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Introduction to Mobile IPv6IIS5711: Mobile Computing

Mobile Computing and BroadbandNetworking Laboratory

CIS, NCTU

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Outline Introduction

Relevant Features of IPv6

Major Differences between MIPv4 and MIPv6

Mobile IPv6 Operation

Home Agent Discovery Mechanism

Handover Quality of Service

Conclusions

References

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Introduction Mobile IPv6 is intended to enable IPv6

nodes to move from one IP subnet toanother

While a mobile node is away from home

It sends information about its current

location to a home agent

The home agent intercepts packetsaddressed to the mobile node and tunnelsthem to the mobile nodes present location

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Introduction (cont.) Mobile IPv6 scenario

Internet

Home Agent

Correspondent Node

Mobile Node

Router

Router

Router

Home Link

Link A

Link B

Link C

move

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Relevant Features of IPv6 Address Autoconfiguration

Stateless autoconfiguratoin Network Prefix + Interface ID

Stateful autoconfiguration DHCPv6

Neighbor Discovery

Discover each others presence and find routers

Determine each others link-layer addresses

Maintain reachability information

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Relevant Features of IPv6

(cont.) Extension Headers

Routing header

For route optimization

Destination Options header

For mobile node originated datagrams

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Major Differences between

MIPv4 and MIPv6 No FA in Mobile IPv6

Mobile IPv6 requires every mobile node tosupport

IPv6 Decapsulation

Address Autoconfiguration

Neighbor Discovery

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Major Differences between

MIPv4 and MIPv6 (cont.) Packets delivery

MIPv6 mobile node uses care-of address assource address in foreign links

No ingress filtering problem

Correspondence Node uses IPv6 routing

header rather than IP encapsulation Supports Route Optimization naturally

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Mobile IPv6 Messages and

Related Data StructuresAll new messages used in MIPv6 are

defined as IPv6 Destination Options

These options are used in IPv6 to carryadditional information that needs to beexamined only by a packets destination

nodeNext Header Hdr Ext Len

Options

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Mobile IPv6 Messages and

Related Data Structures (cont.) Four new Destination Options

Binding Update

Used by an MN to inform its HA or any otherCN about its current care-of address

Binding Acknowledgement

Used to acknowledge the receipt of a BindingUpdate

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Mobile IPv6 Messages and

Related Data Structures (cont.) Binding Request

Used by any node to request an MN to send a

Binding Update with the current care-ofaddress

Home Address

Used in a packet sent by a mobile node to

inform the receiver of this packet about themobile nodes home address

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Mobile IPv6 Messages and

Related Data Structures (cont.) Data Structures

Binding Cache

Binding Update List

Home Agent List

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Mobile IPv6 Operation Home Agent Registration

An MN performs address autoconfiguration

(stateful or stateless) to get its care-ofaddress

The MN registers its care-of address withits home agent on the home link Use Binding Update Destination Option

The HA uses proxy Neighbor Discovery andalso replies to Neighbor Solicitations onbehalf of the MN

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Mobile IPv6 Operation (cont.) Home Agent Registration

Internet

Home Agent

Correspondent Node

Mobile Node

Router

Router

Router

Home Link

Link A

Link B

Link C

(1) Binding Update

(2) Binding Acknowledgement

(1)

(2)

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Mobile IPv6 Operation (cont.) Route Optimization

To avoid triangle routing

Internet

Home Agent

Correspondent Node

Mobile Node

Router

Router

Router

Home Link

Link A

Link B

Link C

(1)Packet(2) Tunneled Packet(3) Packet

(2)

(1)(3)

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Mobile IPv6 Operation (cont.) Route Optimization

Internet

Home Agent

Correspondent Node

Mobile Node

Router

Router

Router

Home Link

Link A

Link B

Link C

(1) Binding Update(2) Packet

(1)(2)

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Mobile IPv6 Operation (cont.) MN-Terminated Packet Delivery

