• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2261-2280
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• 2014

Recently, network traffic has become more complex and diverse due to the emergence of new applications and services. Therefore, the importance of application-level traffic classification is increasing rapidly, and it has become a very popular research area. Although a lot of methods for traffic classification have been introduced in literature, they have some limitations to achieve an acceptable level of performance in real-time application-level traffic classification. In this paper, we propose a novel application-level traffic classification method using payload size sequence (PSS) signature. The proposed method generates unique PSS signatures for each application using packet order, direction and payload size of the first N packets in a flow, and uses them to classify application traffic. The evaluation shows that this method can classify application traffic easily and quickly with high accuracy rates, over 99.97%. Furthermore, the method can also classify application traffic that uses the same application protocol or is encrypted.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.4
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• pp.191-199
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• 2014

Currently, HTTP traffic has been developed rapidly due to appearance of various applications and services based web. Accordingly, HTTP Traffic classification is necessary to effective network management. Among the various signature-based method, Payload signature-based classification method is effective to analyze various aspects of HTTP traffic. However, the payload signature-based method has a significant drawback in high-speed network environment due to the slow processing speed than other classification methods such as header, statistic signature-based. Therefore, we proposed various classification method of HTTP Traffic based HTTP signatures of hierarchical structure and to improve pattern matching speed reflect the hierarchical structure features. The proposed method achieved more performance than aho-corasick to applying real campus network traffic.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.434-437
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• 2010

NIPS(Network Intrusion Prevention System) is in line at the end of the external and internal networks which performed two kinds of action: Signature-based filtering and anomaly detection and prevention-based on self-learning. Among them, a signature-based filtering is well known to defend against attacks. By using signature-based filtering, intrusion prevention system passing a payload of packets is compared with attack patterns which are signature. If match, the packet is discard. However, when there is packet delay, it will increase the required pattern matching time as the number of signature is increasing whenever there is delay occur. Therefore, to ensure the performance of IPS, we needed more efficient pattern matching algorithm for high-performance ISP. To improve the performance of pattern matching the most important part is to reduce the number of comparisons signature rules and the packet whenever the packets arrive. In this paper, we propose an improve signature hashing-based pattern matching method. We use tuple pruning algorithm with Bloom filters, which effectively remove unnecessary tuples. Unlike other existing signature hashing-based IPS, our proposed method to improve the performance of IPS.

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.19-33
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• 2011

The need for application traffic classification becomes important for the effective use of network resources. The header-based identification method uses the header signature {IP address, port number, transport layer protocol TCP/UDP)}extracted from Internet application server to overcome some limitations overhead, payload encryption, etc.) of previous methods. A lots signature is extracted because this method uses header information of server. So, we need a maintenance method to keep essential signatures. In this paper, we represent the signature maintenance method using properties of identified traffic and history of the signature. Also, we prove the feasibility and applicability of our proposed method by an acceptable experimental result.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.98-107
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• 2017

In these days, the increase of applications that highly use network resources has revealed the limitations of the current research phase from the traffic classification for network management. Various researches have been conducted to solutions for such limitations. The representative study is automatic finding of the common pattern of traffic. However, since the study of automatic signature generation is a semi-automatic system, users should collect the traffic. Therefore, these limitations cause problems in the traffic collection step leading to untrusted accuracy of the signature verification process because it does not contain any of the generated signature. In this paper, we propose an automated traffic collection, signature management, signature generation and signature verification process to overcome the limitations of the automatic signature update system. By applying the proposed method in the campus network, actual traffic signatures maintained the completeness with no false-positive.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1572-1593
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• 2018

The diversity and fast growth of Internet traffic volume are highly influenced by mobile and computer applications being developed. Moreover, the developed applications are too dynamic to be identified and monitored by network administrators. Several approaches have been proposed to identify network applications, however, are still not robust enough to identify modern applications. This paper proposes both, TSA (Traffic collection, Signature generation and Applications identification) system and a derived algorithm so called CSP (Contiguous Sequential Patterns) to identify applications for management and security in IP networks. The major focus of this paper is the CSP algorithm which is automated in two modules (Signature generation and Applications identification) of the proposed system. The proposed CSP algorithm generates DNA-like unique signatures capable of identifying applications and their individual services. In this paper, we show that the algorithm is suitable for generating efficient signatures to identify applications and application services in high accuracy.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.123-130
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• 2008

