• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1998년도 추계종합학술대회 논문집
• /
• pp.47-50
• /
• 1998

In recent years, it is required that computing support mobile user with computer. The advantage of mobile computing is that users may access all their applications from any location, whether they are in another building or a different state. So, Internet combines with mobile computing technology to make new communication environment for supporting mobility. The research for solving the problem of mobility is actively in progress. This paper describes the implementation of tunneling method for flexible bypass between specific region. Tunneling method provide mobile service to mobile hosts. IP datagram's address tranform method is IP-within-IP encapsulation by which an IP datagram may be encapsulated within an IP datagram. The developed IP-within-IP protocol can provide not only enhanced performance because it is implemented in kernel mode, but also convenience of usage to the application developers because it gives user interface as a dynamic link library. Verification of IP packet tunneling was text file transfer program.

• 한국컴퓨터정보학회:학술대회논문집
• /
• 한국컴퓨터정보학회 2019년도 제60차 하계학술대회논문집 27권2호
• /
• pp.245-246
• /
• 2019

본 논문에서는 GUI(Graphical User Interface)를 이용하여 다수의 드론을 동시 제어하는 시스템 구현 결과를 보인다. 네트워크 소켓(Network Socket) 응용 프로그램인 Packet Sender를 이용하여 다수의 드론을 AP(Wireless Access Point)에 연결하였다. Python 응용 프로그램으로 UDP(User Datagram Protocol) 소켓을 통해 AP에 연동된 드론으로 명령을 전송하여 제어한다. Python GUI 모듈인 Tkinter를 이용하여 사용자에게 GUI를 제공함으로써 접근성(Accessibility)을 높인 시스템을 개발하였다.

• ETRI Journal
• /
• 제43권3호
• /
• pp.561-570
• /
• 2021

This paper presents master key identifier based protocol steganography (MKIPS), a new approach toward creating a covert channel within the Secure Real-time Transfer Protocol, also known as SRTP. This can be achieved using the ability of the sender of Voice-over-Internet Protocol packets to select a master key from a pre-shared list of available cryptographic keys. This list is handed to the SRTP sender and receiver by an external key management protocol during session initiation. In this work, by intelligent utilization of the master key identifier field in the SRTP packet creation process, a covert channel is created. The proposed covert channel can reach a relatively high transfer rate, and its capacity may vary based on the underlying SRTP channel properties. In comparison to existing data embedding methods in SRTP, MKIPS can convey a secret message without adding to the traffic overhead of the channel and packet loss in the destination. Additionally, the proposed covert channel is as robust as its underlying user datagram protocol channel.

• ETRI Journal
• /
• 제34권6호
• /
• pp.827-837
• /
• 2012

We propose a flow admission control (FAC) for setting up a wire-speed connection for new flows based on their negotiated bandwidth. It also terminates a flow that does not have a packet transmitted within a certain period determined by the users. The FAC can be used to provide a reliable transmission of user datagram and transmission control protocol applications. If the period of flows can be set to a short time period, we can monitor active flows that carry a packet over networks during the flow period. Such powerful flow management can also be applied to security systems to detect a denial-of-service attack. We implement a network processor called a flow management network processor (FMNP), which is the second generation of the device that supports FAC. It has forty reduced instruction set computer core processors optimized for packet processing. It is fabricated in 65-nm CMOS technology and has a 40-Gbps process performance. We prove that a flow router equipped with an FMNP is better than legacy systems in terms of throughput and packet loss.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제4권3호
• /
• pp.341-357
• /
• 2010

