Vehicular Ad Hoc Network (VANET) is an emerging technology in which mobility management, continuous connectivity and security on data transmission between vehicles with high speed or during the change of topology of the network acts as a challenging exploration issue of Intelligent Transportation System (ITS) applications. This paper aims to formulate a ubiquitous connectivity to nodes by keeping the established connections before and after handover thereby minimizing the delay, packet loss and provide secured acknowledgement for handover. The Secured Efficient Fast Handover Multihoming Based NEMO+ (SEFMNEMO+) framework helps to optimize the NEMO+ scheme that supports multihomed network, handover and security. The predictive policy exchangemethod is used to update the future handover for minimizing the overhead delay and packet loss. The multihomed feature in NEMO+ supports efficient handover mechanism between heterogeneous networks when VANET connection fails. Public key cryptography provides the secure acknowledgement before handover i.e ., the acknowledgement is encrypted with digital signature.
Vehicular network adapts the techniques of Intelligent Transportation Systems (ITS) [
VANET [
NEMO is aligned with Mobile IPv6 [
In this paper the EFNEMO+ [
Tarik Taleb et al. [
D. Tamil Selvan et al. [
Dae Won Lee [
Park, Hee-Dong, et al. [
Illkyun, et al. [
As a part of the analysis done on Vehicular handovers, the following methodology namely Secured Efficient Fast Handover Multihoming Based NEMO+ (SEFMNEMO+) is proposed.
In SEFMNEMO+, the registration of MR to HA be performed in advance to enhance the handover progression, i.e. an uncertain registration to HA is done simultaneously before actual handover is happened. Mobile Network Nodes (MNN) conveys the packets between MR and NAR in different path, but not through the burrow between PAR and NAR in order to diminish the burden in the burrow and idleness of handover. The optimize delivery of the packet to the destination network is performed using the triad protocol such as Tree Discovery (TD), Network In Node Advertisement (NINA), Reverse Route Header (RRH). SEFMNEMO+ mechanism is introduced in multi homed mobility configuration based on flow binding to access the destination network from multiple network to predicts the handover process by accessing the information about actual location and previously recorded context data. In order to provide the seamless connectivity to the MR the predictive policy exchange message is used and it will avoid packet from the delay and loss during handover. The Private Key-based Binding Update (PKBU) protocol is to effectively protect the FBU message against attacks by adversary.
EFNEMO+ scheme is used to optimize the delivery of packet in the VANET. The optimize path is decided using interoperation protocols such as
・ Tree Discovery (TD) is used to describes the flows of message out of MR Ingress interface
・ Network in Node Advertisement (NINA) is used to subsequent flow of message out of MR egress interface.
・ Reverse Route Header (RRH) is used to establish the registrations of MR in HA.
NEMO+ efficient handover mechanism is introduced in multihomed mobility configuration based on flow binding to access the destination network from multiple networks. It predicts the handover by using the actual location information and previously recorded context data.
The first level of protocol in NEMO+ is Tree decision (TD) protocol which is used to discover and connect multiple MR in the network. With IPv6 Neighbor discovery (ND) Route Advertisement (RA) augments it by MR to transmit the TD, which allows MR to distribute information among the other MR that connects to its ingress interface. This helps MR to decide which MR has to connect with other MR in order to form a tree structure. This is achieved by Tree Information Option (TIO) which is augmented in RA as RA+TIO, where TIO has the information regarding the TD that decides the MR whether to connect another MR or not. Spontaneous attachment of MR will be designed as graphs by itself which do not accept to form loops, because looping may conflicts the MR when it is listening to RA from its own Ingress interface to access the internet. The aim of TD is to prevent router from looping. This is achieved through TD that provides the information regarding the router selection and it carries another information such as whether MR in the tree is connected to internet, or how long each MR in the EFNEMO, or the bandwidth capability of MRs Internet.
Above flow chart explains the selection of efficient mobile router using TD in order to provide internet services to all mobile routers in optimize manner as well as prevent from looping (
Second level of NEMO+ protocol is Network in Node Advertisement (NINA) which is used to ensure the routes of all MN through EFNEMO are enclosed in a tree structure. MR runs the NINA protocol that rely upon RA+TIO, which in turn MR responds to source of RA+TIO with NINA response, which contains all the details of previous information that currently maintained by MR. Once receiving the NINA response, source of RA+TIO starts forwarding the NINA message to current attachment of MR; It contains both the prefix of MR which is already maintained and the prefix of MR that are currently attached. The process is repeated until top of the tree is reached in EFNEMO+ i.e. Process is repeated until entire MR is appraised that are connected in EFNEMO+. As with TD, NINA inherits behavior of EFNEMO MRs by augmenting the NA with NINO (Network in Node Option) messages. TD augments RA messages to act MR as mobile router to its ingress interface. When MR ingress interfaces, it acts itself as individual host, advertisement is done by itself using NA message and it carries information about network prefix to reach itself in these NA message by single node advertisement. An effective technique Route propagation model is engaged in NINA for frequent updates of MR. NINA will hide the changes in the topological structure of MR and to endure the reachability of MR it will also hide the
movements of sub tree from parent sub tree in Ingress interface of MR. As a result, the MR which is closer to gateway-MR is observed less for MR mobility, the routes are maintained for more prefixes. Meanwhile the MR which is far away from gateway-MR will observe more for mobility of MR and the routes are maintained for less prefixes.
