• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.277-280
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• 2011

VoIP is a technology of voice communication, using the existing internet network which sends and receives voice packets. VoIP has an advantage that VoIP is cheaper than an existing telephony, and the tech is vitalized lately. But recently you can download Volp Application in the Market that have a vulnerability(Anyone Can Upload). This weakness is wrongfully used that People are downloaded by encouraging about malignant code is planted. Signal intercepts indicates from this case. and paralysis by DDoS Attack, bypass are charged for hacking. Judging from, security threat of VolP analysis and take countermeasures. In the thesis we analyze the VoIP security caused on 'Soft Phone' and 'Smart Phone', and figure out security policies and delineate those policies on the paper.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.261-264
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• 2011

Corded telephone to the phone using a wireless phone as the trend to switch, free Wi-Fi-enabled mobile phones, netbooks, and mobile devices, are spreading rapidly. But wireless Internet phone calls using your existing Internet network to deliver Internet services because it has a vulnerability that will occur. Government agencies are using Voice over Internet Protocol(VoIP) calls from the current wired and wireless connection and usage is increasing. In this paper, we have discovered that the vulnerability of wireless internet Wi-Fi AP and the FMC administrative agencies, such as VoIP on your wireless device to study the vulnerability. Wi-Fi AP and the FMC is to analyze the vulnerability. VoIP call interception, attack, attack on the base of the experiment is the analysis. Security-enhanced VoIP call for a Wi-Fi AP and the FMC's defense against man-in-the-middle attacks and is the study of security measures.

• Journal of KIISE:Information Networking
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• v.30 no.6
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• pp.787-798
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• 2003

The flow label field in IPv6 has been proposed to provide the QoS. Since the existing flow label specification scheme like random-number format utilizes the label only as the identifier of flow, it is not appropriate for providing differentiated services according to the characteristics of various types of real-time traffic. This paper proposes a hybrid scheme that makes use of the flow label fields as components of flow and QoS parameters as well. To be specific, this paper investigates a scheme that both guarantees the end-to-end service quality and utilizes efficiently backbone resources by allowing users to specify QoS parameters using flow labels. Assuming an MLPS-TE network as the backbone, we compare the performance of our proposed scheme with that of random-number scheme through simulation. The simulation result shows that our scheme is more efficient than the existing one in terms of the transmission rate as well as the resource utilization of the backbone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1369-1375
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• 2007

The recent, a large capacity of telecommunication networks is required in order to it is in proportion to capacity of information communication increase and to satisfy a demand because of the demand about Internet, a multimedia service of internet, Video of internet protocol(VoIP), Audio/Video streaming. As a result, DWDM(Dense Wavelength Division Multiplexing)technologies are emerging to be a prevailing the method of solving it without additional optical fiber network building and high-speed equipment. Therefore this thesis proposed the optical filter of fiber/multilayer slab coupled structure combining it to multilayer slab waveguide by polishing the cladding of one side of fiber to design the optical filter having these functions. When a separation distance of fiber and slab was $3{\mu}m$, The optical filter proposed as the simulation result was satisfied with a DWDM filter characteristic with FWHM of 0.1nm on TM mode and TE mode as 32nm polarization independence in a communication window of $1.3{\mu}m$ when center wavelength was each ${\lambda}_0=1.274755{\mu}m$ and ${\lambda}_0=1.30591{\mu}m$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1222-1229
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• 2012

For the reduction of electric energy consumption and its efficient use at homes or buildings, a new work item proposal for new architecture and functional requirements of Energy Saving System (ESS) was proposed to IEC TC 100 and accepted as a new project, IEC PT 62654 in 2009. Recently, the final ballot for publication passed without negative votes and IEC TS 62654 was finally published in August 2012. For the verification of this standard, Prototype of ESS system composed of an ESS server, ESS clients, and portable ESS terminal were especially implemented in parallel with the standardization. Electric Power Control and Management (EPCM) protocol for the communication between ESS server and clients was also implemented, which supports self-configuration of ESS network, power consumption monitoring, remote power control, and additional functions for intelligent energy saving services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9A
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• pp.844-851
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• 2010

