Unified Layer 2 (L2) Abstractions for Layer 3 (L3)-Driven Fast Handover 移动IP技术 教学课件.pptVIP

Fast Handover For Mobile IPv6 –RFC4068 Message Flow - Predictive Message Flow - Reactive This document defines nine kinds of L2 abstractions in the form of primitives to achieve fast handovers in the network layer. Because the network layer initiates L2 and L3 handovers by using the primitives. The primitives defined in this document make use of only the information available in the mobile node IEEE 802.21 introduces the information server in the network to provide the mobile node with network-related information, such as a global network map. Primitives for L2 Abstractions Using Three different usages of primitives Type 1. Provide L2 information to upper layers request: Acquisition request confirm: L2 information Type 2. Notify upper layers of L2 events request: Registration for notification confirm: Valid or invalid indication: Asynchronous notification Type 3. Control L2 actions from upper layers request: Control confirm: Ack or nack Definitions of Primitives PoA (Point of Attachment) -(e.g., an access point in 802.11 networks). L2-PoAList (Type 1) The L2-PoAList.request primitive is sent to the link layer when an upper layer requires a list of the candidate PoAs. L2-PoAFound (Type 2) The L2-PoAFound.indication primitive is asynchronously provided to an upper layer when new PoAs are detected. L2-PoALost (Type 2) The L2-PoALost.indication primitive is asynchronously provided to an upper layer when a PoA included in the list of candidate PoAs disappears. Definitions of Primitives L2-LinkStatus (Type 1) The L2-LinkStatus.request primitive is sent to the link layer when an upper layer requires the current information of a link. L2-LinkStatusChanged (Type 2) The L2-LinkStatusChanged.indication primitive is asynchronously provided to an upper layer when the status of a link has changed. L2-LinkDown (Type 2) The L2-LinkDown.indication primitive is asynchronously provided to an upper layer when an existing link is disconnected and IP packets cannot be transmi