To ensure the efficient delivery of the packets beyond the Gateway-MR, a Reverse Routing header (RRH) protocol is introduced to prevent occurrence of pinball routing. In RRH each MR in the EFNEMO update their HA with current location of the gateway-MR, to ensure the direct delivery of packets to their current location, this is achieved by combining the source routing protocol in EFNEMO with traditional IP routing. As the packets travels towards internet, RRH record the routes of the packets flow. This is done when each MR overwrites the source filed of the outer IPV6 header of the travelled packets and overwrites the existing source addresses are recorded. By this, each MR sends the packets to its actual COA of the gateway-MR as it is source address and the routes are taken back to reach the actual MR by RRH method. This information is stored in HA and successively assigns the destination of the outer IPV6 header to the Gateway-MR COA and RRH is set to the packets to transmit from CN to MR. Before the packets are delivered to destination COA that are recorded in RRH, it first delivers to its Gateway-MR COA.
If NINA is not present, RRH is designed to record the path through the EFNEMO. When NINA is supported by MR, then role of RRH has to record the actual COA of the MR and check correctness of topology in Gateway-MR COA and report it to MRs HA. In the return flow of communication HA to MR, MR acts as a destination COA and the packet will be routed using the NINA protocol.
During handover, the MR discover the entire MR’s in the ingress interface network and sends the NINA message to each egress interface of MR that advertised about the subsequent flow of routes in the MR. The handover operation is divided in two modes predictive (
After receiving the acknowledgement from CN, HA probably use binding information to create an extra entry in the Binding Cache Entry ( BCE ) for coexisting MR’s HoA. To stay away from the Ping-Pong impact, during handover HA forward the packets to PAR because MR does not move to the NAR after sending TBU message to HA. TBU message contains address of MR’s HoA, the NCoA, and the short binding lifetime.
In order to avoid burrow burden between PAR and NAR, NAR starts buffering the packets which are sent from HA, and from NAR it reaches destined MNN through various paths. In EFNEMO+, the burrow between the PAR and the NAR still remains, the burrow is used when the HA can’t handle the TBU message, or the TBU message is not conveyed to NAR. After handover process in Layer-2, through normal BU message MR registers the NCoA with HA and updates it in BCE. Before handlayer2 happens MR has to receive the Fback message from HA to continue in predictive mode else EFNEMO+ operates in reactive mode. In reactive mode activates, after layer2 handover is completed; then MR sends the UNA (Unsolicited Neighbor Advertisement) is embedded in FBU to NAR. Then PAR receives the FBU message from NAR. HI, HACK messages are exchanged between PAR and NAR, which creates burrow to forward the packets when Hack message is received by PAR and sends the Fback message to NAR. The packets are delivered to MNN before registering NCoA. Burrow is used to deliver the packets between MNN and HA, When TBU message is not accomplished in predictive mode
Multi homing refers to the phenomena of one network end node accesses to the Internet uses multiple network paths to accesses the Internet, it consider the fault resilience. The multi homed network end node habitually possesses several addresses to access the internet via multiple path networks i.e. if the current network path fails, it can immediately switch to another address and another network path for communication. EFNEMO+ efficient handover mechanism is introduced in multi homed mobility configuration based on flow binding to access the destination network from multiple networks (
・ Access Network Prediction (ANP)
・ MR’s Handover Manager (HM-MR)
・ Home Agent (HM-HA)
To ensure the secure transmission of BU data from the adversary attack the Elliptic Curve Cryptographic system (ECC) [
In this paper, CN stay away from false binding; the reachability of MR and address proprietorship of MN is verified. Address of the MR is created by 128-bit NEMO+ based on MR’s private key and one way hash function is compute for authenticating the authority of MR’s. By using MR's private key and a valid subnet prefix, the proprietorship of MR’s IP address is verified by CN.
Second reachability of MR is verified in PKBU. In this method, MA sends the hash value of the MR’s HoA, the public key of MR, and request for the CN’s public key to the CN through HA. Once MR receives the CN’s Public key, the messages are sent directly to CN; by using CN’s Public key MR encrypts the MR’s COA and HOA in the message. When message are delivered to CN, it uses the MR’s public key to verify the signature, and then MN’s CoA and HoA is gained after decrypting the message. Then CN compares the hash value of HoA with hash value of the received message from MR. While checking and the validating the MR’s HoA and CoA is result in positive, then the CN allows MR to register in that CoA.
Exchange of messages between the nodes in the PKBU protocol involves three stages. In Stage 1 the proprietorship of the MR’s IP address which involves three strides. In Stage 2, the reachability of MR is verified. Stage 3 is validation process which consists of four strides. During validation process CN has to ensure the proprietorship of MR and reachability of HoA and CoA.
