Introduction to L3 Movement Detection and L3 Link Identifier. Xiaoyu Liu [email protected] 2004-05-07. Contents. Background Link ID in L3 Movement Detection Concept of “L2 Link” and “L3 Link” L3 Movement Detection (MD) Problems and Approaches of L3 MD
AP3Concept of “L2 Link”
“L2 Link” is Attachment Point to wireless/wired networks
Changes of “L2 Link” will result in a L2 handover
Three “L2 Links” (radio link ) in the shown example scenario
“L2 Link” 1
“L2 Link” 2
“L2 Link” 3
AP3Concept of “L3 Link”
Changes of “L3 Link” will result in a L3 handover
STA changes its attachment from AP1 to AP2 and its IP address needs to change, i.e., “L3 link” changes.
STA changes its attachment from AP2 to AP3 but its IP address does not need to change, i.e. still remains at the same L3 link.
Only two “L3 Links” in the shown scenario.
“L3 Link” 2
“L3 Link” 1
* L3 Link:
a communication facility or medium over which nodes can communicate at the link layer
Note: Assignment of ARID should take this scenario into consideration.
AP2L3 Movement Detection
APA Possible Solution
0. An AP caches an RA with a Link ID.
1. STA establishes a new “L2 link” association with AP.
2. After a new “L2 link” is connected, the AP immediately sends STA a cached RA with a Link ID.
3. STA receives a RA with a Link ID.
4. STA checks “L3 link” change using the received Link ID.
5. In case of “L3 link” change, STA initiates a new IP configuration.
Reduce the redundant message exchanges and random L3 MD delay; Solve the problems of the extension of L2 frames to include L3 MD info.