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 Types unicast: for one-to-one communication multicast: for one-to-many communication anycast: for one-to-nearest communication U M M M A A A

Relevant Features of IPv6 Address Autoconfiguration Stateless autoconfiguratoin Network Prefix + Interface ID Stateful autoconfiguration DHCPv6

ICMP Role R message Back When an IPv6 node discards a packet, it sends an error message to the source. There are four types of message: Destination unreachable (type=1). Sent by a router to the source when a packet cannot be forwarded to its destination. Packet too big (type =2). Used when the link MUT on the forwarding link is smaller than the packet. Time exceeded (type=3). Indicates that the packet's hop limit field is zero. 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 Network C R Error Message 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.

Tunneling Encapsulation Decapsulation Source Destination 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 Detection While 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 Mobile Node Binding Update Binding Acknowledgement Link B Home Link Link A Internet (1) Router Link C Router (2) Router Home Agent Correspondent Node

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. Binding Update Binding (both at HA and CN) has a life-time. MN is expected to update HA within this time. CN is requested to seek updates. Mobile Node Network C R Binding Request Correspondent. Node C

Dynamic Home Agent Address Discovery Home Agents List Priority Home Agent 3 9 Home Agent 1 2 Home Agent 2 -3 R Home Agent 3 R Internet Mobile Node Home Agent 1 Home Agent 2 Mobile Node sends Binding Update to the Home Agents Anycast Address of its home network One Home Agent answers containing a list of available Home Agents

Registration at selected Home Agent Home Agents List Priority Home Agent 3 9 Home Agent 1 2 Home Agent 2 -3 R Home Agent 3 R Internet Mobile Node Home Agent 1 Home Agent 2 Mobile Node sends Binding Update to the first Home Agent contained in the Home Agents List Binding Acknowledgement completes Registration process

Handover 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 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.