# Content Management Based on Content Popularity Ranking in Information-Centric Networks
## 4 Performance Analysis
### Average Hop Count  
We assessed the Average Hop Count (AHC) as one of the key performance indicators. AHC points to the number of hops, which means the number of server nodes each content request needed to go through on average before the content could be located. The number of hops also means how many intermediate server nodes had to run the content caching scheme presented in Algorithm 1, excluding the initial server that received the content request. A lower AHC means that the request had to go fewer nodes up to find the requested content. Hence, a shorter delay in retrieving the requested content can be achieved. The value of AHC for the same content becomes less than the maximum number of hop available in the network topology as soon as the 2 nd request of the same content arrives, as that content may have been cached at a nearer node. In the proposed caching scheme, the requested content is always cached at the initial server nodes, and the intermediate nodes may or may not cache the content based on the CPR of that content. When a request for \begin{table}
\begin{tabular}{c c c} \hline \hline
**Y-Axis Parameters** & \multicolumn{1}{c}{\(X\)**-Axis Parameters**} & \\ \hline Average Hop Count & Size of the Cache Repository per Server & \(10\)–\(150\) \\ Cache Hit Ratio & Max Number of Forms of Content a Client can Request & (MIP) \\ Content Delivery Time & Max Number of Clients & \(10\)–\(90\) \\  & Attached per Server & \(5\)–\(50\) \\ \hline
**Total Resources** & \multicolumn{1}{c}{**Schemes Compared**} & \\ \hline
**Nodes and Content** & **Caching** & **Removal** \\ \hline Servers & 20 & CPR-Based \\ Clients & 100 & LCE \\ Content & 150 & LCD \\ \hline \hline \multicolumn{3}{c}{**Network Architectures**} \\ \hline Host-based & Basic CCN with Compared & \\ Internet & Schemes & CCN with Proposed CPR-based Schemes \\ Architecture & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Configuration of the network topology. Figure 1: Depiction of one of the network topologies. the same content comes to the same initial server node where it is already stored, it can be delivered immediately without traveling to the remote server. Although the content may be removed before the subsequent request comes, in case the storage capacity is not enough, then the content needs to be fetched again from an intermediate node or the original server node in the worst case. Therefore, the cache size plays a vital role in determining AHC, and as the cache size gets bigger, AHC becomes lower. During each content request, all the involved intermediate server nodes passed the number of hops information to the initial server nodes, and the initial server nodes calculated AHC using (9) after delivering each requested type of content to the clients. \[AHC_{n}=\frac{1}{m}\sum_{i=1}^{m}(HopCounts_{i}) \tag{9}\]  
Here, \(m\) is the total amount of content that the initial server node \(n\) fetched from the other servers and \(AHC_{n}\) is the Average Hop Count for the server node \(n\). \(HopCounts_{i}\) is the number of hops needed to retrieve the content \(i\). The performance of the proposed CPR-based caching scheme was compared in terms of AHC with two other caching schemes: LCE and LCD. All these schemes were implemented separately within the CCN architecture for the experimental results of this subsection. LCE caches all the content at all the nodes; hence it should have a lower AHC; however, this content also needs to be removed frequently due to cache overflow. Therefore, the requested content needed to be fetched from other servers again, and the AHC increased as a consequence. On the other hand, LCD caches only at the next-hop node; hence it takes a longer time to store content at a server node that is nearer to the requesting client. The proposed CPR-based content caching scheme stores the frequently requested popular content at various intermediate server nodes and achieves a lower AHC by delivering the requested content from a nearer source.