MOBILITYMANAGEMENT PROTOCOLS FORWIRELESS MOBILENETWORKS

International Journal of Computer ScienceandCommunication Vol. 2, No. 1, January-June2011, pp. 3 1-39 MOBILITYMANAGEMENT PROTOCOLS FORWIRELESS MOBILENETWORKS Chandralekha 1, PraffulaKumar Behera 2 1 Orissa Computer Academy, Krupajal Group of Institutions Bhubaneswar, Orissa, India, E-mail: moon_lekha@rediffmail.com. 2 School of Mathematics and Statistics, Utkal University, Bhubaneswar, Orissa, India, E-mail: p_behera@hotmail.com ABSTRACT 4 G Wireless networks are envisioned to provide high raw data rates in the downlink as well as in the uplink directions. These networks are driven by the need to support context-rich multimedia services and applications. 4G wireless networks also support global roaming and multiple classes of services with variable end-to-end QoS requirements across heterogeneous wireless systems. Mobility management became an important issue since when the mobile devices are become more and more popular. This paper gives an overview of mobility management in mobile network which includes the concept of location management and handoff management. An introduction to different mobility management models are defined that can be used for micro and macro mobility solutions. Keywords: Location Management, MIP, Cellular IP, Handoff Management, HAWAII, Micro and Macro Mobility. 1. INTRODUCTION 4G wireless networks will integrate services of different segments such as cellular network, WLAN, WPAN and even LEO satellites. Several alternative backbone networks like the public land mobile networks (PLMN), mobile internet protocol (MIP), wireless asynchronous transfer mode (WATM) networks, and low earth orbit (LEO) networks will be used. The fantastic and important characteristic of wireless network that makes this a reality is mobility. In the field of computing and communication technologies, to be able to communicate with other persons and access and process information simultaneously while moving has been a long expectation that causes great deal of efforts having been made to turn the fancy into fact. The advances in technical are such as VLSI, antenna and battery technologies which make small and light portable devices like laptop, cellular phone, in wireless communication theory which make several types of wireless networks with different air interfaces (TDMA, DMA, FDMA etc.) and wired infrastructures (Internet, ATM, etc.) has made it possible to maintain the mobility characteristics of networks. The development in software technology such as distributed computing, software engineering, language technology, modern database, etc. make various mobile services with effective supports facilitate human s work and life. Next generation mobile systems need the support of all the advances on new theories, algorithms, architectures, standards and protocols. In the future, more and more internet based services like web services can be smoothly accessed with various mobile devices through the widely deployed wireless networks. At present, 3 G mobile communication systems are just at the beginning stage to be deployed for multimedia applications, while research on the 4G mobile communications has begun to shine the way for future. The mobile personal telecommunications systems and wireless computer network are converging in the coming new generation of mobile communications. Future mobile communication systems would evolve with the trend of global connectivity through the internetworking and interoperability of heterogeneous wireless networks. Roaming in such network architecture is a very complex situation and it causes many new problems. However, in wireless systems, mobile hosts constantly changes the points of attachments to the wired networks, causing frequent disruptions to the ongoing network traffic. An infrastructure supported approach is required to meet the delay and jitter requirements in nondisrupted services. The boundary between mobile personal telecommunications and wireless network is disappearing, through the converging of mobile and wireless communications with the Internet services. With the rapid improvement in both wireless networks and mobile terminals, great increases have emerged in all the fields of mobile communications, including the number of mobile subscribers, the deployment of mobile communication systems, the new advances in mobile techniques along with the different types of mobile services. One of the most important and challenging problems for seamless access of wireless networks and mobile services is mobility management. Mobility management is the fundamental technology used to automatically support mobile terminals enjoying their

