The expansibility of PKI is expected to have the features that when the amount of user exceeds the system capacity, the users’ requirement can still be met by simply expanding the number of PKI entities and managemen...The expansibility of PKI is expected to have the features that when the amount of user exceeds the system capacity, the users’ requirement can still be met by simply expanding the number of PKI entities and management levels, and this expansion should be achieved smoothly from the original system. The upward, downward, and horizontal expansions of PKI are discussed in this paper. A path discovery method is suggested to reduce the effect of PKI expansion to the end entities, so as to enhance the availbility of PKI services.展开更多
The distributed passive measurement is an important technology for networkbehavior research. To achieve a consistent measurement, the same packets should be sampled atdistributed measurement points. And in order to es...The distributed passive measurement is an important technology for networkbehavior research. To achieve a consistent measurement, the same packets should be sampled atdistributed measurement points. And in order to estimate the character of traffic statistics, thetraffic sample should be random in statistics. A distributed samplingmask measurement model isintroduced to tackle the difficulty of measuring the full trace of high-speed networks. The keypoint of the model is to choose some bits that are suitable to be sampling mask. In the paper, thebit entropy and bit flow entropy of IP packet headers in CERNET backbone are analyzed, and we findthat the 16 bits of identification field in IP packet header are fit to the matching field ofsampling mask. Measurement traffic also can be used to analyze the statistical character ofmeasurement sample and the randomicity of the model. At the same time the experiment resultsindicate that the model has a good sampling performance.展开更多
文摘The expansibility of PKI is expected to have the features that when the amount of user exceeds the system capacity, the users’ requirement can still be met by simply expanding the number of PKI entities and management levels, and this expansion should be achieved smoothly from the original system. The upward, downward, and horizontal expansions of PKI are discussed in this paper. A path discovery method is suggested to reduce the effect of PKI expansion to the end entities, so as to enhance the availbility of PKI services.
文摘The distributed passive measurement is an important technology for networkbehavior research. To achieve a consistent measurement, the same packets should be sampled atdistributed measurement points. And in order to estimate the character of traffic statistics, thetraffic sample should be random in statistics. A distributed samplingmask measurement model isintroduced to tackle the difficulty of measuring the full trace of high-speed networks. The keypoint of the model is to choose some bits that are suitable to be sampling mask. In the paper, thebit entropy and bit flow entropy of IP packet headers in CERNET backbone are analyzed, and we findthat the 16 bits of identification field in IP packet header are fit to the matching field ofsampling mask. Measurement traffic also can be used to analyze the statistical character ofmeasurement sample and the randomicity of the model. At the same time the experiment resultsindicate that the model has a good sampling performance.
