Due to their easy-to-deploy and self-healing features, WMNs (Wireless Mesh Networks) are emerging as a new promising technology with a rich set of applications. While the IEEE standardization of this new technology is...Due to their easy-to-deploy and self-healing features, WMNs (Wireless Mesh Networks) are emerging as a new promising technology with a rich set of applications. While the IEEE standardization of this new technology is still in progress, its main traits are already set, e.g., architecture and MAC routing. WMNs are attracting considerable research in academia and industry as well, but the lack of open-source testbeds is restricting such a research to simulation tools. The main problem with simulation tools is that they do not reflect the complexity of RF propagation, especially in indoor environments, of which IEEE 802.11s WMNs are an example. This paper presents an open-source implementation of an indoor IEEE 802.11s WMN testbed. The implementation is transparent, easy-to-deploy, and both the source code and deployment instructions are available online. The implementation can serve as a blueprint for the WMN research community to deploy their own testbeds, negating the shortcomings of using simulation tools. By delving into the testbed implementation subtleties, this paper is shedding further light on the details of the ongoing IEEE 802.11s standard. Major encountered implementation problems (e.g., clients association, Internetworking, and supporting multiple gateways) are identified and addressed. To ascertain the functionality of the testbed, both UDP and TCP traffic are supported and operational. The testbed uses the default IEEE 802.11s HWMP (Hybrid Wireless Mesh Protocol) routing protocol along with the default IEEE 802.11s Airtime routing metric.展开更多
根据无线网络的特点和需求,IEEE802.11工作组提出了二层路径转发的概念,即在数据链路层通过Mac地址进行数据转发。HWMP(Hybrid Wireless Mesh Protocol)和Batman-adv(Better Approach to Mobile Ad-hoc Networking Advanced)都是基于数...根据无线网络的特点和需求,IEEE802.11工作组提出了二层路径转发的概念,即在数据链路层通过Mac地址进行数据转发。HWMP(Hybrid Wireless Mesh Protocol)和Batman-adv(Better Approach to Mobile Ad-hoc Networking Advanced)都是基于数据链路层的路由协议,本文通过对两种协议的原理进行介绍,并在相同条件下进行对比实验,分析两种路由协议的传输稳定性和路由收敛性。结果表明Batman-adv路由协议在传输稳定性方面比HWMP表现更优,在收敛性方面表现HWMP和Batman-adv路由协议表现都较好。展开更多
Network coding mechanisms, such as COPE, can improve network throughput effectively in Wireless Mesh Networks（WMN）. While the Hybrid Wireless Mesh Protocol（HWMP） is suitable for WMN, its extension with COPE does n...Network coding mechanisms, such as COPE, can improve network throughput effectively in Wireless Mesh Networks（WMN）. While the Hybrid Wireless Mesh Protocol（HWMP） is suitable for WMN, its extension with COPE does not provide any added benefits; specifically, HWMP cannot establish paths with more coding opportunities. As a result, the advantages of network coding cannot be exploited sufficiently. This paper proposes improvements upon HWMP with a new, network Coding-Aware routing protocol（CAHWMP） for WMN. In the CAHWMP protocol, we propose a coding criterion based on data streams to devise an algorithm for actively detecting coding opportunities during path discovery. CAHWMP subsequently establishes paths using the codingaware routing metric, which can balance channel resource consumption and the gain due to sharing resources introduced by network coding. Simulation results show that CAHWMP can establish paths with more coding opportunities; as a result, it improves network performance such as network throughput.展开更多
文摘Due to their easy-to-deploy and self-healing features, WMNs (Wireless Mesh Networks) are emerging as a new promising technology with a rich set of applications. While the IEEE standardization of this new technology is still in progress, its main traits are already set, e.g., architecture and MAC routing. WMNs are attracting considerable research in academia and industry as well, but the lack of open-source testbeds is restricting such a research to simulation tools. The main problem with simulation tools is that they do not reflect the complexity of RF propagation, especially in indoor environments, of which IEEE 802.11s WMNs are an example. This paper presents an open-source implementation of an indoor IEEE 802.11s WMN testbed. The implementation is transparent, easy-to-deploy, and both the source code and deployment instructions are available online. The implementation can serve as a blueprint for the WMN research community to deploy their own testbeds, negating the shortcomings of using simulation tools. By delving into the testbed implementation subtleties, this paper is shedding further light on the details of the ongoing IEEE 802.11s standard. Major encountered implementation problems (e.g., clients association, Internetworking, and supporting multiple gateways) are identified and addressed. To ascertain the functionality of the testbed, both UDP and TCP traffic are supported and operational. The testbed uses the default IEEE 802.11s HWMP (Hybrid Wireless Mesh Protocol) routing protocol along with the default IEEE 802.11s Airtime routing metric.
文摘HWMP(hybrid wireless mesh protocol)协议中的路径选择判据仅注重考虑链路中节点所占信道的资源量,而没有综合考虑其它节点的干扰。针对该问题,结合802.11sMAC层的特点,通过提取MAC层中的网络分配矢量(networkallocation vector,NAV)参数,在基于空中传播时间链路判据(airtime link metric,ALM)的基础上,提出了一种新的路径选择判据E-ALM(enhanced-airtime link metric)。仿真实验结果表明:新的路径选择判据有助于提高网络吞吐量、降低时延和丢包率,并在一定程度上避免了网络拥塞。该判据对基于802.11s的无线网状网路径选择进行了优化,从而提高了网络的整体性能。
文摘根据无线网络的特点和需求,IEEE802.11工作组提出了二层路径转发的概念,即在数据链路层通过Mac地址进行数据转发。HWMP(Hybrid Wireless Mesh Protocol)和Batman-adv(Better Approach to Mobile Ad-hoc Networking Advanced)都是基于数据链路层的路由协议,本文通过对两种协议的原理进行介绍,并在相同条件下进行对比实验,分析两种路由协议的传输稳定性和路由收敛性。结果表明Batman-adv路由协议在传输稳定性方面比HWMP表现更优,在收敛性方面表现HWMP和Batman-adv路由协议表现都较好。
基金supported by the National Natural Science Foundation of China (No. 61301110)
文摘Network coding mechanisms, such as COPE, can improve network throughput effectively in Wireless Mesh Networks（WMN）. While the Hybrid Wireless Mesh Protocol（HWMP） is suitable for WMN, its extension with COPE does not provide any added benefits; specifically, HWMP cannot establish paths with more coding opportunities. As a result, the advantages of network coding cannot be exploited sufficiently. This paper proposes improvements upon HWMP with a new, network Coding-Aware routing protocol（CAHWMP） for WMN. In the CAHWMP protocol, we propose a coding criterion based on data streams to devise an algorithm for actively detecting coding opportunities during path discovery. CAHWMP subsequently establishes paths using the codingaware routing metric, which can balance channel resource consumption and the gain due to sharing resources introduced by network coding. Simulation results show that CAHWMP can establish paths with more coding opportunities; as a result, it improves network performance such as network throughput.