32 International Journal of Computer Science and Communication (IJCSC) services while simultaneously roaming freely without the disruption of communications. It is one of the important functions of the cellular network that allows mobile to find out where the subscribers are, so that calls, SMS and other multimedia services can be delivered to them. This paper is organized as follows. Section 2, describes the issues, concepts and operations of mobility management. Section 3, describes the mobility management models that are followed to propose any solutions or protocols for mobility management problems. Section 4 describes the protocol Mobile IP as macro mobility solution and Section 5 describes four main proposals for micro mobility solutions. At last, the paper is summarized by conclusions in Section 6. 2. BASICCONCEPT ANDOPERATIONOFMOBILITY MANAGEMENT Mobility management is the useful technology that supports mobile terminals, allows the user to roam while simultaneously offers them incoming calls and supporting calls in progress through wireless networks. According to functionality, Mobility management enables communication networks to locate roaming terminals in order to delivery data packets which is a function of static scenario and maintain connections with terminals moving into new areas which is a function of dynamic scenario So, mobility management consists of two distinct related components ( i) Location management, (ii) Handoff management. Location management (Fig. 1) is a process that enables the network to discover the current point of attachment of the mobile user for call delivery. In location management two functions are managed (a) Call delivery (b) Location registration. Fig. 1 In location registration, the mobile terminal periodically notifies the network of its new access point, allowing the network to authenticate the user and revise the user s location profile where as in call delivery the network is queried for the user location profile and the current position of the mobile host is found. The main issues in location management involve: 1. Database architecture design. 2. Messaging procedure design. 3. Transmission of signaling messages between various components of a signaling network. 4. Security. 5. Dynamic database updates. 6. Querying delays. 7. Terminal paging. 8. Paging delays. Handoff (Handover) (Fig. 2) management enables the network to maintain a user s connection as the mobile continues to move and change its access point to the network. The three-stage process of handoff involves initiation, where the user, a network agent or changing network conditions identify the need for handoff. Then the new connection generation stage, where the network must find new resources for the handoff connection and perform any additional routing operations. Under mobile-assisted handoff (MAHO), the network generates a new connection by finding new resources for the handoff and performing any additional routing operations. The last stage is data-flow control, where the delivery of data from the old connection path to the new connection path is maintained according to agreed upon QoS. Fig. 2 Handoff management includes two conditions: (a) Intracell handoff. (b) Intercell handoff. Intracell handoff occurs when the user moves within a service area (or cell) and experiences signal strength deterioration below a certain threshold that results in the transfer of the user s call to new radio channels of appropriate strength at the same base station. Intercell handoff occurs when the user moves into an adjacent cell and all of the terminals may connect to a new base station. While performing handoff, the terminal may connect to multiple base stations simultaneously and use some form of signaling diversity to combine the multiple signals. This is called soft handoff. But, if the terminal stays connected to only one base station at a time, clearing the connection with the former base station immediately before or after establishing a connection with the target base station, then the process is referred to as hard handoff. Handoff management issues are: 1. Efficient and expedient packet processing. 2. Minimizing the signaling load on the network. 3. Optimizing the route for each connection. 4. Efficient bandwidth reassignment.

Mobility Management Protocols for Wireless Mobile Networks 33 5. Refining quality of service for wireless connections. 2.1 Requirements andsolutions There are many requirements on performance and scalability that should be carefully taken into account when toying to design or select a mobility management scheme such as: (a) Fast handoff: The handoff operation should be quick enough in order to ensure that the mobile node can receive IP packets at its new location within a reasonable time interval and so reduce the packet delay as much as possible. (b) Seamless handoff: The handoff algorithm should minimize the packet loss rate into zero or near zero. (c) Signaling overhead: The control data load, the number of access to the related databases, should be lowered to within an acceptable range. (d) Routing efficiency: The routing paths between the communication nodes to the mobile nodes should be optimized to exclude redundant transfer or bypass path, e.g. triangle routing. (e) QoS: The mobility management schemes should support the establishment of new QoS