China Organizational Name Administration Center

Beijing, China

China Organizational Name Administration Center

Beijing, China
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Wang Z.,Chinese Academy of Sciences | Wang Z.,China Organizational Name Administration Center
Applied Mathematics and Information Sciences | Year: 2014

One major concern for mobile networks consists of finding efficient ways of handling user mobility so that the handover process has minimum effect on users' ongoing sessions. Although COAP provides an efficient way for mobility management in IEEE 802.11 wireless mesh networks, it does not control load among multiple MAPs in the network. Thus, in many cases, the attached MAP is overloaded, and extensive delays are experienced during the routing process. To tackle this problem, this paper proposes a load-aware mobility management scheme. The overloaded MAP is detected according to the load estimation. Then the overloaded MAP initiates the search procedure to find the underutilized MAP and transfer the MN's attachment request to it. The proposed scheme can efficiently balance the handover load among MAPs at the cost of slightly prolonged attachment delay and increased attachment messages compared with COAP. © 2014 NSP Natural Sciences Publishing Cor.


Liu R.,Xidian University | Li Z.,Xidian University | Xiao L.,China Organizational Name Administration Center
2013 International Conference on Wireless Communications and Signal Processing, WCSP 2013 | Year: 2013

In this paper a scheduling algorithm based on proactive co-channel interference (CCI) evaluation for multiuser multiple-input multiple-output (MU-MIMO) broadcast channel (BC) is proposed. The strategy converts user scheduling to spatial subchannel selection problem. A new parameter & eta;, named as proactive CCI evaluation factor is defined for estimating the existing and potential mutual interference. With different settings of & eta;, the proposed algorithm can be generalized to some existing reactive scheduling methods. The user and subchannel scheduling criterion as well as processing procedure are presented in this paper. By appropriately choosing & eta; and comprehensively considering candidate subchannel transmission gain, along with mutual interference among candidate and activated subchannels as well as those would be selected subsequently. A set of sub-channels with less CCI are scheduled, and an improvement of system sum rate is achieved. Simulation results show that compared with those reactive methods, given appropriate & eta; the proposed algorithm could achieve better tradeoff between system sum rate improvement and computational complexity control. © 2013 IEEE.


Wang Z.,Chinese Academy of Sciences | Wang Z.,China Organizational Name Administration Center
The Scientific World Journal | Year: 2013

This paper studies the DNS cache effects that occur on query distribution at the CN top-level domain (TLD) server. We first filter out the malformed DNS queries to purify the log data pollution according to six categories. A model for DNS resolution, more specifically DNS caching, is presented. We demonstrate the presence and magnitude of DNS cache effects and the cache sharing effects on the request distribution through analytic model and simulation. CN TLD log data results are provided and analyzed based on the cache model. The approximate TTL distribution for domain name is inferred quantificationally. © 2013 Zheng Wang.


Wang Z.,China Organizational Name Administration Center | Wang R.,China Organizational Name Administration Center
International Telecommunication Union - Proceedings of the 2013 ITU Kaleidoscope Academic Conference: Building Sustainable Communities, K 2013 | Year: 2013

Domain Name System (DNS) reverse resolution is commonly relied on by anti-spam techniques to verify the email origins and by measurements or applications to uncover the host information. But the current practice is not able to clarify the IP addresses with no reverse resolution response and the source verification process is not optimized in terms of network bandwidth and response latency. This paper proposes an explicit scheme to bind A/AAAA resource records (RRs) with their matching PTR RRs by introducing APTR/AAAAPTR RR types. The DNS cache server can automatically switch from forward resolution to reverse resolution when handling the APTR/AAAAPTR RR types. This scheme enables the negative verification if no reverse records are returned for APTR/AAAAPTR records. Furthermore, the analytical and numerical results show that the number of queries and response delay are significantly cut by the proposed scheme. © 2013 ITU.


