# Adjacency-Information-Entropy-Based Cooperative Name Resolution Approach in ICN
## 4 Proposed Approach
### Latency Neighbor Maintenance  
In addition to the latency neighbor discovery and cooperative name resolution methods described above, the dynamic structure maintenance mechanism in the ACNR approach is also designed to cope with the dynamics caused by changes in network topology and network latency. Throughout the lifetime of each name resolution node, it needs to perform latency measurements and heartbeat detection with its latency neighbor nodes periodically. When a name resolution node finds that a latency neighbor failed to respond or the communication latency between them is no longer satisfying the constraints in the definition of latency neighbor, it needs to remove that name resolution node from its latency neighbor list. When the latency neighbor list of a name resolution node becomes empty, the discovery process of latency neighbors needs to be re-executed. The maintenance mechanism here ensures the validity of the latency neighbors and makes ACNR work better in the NRS. The dynamic maintenance mechanism of the tree structure is not the focus of this paper and will not be discussed here. ```
0:\(HN_{i}^{l}\), \(T=\{t_{1},t_{2}\ldots\,t_{L}\}\), Request
0:Response
1: initialization:\(\mathit{locators}\gets HN_{i}^{l}\). neighbors
2:if\(HN_{i}^{l}\). currentLoad < MN_{i}^{l}\). LoadLimitthen
3:\(\mathit{locators}\leftarrow\) local name resolution by \(MN_{i}^{l}\)
4:if\(\mathit{locators}\) is emptythen
5:\(\mathit{validNeighbors}\gets null\)
6:for\(\mathit{mn}\) in \(MN_{i}^{l}\). neighborsdo
7:if\(d\left(MN_{i}^{l},\;mn\right)<\mathit{tl}-\mathit{d}\left(MN_{i}^{l},\;\mathit{Requestsource}\right)\)then
8: add \(\mathit{mn}\) to validNeighbors
9: sort validNeighbors with ILN in descending order
10:for\(\mathit{mn}\) in the first \(\mathit{k}\) validNeighborsdo
11: send a cooperative name resolution request to \(\mathit{mn}\)
12:whilewaitTime \(<\) t\({}_{l}-\mathit{d}\left(MN_{i}^{l},\;\mathit{Requestsource}\right)\)do
13:\(\mathit{resp}\leftarrow\) cooperative name resolution response from \(MN_{i}^{l}\). neighbors
14:if\(\mathit{resp.locators}\) is not emptythen
15:\(\mathit{Response.locators}\leftarrow\mathit{resp.locators}\)
16:break



### Experimental Setup

To evaluate our approach, we performed the implementation of the ACNR approach and several comparison algorithms based on Simpy [48]. Simpy is an efficient and powerful discrete event simulator that allows researchers to easily test customized algorithms and strategies. We generated random topologies following the Barabasi-Albert scale-free model [49]. It is a typical power law degree-distributed network that is widely used to simulate real-world network topologies. According to [50], the current end-to-end latency of the internet is in the order of 10 milliseconds, and we randomly set the latency of each edge from 2 ms to 10 ms. Considering the different requirements of latency for the main application scenarios in 5G/B5G, we choose \(T=\{10\text{ ms},25\text{ ms},50\text{ ms}\}\) as upper bounds for the one-way transmission latency [51]. We distribute \(10^{4}\) contents evenly across network nodes in the network and set up \(5\times 10^{4}\) name resolution requests as workloads for the experiment. These workloads are initiated by the network nodes in a stable distribution, where the content of the requests follows a Zipf [52] distribution with parameter \(\lambda=0.9\), and the request event happens following a Poisson distribution, with a default rate of 1000 requests per second. We assume that the network is responsible for route forwarding with cache-supporting ICN routers, each ICN router sets the same size of cache space and enforces a cache replacement policy of least recently used (LRU) [53]. To address the cold-start problems of network states, such as caching and NRS registration, we treat \(10^{4}\) requests of the workload as warm-up traffic and do not record these request events; the remaining \(10^{4}\) requests are recorded to obtain statistics for analyzing neighbor cooperative name resolution.