reservation in order to deliver a variety of traffic, while minimizing the disruptive effect during the establishment. (f) Fast security: The mobility management schemes should support different levels of security requirements such as data encryption and user authentication, while limiting the traffic and time of security process, e.g. key exchange. (g) Special support required: It is better for a new mobility mechanism to require minimal special changes on the components, e.g. mobile node, router, communication media, networks, other communication nodes, etc. 3. MOBILITY MANAGEMENT MODELS The MM models can be of two types: 3.1 General MobilityManagement Model (Fig. 3) The main components in the model are represented by: (a) Two mobile networks entities: MM is a node (terminal device) that can change its point of attachment to the n/w from one link to another by freely roaming with its user, while still being reachable. CN (corresponding node) is either a mobile or a stationary node that can communicate with the concerned MN by sending or receiving packets to or from the MN. (b) Two networks: Home network is the unique n/w at which the MN is continually reachable to the other corresponding nodes, by the home address. FN is the Fig. 3 n/w to which the MN is currently attached instead of its original home network and is reach-able by a new generated address CoA (Care of Address). (c) Two addresses: Home address is the static unchangeable RP address assigned to the MN that is used to identify the MN when it is in its Home n/w CoA is the IP address to identity the MN s current point of attachment to the Internet, when it is in a FN. (d) Two mobility agents: HA (Home agent) is a router on the HN that makes the MN reachable when the MN is attached to a FN. A FN (Foreign network) is a router on the FN that assists the MN to access the Internet by receiving data grams delivered to the CoA. 3.2 Hierarchical Mobility Management Model Hierarchical MM schemes localize the management of mobility by introducing the concept of domain, in order to achieve the requirements on performance and flexibility especially for frequently moving hosts. A domain is defined as a collection of networks sharing a common network administration, which may include one or more Fig. 4

34 International Journal of Computer Science and Communication (IJCSC) FN. Taking into consideration the domain factor, two types of mobility can be defined. They are: (a) Micro mobility: Here MN s movements is inside a domain to which intra-domain mobility management solution are suitable, focusing mainly on a fast, efficient, seamless mobility support within a restricted coverage. (b) Macro mobility: Here MN s movements is between different domains, to which inter domain mobility. Management schemes can be employed, acting as a global mobility solution with the advantages of flexibility, robustness and scalability. The concepts micro and macro mobility based on the definition of domain are recursive, i.e. a movement may be micro in one domain whereas macro in another. The next section defines the schemes or protocols that can be used to provide mobility management solutions in wireless network through mobile nodes. The macro-level or inter domain mobility management can be achieved by implementing MIP and its extension MIPV6. The micro-level or intra-domain mobility management can be achieved by implementing the protocols such as HMIP, Cellular IP, and HAWAII, IDMP and edge mobility architecture. 4. MACROMOBILITYSOLUTIONTECHNIQUES 4.1 MIP (Mobile Internet Protocol) The macro mobility solutions are provided by MIP that allows nodes to continue to receive datagram s no matter where they happen to be attached to the Internet. MIP is a modification to IP that includes some control messages that allows the IP nodes involved to manage their IP routing tables reliably. The functional entities of MIP are Mobile node (MN), Home agent (HA), foreign agent (FA), Correspondent node (CN) and access router (AR). The MN has a home address, which is registered in a domain name server (DNS). The home link has at least one AR that can offer HA services to MN. When the MN moves out of the home n/w into any other FN, it can be reached through obtaining a cane-of-address (CoA). When away from home, MP uses protocol tunneling to hide a MN's HA from intervening routers between it s HA and its current location. The Tunnel terminates at the MN s CoA, MIP provides two ways to acquire a CoA. (a) A FA CoA is a CoA provided by a FA through its agent advertisement messages. (b) A collocated CoA is a CoA acquired by the MN as a local IP address through some external means, which the MN then associates with one of its non n/w interfaces. MIP is responsible for handling the following functions. 