###### Abstract  
As a new network architecture, information-centric networking (ICN) decouples the identifiers and locators of network entities and makes full use of in-network cache technology to improve the content distribution efficiency. For reliable multicast, ICN in-network cache can help reduce the loss recovery delay. However, with the development of applications and services, a multicast tree node often serves multiple reliable multicast groups. How to reasonably allocate cache resources for each multicast group will greatly affect the performance of reliable multicast. In order to improve the overall loss recovery performance of reliable multicast, this paper designs a dynamic cache allocation mechanism (DCAM). DCAM considers the packet loss probability, the node depth of the multicast tree, and the multicast transmission rate of multicast group, and then allocates cache space for multicast group based on the normalized cache quota weight. We also explore the performance of three cache allocation mechanisms (DCAM, AARM, and Equal) combined with four cache strategies (LCE, CAPC, Prob, and ProbCache), respectively. Experimental results show that DCAM can adjust cache allocation results in time according to network changes, and its combinations with various cache strategies outperform other combinations. Moreover, the combination of DCAM and CAPC can achieve optimal performance in loss recovery delay, cache hit ratio, transmission completion time, and overhead. reliable multicast; cache allocation; loss recovery; ICN +
Footnote †: journal:  
0000-0001-4000-40  
MobilityFirst [11]. However, it still has some problems [12], such as the reliability of multicast transmission. In ICN, multicast application scenarios with reliability requirements are ubiquitous, such as file transfer, software upgrade, and distribution of key data in the Internet of Things. Although multicast improves network bandwidth utilization by simultaneously sending information from one or more points to a group of other points [13], it does not guarantee reliable and orderly delivery of all data to each multicast receiver [14]. Loss recovery is the core issue of reliable multicast, and the recovery delay seriously affects the performance of reliable multicast applications [15]. The in-network cache capability of the ICN enables multicast tree nodes to cache multicast data and retransmit the requested data immediately after receiving the retransmission request, which greatly reduces the recovery delay. Researchers have proposed several cache strategies for a single multicast group to improve the loss recovery performance. However, a multicast tree node (MTN) often serves multiple multicast groups at the same time, and the multicast traffic flowing through the same multicast tree node may reach different downstream links respectively. The packet loss situation of each multicast group may be different, and the demand for cache resources of multicast tree nodes is different [16]. In the above network scenario, the allocation of cache space of multicast tree nodes has a great impact on the performance of reliable multicast. If the cache space of each multicast tree node in the network is arbitrarily allocated, it is unfair and unreasonable. For example, the multicast group with a small retransmission requirement may cause a waste of cache space; for a multicast group with a large retransmission requirement, the cache quota of the multicast tree node may be insufficient [17], resulting in a large delay in loss recovery. Therefore, it is very important to reasonably allocate the cache space of multicast tree nodes to each multicast group. In order to optimize the overall loss recovery performance of all multicast groups and improve the utilization of cache resources in the network, this paper comprehensively considers the packet loss probability, node depth, and transmission rate to design a dynamic cache allocation mechanism (DCAM).