What is Mobility Management? ● Mobility Management involves handling movement of any IP devices in a mobile environment ● Mobility Management can be  Local  Global ●

Local Mobility vs Global Mobility ● Access Network  An Access Network consists of following three components: wireless or other access points, access routers, access network gateways which form the boundary to other networks ● Local Mobility  Local Mobility is mobility over a restricted area of the network topology.  Local Mobility is when the mobile node moves between different access routers in Access Network.

Contd.. ● Intra Link Mobility  Intra-Link Mobility is mobility between wireless access points within an IP Link  Is between local mobility and global mobility ● Global Mobility  Global mobility involves movements across broader administrative, geographical, and topological domains  Global mobility is when the mobile node moves from one Access Network to other

Global Mobility Management ● Global Mobility Protocol is a mobility protocol used by the mobile node to change the global, end-to-end routing of packets when movement causes a topology change and thus invalidates a global unicast address on the local IP link currently in active use by the mobile node ● Global Mobility Anchor point  A node in the network where the mobile node has its fixed home address that maintains the mapping between the home address and care-of address

contd.. ● Local mobility occurs when a mobile node moves between two access points connected to two different access routers. ● Global mobility protocols allow a mobile node to maintain reachability when a change between access routers occurs, by updating the address mapping between the home address and care-of address at the global mobility anchor point. ● Global Mobility protocols hence can be used for Local Mobility but there are some problems..

Problems ● Location Privacy  The change in care-of address as the mobile node moves exposes the mobile node's topological location to correspondents ● Signalling overhead  including all the signalling required to configure an IP address on the new link and global mobility protocol signalling back into the network for changing the home to care-of address mapping  Might have impact on bandwidth & performance ● Update Latency  The global mobility update may require a considerable amount of time if distance b/w anchor point and correspondent node is high

Localized Mobility Management ● Localized Mobility Management is a generic term for protocols dealing with IP mobility management confined within the access network ● Localized mobility management can provide a measure of local control, so mobility management can be tuned for specialized local conditions ● Localized mobility management signalling is not routed outside the access network

Scenario's for Localized Mobility Management ● Large Campus with Diverse Physical Interconnectivity  Campus wireless LAN deployment in which parts of the campus are connected by links  Campus is divided into separate IP links each served by one or more access routers  This is deployed using wireless LAN switches which do IP mobility between them and using Localized Mobility Management at the link layer

contd.. ● Advanced Cellular Network  Next generation cellular protocols such as e and Super 3G/3.9G have the potential to run IP deeper into the access network  Interoperable localized mobility management can unify local mobility across a diverse set of wireless protocols all served by IP  A standardized, interoperable LMM protocol can remove the dependence on IP layer localized mobility protocols that are specialized to specific link technologies thus reduction in cost and deployment

IETF Working Group:NETLMM ● Active group in IETF developing protocols for network based localized mobility management ● Framework  Mobility anchor points within the backbone network maintain a collection of routes for individual mobile nodes.  Packets for the mobile node are routed to and from the mobile node through the mobility anchor point  When a mobile node moves from one access router to another, the access routers send a route update to the mobility anchor point.

Contd.. ● No mobile node to network protocol will be required for Localized Mobility Management ● Functions of the protocol  Handles routing update when a mobile node moves from one access router to another within the localized mobility management domain  Handles a new mobile node that powers on or moves from another localized mobility management domain  Need for additional protocol functions might arise

Solutions for LMM ● Proposed Solutions for LMM fall into 3 categories 1) Interoperable IP level protocols that require changes to the mobile node's IP stack and handle localized mobility management as a service provided to the host by the access network, 2) Link specific or proprietary protocols that handle localized mobility for any mobile node but only for a specific type of link layer, namely running on an wired network back haul. 3) Use of a standard IGP such as OSPF or IS-IS to distribute host routes, and updating the host routes when the mobile node moves.