1. Movement detection and agent discovery: Agent discovery is the method by which a mobile mode determines whether it is currently connected to its HN or to a FN and detects when it has moved from one n/w to another. MAs make themselves known by periodically sending mobility agent advertisement messages which are formed by including a mobility agent advertisement extension in an ICMP (Internet control message Protocol) router advertisement. The ICMP routers advertisements include link-layer fields, IP fields and ICMP fields within an agent advertisement message. If an MN cannot receive the agent advertisement from its original agent for a specified time, it will be assumed to have moved into a new area and the MN may passively wait for another agent advertisement. When an MN roads to get a new CoA but does not want to wait for the periodic agent advertisement, it can also actively broadcast an agent solicitation to solicit a new mobility agent in order to get a new CoA. 2. Registration: A MN is required to be configured with its home address and a net mask and a mobility security association for each home agent. MIP follows two types of registration procedure either by means of a FA that relays the registration to the MN s NA or without a FA. The registration procedure requires four messages, registration request, registration relay, registration reply and registration reply replay, but when the MN registers directly with it s HA, the registration procedure requires only two messages that is registration request and registration reply. MIP registration messages use the UDP. Fig. 5 3. Tunneling and Routing: After the registration of a new CoA, the further packets destined to the MN s Ha will be redirected to the MN s CoA by constructing a new IP header tunnel header that contains the MA s CoA as the destination address. The MIP required the use of encapsulation to deliver datagram from the home n/w to the current location of the MN (CoA). Several methods such as IP-in-IP encapsulation, minimal encapsulation and GRE are used for tunneling. To encapsulate an IP datagram using IP in -IP encapsulation, an outer IP header is inserted before the datagram s existing IP header. To encapsulate an IP

Mobility Management Protocols for Wireless Mobile Networks 35 datagram using minimal encapsulation, the minimal forwarding header is inserted into the datagram in generic routing encapsulation (GRE) numerous other protocols besides IP. The MIP is operated as follows: 1. MAs advertise their presence via agent advertisement messages. 2. A MN receives an agent advertisement and determines whether it is on its home network or FN. 3. When the MN detects that it is located on its HN, it operates without mobility services. It returning to its HN from being registered elsewhere, the MN deregisters with its HA through a variation of the normal registration process. 4. When a MN detects that it has moved at a FN, it obtains a CoA on the FN which can either be a FA's CoA or CCoA. 5. The MN, operating away from home, them registers its new CoA with its HA through the exchange of a registration request and registration reply message. 6. Data grams sent to the MN's home address and intercepted by its HA, tunneled by the HA to the MH s CoA, received at the tunnel endpoint and finally delivered to the MN. 7. In the reverse direction, data grams sent by the MN may be delivered to their destination using standard IP routing mechanisms, without necessarily passing through the HA. The strength of MIP is the transparency to the MHs, the transparency to higher layers in the protocol stack and the fact that the mobile host Keeps it IP address for identify purposes, allowing it to continues to function as a server without the need for trouble some patches whenever it moves. The weakness of MIP includes triangular routes, single point of failures, potentially high latency handoffs, and potentially high signaling load. These problems are solved by some optimization protocol. The triangle route problem is solved by MIP- RO (Route optimization) protocol. This protocol has 4 parts (a) updating binding caches, (b) Managing smooth handoffs between FAs, ( c) Acquiring registration keys for smooth handoffs, ( d) using special tunnels. The process of smooth handoff tries to overcome the packet loss within the handoff interval by optimizing the basic MIP. As an extension of the registration process, the MN s new FA may send a previous FA notification message, including a binding update (BU), to the previous FA. The previous FA then updates its binding cache and retunnels any packets destined to the MN to its new CoA. 4.2 MIPV6 IPV6 is defined in the IETF working group of IP next generation, by providing enhancements over the capabilities of existing IPV4 service. Basic improvements to IPV4 include, bigger address space, reduced administrative overhead, support for address renumbering, improved header processing, reasonable security and QoS support. The mobility for IPV6 borrows the general ideas of a HN, HA and CoA from MID for IPV4. The main changes in MIPV6 standard are as follows: 1. In MIPV6 there is no mandatory need for FA as the requirement in IPV4 of sharing IP address in order to save the limited address space has disappeared. 