Introduction to Mobile IPv6. Major Differences between MIPv4 and MIPv6 No FA in Mobile IPv6 Mobile IPv6 requires every mobile node to support IPv6 Decapsulation.

Introduction to Mobile IPv6

Major Differences between MIPv4 and MIPv6

No FA in Mobile IPv6 Mobile IPv6 requires every mobile node

to support IPv6 Decapsulation Address Autoconfiguration

Major Differences between MIPv4 and MIPv6 (cont.)

Packets delivery MIPv6 mobile node uses care-of address as

source address in foreign links No ingress filtering problem

Correspondence Node uses IPv6 routing

Supports “Route Optimization” naturally

Basic IPv6 Address Typesunicast:

for one-to-onecommunication

multicast:for one-to-manycommunication

anycast:for one-to-nearestcommunication

M

M

M

A

A

A

U

Relevant Features of IPv6

Address AutoconfigurationStateless autoconfiguratoin

Network Prefix + Interface ID

Stateful autoconfiguration DHCPv6

ICMP RoleWhen an IPv6 node discards a

packet, it sends an error message to the source. There are four types of message:

1. Destination unreachable (type=1). Sent by a router to the source when a packet cannot be forwarded to its destination.

2. Packet too big (type =2). Used when the link MUT on the forwarding link is smaller than the packet.

3. Time exceeded (type=3). Indicates that the packet's hop limit field is zero.

4. Parameter problem (type=4). Indicates that a field of the datagram is not recognized as valid and the packet can thus not be processed.

Mobile Node

message Back

Error Message

R

R

Network C

ICMP: Includes the so-called Neighbor Discovery mechanisms, the terminal autoconfiguration mechanisms and address resolution mechanisms.

Mobile IPV6 Transparency Link To achieve Transport layer transparency for the home address while the mobile

node is assigned a care-of address, Mobile IPv6-capable nodes use the following

If a correspondent node is not Mobile IPv6-capable, then packets sent between the correspondent node and the mobile node that is away from home are exchanged via the home agent. The correspondent node sends packets to the mobile node's home address. These packets are intercepted by the home agent and tunneled to the mobile node's care-of address.

Mobile IPv6 Components

Mobile IPv6 Components□ Home agent

Maintain registrations of mobile nodes that are away from home. Tunnels

data sent to the mobile nodes’ address to the mobile node’s home address

to the mobile node’s current address and forwards tunneled data sent by

the mobile node.

□ Home link

The link that is assigned the home subnet prefix, from which the mobile node

obtains its home address.

□ Foreign link

A link that is not the mobile node’s home link.

□ Mobile node

A node that can change its point of attachment from one link to another,

while still being reachable via its home address.

□ Correspondent node

A peer node with which a mobile node is communicating. The correspondent

node may be either mobile or stationary.

Mobile IPv6 Components□ Care-of address

A unicast routable address associated with a mobile node while visiting

a foreign link.

□ Binding

The association of the home address of a mobile node with a care-of address

for that mobile node.

□ Movement

A change in a mobile node’s point of attachment to the internet. If a mobile

node is not currently attached to its home link, the mobile node is said to

be “away from home”.

Mobile IPv6 Data Structures

□ Binding Cache The binding cache is a table maintained by each correspondent node and home agent that contains the current bindings for mobile nodes .□ Binding Update List The binding update list is maintained by a mobile node to record the most

recent binding updates sent for the home agent and correspondent nodes. □ Home Agent List Home agents maintain the home agents list so that they can send the list of home agents to a requesting mobile node away from home during home agent address discovery.

TunnelingDecapsulationEncapsulation

SourceDestination

Tunnel: The path followed by a datagram while it is encapsulated. While encapsulated, a datagram is routed to a knowledgeable agent, which decapsulates the datagram and then forwards it to its ultimate destination.

Return Routability Procedure

□ Home test init ▪ Source Address=home address ▪ Destination Address=correspondent ▪ It is reverse tunneled through the home agent. The mobile node also sends along a home init that the correspondent node must return later. ▪ To assurance that its protocol message are being processed by the desired correspondent node.□ Home test ▪ Response to a home test Init message. ▪ This means that the mobile node already have sent a binding update to the home agent.

Return Routability Procedure□ Care-of Test Init ▪ Source address=care-of address ▪ Destination address=correspondent ▪ The mobile node sends test init message to correspondent node directly and correspondent node must return later.□ Care-of Test ▪ Response to Care-of test init message. ▪ Verify that the mobile node is reachable at the care-pf address.□ Detecting correspondent nodes not mobile IPv6-capable ▪ If CN is not mobile IPV6-capable, it will not recognize message sent by mobile node. Mobile node records the CN lack of support for mobile IPv6 in binding update list. Packet sent to CN via home

agent.

Return Routability Procedure

Mobile IPv6 Operation

Movement DetectionWhile away from home, an MN selects one

router and one subnet prefix advertised by that router to use as the subnet prefix in its primary care-of address

Mobile IPv6 Operation (cont.)

Home Agent Registration

筆記型電腦

電腦

路由器 Internet

路由器

路由器

工作站

Home Agent

Correspondent Node

Mobile Node

Router

Router

Router

Home LinkLink A

Link B

Link C

(1)Binding Update(2)Binding Acknowledgement

(1)

(2)

Indirect delivery via Home Agent (bidirectional tunneling)

Indirect delivery via Home Agent (bidirectional tunneling)

Direct delivery (Route Optimization)

Mobile Node Initiates Communication with a New Correspondent Node

Binding Request

Binding (both at HA and CN) has a life-time. MN is expected to update

HA within this time. CN is requested to seek up

dates.

Mobile Node

Binding Update

Binding Request

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R

Network C

Correspondent.Node C

InternetMobile Node

Home Agent 2

Home Agent 3

Mobile Node sends Binding Update to the Home AgentsAnycast Address of its home network

One Home Agent answers containing a list of available Home Agents

Home Agent 1

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Home Agent 3 9Home Agent 1 2Home Agent 2 -3

Home Agents List Priority

Dynamic Home Agent Address Discovery

Mobile Node sends Binding Update to the first Home Agentcontained in the Home Agents List

Binding Acknowledgement completes Registration process

InternetMobile Node

Home Agent 2

Home Agent 3

Home Agent 1

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Home Agent 3 9Home Agent 1 2Home Agent 2 -3

Home Agents List Priority

Registration at selected Home Agent

Handover

Three kinds of handover operationsSmooth Handover

Minimizes data loss during the time that the MN is establishing its link to the new access point

Fast Handover Minimizes or eliminates latency for establishing

new communication paths to the MN at the new access router

Seamless Handover Both Smooth and Fast Handover

Summarizes

□ Easy to Implemention.□ Dynamic home agent address discovery mechanism in mobile IPV6 returns a single replay to the mobile node.□ Most packets to a mobile node while away from home in mobile IPV6 are sent using an IPV6 roting header rather than IP encapsulation, reducing the amount of resulting overhead compared to mobile IPV4.□ Support for route optimization is a fundamental part of the protocol ,rather than a nonstardard set of extensions.□ Mobile IPV6 will be an important feature of the next generation Internet.