International Conference on Computing, Communication and Automation (ICCCA 2016) A Constructive Review of In-Network Caching: A Core Functionality of ICN Anshuman Kalla, Sudhir Kumar Sharma Department of Electronics & Communication Engineering Jaipur National University, India Email: {kallajnu,sudhir.732000}@gmail.com Abstract—Over the years, caching has been leveraged (and established) as an add-on functionality to enhance network performance. However, Information Centric Networking (ICN) conceives caching at network layer (i.e. beyond the premise of end-to-end principle) thereby making it one of the core functionalities. Further, ICN advocates named-content (another core functionality) that allows content-consciousness within net- works. Together the two functionalities result in content-aware ubiquitous in-network caching that has received significant at- tention of researcher all-around. The aim of this paper is to probe in depth and review some of the work done pertaining to in-network caching in ICN, in order to understand their aims, assumptions, approaches, simulation set-ups used, network topologies exploited, traffic pattern fed-in, performance metrics used, parameter(s) tuned-in to optimize the performance and the significance of the results obtained by the researchers. The paper also lists out advantages of in-network caching, related issues, factors that affect in-network caching and relevant performance metrics. The paper intends to assist researchers who are searching ways to put-forward (an acceptable) proof of their ideas. I. I NTRODUCTION Early 1970s marks the ear of design and development of todays networking ecosystem. Efficient sharing of expensive resources was the ultimate aim then. Since then numerous technological advancements (like proliferation of economical hand-held networking devices, multiple simultaneous connec- tivities, availability of high speed data communication links, advancements in multi-core processors technology, consistent decline in the cost of memory for data storage etc.) have fallen in line to support the flawless evolution of networking facility. Unfortunately, in spite of years of maturity and all related technological developments, it is being experienced that networking still falls short of users’ expectations. Some of the issues ( [1], [2]) that have in a way plagued current TCP/IP networking architecture over the years are: • Data Dissemination & Service Access: Today Internet is prominently being used for dissemination/retrieval of c 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all the other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works staggering amount of content and service access, for which it was not tailored. • Named Host: TCP/IP networking translates (according to DNS mapping) name of every content (to be retrieved) to an IP address which signifies the location of a host (serv- ing that content) in network space. Thus Internet today comprises of named-hosts instead of named-contents. • Mobility: Mobility causes intermittent connectivity which might lead to change in IP address thereby com- pelling ongoing TCP/IP application(s) to restart. • Availability: It implies existing content or service should be always available to the users with high reliability (preferably with low latency). • Security: So far, security and authenticity of data has been realized at network-level by ensuring communica- tion over a secured channel with a trusted server. Data- level security is however still missing. • Flash Crowd: Leads to network congestion, Denial-of- Service (DoS), poor QoS etc. Existing content-oblivious networking is natively incapable to tackle such a practical phenomenon. To handle these issues, the trend being followed so far is to progressively design and deploy a fix for every issue that is encountered. To mention some are CDN (Content Distribution Network) and P2P applications for efficient data dissemination, DNS for resolving an identifier (URL) to a locator (IP address), MobileIP and Shim layer for supporting mobility, DNSSec & IPSec for ensuring security, web caching & intelligent DNS for availability issue etc. As a result of such patches the networking today is surviving critically. In order to permanently conciliate the problem in unified manner, numerous clean slate Information Centric Networking (ICN) approaches have been recently proposed. Albeit, the design details of the proposed architectures are different but they unanimously talks about retiring the host-centric (host-to- host) communication model and bring in place the content- centric (host-to-content) communication model. Readers are referred to seminal works [1], [2], [3], [4], [5], [6], [7], [8] for CCN, NDN Project, 4Ward Project, NetInf, PSIRP, PURSUIT, DONA and SAIL respectively. Next section II introduces in-network caching, its advan- tages, issues involved in cache management, factors that affect ISBN: 978-1-5090-1666-2/16/$31.00 c 2016 IEEE