486 research outputs found

    Seamless Infrastructure independent Multi Homed NEMO Handoff Using Effective and Timely IEEE 802.21 MIH triggers

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    Handoff performance of NEMO BS protocol with existent improvement proposals is still not sufficient for real time and QoS-sensitive applications and further optimizations are needed. When dealing with single homed NEMO, handoff latency and packet loss become irreducible all optimizations included, so that it is impossible to meet requirements of the above applications. Then, How to combine the different Fast handoff approaches remains an open research issue and needs more investigation. In this paper, we propose a new Infrastructure independent handoff approach combining multihoming and intelligent Make-Before-Break Handoff. Based on required Handoff time estimation, L2 and L3 handoffs are initiated using effective and timely MIH triggers, reducing so the anticipation time and increasing the probability of prediction. We extend MIH services to provide tunnel establishment and switching before link break. Thus, the handoff is performed in background with no latency and no packet loss while pingpong scenario is almost avoided. In addition, our proposal saves cost and power consumption by optimizing the time of simultaneous use of multiple interfaces. We provide also NS2 simulation experiments identifying suitable parameter values used for estimation and validating the proposed mode

    Adoption of vehicular ad hoc networking protocols by networked robots

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    This paper focuses on the utilization of wireless networking in the robotics domain. Many researchers have already equipped their robots with wireless communication capabilities, stimulated by the observation that multi-robot systems tend to have several advantages over their single-robot counterparts. Typically, this integration of wireless communication is tackled in a quite pragmatic manner, only a few authors presented novel Robotic Ad Hoc Network (RANET) protocols that were designed specifically with robotic use cases in mind. This is in sharp contrast with the domain of vehicular ad hoc networks (VANET). This observation is the starting point of this paper. If the results of previous efforts focusing on VANET protocols could be reused in the RANET domain, this could lead to rapid progress in the field of networked robots. To investigate this possibility, this paper provides a thorough overview of the related work in the domain of robotic and vehicular ad hoc networks. Based on this information, an exhaustive list of requirements is defined for both types. It is concluded that the most significant difference lies in the fact that VANET protocols are oriented towards low throughput messaging, while RANET protocols have to support high throughput media streaming as well. Although not always with equal importance, all other defined requirements are valid for both protocols. This leads to the conclusion that cross-fertilization between them is an appealing approach for future RANET research. To support such developments, this paper concludes with the definition of an appropriate working plan

