Transcript IPng Workinging Group April

Movement Detection
in Mobile IPv6
JinHyeock Choi, Samsung AIT
[email protected]
2003.07.18
Contents
•
•
•
•
•
MD Overview
MD Process
MD Methods
MD Problems
MD Requirement & Further Steps
MD, rough sketch
1. MN is attached to AR1 via AP1
Internet
AR1
AR2
AP1
AP2
MN
MD, rough sketch
1. MN is attached to AR1 via AP1
2. MN changes its attachment to
AR2 via AP2.
Internet
AR1
AP1
AR2
3. MN receives some hint that it
might have moved.
AP2
4. MN checks whether it can still
reach the current Access
Router, AR1 using NS/ NA
exchange.
5. MN checks it can still use the
current CoA using RS/ RA
exchange.
MN
6. If a MN can no longer use its
current CoA, it gets another CoA
and sends BU.
MD, rough sketch
1. MN is attached to AR1 via AP1
2. MN changes its attachment to
AR2 via AP2.
Internet
AR1
AP1
AR2
3. MN receives some hint that it
might have moved.
AP2
4. MN checks whether it can still
reach the current Access
Router, AR1 using NS/ NA
exchange.
5. MN checks it can still use the
current CoA using RS/ RA
exchange.
MN
6. If a MN can no longer use its
current CoA, it gets another CoA
and sends BU.
MD Process
•
•
•
•
Step1: Hint
Step2: Checking the reachability of current AR.
Step3: Checking the validity of current CoA
Step4: Router Discovery with all the necessary
information
MD methods
• Hint
– L2 trigger
– New RA message
– RA beaconing
• Checking the reachability of current AR
– NUD (3 NS probes)
– One NS and timeout
– RA beaconing
• Checking the validity of the current CoA
– RS/ RA exchange
– Checking whether the prefix of the current CoA is in RA.
• Router Discovery with all the necessary information
– RS/ RA exchange
MD Problems
• The inconsistency of RA information
– Link local scope of router address
– Some prefix may be omitted.
• The delay to check the reachability of current CoA
– It’s difficult to detect something is NOT there.
– Roughly 3 secs for NUD
• Random Delay in RS/ RA exchange
• Erroneous detection/ Unnecessary signaling
– ECS without L2 support
MD Requirements & further steps
• MD scheme requirements
– Fast: low time delay
– Precise/ Secure: Little error
– Efficient: limit signaling (NS/NA or RS/RA)
• Further Step
– A Basic MD scheme as a guideline for MIPv6 implementators
– A Optimized MD scheme capable of seamless handoff