Papers by Dhiman Chowdhury
Synchronization for Telecom Infrastructure
Springer eBooks, 2021
Telcom infrastructure including mobile communications undergone tremendous change over last few d... more Telcom infrastructure including mobile communications undergone tremendous change over last few decades. These changes are linked and leapfrogged but that is about to change as 5G moves in. However, 5G cannot be realized without adequate attention to network synchronization and careful time error budget estimate for the network. Synchronization also need to be understood from historical perspective as it applies to mobile communications and overall telecom infrastructure with highlights and learning from 2G to 4G. The future of telecom infrastructure is the one that brings power of distributed data center with virtual RAN and network technologies coupling this with virtualization and network intelligence to create dynamic, state aware, on demand and service-oriented network, welcome to the world of “Telcom Cloud.” However, challenges remain on such challenge is sync plane issue. Learning in this chapter will help academic, network, and telecom professionals to better understand technological options and appropriate synchronization need to build future telecom cloud network.
Synchronization for Data Center and MSO Infrastructure
Springer eBooks, 2021
Synchronization is essential to modern data centers and MSO (Multiple-System Operator) infrastruc... more Synchronization is essential to modern data centers and MSO (Multiple-System Operator) infrastructures. Moreover, sync plane is inherent to the operations of both data center and MSO infrastructures. Data center infrastructure has traditionally used NTP for sync plane, but many applications today demand high-precision synchrony requiring a better sync plane strategy. To address the challenge of distributed database, live VM migration, and big data analytics, some hyperscalers have implemented a dynamic yet guaranteed clock service while others have replaced traditional ntp daemon with Chrony. Yet, such solutions are not equally applicable to many data centers. A better approach should be an application-centric sync plane that localizes PRTC providing guaranteed sync services while minimizing timing error due to network jitters. Furthermore, today’s technology allows extensibility of PTP-based high-precision application-centric sync plane distributed across geographically dispersed data centers or point of presences (POPs).
Routing Technologies
Springer eBooks, 2001
Synchronization for Industrial Networks
Springer eBooks, 2021
Method of Time Distribution
Springer eBooks, 2021
GNSS receiver that provides key PRTC function for primary time reference source requires the supp... more GNSS receiver that provides key PRTC function for primary time reference source requires the support of several protocols to configure its interface and communications parameters. Trimble Standard Interface Protocol (TSIP), National Marine Electronics Association (NMEA), and Radio Technical Commission for Maritime (RTCM) are some of the industry-standard protocols commonly used for GRU interface configurations. For time distribution, there are two distinct types of methods: packet timing protocols and frequency time distribution. Traditionally, BITS (Building Integrated Timing Supply), SSU, and IRIG-B (Inter-Range Instrumentation Group time code B) are used in frequency level time distribution. With increased penetration of Ethernet, SyncE (Synchronous Ethernet) has emerged as a viable solution for frequency level clock distribution in modern ethernet networks.
The Ethernet
Springer eBooks, 2000
Token Ring
Springer eBooks, 2000
Timing Parameters
Springer eBooks, 2021
GNSS Time
Springer eBooks, 2021
Fundamentals of Time Synchronization
Springer eBooks, 2021
Communication infrastructure that enables today’s connected digital economy relies on synchroniza... more Communication infrastructure that enables today’s connected digital economy relies on synchronization of clocks. Improper synchronization of clocks may render serious network issues from performance degradation to catastrophic failure depending upon applications. Synchronization is categorized based on frequency, phase, and time for which oscillator serves as the core clock source. Atomic clock or atomic frequency standard remains to be the most sought-after yet expensive proposition for primary clock source. There are different atomic clock standards such as hydrogen maser, rubidium, cesium, and quantum. However, these clocks are bulky and may not be suitable for most environments. The chip-scale atomic clock (CSAC) is an effort undertaken by DARPA and NIST to miniaturize atomic clock. For worldwide coordination of these clocks, a unit of time is important and thus UTC was defined to regulate clocks and provide a standard time for coordination.
Packet Timing: Network Time Protocol
Springer eBooks, 2021
The NTP (Network Time Protocol) is most commonly used packet timing protocol that provides timing... more The NTP (Network Time Protocol) is most commonly used packet timing protocol that provides timing accuracy in tens of milliseconds. Although this protocol may not be ideal for real-time and near real-time applications, it is widely used in today’s environment and suitable for generic applications. NTP is hierarchical in nature and deployed based on stratum clock levels. The protocol is part of TCP/UDP/IP suits and normally uses UDP for server client communications. The NTP implementation is based on ntpd (ntp daemon) that runs on linux servers, a variant of it is chrony daemon that is found to be more effective for high-precision accuracy. Though NTP uses symmetric keys and autokey mechanism for security, those mechanisms are not effective against DDOS attacks which led to the work of NTS and NTPsec. Defined by RFC8915, NTS provides more advanced cryptographic protection among other features to secure communications between client and server. On the other hand, NTPsec is an open-source program for linux distributions that utilizes NTS for NTP implementations.