    Analysis of IPv6 Neighbor Discovery for Mobile and Wireless Networks

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    The majority of the current 3GPP and M2M networks use or will use IPv6 for accessing the internet. These IPv6 networks use Neighbor Discovery as defined in RFC 4861 to identify their neighbors on the link and see if they are active. The increase in the complexity of wireless networks and introduction of battery operated devices sets forth notable challenges to certain assumptions in the RFC 4861. The RFC 4861 is more suited for wired networks and its implementation in wireless networks makes it more inefficient. This thesis work focuses on the energy efficient implementation of RFC 4861 using the protocols mentioned in draft-chakrabarti-nordmark-6man-efficient-nd-06. The draft suggests a method of registering all the nodes in the network to their default router, so that the router takes care of all the basic neighbor discovery functionalities without disturbing the battery operated devices which are in sleepy mode. Alongside the legacy Neighbor Discovery, the optimizations proposed by the draft are implemented, on a RADVD based router and an Ubuntu host, to reduce redundant multicast signaling in mobile networks. These optimizations are theoretically analyzed to check if the draft is beneficial for the scalability and transient nature of the wireless networks.Popular Science Report With the rise of Internet of Things (IoT) and Machine to Machine communication (M2M) based networks, more and more wireless devices are communicating to each other and hence there is a need for IPv6 (Internet Protocol version 6) addressing. This new type of addressing forces us to make some design changes in the existing protocols. Wireless devices are mostly mobile, battery operated (hence a power constraint exists) and can undergo several disconnections and reconnections while moving inside the network, whereas wired devices are less prone to network instabilities and almost always connected to a power source. Because of these differences, the protocols of wired devices are not always suitable for wireless networks. Still today’s wireless devices often use protocols that were designed for wired devices and tend to be inefficient. This thesis work deals with one such protocol called Internet Control Message Protocol (ICMP), which is widely used to send control messages across the network between different nodes. Neighbor Discovery Protocol (NDP) is a part of ICMPv6 that helps a node in the network identify its Neighbors on the other side of the link. Present generation wireless devices use the protocols defined in RFC 4861 (a common reference used by major communication companies while creating products) for Neighbor discovery. But this protocol proves to be inefficient by flooding the network with unwanted multicast control messages. Hence we analyze a modified version of the existing NDP against the legacy protocol. RFC 4861 based ‘legacy NDP’ works based on multicasting. Every IPv6 host is a part of several solicited node multicast groups. All nodes with the same last 24 IPv6 address bits belong to the same solicited node multicast group. NDP is also performed based on 4 major control message packets namely, Router Solicitation (RS), Router Advertisement (RA), Neighbor Solicitation (NS) and Neighbor Advertisement (NA). RA is the packet from the router which contains all the information about the network and the router. It is flooded periodically through an all node multicast group to all IPv6 nodes. When a node wants a particular router to send some information about the network immediately without waiting for periodic RAs, it sends an RS. Neighbor Advertisement is used by a node to send information about itself to other nodes in the network. Neighbor Solicitation, as name suggests, is used by a particular node to request for information about another node. Consider the case of a network with a host and a router, and a new node enters the network. It sends out RS to the all routers multicast group, and the router responds with an RA. The new host reads the information about the network and begins address configuration. Stateless Address Auto Configuration (SLAAC) is the most suitable method of address configuration for M2M networks. Hence according to SLAAC, the new host chooses an IP address and checks if the address has already been used by some other host. This process is called as Duplicate Address Detection (DAD) and is carried out by sending out NS for that chosen IP address at the solicited node multicast group address. This means that the new host asks information about a node with that IP address, which may or may not exist at all. If a reply comes, it means that there is a node using this address. If a reply does not come, then it is free to choose the address. The response NA in case of a duplicate address, will be broadcast to all IPv6 nodes. A NS-NA pair is also used to resolve each other’s IP addresses against their MAC addresses. One of the major reasons why this method seems to be inefficient is that current wireless devices are programmed to be in sleep modes when not in use. The flow of control messages to unrelated nodes (because of multicast) will only lead to disrupted sleep. Consider a host A in the network which is in sleep mode, and has an IP address aaaa::aaaa:aaaa:a. When a new host arrives and wants to register itself with an address of aaaa::baaa:aaaa:a, it sends out NS to the multicast group of A (because A has the same last 24 bits). When a packet reaches A, it wakes up from sleep mode, reads the message and identifies that this message was not destined to it. If there was another host in the group which used the same IP address, then host A will also receive another NA, which again is not of any use. Hence this protocol proves to be inefficient. The new proposed protocol works with an efficient implementation of the NDP. It introduces a concept of registering a host with a router. And the router sends out NS and NA instead of the host. Hence each router’s NCE will be the source of information for those hosts which are registered to that router. If a node will request for details about another host, the details will either be fetched from that router’s NCE or the NS will be forwarded to that particular host instead of being multicast. The router to whom the destination host is registered will then send NAs on behalf of its host. Hence in this protocol, the router performs more work and the host less, allowing the host to stay in sleep modes without any problems. The analysis of the two protocols begins with their implementation. We decided to test the working of the two protocols at two specific case scenarios: when several hosts join the network and when the channel links are unsteady. Both protocols were implemented and compared. The implementation of the legacy NDP began with a router and a host system. We used an Ubuntu PC (which generally works as a host) as a router. RADVD is an open source software that helps to generate RAs and Wireshark the software used to analyze packets in the network. To make a host work as a router, the following changes were made: 1. Turn on forwarding in the PC 2. Configure the router with a static IP address 3. Configure the interfaces and add corresponding routing information 4. Install RADVD and include all the network parameters in the config file 5. Turn on Wireshark 6. Turn on RADVD Once all these steps are done in order, the RADVD sends out periodic RAs that can be viewed on the Wireshark. When the host is connected to the network, the entire process of address configuration and DAD can be identified. When pinged, the address resolution process can also be verified. To implement the new protocol, we downloaded the source code of the open source RADVD from GitHub and change the packet formats of the RA, NS and NA. When the router works as a NEAR (Neighbor Discovery Efficiency Aware Router), the host has to understand that it should not use legacy NDP anymore and must act as an Efficiency Aware host (EAH). This information comes with the RA in the form of a flag. When this is done, the host sends an NS in the form of registration request. The details of the host go in the Address Resolution Option (ARO) of the NS. The router responds with an NA which is the acknowledgement for the registration request. Now the host can enter into sleep mode and the router will send control packets to it only when required. When the registration expires, a new registration process has to be setup or a de-registration process has to happen by setting the ARO option in the NS to 0. To implement the changes in the host side, we downloaded the source code for Linux from GitHub and led the decoder side. The process ends by making all the necessary code changes, recompiling a new Kernel and installing the new version of Linux on the hosts. However, the complete reprogramming of the kernel is not handled in this thesis work. But the entire plan for the programming and the rest of the implementation is included in this report. The theoretical analysis of the protocols is also included in this report. This report concludes with a general analysis of the whole protocol. The whole protocol which was completely decentralized has a certain degree of centralized control now. As with all systems, centralization introduces better control but there is always a problem of device failure which can completely collapse the system. The protocol also provides solutions for router failure and recovery and hence the system is a good compromise between centralized and decentralized systems. If properly implemented, there will be an increase in the network efficiency (inversely proportional to the number of control packets for every single data point). This thesis ends with the theoretical analysis. A proper implementation followed by a practical analysis would be a natural future amendment to the projec

