# Content Management Based on Content Popularity Ranking in Information-Centric Networks
## 4 Performance Analysis
### Content Delivery Time  
The proposed CPR-based schemes for content caching and cache removal were implemented together within the CCN architecture and evaluated in a combined manner using the key performance indicator Content Delivery Time (CDT) that shows the time elapsed from sending the content request by a client node until receiving that content completely from the server node. The previous two graphs indicated that LCE performed better than LCD as a content caching scheme, and LRU performed better than LFU as a cache removal scheme. Therefore, we combined the LCE and LRU schemes and implemented them within the CCN architecture for the experimental results of this subsection. Additionally,  
Figure 3: Cache hit ratio against increasing number of content. the host-based Internet architecture was also brought to the spot, and content request and retrieval experiments were executed to measure the performance in terms of CDT. The differences in the content delivery times for different networks arose predominantly because of whether the requested content are readily available or not and the number of hops or distance of the server nodes from where the requested content was being delivered to. The content is always delivered from the original remote server node for the host-based Internet architecture, as no intermediate node caches the requested content. Additionally, more time is needed in order to establish a secure connection in the host-based Internet architecture. Thus, the host-based Internet architecture takes a longer time to deliver the requested content than the basic CCN architecture, which may deliver the requested content from an intermediate node and secure the content itself rather than spending time to secure the transmission path. CCN architecture incorporating LCE and LRU schemes caches all the content at all the nodes and removes the content accessed before the other content; hence, it can deliver the requested content faster than the host-based Internet from an intermediate node. However, frequent cache overflows and cache misses may occur due to the policies taken by these schemes, as explained in the previous two subsections. In contrast, server nodes utilizing the proposed CPR-based schemes for content caching and cache removal implemented within the CCN architecture can perform better than these two other architectures because of the selective caching of the frequently requested popular content and cache removal of the less popular content that ensures a smaller number of content requests have to travel farther in order to locate the requested content. The results of the experiments in terms of CDT are demonstrated in Figure 4. In this graph, the maximum number of pieces of content a client can request was 60, and the cache repository size for each server node was fixed at 130 MB. The performance trend in terms of CDT was similar while we varied these two parameters. The \(Y\)-axis indicates CDT values, which are the required times for retrieving the content requested by the clients. The corresponding server nodes measure the CDT from the time they received content request from a client until the time that content was delivered entirely to that client. The \(X\)-axis shows the groupings of the maximum number of clients that can simultaneously attach to a server node. This number indicates the traffic load that a server node had to handle during this experiment. A larger number of clients  
Figure 4: Average content delivery times against an increasing number of clients. at a time means a higher traffic load occurs for each server node; this is the reason for the increasing trend of delay in the average CDT. The times are measured in seconds (s), and the indicated times in the \(Y\)-axis are the average times for all the clients in that group for all the successful content requests.