CRL license revocation list (Certification Revocation List)
CRL is a digital certificate to confirm the traditional approach has been used to set out to terminate an invalid digital certificate. The list is available for external download, because it is will be updated from time to time between the user must periodically download the data, only to obtain the latest information.
CRL lists all valid yet to come, but has been certificate agency (CA; Certification Authorities) revocation of digital certificates. The certificate has been revoked certificates listed agencies, the CRL will be described in the latest part to CRL's expiration date, and where to get the latest version of the CRL.
CRL itself is due to update the model, leading the user to be kept up to date, but there could be security vulnerabilities. For example, an employee at the 12 noon departure, but the latest of a CRL in the 11:50 update is complete, but the next CRL update time is 5 pm, there will be this interval of time, staff can still leave Any use of the Chang certificate issue. Download the CRL program is not only cumbersome and updated several times a day because the certificate body, you have to download several times; while CRL file size is usually large, we will increase the burden on network traffic, and take a very long download time.
To address this problem, the industry to discuss new ways of updating, online certificate status protocol (OCSP; Online Certificate Status Protocol) will be born, can provide to give users one or more of the digital certificate of the valid data at the same time built a immediate response mechanism to allow users to instantly confirm the validity of the certificate of each one to address the potential crisis that might arise CRL.
CSMA / CD Carrier sensing more from the Access / Collision Detection
CSMA / CD (Carrier Sense Multiple Access with Collision Detection). Local area network switch is a communication agreement from the carrier sensing multiple access / collision detection.
Local area network nodes have to have full duplex capabilities, which is the node to send data from other regions can also detect whether the network node to send data, the above mechanism for the carrier sensing.
Local area network node may at any time without detection from the other regions of the network node is sending data frame sent on the first or information from the mechanism for multi-access. If at the same time there are two or more of the local area network nodes sending frame or data, this situation is called collision.
When the collision occurs; that the detection of collisions, all nodes of local area network to suspend or information sent frame, and wait a moment. After the break, if the LAN is idle, then any node can be re-sent frame or information. After the break, if the local area network is still busy, the collision occurs second time. To avoid such things from happening, then the rest of the length of the random number is set to random (Random), helps reduce the chances of collision.
CWDM coarse wavelength division multiplexing type conversion
CWDM (Coarse Wavelength Division Multiplexing)
CWDM is to use thin-film filter (Thin Film Filter) technology, optical fiber transmission modules, and the difference lies in its DWDM is mainly used in area Ethernet.
CWDM filter modules as the number of only two wavelength channels (DWDM module at least four or more), and the wavelength spacing of up to 400 GHz (DWDM module, in the 200 GHz or less), so the relative technical difficulty the lower, cost control and maintenance of long-term clients will be relatively more important.
Compared to DWDM, CWDM small amount of data transfer, sending and receiving equipment at both ends of its lower cost, it can attract investment capital over CWDM lack of customer.
CXO business executives
Business executives, the "long" Generation name is a generic term. For example, Chief Executive (CEO: chief executive officer), chief information officer (CIO: chief information officer), or the chief technology officer (CTO) and so on.
CxO although often only the middle of "x" in different words, but some business executives would be fantastic and think of something different names, for example, Microsoft Chairman Bill Gates will have a distinctive title: Chief Software Architect (software architect) .
Here are some collected from the network to the CxO office name: chief academic officer
chief accounting officer
chief acquisition officer
chief administration officer
chief administrative officer
chief advertising officer
chief business officer
chief competitive officer
chief concept officer
chief crisis officer
chief demonstration officer
chief eating officer
chief e-business officer
chief e-commerce officer
chief economic officer
chief evil officer
chief financial officer
chief fun officer
chief futurist officer
chief glitch officer
chief growth officer
chief hacking officer
chief health officer
chief information officer
chief information security officer
chief innovation officer
chief intellectual officer
chief intelligence officer
chief marketing officer
chief operating officer
chief privacy officer
chief revenue officer
chief risk officer
chief safety officer
chief sales officer
chief science officer
chief scientific officer
chief security officer
chief vision officer
chief visionary officer
chief web officer
chief wireless officer
chief Xbox officer
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