    How efficient is Efficient NDP?

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    In the following years we will experience a transition towards Internet Protocol version 6 (IPv6). The reason is the depletion of IPv4 address space due to the rapid increasing numbers of Internet of Things (IoT) devices connection. This transition however poses a problem, since the majority of these devices mostly are mobile and not connected to power source. Neighbor Discovery Protocol (NDP) defined in RFC 4861 is used in IPv6 networks, to manage the address configuration as well as the network prefix and maintain lists of all the neighbors connected to that network. However, this protocol does not work as good in wireless connected devices as in wired. The messages exchange in the network disrupts the sleep mode of the nodes resulting in lower battery time. Hence the energy efficiency of these devices is now something we should consider. To solve this problem, the Efficient NDP draft was introduced as one of the optimized methods. This thesis takes the previous theses of analysis and simulations of IPv6 Neighbor Discovery for wireless networks further, to explore the ND protocol in RFC 4861 (legacy NDP), and compare it to the Efficient NDP draft in terms of energy efficiency for the devices mentioned above. Several dynamic network cases are taken into analysis, and simulation scenarios for these cases are tested in OMNeT++. These simulation models follow the implementation process introduced in the protocols with consideration of network scalability, and present the result that the Efficient NDP has large improvement in saving multicast messages in ND process.In the real world, people need addresses to identify their locations. Similar to this, devices also need to have network labels which called IP addresses for identification and locating when they connect to the Internet. Internet Protocol version 4 (IPv4) is a protocol which introduces a 32-bits IP address format and popularly used in today’s networks. However, the increased number of devices connecting to the Internet has led to the depletion of available IPv4 addresses. IPv6 was introduced with more address space to solve IPv4 address exhaustion problem. But on the other hand, many existing protocols used in IPv4 have to be extended or redesigned to fit IPv6 networks. A network always contains many nodes (routers and hosts). A node recognizes other nodes in its located network as its neighbors. Discovering neighbor locations, gathering neighbor information and defining the communication methods between neighbors are the contents in IPv6 Neighbor Discovery Protocol (NDP). The legacy NDP was announced 10 years ago in RFC 4861. It relies on periodical multicast Internet Control Message Protocol version 6 (ICMPv6) control messages to maintain relationship between neighbors. Which means that these control messages are sent to all the members in a group. Although these messages are only relevant to a specific member in this group at most of time, other members also have to receive and process them. As we known, receiving and processing messages require power consumption. It is inefficient for nodes to handle these unnecessary messages frequently, especially for wireless devices. As wireless devices are always not connected to power supplies, power saving becomes an important point for their battery life. To solve the high power consumption problem in legacy NDP, a more efficient protocol the Efficient NDP was announced. This protocol introduces a registration mechanism for hosts with a router. In this mechanism, the router does not need to send periodical control messages to the hosts for asking their updates, but give a registration timer to each host. A host only has to wake up and send messages to the router when the timer is reached, and can keep in sleep mode for a long time. This can significantly reduce the power consumption. On the other hand, as the router functions as a registration point in the network, it has the knowledge of each node address information, so it can help hosts for handling address related issues with their neighbors. From analysis, we have already known that the Efficient NDP provides a good solution in power saving, comparing with the legacy NDP. But how efficient it can achieve? To answer this question, an evaluation is required. As today’s networks are always dynamic networks, nodes are able to enter, leave and change their locations in networks at any time, it is worth for us to analyze the performance of these two protocols in this environments. However, as implementing a real dynamic network environment is too complex, simulation becomes an ideal method for evaluation. Two scenarios were taken into analysis and simulations in this thesis, one is nodes entering and leaving a network scenario, and another is nodes losing connection to a network case in movement scenario. As network scalability is an important parameter for evaluation, simulation models were designed with different network sizes. The obtained results indicate that in both of these scenarios, the Efficient NDP can achieve very high messages saving percentages in large networks. On the other word, it provides a great power saving solution