Internet

Src: CNs addressDst: MNs home address

Src: CNs addressDst: MNs care-of address

Routing Header:MNs home address

Src: CNs addressDst: MNs care-of address

Routing Header:MNs home address

Src: CNs addressDst: MNs home address

MN receives packets from

loopback interface

Binding cache hit

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Mobile IPv6 Operation (cont.) MN-Originated Packet Delivery

Internet

Src: MNs home address

Dst: CNs address

Src: MNs home addressDst: CNs address

Src: MNs care-of addressDst: CNs address

Destination Optoins header Home Address Option:

MNs home address

MN at home:

MN at visited network:

Src: MNs care-of addressDst: CNs address

Destination Optoins header

Home Address Option:MNs home address

Move MNs home addressto Source Address

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Mobile IPv6 Operation (cont.) Movement Detection

While away from home, an MN selects onerouter and one subnet prefix advertised bythat router to use as the subnet prefix inits primary care-of address

To wait for the periodically sent RouterAdvertisements

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Mobile IPv6 Operation (cont.) Binding Management

To trigger Binding Acknowledgement, the

MN sets the Acknowledge bit in the BindingUpdate Retransmitting the Biding Update periodically

until receipt of the acknowledgement

An MN MUST set the Acknowledge bit inBinding Updates addressed to an HA

The MN MAY also set the Acknowledge bitin Binding Updates sent to a CN

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Home Agent Discovery

Mechanism

Internet

Home Agent3

Correspondent Node

Mobile Node

Router

Router

Router

Home LinkLink A

Link B

Link C

(1) Binding Update to Home-Agents anycast address(2) Binding Acknowledgement including the Home Agents List;

rejects the registration request

Home Agent 1 Home Agent2

Home Agents List Preference ValueHome Agent3 9Home Agent 1 2Home Agent2 -3

(1)

(2)

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Home Agent Discovery

Mechanism (cont.)

Internet

Home Agent3

Correspondent Node

Mobile Node

Router

Router

Router

Home LinkLink A

Link B

Link C

(1) Binding Update to Home Agents 3(2) Binding Acknowledgement, registration OK

Home Agent 1 Home Agent2

Home Agents List Preference ValueHome Agent3 9Home Agent 1 2Home Agent2 -3

(1)

(2)

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Handover Router-Assisted Smooth Handovers

IPv6 routerwith HA func.

IPv6 router

move

(1)MN sends a Binding Update toan HA on previous network

(2) HA returns a BindingAcknowledgement

(3) HA tunnels packets to MN

(4)MN sends a Binding Update toCN

(1)

(3)(4)

(3)

(2)

CN

MN

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Handover (cont.) Three kinds of handover operations

Smooth 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 thenew access router

Seamless Handover Both Smooth and Fast Handover

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Quality of Service IPv6 header has two QoS-related fields

20-bit Flow Label Used by a source to label sequences of packets

for which it requests special handling by theIPv6 routers

Geared to IntServ and RSVP

8-bit Traffic Class Indicator Used by originating nodes and/or forwarding

routers to identify and distinguish betweendifferent classes or priorities of IPv6 packets

Geared to DiffServ

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Quality of Service (cont.) New IPv6 option QoS Object

QoS Object describes QoS requirement,traffic volume and packet classificationparameters for MN's packet stream

Included as a Destination Option in IPv6

packets carrying Binding Update and BidingAcknowledgment messages

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Conclusions Mobile IPv6 is

An efficient and deployable protocol forhandling mobility with IPv6

Lightweight protocol

To minimize the control traffic needed to

effect mobility

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References C. Perkins, Mobility for IPv6,Internet Draft, June 2002.

K. Zhigang et al., QoS in Mobile IPv6, in Proc. of

International Conferences on Info-tech and Info-net 2001,vol. 2, pp. 492 -497.

N. Montavont and T. Noel, Handover Management for

Mobile Nodes in IPv6 Networks,IEEE Communication

Magazine, pp. 38-43, Aug. 2002.