2. Support for mobility is a built-in feature as a fundamental part of the IPV6. A new CoA can be generated by the IPV6 mechanism of stateless autoconfiguration and IPV6-within-IPV6 tunneling is also used to tunnel packets arriving at the HA to the MH at its auto-configured CoA. 3. Due to the router s effect of ingress filtering, it is not always possible for an MN to send packets directly to CN without being routed by the HA in MIPV4. To solve this, reverse tunneling has to be used in MIPV4 with the sacrifice of routing efficiency optimization. Whereas in MIPV6, since the CN can cache MN s BU, the problem of reverse tunneling is solved without affecting the operation of ingress filtering. 4. Since it is supposed that all IPV6 nodes are to implement strong authentication and encryption features in order to improve internet security, the MIPV6 is simplified so that it need not specify the security procedures by itself. 5. MICRO-LEVEL OR INTRA-DOMAINMOBILITY MANAGEMENT PROTOCOLS MIP is an IETF RFC that supports transparent host migration on the Internet it provides an elegant solution for inter-domain or macro mobility management, but lucks critical aspects of micro mobility management that are needed within cellular network. This disadvantage has led to the recent emergence of micro mobility management protocols. The generic set of requirements that must be met by all these protocols can be identified as: 1. Support for fast handoff: The mobility management architecture and protocol should be able to seamlessly redirect packets to the mobile s new point of attachment with minimum latency. To support real-time IP applications, including voiceover-ip (VOIP), the latency typical associated with the registration process must be decreased and bounded. 2. Reduction in packet loss during movement: With new emerging applications for cellular network, the packet loss during handoff should be minimum. 3. Support for paging: Paging enables a MN to significantly reduce the mobility-related signaling

36 International Journal of Computer Science and Communication (IJCSC) traffic. Any mobility management protocol should have the paging functionality to minimize n/w signaling and conserve battery power. 4. Support for multipath distribution techniques: The intra domain protocols should be able to support multiple traffic paths, which are used for providing redundancy and greater transmission reliability. 5. Support for QoS: The protocols should be able to meet the Qos requirements. Some pioneering proposals that provide such functionality include. 1. Cellular IP. 2. Hierarchical MIP (HMRD). 3. HAWAII (Handoff aware wireless access Internet infrastructure). 4. IDMP (Intra domain mobility management protocol). 5.1 Cellular IP Columbia University and Ericsson propose the cellular IP for very frequently moving hosts as well as rarely moving and totally static hops. The CIP combines the capability of cellular networks in providing smooth fast handoff and efficient location management for active and idle MH with the inherent flexibility, robustness and scalability found in IP networks. Location management and handoff support are integrated with routing in CIP access networks. The CIP is intended for use in local or metropolitan area n/w. It is an extension to basic MIP. The basic structure of Internet containing CIP access networks can be represented as the universal component of a CIP networks the BS serving as an access point. The boundary between a CIP access n/w and the Internet is the gateway router; mobility between gateways in macro, while within the access networks it is micro and handled by CIP. The IP address of the gateway is the COA of all the MN attached to the access network. Packets destined to the MN are first routed to the gateway. Within the CIP Fig. 6 access networks, the MN are identified by it s HA and packets are forwarded to the MN through BSs hop-byhop instead of using tunneling or address conversion. The gateway periodically broadcasts a beacon packet depending on which each BS can form the uplink to the gateway and then route the uplink packets from the NM to the Gateway hop-by-hop accordingly. Each BS is also responsible for maintaining a routing cache. An entry in the routing cache binds the MN's Home address with the interface through which the MN can be arrived at. The routing information of the entry is generated and refreshed by monitoring regular packets sent by an MN in order to minimize control messaging. The downlink path can then be formed by reversing the path. Since the bindings in the routing caches have timeout values, on MN can keep the entry valid by sending empty packets (route-update packets) to the Gateway at regular intervals. CIP supports two types of handoff scheme: Hard handoff and semi soft handoff. Hard handoff is based on a simplistic approach that supports fast and simple handoff by minimizing handoff signaling with the potential packet loss. Handoff is initiated by the MN on the basis of signal strength measurements and performed