Academia.eduAcademia.edu

where D=[D,], x=1,..,n represents the combined delivery method for each of the n VoD channels, Dejoyg=[Dx], x=1,...n corresponds to the delivery over the cloud, Depy=[Dx], x=1,..,.n to the delivery with use of CDN and Dyye¢c=[D,], x=1,..,n to the use of P2P network between EHG devices. In the formula W=[W,yy], X=I,...n, y=l,.,m, where W,y represents the proportion of video channel x’s requests directed to Data Center(DC) y. A=[a,] and B=[b,],  x=1,...,n, where the variables can only take the values 0 and | to enable or disable the use of Cloud and P2P delivery respectively. In case of enabling P2P delivery, for a specific VoD, EHGs devices implement proper P2P algorithms to take the decisions about the load distribution. The corresponding algorithm as implemented in the MDM is presented below.  It can be observed that the higher value can be taken among the current and the predicted bandwidth need. If it is below a preset limit (based on administrative high level decisions and network status), only the Cloud delivery will be used. If it is above the limit, CDNs will be used and the number of CDNs used is increasing according the demand. After the top limit is reached, a P2P delivery method is exploited. This algorithm provides the advantage that the data is not distributed before the actual need. In the case of a VoD with low customers demand, the CDNs will not been used for its distribution. On the other hand, if a popular VoD is requested, an early prediction will occur, while the number of CDNs, distributing the VoD will rapidly increase based on the demand. Finally, the P2P delivery method will be used, only when needed, while at the time that this happens, the number of the users already possessing the specific video will be satisfactory with those users, acting as seeders to distribute the VoD to the others.

Table 1 where D=[D,], x=1,..,n represents the combined delivery method for each of the n VoD channels, Dejoyg=[Dx], x=1,...n corresponds to the delivery over the cloud, Depy=[Dx], x=1,..,.n to the delivery with use of CDN and Dyye¢c=[D,], x=1,..,n to the use of P2P network between EHG devices. In the formula W=[W,yy], X=I,...n, y=l,.,m, where W,y represents the proportion of video channel x’s requests directed to Data Center(DC) y. A=[a,] and B=[b,], x=1,...,n, where the variables can only take the values 0 and | to enable or disable the use of Cloud and P2P delivery respectively. In case of enabling P2P delivery, for a specific VoD, EHGs devices implement proper P2P algorithms to take the decisions about the load distribution. The corresponding algorithm as implemented in the MDM is presented below. It can be observed that the higher value can be taken among the current and the predicted bandwidth need. If it is below a preset limit (based on administrative high level decisions and network status), only the Cloud delivery will be used. If it is above the limit, CDNs will be used and the number of CDNs used is increasing according the demand. After the top limit is reached, a P2P delivery method is exploited. This algorithm provides the advantage that the data is not distributed before the actual need. In the case of a VoD with low customers demand, the CDNs will not been used for its distribution. On the other hand, if a popular VoD is requested, an early prediction will occur, while the number of CDNs, distributing the VoD will rapidly increase based on the demand. Finally, the P2P delivery method will be used, only when needed, while at the time that this happens, the number of the users already possessing the specific video will be satisfactory with those users, acting as seeders to distribute the VoD to the others.