### Collaborative Storage and Resolution Methods  
Name resolution systems with different structures use different collaborative storage and resolution methods. In name resolution systems based on single-layer structure (e.g., NetInf [24], DHT-NRS [25], etc.), when resolution requests cannot be fulfilled locally, the resolution request is routed to the next resolution node according to different DHT implementations. In tree-based hierarchical name resolution systems (e.g., DONA [26], Ftree [27], etc.), resolution requests are forwarded up along the tree structure until the request is fulfiled by a resolution node or the request reaches the root of the tree structure. In DHT-based hierarchical name resolution systems (e.g., MDHT [28], HSkip [29], etc.), if a resolution request is not fulfilled locally, it is firstly redirected in the local DHT structure; if it is still not fulfilled, it will be redirected by the super node in the local structure to nodes in the DHT structure of the higher level, until it reaches the highest level. In LNMRS, a user can only resolve mapping records from the resolution node in whose service area it resides, and it is because of this special service pattern that resolution service latency is guaranteed to be smaller than a deterministic latency value. If a user sends a resolution request to a resolution node outside of the service area it resides in, as in the commonly used collaborative resolution methods mentioned above, the special service pattern is violated, and the resolution service latency cannot be guaranteed.  
In this paper, we propose a collaborative storage and resolution method between layers under the constraint of deterministic service latency feature in LNMRS, by which resolution nodes with excessive storage load could store part of the mapping records to the child nodes with a lighter storage load, which relieves storage pressure on higher-level resolution nodes and improves the overall storage resource utilization of the system. The main contributions of this paper are as follows:* We analyze latency constraints required for inter-layer collaborative storage and resolution under the constraint of a deterministic service latency feature, and define the nodes that satisfy the above constraints as index neighbors. Then we propose an index neighbor construction method based on the MK-Mediod algorithm.
* We propose the collaborative storage and resolution method based on index neighbor structure, and conduct experiments to compare the latency measurement cost and computation cost of our index neighbor construction algorithm against several other approaches. Meanwhile, experiments are also conducted to compare the increase of total storage load and service latency when the constructed index neighbor structure is used to implement collaborative storage and resolution.  
The rest of this paper is organized as follows: in Section 2, we analyze latency constraints that need to be satisfied by the resolution nodes used for inter-layer collaborative storage in LNMRS, construct index neighbor structure based on the proposed MK-Mediod algorithm, and use this structure to implement inter-layer collaborative storage and resolution. In Section 3, we evaluate and discuss the performance of the proposed method through comparative experiments with several neighbor construction algorithms, and Section 4 concludes our work.