Neminath Hubballi

Pankaj Chaudhary, Neminath Hubballi, Sameer G. Kulkarni

Information Centric Networking (ICN) is a new network architecture (Internet) that focuses on content rather than the end-hosts. Named Data Networking (NDN) is a specific implementation of ICN, which relies on the use of named data and a request-response model for content distribution. These Internet architectures are known for their ability to cache content at the network level. Many caching techniques have been designed as part of various ICN/NDN projects. Caching techniques help improve the content delivery performance by storing content in the router to meet future demand. In this survey, we provide a structured review of caching algorithms designed for ICN, with a particular emphasis on NDN. We first present a taxonomy of caching techniques, followed by a detailed discussion of the various methods. Alongside their working principles, we also summarize their advantages and disadvantages. Finally, we discuss the performance metrics commonly used in the literature to evaluate caching methods and outline directions for future research in this area.

Nikhil Tripathi, Neminath Hubballi

Network Time Protocol (NTP) is used by millions of hosts in Internet today to synchronize their clocks. Clock synchronization is necessary for many network applications to function correctly. Unsynchronized clock may lead to failure of various core Internet services including DNS and RPKI based interdomain routing and opens path for more sophisticated attacks. In this paper, we describe a new attack which can prevent a client configured in NTP's broadcast mode from synchronizing its clock with the server. We test the attack in real networks and show that it is effective in both authenticated and unauthenticated broadcast/multicast modes of NTP. We also perform experiments to measure the overall attack surface by scanning the entire IPv4 address space and show that NTP broadcast mode is being used in the wild by several low stratum (highly accurate) hosts. We also suggest few countermeasures to mitigate the proposed attack.