Recently, AODV routing protocol which one of the table driven method for the purpose data transmission between nodes has been broadly used in mobile wireless sensor networks. An existing AODV has a little overhead of routing packets because of keeping the routing table for activity route and re-routes to recovery the routes in route discontinuation. However that has faults in that excesses useless of the network bandwidth to recovery the route and takes a lone time to recovery the route. This paper proposes an efficient route recovery method for AODV based on wireless sensor networks in connection breaks. The proposed method. The propose method controls the number of RREQ message considering the energy's node and distance between nodes to restrict the flooding range of RREQ message while expanding the range of local repair. In test results, the proposed method are compared to existing method, the number of drops decrease 15.43% and the delay time for re-route decrease 0.20sec.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.219-228
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• 2012

As the wireless Internet become more widely accessible, variety of Internet services can be used without limitation of location. However, existing mobility management methods such as MIP and PMIP of IETF requires the load of heavy protocol stack on the mobile nodes or the addition of components such as LMA and MAG. In this paper, we proposed the location management technique in the PMIPv6 and Fast Handover technique. according to the moving pattern of the node, the location management technique proposed in order to adjust the paging area dynamically. The Fast Handover technique applied MIH technology and it reduced the handover signal processing time between heterogeneous network. The location management cost in the environment which the node moves in order to evaluate this and handover delay time was calculate. The proposal technique was efficiently more evaluated than PMIPv6 with the smallest 29% and maximum 83%.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.65-72
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• 2002

In this paper, we implement a high-speed swatch tilth the function for label integration to enhance the expansion of networks using the label space of routers efficiently on MPLS over ATM networks. We propose an appropriate hardware structure to support the VC-merge function and differentiated services simultaneously. In this paper, we use the adaptive congestion control method such as EPD algorithm in carte that there is a possibility of network congestion in output buffers of each core LSR. In addition, we justify the validity of the proposed VC-merge method through simulation and comparison to conventional Non VC-merge methods. The proposed VC-merge capable switch is modeled in VHDL. synthesized, and fabricated using the SAMSUNG 0.5um SOG process.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.893-902
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• 2002

MPLS enables efficient explicit routing, and thus provides great advantages in supporting traffic engineering. Exploiting this capability, we Propose a load balancing scheme which deploys a multipath routing. It is named LBM (Load Balancing in MPLS networks), and targets at efficient network utilization as well as performance enhancement. LBM establishes multiple LSP (Label Switched Path)s between a pair of ingress-egress routers, and distributes traffic over these LSPs at the new level. Its routing decision is based on both the length and the utilization of the paths. In order to enhance the efficiency of a link usage, a link is limited to be used by shorter paths as its utilization becomes higher Longer paths are considered to be candidate alternative paths as the utilization of shorter paths becomes higher. Simulation experiments are performed in order to compare the performance of LBM to that of static shortest path only scheme as well as the other representative dynamic multipath traffic distribution approaches. The simulation results show that LBM outperforms the compared approaches, and the performance gain is more significant when the traffic distribution among the ingress-egress pairs is non-uniform.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1694-1705
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• 1997

In the future mobile computing environment, it will be generalized that a mobile host with portable Laptop of Palmtop accesses to database through wireless communication channel. For solving the problems which are caused from low bandwidth of wireless communication, mobile hosts cache the datum used frequently on them. Thus the mobile hosts must always retain the cache consistency for the correctness of the cached datum. the cache consistency is mainly affected from the unrestricted host mobility and the disconnection of the communication between mobile hosts and mobile support station. In this situation, the strategy to retain efficiently cache consistency is required. In this paper, we propose a strategy using updatable message for retaining the cache consistency, in the mobile computing environment, with replicated database supporting 2 phase commit protocol. This strategy makes use of a updatable message to resolve the cache consistency problem, since mobile host crosses the boundary of cell. In using of this updatable, it find out and cache only the update data of missing invalidation message. As a result, the proposed strategy utilizes network bandwidth efficiently because it is not need to delete all the cached datum with any datum change.