Authors: Ing-Ray Chen and Ding-Chau Wang Presented by Chaitanya,Geetanjali and Bavani Modeling and Analysis of Regional Registration Based Mobile Service Management

Overview  Introduction  Related Work  Protocol Description  Model  Numerical Data And Analysis  Simulation

Introduction  Multicasting  Single sender, multiple receivers  Efficient Multicast Protocol  Minimum data duplication  Minimum distance travelled Mobile Multicasting  Multicasting in mobile networks  Challenges for Mobile Multicast Protocol  Dynamic group membership  Dynamic member topology

Basic Schemes for Mobile Multicasting  Remote Subscription (RS):  Mobile host (MH) always needs to subscribe to its multicast group when it enters or changes a foreign network  Handoff frequency of mobile host is proportional to the update frequency of the multicast tree Advantage : Optimal shortest path Disadvantage: Extra Overhead for reconstructing multicast tree

 Bi-directional Tunneling (BT): A MH receives multicast data by way of its home network using unicast mobile IP tunnels from its Home Agent(HA) Advantages:  Handles both source and recipient mobility  No need to update the multicast tree when MH’s location is changed Disadvantages:  Packet delivery path is not optimal  Limited scalability

Related work  mMOM  Hybrid approach of BT and RS  Every MH must re-register with FA after a period of residence time(Life time)  A MH applies either BT or RS based on its mobility  If the MH is highly mobile, BT will be used  If the MH is immobile, RS will be used Advantage: Simple and Practical Disadvantage: Does not allow care of address to be used in mobile IP

 Multicasting with Multicast Agents  Multicast agents(MA)  MA provides multicast services to the mobile group members in the multiple foreign agents.  MA maintains a list of multicast groups and FAs that have visiting mobile members for that group. Routing with multicast agents

 Multicasting with Multicast Agents (Contd.)  MA joins the multicast group on behalf of mobile group members in it service area.  MA tunnels multicast packets for these groups to FA  FA delivers packets to mobile hosts Advantages:  Stable structure  Avoids frequent modifications to multicast tree Disadvantages:  Lacks flexibility  Single point failure

Figure: Setup of a new MHA  Range Based Mobile Multicast (RBMoM)  Introduces a Mobile Multicast HomeAgent(MMA)  MMA multicasts packets to FA to which the MH is currently attached  Each MHA must always be one of the multicast group member

 Range Based Mobile Multicast (RBMoM) (Contd.)  The MHA information is recorded at MHs HAs agent table  MMA handoff s occur if a MH is out of current MMA’s service range Advantages: Dynamic MMA Disadvantages: Communication overhead and performance penalty to the network

 Proposed protocol  User-oriented Regional Registration based Mobile Multicast (URRMoM)  Combines advantages of RS and BT  Each MH’s can autonomously determine its optimal service area (MMA) based on its dynamic mobility and service characteristics Advantages:  No need to maintain Agent table  Minimizes network traffic  Simple, scalable and efficient. Protocol Description

 Protocol Description (Contd.)  MMA is responsible for tunneling multicast packets to FA as long as the FA is within the regional MMA’s service area.  Each MMA will be a member of multicast tree  Each MH should have one MMA  MMA of the MH will change as it roams in the network  Each MH keeps a counter to record the number of subnets it has crossed within the service area of its MMA  Regional service area of MMA = Number of subnets covered by the MMA

 When the FA is MMA  The MMA of the MH will be updated to the current FA  The counter in the MH will be reset to 0 after the MMA reset

 When the FA is not a MMA  The counter in the MH will increment by 1  When the counter in the MH reaches to the regional size (R) the multicast  The new FA will subscribe to tree and become a new MMA for the MH

Types of Moves in RRMoM 1. Intra-Regional:  Occurs? -> Whenever a MH performs a location handoff “within” a multicast service area of a regional MMA.  Change in MMA? -> only if the new FA it enters into is itself a MMA for other MHs.  In this case, the MH’s MMA is updated to the current FA.

