Authors: Ing-Ray Chen Weiping He Baoshan Gu Presenters: Yao Zheng

» Introduction » Related Work » DMAP » Model » Numerical Results » Applicability and Conclusion

» MIPv6 - Mobile IPv6 ˃A version of mobile IP, it allows an IPv6 node to be mobile and still maintain existing connections; » HMIPv6 - Hierarchical Mobile IPv6 ˃Proposed enhancement of MIPv6, it is designed to reduce the amount of signaling required and to improve handoff speed for mobile connections; » MAP – Mobility Anchor Point ˃Serving as a local entity to aid in mobile handoffs, it can be located anywhere within a hierarchy of routers;

» HA - home agent ˃A router on a mobile node’s home network that maintains information about the device’s current location, as identified in its CoA; » CoA - care of address ˃A temporary IP address for a mobile node that enables message delivery when the device is connecting from somewhere other than its home network; » Location handoff ˃Mobile node moves across a subnet boundary; » Service handoff ˃Mobile node moves across a DMAP domain boundary;

» The essence of DMAPwSR is the notion of integrated mobility and service management, which is achieved by determining an optimal service area size; » The objective is to minimize the total network signaling and communication overhead in servicing the mobile node’s mobility and service management operations;

» Intra-regional move ˃When the MN subsequently crosses a subnet but is still located within the service area, it would inform the MAP of the CoA address change without informing the HA and CNs to reduce the network signaling cost;

» Inter-regional move ˃The mobile node makes the AR of the subnet as the DMAP when it crosses a service area, and it also determines the size of the new service area; ˃MN acquires a RCoA as well as a CoA from the current subnet and registers the address pair to the current DMAP in a binding request message;

» Inter-regional move ˃The MN also informs the HA and CNs of the new RCoA address change in another binding message so that the HA and CNs would know the MN by its new RCoA address; ˃DMAP intercepts the packet destined for RCoA, inspects the address pair stored in the internal table, finds out MN’s CoA and forwards the packet to the MN through tunneling;

» A MN’s service area can be modeled as consisting of K IP subnets; » The MN appoints a new DMAP only when it crosses a service area whose size is determined based on the mobility and service characteristics of the MN in the new service area; » The service area size of the DMAP is not necessarily uniform;

» A large service area size means that the DMAP will not change often, while a small service area size means that the DMAP will be changed often so it will stay close to the MN; » There is a trade-off between two cost factors and an optimal service area exists;

» The service and mobility characteristics of a MN are summarized by two parameters: ˃The resident time that the MN stays in a subnet, represented by using the MN’s mobility rate σ; ˃The service traffic between the MN and server applications, represented by using the data packet rate λ; » The ratio of λ/ σ is called the service to mobility ratio (SMR) of the MN;

» A computational procedure to determine the optimal service area size ˃The intent to find the optimal service area based on the MN’s mobility and service behaviors » The computational procedure requires ˃Every AR must be capable of acting as a MAP ˃Each MN must be powerful enough to collect data dynamically and perform simple statistical analysis

» Aim to minimize the communication cost ˃The signaling overhead for mobility management for informing the DMAP of the CoA changes ˃Informing the HA and CNs of the RCoA changes ˃The communication overhead for service management for delivering data packets between the MN and CNs

SymbolMeaning λ Data packet rate between the MN and CNs σMobility rate at which the MN moves across subnet boundaries SMRService to mobility ratio (λ/σ) NNumber of server engaged by the MN

SymbolMeaning KNumber of subnets in one service area τ1-hop communication delay per packet in wired networks αAverage distance between HA and DMAP βAverage distance between CN and DMAP γCost ratio between wireless vs. wired network

Moves Intra Xs MoveNewDMAP MN2DMAP K K A B Pi=1 Pj=1 (Guard:Mark(Xs)=K-1) (Guard:Mark(Xs)<K-1) (Guard:Mark(Xs)=K) A token represents a subnet crossing event by the MN

Moves Intra Xs MoveNewDMAP MN2DMAP K K A B Pi=1 Pj=1 (Guard:Mark(Xs)=K-1) (Guard:Mark(Xs)<K-1) (Guard:Mark(Xs)=K) Mark(Moves)=1 means that the MN just moves aross a subnet A temporary place holds tokens from transition A Mark(Xs) holds the number of subnets crossed in a service area

Moves Intra Xs MoveNewDMAP MN2DMAP K K A B Pi=1 Pj=1 (Guard:Mark(Xs)=K-1) (Guard:Mark(Xs)<K-1) (Guard:Mark(Xs)=K) A timed transition for the MN to move across subnet areas A timed transition for the MN to inform the DMAP of the CoA change A timed transition for the MN to inform the HA and CNs of the RCoA change A guard for transition B that is enabled if a move will cross a service area A guard for transition A that is enabled if a move will not cross a service area

» P i : The steady-state probability that the system is found to contain i tokens in place Xs such that Mark(Xs)=i » C i,service : The communication overhead for the network to service a data packet when MN is in the i- th subnet in the service area A delay between the DMAP and a CN in the fixed network A delay from DMAP to the AR of the MN’s current subnet in the fixed network A delay in the wireless link form the AR to the MN

» C i,location : The network signaling overhead to service a location handoff operation given the MN is in the i-th subnet in the service area ˃If i < K +Only a minimum signaling cost will incurred for the MN to inform the DMAP of the CoA address change ˃If i = K +The location handoff also triggers a service handoff +A service handoff will incur higher communication signaling cost to inform the HA and N CNs of the RCoA address change

A location handoff and a service handoff A minimum signaling cost for the MN to inform the DMAP of the CoA address change

» Summarizing above, the total communication cost per time unit for the Mobile IP network operating under DMAPwSR scheme to service operations associated with mobility and service management of the MN is calculated as: Service management cost Mobility management cost

A service area under hexagonal network coverage model

A service area under mesh network coverage model

Access point locations at Dartmouth College campus

» MIPv6 A delay in the wireless link from the AR to the MN A communication delay from the CN to the AR of the current subnet A delay in the wireless link from the MN to the AR of the subnet that it just enters into A delay from that AR to the HA A delay from that AR to the CNs

» HMIPv6 ˃The placement of MAPs is predetermined ˃Each MAP covers a fixed number of subnets +K H = 4 » A MN crosses a subnet within a MAP ˃It only informs the MAP of its CoA » A MN crosses a MAP ˃Changes the MAP ˃Obtain a new RCoA ˃Informs the HA and CNs of the new RCoA

Cost difference between basic MIPv6, HMIPv6, and DMAPwSR

Cost ratio between DMAPwSR and MIPv6/HMIPv6

Effect of α and β on cost difference between HMIPv6 and DMAPwSR

Simulation versus analytical results: cost difference between HMIPv6 and DMAPwSR

Cost difference under movement-based versus distance- based service area simulation

Cost difference under different residence time distribution

Optimal K versus SMR under various time distributions

Cost difference under different network coverage model

» A novel DMAP scheme for integrated mobility and service management » To apply the analysis results in the paper, one can execute the computational procedure at static time to determine optimal K opt over a possible range of parameter value