Forward Error Correction (FEC) techniques have been adopted to overcome packet losses and to improve the quality of video delivery. The efficiency of the FEC has been significantly compromised, however, due to the characteristics of the wireless channel such as burst packet loss, channel fluctuation and lack of Quality of Service (QoS) support. We propose herein an Adaptive Cross-layer FEC mechanism (ACFEC) to enhance the quality of video streaming over 802.11 WLANs. Under the conventional approaches, FEC functions are implemented on the application layer, and required feedback information to calculate redundancy rates. Our proposed ACFEC mechanism, however, leverages the functionalities of different network layers. The Automatic Repeat reQuest (ARQ) function on the Media Access Control (MAC) layer can detect packet losses. Through cooperation with the User Datagram Protocol (UDP), the redundancy rates are adaptively controlled based on the packet loss information. The experiment results demonstrate that the ACFEC mechanism is able to adaptively adjust and control the redundancy rates and, thereby, to overcome both of temporary and persistent channel fluctuations. Consequently, the proposed mechanism, under various network conditions, performs better in recovery than the conventional methods, while generating a much less volume of redundant traffic.

• Journal of Communications and Networks
• /
• 제10권3호
• /
• pp.316-330
• /
• 2008

This paper proposes a novel method for transporting various types of user traffic effectively over the next generation network called integrated services digital network 3 (ISDN3) (or quantum network) using quantum packets. Basically, a quantum packet comprises one or more 53-byte quanta as generated by a "quantumization" process. While connection-oriented traffic is supported by fixed-size quantum packets each with one quantum to emulate circuit switching, connectionless traffic (e.g., IP packets and active packets) is carried by variable-size quantum packets with multiple quanta to support store-and-forward switching/routing. Our aim is to provide frame-like or datagram-like services while enabling cell-based multiplexing. The quantum packet method also establishes a flexible and extensible framework that caters for future packetization needs while maintaining backward compatibility with ATM. In this paper, we discuss the design of the quantum packet method, including its format, the "quantumization" process, and support for different types of user traffic. We also present an analytical model to evaluate the consumption of network resources (or network costs) when quantum packets are employed to transfer loss-sensitive data using three different approaches: cut-through, store-and-forward and ideal. Close form mathematical expressions are obtained for some situations. In particular, in terms of network cost, we discover two interesting equivalence phenomena for the cut-through and store-and-forward approaches under certain conditions and assumptions. Furthermore, analytical and simulation results are presented to study the system behavior. Our analysis provides valuable insights into the. design of the ISDN3/quantum network.

• 한국통신학회논문지
• /
• 제32권4B호
• /
• pp.227-233
• /
• 2007

최근 네트워크 기술이 발전하면서 사용자들의 요구가 다양화되고 대용량의 멀티미디어 데이터에 대한 필요성이 증가하고 있다. 실시간성과 동시성이 중요시 되는 멀티미디어 데이터의 전송에는 UDP(User Datagram Protocol) 트래픽이 사용되고 있는데, UDP 트래픽은 현재의 인터넷 기반인 TCP(Transmission Control Protocol) 트래픽과 경쟁 관계에 있어 네트워크의 혼잡을 초래하는 경우가 많았다. 반면 TCP 트랙픽은 네트워크의 혼잡제어를 수행하지만 수신자의 관점을 고려하지 않은 점이 있어서 스트리밍 전송에는 적합하지 않은 단점을 가지고 있다. 본 논문에서는 네트워크의 형평성 문제를 해결하고 수신자의 관점에서 RTP/RTCP(Real-time Trasport Protocol/Realtime Transport Control Protocol)를 기반으로 하는 네트워크 알고리즘을 제안한다. 네트워크에 우선순위를 적용하여 수신자의 버퍼를 고려한 혼잡제어 알고리즘인 POBA(Priority-Ordered Buffer Algorithm)는 시뮬레이션 결과를 통해 우선 순위가 없는 기존 네트워크에 비해 패킷 손실률과 버퍼 점유도 면에서 스트리밍 전송에 적합한 환경을 제공하고 있음을 확인할 수 있었다.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2000년도 추계학술발표논문집 (하)
• /
• pp.1145-1148
• /
• 2000