To avoid some protection systems such as firewall, P2P applications have recently used to apply dynamic port numbers. Reliable estimates of P2P traffic require examination of packet payload, a methodological land mine from legal, privacy technical, logistic, and fiscal perspectives. Indeed, access to user payload is often rendered impossible by one of these factors, inhibiting trustworthy estimation of P2P growth and dynamics. Despite various methods such as port-based and signature-based techniques, it still dose not satisfy the method which uses both qualitative and quantitative aspects. In this paper, a method using SVM mechanism which discriminate the P2P traffic from non-P2P traffics using differences between P2P and other application traffics is suggested. This is a systematic methodology to identify P2P networks, and without relying on packet payload.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1112-1115
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• 2009

네트워크 관리자 입장에서 효율적인 네트워크 관리를 위해 응용 프로그램 별 트래픽 분류의 중요성이 커지고 있다. 응용 프로그램 별 트래픽 분류를 위해 signature 기반, machine learning 방법들이 제안되고 있지만 p2p 방식의 Skype 응용프로그램에 대한 적용결과는 그 신뢰성이 떨어지고 있는 것은 사실이다. 본 논문에서는 Skype의 트래픽을 분류하기 위해 각 Client 마다 Skype application install 시 동적으로 변화하는 Port 를 알아내는 방법, UDP 패킷의 특정위치의 특정 signature, TCP signal flow의 특정위치 패킷에 대한 payload 크기 등을 이용한 Skype traffic 분류 방법을 제안한다. 제안된 방법론은 학내 네트워크에 적용하여 그 타당성을 TMA를 통해 검증하였다.

• Journal of KIISE:Information Networking
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• v.31 no.4
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• pp.363-374
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• 2004

In this paper, we propose an in-line mode NIDS using network processors(NPs) that achieve performance comparable to ASIC and flexibility comparable to general-purpose processors. Even if many networking applications using NPs have been proposed, we cannot find any NP applications to NIDS in the literature. The proposed NIDS supports packet payload inspection detecting attacks, as well as packet filtering and traffic metering. In particular, we separate the filtering and metering functions from the complicated and time-consuming operations of the deep packet inspection function using two-level searching scheme, thus we can improve the performance, stability, and scalability of In-line mode system. We also implement a proto-type based on a PC platform and the Agere PayloadPlus (APP) 2.5G NP solution, and present a payload inspection algorithm to apply APP NP.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.125.1-125.1
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• 2012

The wave number 4 (wave-4) and wave number 3 (wave-3) longitudinal structures in the thermospheric neutral mass density are understood as tidal structures driven by diurnal eastward-propagating zonal wave number 3 (DE3) and wave number 2 (DE2) tides, respectively. However, those structures have been identified using data from limited time periods, and the consistency and recurrence of those structures have not yet been examined using long-term observation data. We examine the persistence of those structures by analyzing the neutral mass density data for the years 2001-2008 taken by the CHAllenging Minisatellite Payload (CHAMP) satellite. During years of low solar activity, the amplitude of the wave-4 structure is pronounced during August and September, and the wave-4 phase shows a consistent eastward phase progression of $90^{\circ}$ within 24 h local time in different months and years. During years of high solar activity, the wave-4 amplitude is small and does not show a distinctive annual pattern, but the tendency of the eastward phase shift at a rate of $90^{\circ}$/24 h exists. Thus the DE3 signature in the wave-4 structure is considered as a persistent feature. The wave-3 structure is a weak feature in most months and years. The amplitude and phase of the wave-3 structure do not show a notable solar cycle dependence. Among the contributing tidal modes to the wave-3 structure, the DE2 amplitude is most pronounced. This result may suggest that the DE2 signature, although it is a weak signature, is a perceivable persistent feature in the thermosphere.