Spring 2004 Mobile IPv6 School of Electronics and Information Kyung Hee University Choong Seon HONG

Spring  Why IP Mobility?

Spring  Why IP Mobility?

Spring  Overview of Mobile IPv6(1) Mobile IPv6 Message Binding Update(BU) –Used by a MN to inform its HA or CN about its current COA Binding Acknowledgement –Used to acknowledge the receipt of BU Binding Request –Used by any node (HA or CN) to request a MN to send a BU with current COA Home Address –Used in a packet sent by a MN to inform the receiver of this packet about the MN’s home address

Spring  Overview of Mobile IPv6(2)  Binding Cache Every IPv6 node has a binding cache which is used to hold the binding for other nodes  Binding Update List Every node has a Binding Update List Binding update information sent from MNs  Home Agent List HA has information of HAs in a Link using Unsolicited Multicast Router Advertisements Used for Dynamic Home Agent Discovery Mechanism

Spring  Mobile IPv6 Operation (1) MN has just moved from link A to link B MN receives Router Advertisement message from router that is located link B MN selects subnet prefix in Router Advertisement message to use as the subnet prefix in its COA MN configures a COA(Address Autoconfiguration)

Spring Home Agent Registration  Mobile IPv6 Operation (2)

Spring Triangle Routing  Mobile IPv6 Operation (3) Procedure: The Mobile Node gets an IPv6 care-of address (CoA) in the Foreign Network (via auto-config) Registers CoA with Home Agent, who routes packets destined for the Mobile Node via a Tunnel (similar to Mobile IPv4)

Spring Route Optimization  Mobile IPv6 Operation (4) Procedure: Route Optimisation allows short-cut routing. TheMobile Node informs the Correspondent Node of its current address on the Foreign Network via a Binding Update

Spring  Advantage of Mobile IPv6 Enough addresses available Mobile IPv6 can use IPsec for all security requirement Route Optimization is an additional functionality for Mobile IPv4. It is an integral part of Mobile IPv6  To avoid waste of bandwidth due to triangle routing Using address autoconfigration Mobile IPv6 neither needs DHCP nor FA

Spring  Securing Route Optimization Signaling Why do we need to secure it?  The BU orders the receiver to send traffic to a different IP address (e.g. Packets intended for address X should be sent to Y)  Attackers can: Direct a MN’s traffic to themselves (steal traffic) Direct a MN’s traffic somewhere else (Bombing attacks) Deny a MN from communicating with other nodes (DoS attacks). More attacks are possible.

Spring  Securing Route Optimization Signaling

Spring  Securing Route Optimization Signaling What type of security is needed?  The CN needs to determine whether the MN has the right to send the BU  To do this the MN must prove that it owns both Home Address and Care of Address  Encryption is not required, no confidential information. Is a proof of identity enough?  Proof that a user is does not mean that Person owns home address X or CoA Y.  Certificate including Home Address could be used but can be complex to set up in practice (i.e. who gives out these special certificates, global PKI)

Spring  Return Routability Protects the integrity of the CN Binding Update Protects against replay attacks and addresses some DoS attacks Design goal: protect against extra threats, introduced by IP mobility

Spring  MIPv6 Security – Return Routability

Spring  Return Routability : Step 1

Spring  Return Routability : Step 2

Spring  Return Routability : Step 3

Spring 2004 Cellular IP

Spring Need  Development of commodity-based palmtop devices with built-in high-speed packet radio access to the Internet  Mobile users equipped with wireless IP-enabled communicators with access to a wide array of Web- based mobile multimedia services.  Picocellular environments call for simple, low-cost wireless infrastructure that ultimately must compete with wireline LAN service quality, cost, security, and plug-and-play scalability.

Spring  Existing Solutions  Mobile IP  Merit - A simple and scalable global (macro-level) mobility solution  Demerit - Suitable for slow moving hosts  Cellular Systems  Merit - Seamless Mobility support  Demerit - Lacks inherent flexibility, robustness and scalability found in IP networks

Spring  Cellular IP  A host micro-mobility protocol that is optimized for wireless access networks and highly mobile hosts.  Design Goals: Simplicity – A Cellular IP wireless access point (base station) can be implemented as a small and cheap “commodity device” Scalability – Cellular IP distributed location management  Benefit: Fully compatible with IP