최근 멀티미디어 데이터에 대한 요구는 사용자가 증가함에 따라 데이터 양도 증가하고 있다. 이에 반해 서버시스템이나 네트워크의 대역폭은 이러한 서비스 요구를 충족시키기에 미흡하다. 본 논문에서는 리눅스 환경에서 일반적인 UDP(User Datagram Protocol) 전송 메커니즘을 SIO(Special Input/Output) 시스템 콜을 커널 내부에 추가하였다. UDP전송을 커널 내부에서 수행함으로써, 사용자 모드와 커널 모드사이의 데이터 복사의 횟수와 문맥 교환을 줄였다. 커널 내부에서 수행하게 SIO 시스템 콜을 설계하고 구현함으로써 일반적인 리눅스 환경보다 약 31%의 성능향상을 보았다. 본 논문에서는 SIO와 같은 효과적인 커널 내부의 전송 시스템 콜을 사용함으로써 멀티미디어 관련 서버에 적응할 수 있도록 하였다.

• International Journal of Computer Science & Network Security
• /
• 제22권2호
• /
• pp.327-333
• /
• 2022

Internet Protocol Television (IPTV) has emerged as a personal entertainment source for home users. Streaming IPTV content over a wireless medium with good Quality of Service (QoS) can be a challenging task as IPTV content requires more bandwidth and Wireless Local Area Networks (WLANs) are susceptible to packet loss, delay and jitter. This research presents the capacity of IPTV using User Datagram Protocol (UDP) and TCP Friendly Rate Control (TFRC) over IEEE 802.11ac WLANs in good and bad network conditions. Experimental results show that in good network conditions, UDP and TFRC could accommodate a maximum of 78 and 75 Standard Definition Television (SDTV) users, respectively. In contrast, 15 and 11 High-Definition Television (HDTV) users were supported by UDP and TFRC, respectively. Performance of UDP and TFRC was identical in bad network conditions and same number of SDTV and HDTV users were supported by TFRC and UDP. With background Transmission Control Protocol (TCP) traffic, both UDP and TFRC can support nearly the same number of SDTV users. It was found that TFRC can co-exist fairly with TCP by giving more throughput to TCP unlike UDP.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제15권2호
• /
• pp.114-124
• /
• 2009

본 논문에서는 인터넷과 같은 IP망에서 SVC(scalable video coding) 비디오를 전송할 때 주어진 최소 전송대역폭 조건에 부합되는 실용적인 TCP 친화적 전송률 제어 기법을 제안한다. UDP 프로토콜을 이용하여 실시간 비디오를 전송할 때 상위 응용계층의 프로토콜로서 실시간 수송 프로토콜(RTP)과 실시간 수송 제어 프로토콜(RTCP)이 일반적으로 사용이 되는데, 이때 발생되는 패킷 스트림의 전송률을 네트워크 내에서의 다른 TCP세션과 공평하게 분배하여 결정할 수 있는 방법이 TCP 친화적 전송률 제어(TCP-friendly rate control) 기법이다. 기존의 TCP 친화적 전송률 제어 기법에서 제안한 전송률 결정 모델에서는 채널의 최소 전송 대역폭에 대한 고려가 반영이 되지 못하여 패킷 손실이 큰 경우에 대해서는 모델에 의해 결정된 전송률이 채널의 실제 최소 전송 대역폭과 매우 상이한 문제점이 발생한다. 본 논문에서는 최소 전송 대역폭을 고려하여 개선된 TCP 친화적 전송률 제어 모델을 고안하고, 이 모델을 기반으로 SVC의 기본계층(base layer)에 대해 최소 전송률을 할당하며 나머지 가용한 전송률을 향상계층(enhancement layer) 스트림에 할당하는 TCP 친화적 스케일러블 비디오 전송 기법을 제안한다. 실제적인 인트라 및 인터넷 망을 통한 SVC 비디오 전송에 의한 필드 테스트를 통해 제안된 기법의 성능을 검증한다.