Synchronization for Industrial Networks
Unified IP internetworking : with 276 figures and 61 tables
1 IP Internetworking.- 1.1 Introduction.- 1.2 Internet Engineering Task Force (IETF).- 1.3 Layer ... more 1 IP Internetworking.- 1.1 Introduction.- 1.2 Internet Engineering Task Force (IETF).- 1.3 Layer 3 Switch.- 1.4 IP Addressing.- 1.4.1 Subnetting.- 1.4.2 Variable Length Subnet Mask (VLSM).- 1.4.3 Classless Interdomain Routing (CIDR).- 1.5 NAT (Network Address Translation).- 1.5.1 Static Address Mapping.- 1.5.2 Dynamic Address Translation.- 1.5.3 Port Address Translation (PAT).- 1.6 IPv4.- 1.6.1 ARP (Address Resolution Protocol).- 1.6.2 RARP (Reverse Address Resolution Protocol).- 1.6.3 BOOTP.- 1.7 IPv6.- 1.7.1 IPv6 Header Format.- 1.7.2 IPv6 Addressing Architecture.- 1.7.3 IPv6 Transmission.- 1.7.4 Transition Criteria.- 1.7.5 IPv6 Tunnel.- 1.7.6 ICMPv6.- 1.7.7 Address Autoconfiguration.- 2 Routing Technologies.- 2.1 Introduction.- 2.2 Routing.- 2.2.1 Routing Tables.- 2.2.2 Routing Protocols.- 2.3 RIP (Routing Information Protocol).- 2.3.1 Message Format.- 2.4. OSPF Protocol.- 2.4.1 Dijkstra SPF Algorithm.- 2.4.2 OSPF Concept.- 2.4.3 Basic Operation.- 2.4.4 OSPF Message Format.- 2.5 ...
Synchronization for Data Center and MSO Infrastructure
NextGen Network Synchronization, 2021
Synchronization is essential to modern data centers and MSO (Multiple-System Operator) infrastruc... more Synchronization is essential to modern data centers and MSO (Multiple-System Operator) infrastructures. Moreover, sync plane is inherent to the operations of both data center and MSO infrastructures. Data center infrastructure has traditionally used NTP for sync plane, but many applications today demand high-precision synchrony requiring a better sync plane strategy. To address the challenge of distributed database, live VM migration, and big data analytics, some hyperscalers have implemented a dynamic yet guaranteed clock service while others have replaced traditional ntp daemon with Chrony. Yet, such solutions are not equally applicable to many data centers. A better approach should be an application-centric sync plane that localizes PRTC providing guaranteed sync services while minimizing timing error due to network jitters. Furthermore, today’s technology allows extensibility of PTP-based high-precision application-centric sync plane distributed across geographically dispersed data centers or point of presences (POPs).
IP Internetworking
Unified IP Internetworking, 2001
Wireless LAN
High Speed LAN Technology Handbook, 2000
Unified IP Internetworking
Page 1. Page 2. Page 3. Unified IP Internetworking s One CGJY-GKH-XX1G Page 4. Springer Berlin He... more Page 1. Page 2. Page 3. Unified IP Internetworking s One CGJY-GKH-XX1G Page 4. Springer Berlin Heidelberg New York Barcelona Hong Kong London Milan Paris Singapore Tokyo Page 5. Dhiman D. Chowdhury Unified IP ...
High Speed LAN Technology Handbook: With 100 Tables
gin.confex.com
Corporations are the DNA of modern economic life and their unparallel success in transforming ear... more Corporations are the DNA of modern economic life and their unparallel success in transforming earth's resources into wealth has shaped the physical and social world we live today. However, problems arise when corporations through their behavior causes upheavals in global economy, society and environment. Despite the global legislative measures, an increasing numbers of corporations and their leaders demonstrated disdain on issues related to society and environment. The issue here is multifold; first, corporations are lacking an understanding that "Pareto Efficiency" of competition defined in Walrasian model of economics is obsolete. Secondly, resources cannot be consumed without having regards for it's consumption as resources are not infinite, and third, economy, society and environment are entwined. Thus concentrating on one attribute of sustainability e.g. economics is absurd and detrimental to the corporations' own survival. Nonetheless, little has been achieved thus far to address sustainability issues. This is due to the fact that the very essence of Brundtland statement bringing together institution and human values are poorly emphasize or lost in the more complex definition of sustainability. Initiatives of sustainability give hope to human species to exist and foster in our common biosphere. Essential to this pensiveness of hope is the integration of institutions and human values, and without corporation such integrative purview is incomplete. However, much of corporate sustainability approach is about reactive and compliance than creative and proactive competence of meeting multiple stakeholders' needs and demands towards economic, social and environmental equity. This paper presents a different perspective of corporate sustainability approach emphasizing the benefits of the sociological paradigm incorporating a bottom up method by means of value ingrained culture that fosters creative and proactive competence and builds capability. It is a departure from the notion of sustainability in business that is much about compliance and reactive in response. For corporation, it means developing organizational citizenship behavior and integrating "sustainability value culture" to the integrative framework of corporate sustainability. My contention is that OCB (Organizational Citizenship Behavior), the derivatives of ingrained human values can excerpt significant influence corporate sustainability allowing the enterprise to meet multiple stakeholders' needs and demands towards economic, social and environmental equity. OCB has the potential to improve firm's sustainability performance and in the very essence of being inner drive will serve dual purposes: first, it will build capability and values in an organization to effectively face endogenous and exogenous threats and secondly, it will significantly improve organization's sustainability performance, long term growth and profitability. The paper presents a theoretical argument that can serve as the basis for further research on OCBS (Organizational Citizenship Behavior towards Sustainability).
Structured Approach to Improve Passive Aggressive Organizational Behavior: An Empirical Research
books.google.com
Page 1. STRUCTURED APPROACH TO IMPROVE PASSIVE AGGRESSIVE ORGANIZATIONAL EHAVIO Dhiman Deb Chowdh... more Page 1. STRUCTURED APPROACH TO IMPROVE PASSIVE AGGRESSIVE ORGANIZATIONAL EHAVIO Dhiman Deb Chowdhury Page 2. STRUCTURED APPROACH TO IMPROVE PASSIVE AGGRESSIVE ORGANIZATIONAL ...
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Papers by Dhiman Chowdhury