    A network mobility management architecture for a heteregeneous network environment

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    Network mobility management enables mobility of personal area networks and vehicular networks across heterogeneous access networks using a Mobile Router. This dissertation presents a network mobility management architecture for minimizing the impact of handoffs on the communications of nodes in the mobile network. The architecture addresses mobility in legacy networks without infrastructure support, but can also exploit infrastructure support for improved handoff performance. Further, the proposed architecture increases the efficiency of communications of nodes in the mobile network with counter parts in the fixed network through the use of caching and route optimization. The performance and costs of the proposed architecture are evaluated through empirical and numerical analysis. The analysis shows the feasibility of the architecture in the networks of today and in those of the near future.Verkkojen liikkuuvudenhallinta mahdollistaa henkilökohtaisten ja ajoneuvoihin asennettujen verkkojen liikkuvuuden heterogeenisessä verkkoympäristössä käyttäen liikkuvaa reititintä. Tämä väitöskirja esittää uuden arkkitehtuurin verkkojen liikkuvuudenhallintaan, joka minimoi verkonvaihdon vaikutuksen päätelaitteiden yhteyksiin. Vanhoissa verkoissa, joiden infrastruktuuri ei tue verkkojen liikkuvuutta, verkonvaihdos täytyy hallita liikkuvassa reitittimessa. Standardoitu verkkojen liikkuvuudenhallintaprotokolla NEMO mahdollistaa tämän käyttäen ankkurisolmua kiinteässä verkossa pakettien toimittamiseen päätelaitteiden kommunikaatiokumppaneilta liikkuvalle reitittimelle. NEMO:ssa verkonvaihdos aiheuttaa käynnissä olevien yhteyksien keskeytymisen yli sekunnin mittaiseksi ajaksi, aiheuttaen merkittävää häiriötä viestintäsovelluksille. Esitetyssä arkkitehtuurissa verkonvaihdon vaikutus minimoidaan varustamalla liikkuva reititin kahdella radiolla. Käyttäen kahta radiota liikkuva reititin pystyy suorittamaan verkonvaihdon keskeyttämättä päätelaitteiden yhteyksiä, mikäli verkonvaihtoon on riittävästi aikaa. Käytettävissa oleva aika riippuu liikkuvan reitittimen nopeudesta ja radioverkon rakenteesta. Arkkitehtuuri osaa myös hyödyntää infrastruktuurin tukea saumattomaan verkonvaihtoon. Verkkoinfrastruktuurin tuki nopeuttaa verkonvaihdosprosessia, kasvattaenmaksimaalista verkonvaihdos tahtia. Tällöin liikkuva reitin voi käyttää lyhyen kantaman radioverkkoja, joiden solun säde on yli 80m, ajonopeuksilla 90m/s asti ilman, että verkonvaihdos keskeyttää päätelaitteiden yhteyksiä. Lisäksi ehdotettu arkkitehtuuri tehostaa kommunikaatiota käyttäen cache-palvelimia liikkuvassa ja kiinteässä verkossa ja optimoitua reititystä liikkuvien päätelaitteiden ja kiinteässä verkossa olevien kommunikaatiosolmujen välillä. Cache-palvelinarkkitehtuuri hyödyntää vapaita radioresursseja liikkuvan verkon cache-palvelimen välimuistin päivittämiseen. Heterogeenisessä verkkoympäristossä cache-palvelimen päivitys suoritetaan lyhyen kantaman laajakaistaisia radioverkkoja käyttäen. Liikkuvan reitittimen siirtyessä laajakaistaisen radioverkon peitealueen ulkopuolelle päätelaitteille palvellaan sisältöä, kuten www sivuja tai videota cache-palvelimelta, säästäen laajemman kantaman radioverkon rajoitetumpia resursseja. Arkkitehtuurissa käytetään optimoitua reititystä päätelaitteiden ja niiden kommunikaatiokumppaneiden välillä. Optimoitu reititysmekanismi vähentää liikkuvuudenhallintaan käytettyjen protokollien langattoman verkon resurssien kulutusta. Lisäksi optimoitu reititysmekanismi tehostaa pakettien reititystä käyttäen suorinta reittiä kommunikaatiosolmujen välillä. Esitetyn arkkitehtuurin suorituskyky arvioidaan empiirisen ja numeerisen analyysin avulla. Analyysi arvioi arkkitehtuurin suorituskykyä ja vertaa sitä aikaisemmin ehdotettuihin ratkaisuihin ja osoittaa arkkitehtuurin soveltuvan nykyisiin ja lähitulevaisuuden langattomiin verkkoihin.reviewe