Wang Z.,China Organizational Name Administration Center
KSII Transactions on Internet and Information Systems | Year: 2012

The Domain Name System (DNS) is a critical Internet infrastructure that provides name to address mapping services. In the past decade, Denial-of-Service (DoS) attacks have targeted the DNS infrastructure and threaten to disrupt this critical service. While the flooding DoS attacks may be alleviated by the DNS caching mechanism, we show in this paper that flooding DoS attacks utilizing name error queries is capable of bypassing the cache of resolvers and thereby impose overwhelming flooding attacks on the name servers. We analyze the impacts of such DoS attacks on both name servers and resolvers, which are further illustrated by May 19 China's DNS Collapse. We also propose the detection and defense approaches for protecting DNS servers from such DoS attacks. In the proposal, the victim zones and attacking clients are detected through monitoring the number of corresponding responses maintained in the negative cache. And the attacking queries can be mitigated by the resolvers with a sample proportion adaptive to the percent of queries for the existent domain names. We assess risks of the DoS attacks by experimental results. Measurements on the request rate of DNS name server show that this kind of attacks poses a substantial threat to the current DNS service. © 2012 KSII.


Wang Z.,Chinese Academy of Sciences | Wang Z.,China Organizational Name Administration Center | Wang R.,China Organizational Name Administration Center
Applied Mathematics and Information Sciences | Year: 2013

In DNS zone delegation, the NS resource records of the delegated domain appear in both the parent and child zones, which complicates the domain name resolution procedure especially for server selection. In this paper, we investigate the recursive resolution mechanism for the delegated domain and the necessary operations. As there are no specifications for such resolution, we provide some recommendations such as NS record substitution mechanism. Furthermore, we analyze the delegation impacts on server selection as the NS records are obtained from both parent and child zone. We propose an integrated sever selection procedure to handle the lame delegation and enhance server selection efficiency. It makes use of the two stages of server probing information and can help save the initial server probing in the server selection algorithm. Several proposals as to the disposal of NS resource records and the maintenance of the rtt information of servers are also presented. © 2013 NSP Natural Sciences Publishing Cor.


Wang Z.,Qingdao University | Xiao L.,China Organizational Name Administration Center
Proceedings - 2014 IEEE 13th International Conference on Trust, Security and Privacy in Computing and Communications, TrustCom 2014 | Year: 2015

DNS Security Extensions (DNSSEC) is introduced as a set of extensions to DNS which provide data origin authentication, data integrity, and authenticated denial of existence. To maintain the integrity of the DNSSEC system in the case of key compromise, the compromised keys active in the trust chain need to be renewed as soon as possible. This paper is the first to provide extensive and systematic analysis of emergency key rollover in DNSSEC. It identifies the space of key management choices in emergency key rollover. It also presents timelines for the key rollover and discusses considerations surrounding the timing of events in the rolling of a key. The performances of the proposed rollover algorithms are analyzed in four aspects. Finally, the transition delays are evaluated on all signed TLDs. © 2014 IEEE.


Wang Z.,Chinese Academy of Sciences | Wang Z.,China Organizational Name Administration Center
Advances in Intelligent Systems and Computing | Year: 2014

Mobility management consumes a significant portion of resources for personal communications services (PCS) network. Modeling this overhead of mobility management and evaluating how it scales with the service area and user density is the key to planning the PCS systems. This study provides the model of capacity scaling of PCS networks in the context of a constant user arrival rate and presents numerical results and analysis on how the capacity of PCS networks scales with the size of the service area or the number of cells. © Springer India 2014.


Wang Z.,Chinese Academy of Sciences | Wang Z.,China Organizational Name Administration Center | Hu A.-L.,Chinese Academy of Sciences
2013 IEEE 32nd International Performance Computing and Communications Conference, IPCCC 2013 | Year: 2013

The Domain Name System (DNS) resolution is increasingly relied on for replica server selection. However, the prevailing usage of remote DNS causes the source address mismatch between clients and remote resolvers, thus suboptimal performance. We propose a simple and lightweight stub-resolver-based solution, named 'Name Concatenation', which can obtain performance improvements without requiring support of DNS service providers or EDNS0. © 2013 IEEE.


Wang Z.,Chinese Academy of Sciences | Wang Z.,China Organizational Name Administration Center | Hu A.-L.,Chinese Academy of Sciences
2013 IEEE 32nd International Performance Computing and Communications Conference, IPCCC 2013 | Year: 2013

The Domain Name System (DNS) resolution is usually served by multiple geographically distant servers. In planning and optimizing DNS server number, placement, and capacity, it is important to predict server load distribution given some knowledge about the network locations and query rates of active caching resolvers. This poster proposes an analytical model for predicting the DNS server load distribution. The model identifies the dependencies among server load distribution, server selection behavior, DNS response RTT, request processing delay and propagation delay. The preliminary simulation results show that DNS server load distribution can be predicted by solving the model using the iterative approach. © 2013 IEEE.

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