by sending a route update packet. Semi soft handoff takes advantage of the feature that there is a period in which both the old and the new downlink routes are valid and packets are delivered through both BSs. The MN may first initiate a handoff by sending a semi soft packet to the new BS and then perform the regular handoff after a delay during which the new downlink path has been configured. Through this mechanism, the handoff performance is improved by providing a probabilistic guarantee instead of fully eliminating packet loss. An explicit paging scheme is employed by CIP to reduce power consumption at the terminal end and minimize the signaling overhead in the access n/w. An idle state is introduced for the MN that has not received packets for a specified interval but still wants to remain reachable. CIP tracks the location of idle hosts only. A paging cache may be maintained by some BSs and it has a longer timeout period than routing cache. As soon as incoming packets need to be sent to an idle MN, the MN can be paged through a limited scope broadcast if the entry in the routing cache has expired. 5.2 Hierarchical MIP This micro-mobility solution uses a hierarchy of mobility agents. Here, the MN s HA needs not to be informed of every movement that the MN performs inside the FN domain. The proposal from Ericsson and Nokia that employs a hierarchy of FAs to handle the MN s local registration has been introduced. This micro-mobility solution uses a hierarchy of mobility agents. Here, the MN s HA needs not to be

Mobility Management Protocols for Wireless Mobile Networks 37 Fig. 7 informed of every movement that the MN performs inside the FN domain. The proposal from Ericsson and Nokia that employs a hierarchy of FAs to handle the MN's local registration has been introduced.here the FAs in a domain are organized into a hierarchical tree-like structure. The root of the hierarchy (FA1) is a special kind of FA called gateway foreign agent (GFA). An FA s agent advertisement is extended to include in the CoA field the IP addresses of FAs from the FA itself through the entire ancestor FAs until the GFA. The MN s registration is then processed by all the FAs on the uplink path ended by the FGA and finally the HA stores the GFA s IP address as the current CoA of the MN. Through this Mechanism the location information is managed in a distribution mode. When an incoming packet (from the HA or any CN) arrives at the GFA, the downlink path is formed by searching the visitor list for a corresponding entry by each FA on the path. Each of the FA then re-tunnels (de encapsulating and encapsulating) the packet to its next lower - level FA, and the packet is forwarded down the tree of FAs toward the MN's point of attachment. As a handoff occurs, the MN first finds the closest common ancestor (CCA) by comparing the new CoA vector with the old one and choosing the lowest level FA that appears in both CoA vectors. The MN then regionally registers this movement to the CCA and leaves all the higher level FAs unaffected. In the figure, when the MN moves from FA4 to FAs, the FA2 is the CCA. Generally two levels of the hierarchy are considered, at the top level there is one or several GFAs and at the lower level all RAs are connected to the corresponding GFA. If there is a hierarchy of FAs between GFA and the MN's current FA, the FA must support the smooth handover routing optimization. An explicit paging scheme is employed by HMIP that allows idle mobile nodes to operate in a power saving mode while located within a paging area. 5.3. HAWAII (Handoff-awareWireless Access Internet infrastructure) The HAWAII protocol is proposed by Lucent Technologies Bell Labs as a separate routing protocol to take care of the micro mobility inside the visited domain. The main goals of HAWAII are to achieve good perform once to provide intrinsic support for QoS, enhance reliability. The gateway in each domain is called the domain route router (DRR). No HA is involved, when an MN s movement is within the home domain, where the MN is identified by its IP address. When an MN is moving within a FD, the MN is assigned a CCOA. Packets can then be tunneled to the MN by the HA in its HD. This CCOA remains unchanged as long as the MN is moving within the FD, so the HA need not be notified of these movement unless the MH moves to a new domain. Fig. 8 This is achieved by enabling any MH to register with a BS while using a CCOA and then locally handling the registration by the corresponding BS. The processing and generation of the MIP registration messages are split into two parts: between the MH and the base station and between the BS and the HA. Nodes in a HAWAII network execute a generic IP routing protocol and maintain mobility-specific routing information. Location information (I.P. mobile specific routing entities) is created, updated and modified by explicit signaling messages sent by MNs. HAWAII defines different path setup schemes to update the routers in a domain so that the connectivity