Spring  Network Model R Mobile X BS3 BS2 BS4 a BS1 Host Home agent Gateway, care-of address Mobile-IP –enabled Internet IP routing IP tunneling Cellular IP routing

Spring  Network Model (cont’d)  Base Station – Wireless Access Point and router of IP packets while performing all mobility-related functions.  Regular IP forwarding engine with IP routing replaced by Cellular IP routing and location management.  Cellular IP access networks connected to the Internet via gateway routers

Spring  Network Model (cont’d)  Location management and handoff support integrated with routing.  To minimize control messaging, regular data packets used to refresh host location information.  Uplink packets – routed from mobile host to the gateway on a hop-by-hop basis. The path is cached by intermediate base stations.  Downlink packets – routed from the gateway to the mobile host. The cached path is used for this.

Spring  Routing  Cellular IP gateway periodically broadcasts a beacon packet – flooded in the access network  Base stations record the neighbor they last received this beacon from and use it to route packets toward the gateway.  Each base station maintains a routing cache.  Mappings (Source IP address, Base Station) stored in the cache.

Spring  Routing (cont’d)  Soft-state mapping – remains valid for a system-specific time called route-timeout.  Data packets used to maintain and refresh mappings.  Mobile host transmits route-update packets on the uplink at regular intervals called route- update time to keep its routing cache mappings valid.  Route-update packets – special ICMP packets addressed to the gateway.

Spring  Handoff Old BS New BS Mobile host Crossover BS 1. Packets on the old route 2. Mobile host moves 3. Route-update packet 4. Packets on the new route

Spring  Hard Handoff  Trades off some packet loss for minimizing handoff signaling rather than trying to guarantee zero packet loss.  Mobile host tunes its radio to a new base station and sends a route-update packet.  This creates routing cache mappings on route to the gateway hence configuring the downlink route to the new base station.

Spring  Handoff (contd)  Handoff latency equals the round-trip time between the mobile host and the crossover base station. During this interval, downlink packets may be lost.  Mappings associated with the old base station are not cleared at handoff, rather, they timeout as the associated soft-state timers expire.  Time taken to redirect packets to the new point of attachment is shorter than that in Mobile IP.

Spring  Semisoft Handoff  When the mobile host initiates a handoff, it sends a semisoft packet to the new base station and immediately returns to listening to the old base station.  While the host is still in contact with the old base station, the semisoft packets configure routing cache mappings associated with the new base station.  After a semisoft delay, the host can perform a regular handoff.

Spring  Semisoft Handoff (contd)  The semisoft delay ensures that by the time the host tunes its radio to the new base station, its downlink packets are delivered through both the old and new base stations.  Semisoft packet does not, however, fully assure smooth handoff.

Spring  Paging BS with paging cacheBS without paging cache Paging areas

Spring  Paging (cont’d)  Passive connectivity used to reduce the power consumption of idle mobile hosts.  Base stations geographically grouped into paging areas.  When there is no call ongoing, mobile hosts only need to report their position to the network if they move between paging areas. This makes location update and handoff support for idle hosts unnecessary.

Spring  Paging (contd)  When an incoming call is detected at the gateway, a paging message is transmitted to the mobile host’s current paging area to establish the call.  The mobile node informs the infrastructure of its location as a result of the paging process and transition to active mode to take the call.  These hosts transmit paging-update packets at regular intervals defined by paging-update-time.

Spring  Paging Cache  Similar to Routing cache. 2 differences: Longer timeout. Cache updated by both paging and routing update packets.  Idle mobile hosts have mappings in paging caches but not in routing caches.  Active mobile hosts will have mappings in both types of cache.

Spring  Future Research  To analyze the protocol response to link and node failure.  To support multiple gateways in Cellular IP networks.

Spring 2004 Current Issues for MIPv6

Spring  Current Issues Using IPsec to Protect Mobile IPv6 Signaling between Mobile Nodes and Home Agents  draft-ietf-mobileip-mipv6-ha-ipsec-06.txt Fast Handoff for Mobile IPv6  draft-ietf-mipshop-fast-mipv6-01.txt  draft-ietf-mobileip-fast-mipv6-08.txt HMIPv6 updates  draft-ietf-mobileip-hmipv6-07.txt Fast Handovers for  draft-ietf-mipshop-80211fh-00.txt Additional Issues  Mobile IPv6 issues in the presence of firewalls  Mobile IPv6 deployment and transition issues in the presence of IPv4/IPv6 networks  Multicast issues