IPv6 Mobility Support Henrik Petander

Contents Problem of mobility in IP networks. Mobile IPv6 Extensions to Mobile IPv6

Mobility background Mobile devices with Internet connectivity are becoming increasingly common. Mobile phones are becoming Internet capable. Mobility in cellular systems and WLANs is currently handled mostly on the link layer and is invisible to applications and Internet Protocol (IP) layer. Trend for multiple network interfaces in mobile devices.

IPv6 addressing and mobility IPv6 addresses consist of two parts: a 64-bit network prefix and a 64-bit host suffix. Network prefix of address depends on location. When a host moves from one IP network to another, it needs to change the network part of its address. Issues with reachability, session continuity. Network prefixHost suffix Identifies the network to which host is connected Identifies host within the network.

Why do Mobility Management in IP layer Inter-network handoffs require changing of IP address: –Roaming between different operators networks. –Inter-technology handoffs (WLAN – GPRS/UMTS). Ability to choose between multiple IP networks allows a user/device to choose the best network for the situation: –Cheapest –Fastest –Best coverage

Mobile IPv6 Mobility support in IPv6 (RFC 3775) Mobile node (MN) is a mobile device with an IPv6 home address Correspondent node (CN) is a computer with which mobile node communicates using its home address. Home Agent (HA) helps MN to manage its mobility: –Mobile node can always be reached at its home address, regardless of its point of attachment (care-of address) to the Internet. –Connections made with home address survive movement between different IP networks.

Mobile IPv6 addressing IP addresses act as both an identifier for a node and as a locator. Mobile IPv6 separates the identity, home address of mobile node from its locator, known as care-of address (CoA). Without Mobile IPv6 MN can not use its home address for sending and receiving packets when it is outside its home network. Mobile IPv6 uses IP-IP tunneling to create a virtual network between its CoA and HA, so that MN always appears to be in its home network.

Reverse Tunneling IPv6 in IPv6 tunnel is used for delivering traffic to and from home address of MN via HA. HA uses proxy neighbor discovery to redirect packets on home link destined to home address of MN to its own link layer address. HA keeps track of the care-of address of MN to deliver packets to MN. Tunnel IPv6 hdr (CoA –HA)IPv6 hdr (HoA-CN) Data

Mobile IPv6 operation Router solicitation Binding Update Proxy ND for HoA Binding Ack. Tunnel Router Advertisement MN forms Care-of address

Route Optimization in Mobile IPv6 Tunneling of traffic between MN and CN via home agent is not efficient. –HA is a potential bottleneck –Extra routing hop increases network latency Route optimization (RO) allows MN and CN to communicate directly MN sends a BU to CN. MN and CN use home address option and routing header, type 2 to send packets to each other. Route optimization is secured using return routability protocol.

Mobile IPv6 Implementations Windows –MS Research implementation MN, CN, HA –MS CN implementation for Win XP –Elmic software: embedded MN BSD –KAME (Wide project): MN/CN/HA –INRIA: MN/CN/HA –NEC? Linux –MIPL (Helsinki University of Technology): MN/CN/HA –Elmic software: embedded MN Symbian: MN HP-UX 11.11, : HA/CN Cisco: HA Nokia: HA

Mobile IPv6 extensions Localized mobility management –Hierarchical Mobile IPv6 –Fast Mobile IPv6 Context transfer to new router: Context transfer protocol Early discovery of new router: Candidate access router discovery protocol

Network Mobility

NEMO (RFC 3963) Operation IP IP tunnel Network a:1:: Network a:: Network b::

References Mobile IPv6: RFC 3775 Securing Mobile IPv6 MN-HA signaling: RFC 3776 Hierarchical MIPv6: RFC 4140 Fast Mobile IPv6: RFC 4068 Context transfer protocol: RFC 4067 Candidate access router discovery protocol: RFC 4068 Network Mobility (NEMO) Basic Support Protocol: RFC 3963

Thanks! Any questions?