• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1529-1532
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• 2001

ACE 2000 ATM 교환기를 이용하여 MPLS 교환기를 구현 시, ATM 가입자 및 중계선을 수용하여 스위치와 정합 기능을 수행하는 AIM(ATM interface module)에 IP 패킷에 대한 룩업을 수행하여 ATM 스위치로 패킷을 포워딩하는 HFEA(High performance Forwarding Engine board Assembly)를 연동하기 위해서는 UTOPIA Level2 연결이 요구된다. 그러나 HFEA 에서 622Mbps 급 성능의 MXT4400(SAR) 칩은 TSAR(Transmit SAR)로 운용 시 Master모드로 동작하게 되고, AIM 모듈 또한 Rx에서 Master모드로 동작하기 때문에 이들을 연결하기 위해서는 양 모듈간에서 Slave 모드로 동작할 수 있는 UTOPIA Controller가 필요하게 된다. 이에 따라 ALMA(AW Layer Module Assembly)칩과 HFEA TSAR 사이에서 데이터를 전달하는 UTOPIA Controller를 Xilinx를 이용해 FPGA로 구현하였다.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.282-292
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• 2003

This paper proposes an efficient data structure for forwarding IPv4 and IPv6 packets at the gigabit speed in backbone routers. The LPM(Longest Prefix Matching) search becomes a bottleneck of routers' performance since the LPM complexity grows in proportion to the forwarding table size and the address length. To speed up the forwarding process, this paper introduces a data structure named BMT(Bit-Map Tie) to minimize the frequent main memory accesses. All the necessary search computations in BMT are done over a small index table stored at cache. To build the small index table from the tie representation of the forwarding table, BMT represents a link pointer to the child node and a node pointer to the corresponding entry in the forwarding table with one bit respectively. To improve the poor performance of the conventional tries when their height becomes higher due to the increase of the address length, BMT adopts a binary search algorithm for determining the appropriate level of tries to start. The simulation experiments show that BMT compacts the IPv4 backbone routers' forwarding table into a small one less than 512-kbyte and achieves the average speed of 250ns/packet on Pentium II processors, which is almost the same performance as the fastest conventional lookup algorithms.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.328-339
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• 2007

Conventional topology-based routing protocols are not suitable for inter-vehicular communication, where frequent route updates are necessary due to continuous and abrupt changes in network topology Position-based routing protocols are widely accepted to better serve their purpose in such a scenario as they do not require path discovery or maintenance. However they have to deal with the overhead of the location service and inaccurate position information. This paper proposes the MMFP (Multi-hop MAC Forwarding Protocol) for inter-vehicle communication that relies on reachability information collected from received packets in making a forwarding decision without path discovery. The MMFP is designed as an extension to the IEEE 802.11 MAC layer to ensure accuracy in its time-critical operations. This paper also presents some simulation results that demonstrate the superior performance of the MMFP over AODV in a realistic inter-vehicular communication.

• The KIPS Transactions:PartA
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• v.11A no.5
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• pp.333-340
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• 2004

In order that routers forward a packet to its destination, they perform IP address lookup which determines the next hop according to the packet's destination address. In designing high speed routers, IP address lookup is an important issue. In order to design high speed routers, this paper proposes a parallel IP lookup scheme which consists of several IP lookup engines without any modification of already fabricated indirect IP lookup chipsets. Also, we propose a simple rule for partitioning IP prefix entries In an overall forwarding table among several IP lookup engines. And we evaluate the performance of the proposed scheme in terms of the memory size required for storing lookup information and the number of memory accesses on constructing the forwarding table. With additional hardware logics, the proposed scheme can reduce about 30% of the required memory size and 80% of the memory access counts.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.386-388
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• 1998

