NB-Cache: Non-Blocking In-Network Caching for High-Performance Content Routers
NB-Cache: Non-Blocking In-Network Caching for High-Performance Content Routers
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NB-Cache：用于高性能内容路由器的非阻塞网络内缓存
DOI：
10.1109/tnet.2021.3083599
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发表时间：
2021-10
影响因子：
3.7
通讯作者：
Zhang Beichuan
中科院分区：
文献类型：
--
作者：
Pan Tian;Lin Xingchen;Song Enge;Xu Cheng;Zhang Jiao;Li Hao;Lv Jianhui;Huang Tao;Liu Bin;Zhang Beichuan
信息中心网络（ICN）通过网络内缓存和本地多播，在Internet规模上提供了可扩展和高效的内容分发。为了支持这些特性，内容路由器需要在其数据平面上具有高性能，其中包括三个转发步骤：检查content Store (CS)，然后检查Pending Interest Table (PIT)，最后检查forwarding Information Base （FIB）。在这项工作中，我们建立了路由器的分析模型，并确定CS是实际的瓶颈。然后，我们提出了一种称为“NB-Cache”的新机制，从网络范围的角度解决CS的性能问题。在NB-Cache中，当报文到达一个CS满载的路由器时，这些报文不会被阻塞并等待CS，而是被转发到下一跳路由器，而下一跳路由器的CS可能没有满载。这种方法本质上是并行地利用转发路径上所有路由器的内容库，而不是依次检查每个CS。NB-Cache遵循按需负载平衡的设计模式，可以形成一个非平凡的n队列旁路模型。利用马尔可夫链建立其理论基础，找到一种自动生成转移率矩阵的算法。实验表明，数据平面性能显著提高：往返时间（RTT）减少70%，吞吐量提高130%。NB-Cache将快速的数据包转发与较慢的内容检索分离开来，从而大大减少了CS对快速但昂贵的内存的严重依赖。
Information-Centric Networking (ICN) provides scalable and efficient content distribution at the Internet scale due to in-network caching and native multicast. To support these features, a content router needs high performance at its data plane, which consists of three forwarding steps: checking the Content Store (CS), then the Pending Interest Table (PIT), and finally the Forwarding Information Base (FIB). In this work, we build an analytical model of the router and identify that CS is the actual bottleneck. Then, we propose a novel mechanism called “NB-Cache” to address CS’s performance issue from a network-wide point of view. In NB-Cache, when packets arrive at a router whose CS is fully loaded, instead of being blocked and waiting for the CS, these packets are forwarded to the next-hop router, whose CS may not be fully loaded. This approach essentially utilizes Content Stores of all the routers along the forwarding path in parallel rather than checking each CS sequentially. NB-Cache follows a design pattern of on-demand load balancing and can be formulated into a non-trivial N-queue bypass model. We use the Markov chain to establish its theoretical base and find an algorithm for automated transition rate matrix generation. Experiments show significant improvement of data plane performance: 70% reduction in round-trip time (RTT) and 130% increase in throughput. NB-Cache decouples the fast packet forwarding from the slower content retrieval thus substantially reducing CS’s heavy dependency on fast but expensive memory.