Stage 1: Proprietorship of the MR’s IP
In this stage, MR generates its private, public key and interface ID in 3 strides (
1) Creating private key:
MR’s private key is generated by user identity number (UI) is an integer. A hash function with randomly generated integer of an UI is calculated to produce MR’s private key as follows,
where,
2) Creating public key:
In this process, MR creates its own public key. Using ECC the public key of MR is generated with the MR’s private key. Consider the equation C: y2 = x3 + ax + b, where (x, y) are points on the curve, and b values generated for curve. The bounds of ECC are B= {a, b, P, m} where a, b are values of the elliptic curve, P is base point of elliptic curve and m is the order of curves. MR’s public key
3) Creating Interface ID:
In this step, Interface ID is created as 128 bit address, 64 bit given for subnet prefix and 64-bit for interface identifier that are derived from hash value of MR’s private key. This method creates secure binding between MR’s Interface ID and its own Private Key without involving PKI.
Stage 2: Reachability of the MR to CN
Reachability of MR is achieved by sending the CoA to CN through HA by way of IP sec. whenever MR enter into new network it must register with new CoA and the operation on HA is completed before MR uses new CoA. The following steps are to ensure the reachability of MR to CN.
Step 1: MR sends message to CN: MR sends the requirements for routing optimization to CN through HA. In the pre-established burrow MR sends Hash values of MR’s HoA, public key of MR, and requests the public key of CN through HA to CN.
Step 2: CN sends messages to MR: CN responds accordance with request of MR. That is MR receives the CN public key by HA; Hash values of MR’s HoA and MR’s public are stored in CN.
Step 3: Encryption of message in MR: Using CN’s public key the MR encrypts the MR’s CoA and HoA and these cipher text are signed using MR’s private key.
Stage 3: Validation Process
In this stage it validate the process the requirements for security, proprietorship, and reachability of the MN‘s IP addresses. CN authenticate the MR signature by using the MR’s private key. If the sign is not done using the MR’s private key then the process is tends to end. After authenticating the signature, CN checks the message confidentiality by decrypting with the CN private key to gain MR’s CoA and HoA. CN assures the HoA by calculating the hash value of decrypted HoA and the results is compared with the hash value of HoA which are sent by MR. If it results in negative then the message will be prohibited or else if the validate process is result in positive then it approves the proprietorship of MR and when CoA is identified then the MR is reachable to CN will send the binding acknowledgement (BA) message to MR.
The working process of the proposed SEFMNEMO+ algorithm based on the vertical handover mechanism is represented in the form of flow graph (
In the experimental analysis, it analyzes the security, handover efficiency and its performance is analyzed using proposed methodology. The proposed methodology is implemented using NS-2 network simulator tool with a network capacity of 100 mobiles nodes. The simulation is tested for the performance of the handover rate in NEMO+, EFNEMO+, SEFMNEMO+ with the given network capacity.
The simulation parameters are used while implementing this proposed technique, which is summarized below in
The performance of this work is measured using packet loss, average delay, control overhead and average throughput which shows that an efficient result of proposed protocol when compared with existing system. These results are discussed briefly below.
PLR is defined as rate of Number of message received in a packet at the destination by Total number of message sent from source while handover process is taken place. The PLR is measured using following formula.
The average delay is calculated by taking the average of delays for every data packet transmitted to the total number of received packets as defined below in equation. The parameter is measured only when the data transmission has been successful.
Simulation Parameter | Value |
---|---|
Propagation | Two Ray Ground |
Channel | Wireless Channel |
Physical Layer | Wireless Physical |
Queue | DropTail/PriQueue |
Mac | 802_.11 |
X dimension of the topography | 500 |
Y dimension of the topography | 500 |
Ad hoc Routing | AODV |
Antenna | Omni Antenna |
Max packet | 100 |
Number of nodes simulated | 50 |
Cp | ./cbr |
Sc | nodes50 |
Simulation time | 100 s |
Energy | Energy Model |
Initial Energy | 100 |
Min Neighbor | 6 |
Security Duration | 4 |
Adversary node | 5 |
The ratio of total numbers of control packets generated to the total number of data packets received during the simulation time given in equation.
Throughput is defined as total number of kilobytes by total bytes received per second. It is represented by kbps.
In VANET, the seamless connectivity is produced during the handover. The proposed framework is used to improve the seamless connectivity by reducing delay and loss of packet and security mechanism among the VANET. It is achieved by hybrid implementation of NEMO+ scheme and public key cryptography for secured efficient handover mechanism. The experimental analysis of proposed framework EFMNEMO+ is being compared with existing NEMO+ and the results show that the average delay, overhead, packet loss are minimum with higher PDR value and higher throughput. SEFMNEMO+ is found to be better in minimizing the average delay and overhead thus reducing the rate of packet loss when compared to NEMO+ or EFNEMO+.
M. Siva Sangari,K. Baskaran, (2016) Secured Efficient Fast Handover Multihoming Based NEMO+ (SEFMNEMO+) for Vanets. Circuits and Systems,07,239-254. doi: 10.4236/cs.2016.74023