    A Survey on Handover Management in Mobility Architectures

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    This work presents a comprehensive and structured taxonomy of available techniques for managing the handover process in mobility architectures. Representative works from the existing literature have been divided into appropriate categories, based on their ability to support horizontal handovers, vertical handovers and multihoming. We describe approaches designed to work on the current Internet (i.e. IPv4-based networks), as well as those that have been devised for the "future" Internet (e.g. IPv6-based networks and extensions). Quantitative measures and qualitative indicators are also presented and used to evaluate and compare the examined approaches. This critical review provides some valuable guidelines and suggestions for designing and developing mobility architectures, including some practical expedients (e.g. those required in the current Internet environment), aimed to cope with the presence of NAT/firewalls and to provide support to legacy systems and several communication protocols working at the application layer

    Handover management in mobile WiMAX using adaptive cross-layer technique

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    The protocol type and the base station (BS) technology are the main communication media between the Vehicle to Infrastructure (V2I) communication in vehicular networks. During high speed vehicle movement, the best communication would be with a seamless handover (HO) delay in terms of lower packet loss and throughput. Many studies have focused on how to reduce the HO delay during lower speeds of the vehicle with data link (L2) and network (L3) layers protocol. However, this research studied the Transport Layer (L4) protocol mobile Stream Control Transmission Protocol (mSCTP) used as an optimal protocol in collaboration with the Location Manager (LM) and Domain Name Server (DNS). In addition, the BS technology that performs smooth HO employing an adaptive algorithm in L2 to perform the HO according to current vehicle speed was also included in the research. The methods derived from the combination of L4 and the BS technology methods produced an Adaptive Cross-Layer (ACL) design which is a mobility oriented handover management scheme that adapts the HO procedure among the protocol layers. The optimization has a better performance during HO as it is reduces scanning delay and diversity level as well as support transparent mobility among layers in terms of low packet loss and higher throughput. All of these metrics are capable of offering maximum flexibility and efficiency while allowing applications to refine the behaviour of the HO procedure. Besides that, evaluations were performed in various scenarios including different vehicle speeds and background traffic. The performance evaluation of the proposed ACL had approximately 30% improvement making it better than the other handover solutions

    Survey Paper: Mobility Management in Heterogeneous Wireless Networks

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    AbstractEver increasing user demands and development of modern communication technologies have led to the evolution of communication networks from 1st Generation (1G) network to 4G heterogeneous networks. Further, 4G with heterogeneous network environment will provide features such as, “Always Best Connected”, “Anytime Anywhere” and seamless communication. Due to diverse characteristics of heterogeneous networks such as bandwidth, latency, cost, coverage and Quality of Service (QoS) etc., there are several open and unsolved issues namely mobility management, network administration, security etc. Hence, Designing proficient mobility management to seamlessly integrate heterogeneous wireless networks with all-IP is the most challenging issue in 4G networks. Mobile IPv6 (MIPv6) developed by Internet Engineering Task Force (IETF) has mobility management for the packet-switched devices of homogeneous wireless networks. Further, mobility management of homogeneous networks depends on network related parameter i.e., Received Signal Strength (RSS). However the mobility management of heterogeneous networks, not only depends on network related parameters, but also on terminal-velocity, battery power, location information, user-user profile & preferences and service-service capabilities & QoS etc. Designing mobility management with all-IP, while, considering issues such as context of networks, terminal, user and services is the main concern of industry and researchers in the current era
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