Research On Content Acquisition Scheme With Low Delay In Named Data Networking

The Internet has become an integral part of modern life.With the increasing popularity of portable network terminal devices,the size of network users has increased and people's demand for resources has changed dramatically.People are paying less attention to the source of network content and paying more attention to the content itself.The NDN(Named Data Networking)network model has been proposed to fundamentally solve the limitations of network development and provide better network quality.NDN is highly secure,mobile,scalable,and multicast transmission,and can greatly improve network's performance in dle.NDN has natural advantages in content acquisition latency through content aggregation and caching,there is still some room for performance improvement.In this paper,from the perspective of reducing content acquisition latency in NDN networks,we make full use of the content caching feature in NDNs,introduce the idea of ant colony optimization and detection mechanism,and the concept of the multicast tree for basic communication mode and subscription publishing mode,respectively,to reduce the content acquisition latency in both communication modes by distributing content caching in the network so that content requesters can acquire content from a closer location.In this paper,three aspects are accomplished as follows:1.For the basic communication mode in NDN,a low-latency content acquisition strategy combining the idea of ant colony routing and the neighbor detection mechanism is proposed by making full use of the caching feature of NDN.The strategy introduces the idea of adjusting the pheromone concentration to select the optimal path in the ant colony routing algorithm on the one hand and adjusts the way of pheromones on the relevant path by Data packets on the path from content providers to content requesters based on the content in Data packets cached by upstream nodes to strengthen the effective path and improve the probability of the corresponding Interest packets to select the path afterward;on the other hand,through periodic information exchange between neighboring nodes for neighborhood detection,which enables each node to obtain the information storage of one-hop neighbors to enhance the neighborhood discovery capability.This content acquisition mechanism makes full use of the caching feature of the NDN,which enables nodes to obtain the required content from the nodes that cache the content as close as possible instead of the original content producer that is farther away,thus reducing the content acquisition delay.2.A multicast tree-based low latency content acquisition strategy is proposed for the content subscription publishing mode in NDN.The strategy uses the subscription request information sent by subscribers to publishers to build a multicast tree with publishers as the root and covering all subscribers during the establishment of the content subscription distribution mode,and selects key nodes in the multicast tree based on the nodes' positions in the multicast tree and the number of received subscription response packets,and maintains the subscription multicast tree through the key nodes to improve the efficiency of subscription information distribution.This strategy reduces the content acquisition latency of subscribers by constructing and maintaining the subscription multicast tree and the key nodes in it so that the subscribing nodes can obtain the required content from the key nodes or publishers promptly.3.By simulating the key components of the NDN communication flow,such as caching,pending interest table,and longest prefix forwarding,C++ simulations are applied to verify the two content acquisition mechanisms proposed in this paper.Experimental results on popular topologies in two NDN networks,DFN and Deltacom,show that in the basic communication mode,the strategy proposed in this paper makes better use of the content cached within the network compared to the mainstream content forwarding strategy of NDN.With the growth of the content request packet delivery rate,the impact of the forwarding mechanism and content detection mechanism based on the idea of ant colony routing on the satisfaction of interest is gradually improved.On the other hand,adding a multicast subscription tree structure to the subscription publishing mode can effectively reduce the delay in content push,subscription update,and acquisition.