ISSUES ● Fast Handover and latency ● Security ● Scalability

Latency AND Handover ● Latency arises when Mobile Node signals its peers for valid IP- Mobile Bindings,so Round Trip Time(RTT) increases and when it crosses particular delay threshold then LMM will insert some latency ● This delay in latency might account for some packet loss during communication ● Protocol operation during Mn's handover from one AR to new AR involve link switching delay,movement detection and IP Address configuration.

Types of Delay Propagation delay Link layer delay  Movement detection  Link resource allocation Network layer delay  Movement detection  IP address configuration  Security association  Location update

Proposed Solution ● The above mentioned latency can be reduced using Fast HandOver Mechanism(FHO) ● In FHO a protocol enhancement is done to allow the MN uses the previous COA(Care Of Address) until it gets registered with the new COA on its new AR

Fast Handover ● FHO mechanism involves 3 stages  Handover Initialization  Tunnel Establishment  Packet Forwarding

Scalability ● There is a constant need for the increase in number of Mobile nodes due to increase in mobile services. So LMM function must allow for incremental development ● This requires even distribution of LMA's over a domain topology such that high concentration MN's under a single LMA (hot-spot) is prevented ● Extraneous forwarding load and routing state must be controlled through appropriate LMA selection

Topological changes ● The LMM function must be able to adapt to topological changes arising within the domain ● introduction of new LMA's within an expanding network domain is also a manifested as a topological change. ● By definition core LMA involves a single point failure because the IP-LMM involves a point of indirection. ● Can be addressed by link replication mechanisms,but it introduces additional complexities ● Dynamic anycast routing was proposed as a solution to deal with these problems

Extent of LMM Function ● An LMM mechanism ideally must not inject any additional LMM functionality to MN because this places additional complexities ● The MN must afford extra functionality to manage regional IP state ● So mobile node might need functional extensions,however LMM mechanism should refrain from involving MN from routing operations

Routing State ● Minimal routing state is important for a scalable LMM function implosion of routing state due to extraneous state maintained for the purposes of mobility protocols/optimizations simply guarantees unscalable mobility management ● Currently, routing state for the purposes of mobility management entails base IP mobility binding cache entries ● LMM-specific routing state must scale linearly with the number of registered MN, while confined only within LMA involved in implementing the LMM function.

Auto Configuration ● Mobile network operators and Internet service/content providers seek to minimize their total cost of ownership of their network domain ● To minimize this cost it is essential that the configuration task of the LMM function can adapt to topological changes with minimal (or no) human intervention ● A self-organising LMA constituency that caters for dynamic discovery, configuration and management while embracing resiliency with respect to state consistency or failure can address successfully meet scalability requirements.

Security ● Security is of paramount importance in any network,LMM scheme should cater for authentication mechanisms that prevent malicious deflection of traffic to a legitimate MN ● Involvement of the LMM function into end-to-end security semantics between the MN and its peers is beyond the functional scope of the protocol extension. ● Thus security associations between the MN and its peers must be considered transparent for the LMM

Contd.. ● There are two kinds of security issues involved in network-based localized mobility management  Security between the mobile node and the network  Security between network elements that participate in the network-based localized mobility management protocol

Security between the mobile node and the network ● There are two kind of threats  Localized mobility management protocols that have signalling between the mobile node and network require a security association between the mobile node and the network entity that is the target of the signalling ● Attacks :DOS Attacks  Second threat is related to Location Privacy i.e in the context of IP Mobility is not to reveal the geographical location of the mobile user ● Attacks : Man in Middle Attack

Security between Network Elements ● Basic threat is an attempt by an unauthorized party to signal a bogus mobility event ● This requires proper bidirectional authentication and authorization of network elements that participate in the network-based localized mobility management protocol

More Attacks ● Message Replay  Signals that are sent by the MN can also be captured and replayed by malicious nodes towards the LMA  Thus LMA must ensure that such signals are authenticated or have a restricted lifetime ● Denial Of Service  It is possible that the LMA may receive signals that incur redundant processing at the LMA and as a result, deprive other MN's from LMM services  The LMM function must ensure that malicious nodes are excluded from further communications with the LMA