Movement Detectionin Mobile IPv6

JinHyeock Choi, Samsung AIT

jinchoe@samsung.com

2003.07.18

Contents

• MD Overview• MD Process• MD Methods • MD Problems• MD Requirement & Further Steps

MD, rough sketch

Internet

AR1

MN

AP1 AP2

AR2

1. MN is attached to AR1 via AP1

Internet

AR1

MN

AP1 AP2

AR2

1. MN is attached to AR1 via AP1

2. MN changes its attachment to AR2 via AP2.

3. MN receives some hint that it might have moved.

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.

6. If a MN can no longer use its current CoA, it gets another CoA and sends BU.

MD, rough sketch

Internet

AR1

MN

AP1 AP2

AR2

1. MN is attached to AR1 via AP1

2. MN changes its attachment to AR2 via AP2.

3. MN receives some hint that it might have moved.

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.

6. If a MN can no longer use its current CoA, it gets another CoA and sends BU.

MD, rough sketch

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