38 International Journal of Computer Science and Communication (IJCSC) to the MN is maintained across handoffs. Two scenarios are considered by HAWAII (a) Power up, (b) Following handoff. Then, two variants of the path setup scheme are described for the operations of handoff, motivated by two types of wireless networks. The forwarding scheme is optimized for networks where the MN is able to listen/ transmit to only one BS (TDMA n/w). The nonforwarding scheme is optimized for n/w where the MN is able to listen transmits to two or more BSS simultaneously (CDMA n/w). An explicit paging scheme is employed by the HAWAII protocol. 5.4 IntraDomainMobilityManagement Protocol The recently proposed Telecommunication Enhanced MIP (Tele MIP) is a scalable and hierarchical IP based architecture that provides lower handoff latency and signaling overhead compared to MIP uses IDMP. IDMP offers intra-domain mobility by using multi CoAs. binding updates are generated only when the MN changes domains and obtains a new GCoA, this approach drastically reduces the global signaling load. When the MN first moves into a domain, it obtains an LCoA by performing a subnet specific registration using IDMP. As requested by IDMP, the serving SA dynamically assigns the MN a MA during this subnet specific registration process. Then the MN performs an intra domain location update by communicating its current LCoA to the designated MA. The MN is responsible for generating a global location update to the necessary remote nodes. After registration, IDMP now allows the MN to retain its global CoA as long as it stays within the same domain. Whenever MN changes subnets within this domain, it performs a new subnet - specific registration with the new SA. The MN then performs a new intradomain location update and informs its MA of its new LCoA as with other hierarchical mobility management schemes, the localization of intra-domain mobility significantly reduces the latency of handoff across subnets within the same domain and also dramatically decreases the frequency of global signaling traffic. Fig. 9 The MA is similar to a MIP-RR (Regional registration) GFA and acts as a domain-wide point for packet redirection. A subnet agent (SA) (Similar to MIP FA in CoA mode and DHCP (Dynamic host configuration protocol) server in (CoA mode) provides subnet-specific mobility services. In IDMP, an MN obtains two concurrent CoAs: (a) Local CoA that identifies the MN s attachment to the subnet. The LCoA in IDMP has local (domain-wide) scope. By updating its MA of any changes in the LCoA, the MN ensures that packets are correctly forwarded within the domain ( b) Global CoA: This address resolves the MN s current location only up to a domain-level granularity and hence remains unchanged as long as the MN stays within a single domain. By issuing global binding updates that contain this GCoA, the MN ensures that packets are routed correctly to its present domain. Under IDMP, packets from a remote CN are forwarded (with or without tunneling) to GCoA and are intercepted by the MA. The MA then tunnels these packets to the MN s current of LCoA. Since global 6. CONCLUSION This paper discusses the mobility management schemes for the next generation mobile networks. Here the mobility management has been divided into two types, macro mobility and micro mobility for macro mobility solutions the basic MI P and MIPV6 has been introduced. For micro mobility solutions cellular IP, Hierarchical IP (HIP), HAWAII and IDMP proposals are given. Further research topics include the evaluation of these entire proposals with actual traffic load and careful consideration of security and QoS. The presented schemes can serve as an efficient guide to the overall solutions and systematic research on the problem of mobility management for the next generation wireless communications. Development of new techniques for location management and handoff management can be taken as the future work and need further research. REFERENCES [1] Jun-Zhau Sun and Jaakko Sauvola, On Fundamental Concept of Mobility for Mobile communications. [2] Ted Taekyoung kwon,mario Gerla, An Ip-level Mobility Management Framework Based on Quasi- Registration in Wireless Technologies Convergence. [3] Jun-Zhau Sun, Jaakko Sauvola and Douglas Howie, Mobility Management Techniques for the Next Generation Wireless Networks. [4] K. Daniel Wong, Hung-Yu Wei, Ashutosh Dutta, and Kenneth Young, Performance of IP Micro-Mobility Management Schemes using Host Based Routing.

Mobility Management Protocols for Wireless Mobile Networks 39 [5] Subir Das, Anthony McAuley, and Ashutosh Duta, IDMP: An Intra Domain Mobility Management Protocol for Next Generation Wireless Networks. [6] Rajeev S. Koodli, Charles E. Perkins, Mobile Internetworking with IPv6: Concepts, Principles, and Practices. [7] Kia Makki, Mobile and Wireless Internet: Protocols, Algorithms and Systems. [8] Marco Carli, Alessandro Neri, Andreya Rem Picci, Mobile IP and Cellular IP Integration for Inter Access Networks Handoff.