Multiprotocol Label Switching(MPLS)는 기존 인터넷 라우팅에서 사용하는 longest prefix match 방식 대신에 short label exact match 방식을 사용함으로써 더 단순한 고속 포워딩 기술을 제공한다. 또한, 동일한 Forwarding Equivalence Class(FEC)에속하는 플로우들을 합성하여 하나의 레이블을 사용하는 방법 즉, Multipoint-to-point Tree(MPT)를 형성함으로써 확장설을 향상시켰다. 본 논문에선 현재 이슈가 괴고 있는 "IP address prefix"와 "host LSP"의 FEC타입과는 전송방식이 다른 브로드캐스팅을 위한"broadcast"FEC 타입을 제안하였으며, 브로드캐스트 패킷을 전송하는데 있어서 각각의Label Switched Path(LSP)제어 방식을 사용할 경우의 문제점을 분석하고, 유니캐스팅과 브로드캐스팅의 서로 다른 레이블 할당방식으로 인한 레이블 충돌을 해결하기 위해서 레이블 범위를 분류하여 사용하는 방식을 제안한다.해서 레이블 범위를 분류하여 사용하는 방식을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.625-627
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• 2005

본 논문은 인텔사의 IXP2400 네트워크 프로세서를 이용하여 IPv6 multicast-enabled 라우터 개발의 예비단계로서 IPv6 멀티캐스트 모듈의 전체적인 설계 및 구현을 다룬다. 특히, 마이크로 엔진할당, IPv6 멀티캐스트 마이크로 블록 및 패킷 복사 마이크로 블록에 중점을 둔다. 우리의 IPv6 멀티캐스트 포워딩 모듈의 성능측정 결과는 이론적 한계치의 $86\%$였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.569-572
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• 2001

무선 LAN 환경의 증가로 인하여 Mobile IP를 기반으로 하는 이동 호스트의 핸드오프 횟수가 증가함에 따라 핸드오프 수행 시 발생하는 패킷 손실, 지연 시간, 오버헤드를 최소화하기 위하여 더 향상된 핸드오프 기법을 제안한다. 제안된 핸드오프 기법은 다음 셀 예측 (Next-Cell Prediction)기법으로 무선 LAN 기술을 이용하며, 현재 FA(Foreign Agent)가 아닌 이동 호스트가 방문할 FA에 패킷을 버퍼링 하고, 버퍼링 된 패킷의 포워딩 시간을 최소로 하며, 셀 사이를 이동할 때에 두 셀의 영역이 중첩되는 지점에서의 계층 이동 여부를 시그널의 세기를 측정하여 결정함으로써 성능 향상을 가져온다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1103-1111
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• 2008

Internet routers forward an incoming packet to an output port toward its final destination through IP address lookup. Since each incoming packet should be forwarded in wire-speed, it is essential to provide the high-speed search performance. In this paper, IP address lookup algorithms using binary search are studied. Most of the binary search algorithms do not provide a balanced search, and hence the required number of memory access is excessive so that the search performance is poor. On the other hand, binary-search-on-range algorithm provides high-speed search performance, but it requires a large amount of memory. This paper shows an optimized binary-search-on-range structure which reduces the memory requirement by deleting unnecessary entries and an entry field. By this optimization, it is shown that the binary-search-on-range can be performed in a routing table with a similar or lesser number of entries than the number of prefixes. Using real backbone routing data, the optimized structure is compared with the original binary-search-on-range algorithm in terms of search performance. The performance comparison with various binary search algorithms is also provided.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.121-126
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• 2018

IEEE 802.1 TSN TG is developing standards for end-to-end delay bounds and zero packet loss based on Ethernet technology. We focus on packet forwarding techniques. TSN packet forwarding techniques can be classified into Synchronous and Asynchronous framework. Synchronous approach allocates fixed time period for a class, yet is complex for large networks. Asynchronous approach provides delay guarantee by regulator-scheduler pair, yet is unnecessarily complex, too. We propose network components for TSN Asynchronous architecture, which remove the complexity of maintaining flow state for regulation decisions. Despite such a simplicity, the proposed architecture satisfies the TSN's delay requirements provided the limited high priority traffic's maximum packet length.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.154-162
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• 2001

In this paper, we investigate the scheduling algorithm of router system for Internet service based on the qualify-of-service (QoS) level of the input source traffics. We suggest an approprite scheduling algorithm in order to satisfy their QoS requirements for the loss-sensitive traffic and delay-sensitive traffic. For this purpose, we first study the service requirements of the multiplexer in Internet and the definition of QoS based on the ITU-T white recommendations. Second. we suggest a functional architecture of the multiplexer and the scheduling algorithm to satisfy various QoS requirements for Internet service. Finally. the performance measures of interest, namely steady-state packet loss probability and average delay, are discussed by simulation results.