Type of Moves - II 2. Inter-Regional: Occurs? -> Whenever a MH moves across a service area (the counter reaches R), thus incurring a multicast service handoff. Change in MMA? -> The MH’s MMA always changes. If the new FA is itself a MMA, then the MH’s MMA is simply updated to the current FA. Otherwise, the current FA becomes the MH’s new MMA. A multicast tree subscription event is triggered to add the new MMA to the multicast tree.

Hypothesis There exists an optimal service area size that will minimize the network traffic generated due to mobile multicast services. It depends on: the mobility of MHs population of the MHs the size and topology of the network.

MODEL Is fixed Each node is a subnet with FA A MH can move in four directions randomly with equal probability

Relationship between λ and μ Let μ = MH’s residence time in FA (exponentially distributed) Let λ = arrival rate of a single MH to any FA in this n x n homogenous network Then, λ = μ / (n2-1)

M/M/∞/M Let M = number of MHs belonging to the multicast group The arrival-departure process of M members to a FA (a subnet) is modeled as M/M/∞/M model

Solving the linear equations for Pi and using P0 = (1-1/n2)M (Substituting, λ = μ / (n2-1))

Average number of members in the multicast group residing under one FA: The average number of multicast members a MMA covers: R. a MMA on average covers R subnets Average number of MMAs in the system is : Probability that a FA in which a MH just enters is a MMA, (P MMA ),

SPN – Behavior of a MH in network

Performance Metrics Total cost is given by: C Maintenance : Cost incurred per unit time due to control packets for tree management = MMA Subscription cost + MMA Un-subscription cost Let r sub = Rate at which a member subscribes a new MMA to the multicast tree after it has crossed R subnets Let β = Average number of hops separating a MMA and multicast source. Let τ = Average per-hop communication cost. Total Subscription Rate = r sub x M Total Unsubscription Rate =

Total Cost C Service = Cost per unit time for delivering multicast packets from the multicast source to MHs in the multicast group. C Service = Cost per packet delivery x rate at which packets are generated = number of hops for multicast packet delivery from the multicast source to MMAs = number of hops through which packets are tunneled from various MMAs to M MHs.

NUMERIC DATA AND ANALYSIS Figure shows the total traffic generated as a function of the service area size R expressed in terms of the number of subnets Optimal service area size under which the network traffic generated is minimized As the mesh network becomes larger, the optimal service area size becomes larger and larger Cost vs. Regional Area Size (R) with varying n.

Cost vs. R with Varying Number of MHs  Figure shows the network traffic generated vs. R as M varies in an 8 by 8 mesh network.  As M increases the optimal R decreases.

Effect of the Distance between Source and MMA Figure shows that when β increases, the optimal range R increases for the case when M is fixed at 100 Here, β =average number of hops to reach the source for multicast tree subscription/un-subscription

Comparison of URRMoM vs RS and RBMoM Figure compares the network traffic generated due to maintenance vs. the network size n for URRMoM vs. RS and RBMoM at optimizing R values under the same set of parameter values. URRMoM always produces the least amount of network traffic compared with RS and RBMoM

SIMULATION SMPL has been used to conduct a simulation study to validate the analytical results reported in Numerical Data and Analysis section. To ensure statistical significance of simulation results, a batch mean analysis (BMA) technique has been adopted

SIMULATION RESULTS Simulation Results - Cost vs. R with varying Number of MHs Simulation Results - Cost vs. R with varying n.

Simulation Results – Comparison of URRMoM vs RS and RBMoM

CONCLUSIONS Proposed and analyzed user-oriented regional registration based mobile multicast (URRMoM) approach Combines distinct performance advantages of remote subscription and bi- directional tunneling Mathematical model to analytically determine the optimal service area size under which the overall network traffic generated due to multicast tree maintenance and multicast packet delivery can be minimized Effect of key parameters on the optimal regional area size Reasons for the sensitivity analysis has been provided

FUTURE WORK In the future, empirical validation of URRMoM in an experimental testbed is planned to be performed

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