What is Mobility Management?

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

2. 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.

3. 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

4. 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

5. 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..

6. 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

7. 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

8. 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

9. contd.. • Advanced Cellular Network • Next generation cellular protocols such as 802.16e 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

10. 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.

11. 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

12. 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 802.11 running on an 802.3 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.

13. ISSUES • Fast Handover and latency • Security • Scalability

14. 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.

15. 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

16. 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

17. Fast Handover • FHO mechanism involves 3 stages • Handover Initialization • Tunnel Establishment • Packet Forwarding

18. 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

19. 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

20. 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

21. 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 LMAinvolved in implementing the LMM function.

22. 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.

23. 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

24. 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

25. 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

26. 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

27. 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