

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Upper layer trigger interface

• MIBs
• Wrong application, not station management, SNMP
  access not required, doesnt fit with link
  traversing triggers
• Programmatic API?
• Goes beyond the 802 spec lt-gt implementation
  domain boundary
• Triggers look similar in type to incoming
  asynchronous data arrival
• Causes indication upwards through MAC SAP
• Are annotated events, not states
• Recommend adding MAC SAP trigger primitives

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Upper layer trigger interface

• Must support trigger registration
• Register interest in a trigger
• Declare supported trigger capabilities
• Still do through MAC SAP? Or use MIBs?
• Link traversing triggers suggest MAC SAP approach

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Trigger Parameters

• Generic
• Type
• Remote, Local?
• Source (UL, MAC, PHY)
• Registered Recipients (LSAP id list)
• Specific
• Reason Codes
• Time Estimates
• Other?

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IETF/3GPP/other

• Triggers are pointless unless upper layer
  handover algorithms are deployed that understand
  them
• We should kickstart the process by drawing up
  strawman trigger specification
• Trigger Semantics
• MAC SAP Primitives
• Iterate and refine with trigger consuming bodies
  such as IETF
• Arrive at base trigger suite that will be
  used/useable
• Standardize them!