An investigation into HFC MAC protocols: Mechanisms, implementation, and research issues

Abstract

This study comprehensively reviews two HFC MAC protocols: Data-Over-Cable Service Interface Specifications (DOCSIS) and IEEE 802.14a. DOCSIS was approved by the ITU as a standard and is supported by many vendors. However, IEEE 802.14a remains a draft due to the delayed standardization process. After briefly introducing the features of HFC networks, the basic operations and mechanisms of these two MAC protocols are then examined. Both standards view an upstream channel as a stream of minislots and have similar mechanisms for upstream bandwidth management, virtual queue, downstream in MPEG-2 format, data-linklayer security, and ranging. However, the standards adopt different mechanisms for upstream access modes, QoS support, and collision resolution. Moreover, the implementation issues over hardware and software design for DOCSIS networks are investigated. This work also identifies the research issues in HFC MAC protocols, particularly allocation and scheduling issues. S U R V E Y S I E E E C O M M U N I C A T I O N S T h e E l e c t r o n i c M a g a z i n e o f O r i g i n a l P e e r -R e v i e w e d S u r v e y A r t i c l e s

Implementation of Both High-Speed Transmission and Quality of System for Internet Protocol Multicasting Services

“…However, previous studies have shown that the time delay of this algorithm increases rapidly while significantly reducing the network throughput under a heavy network work load [4], [5]. It has been shown that this problem can be mitigated to a certain extent by adjusting the length of the back-off window [4], [5]. Hence, broadcastingservice data provided by a video server to an IP set-top box can be transmitted using the same route.…”

“…It utilizes what is known as the Truncated Binary Exponential Backoff (TBEB) algorithm [3], which is similar to that used in the IEEE 802.3 standard. However, previous studies have shown that the time delay of this algorithm increases rapidly while significantly reducing the network throughput under a heavy network work load [4], [5]. It has been shown that this problem can be mitigated to a certain extent by adjusting the length of the back-off window [4], [5].…”

Empirical Evaluation of Upstream Throughput in a DOCSIS Access Network

“…The DOCSIS 1.0 and 1.1 standard [1] was a result of research and development into the performance implications of various QoS mechanisms [2], [3], [4], [5], [6], [7]. Since these were preliminary, prototyping studies, they were conducted using analytical and/or simulation models.…”

Optimized recovery of DOCSIS networks using reserved persistent ranging

“…Issues related to the DOCSIS CATV protocol have been studied over the last few years [4], [5], [6], [11], [14], [15], including service disruption events such as large scale power outages [10], [12], [13]. In case of service disruption the connection between the Head-End (HE) and the subscriber Cable Modem (CM) is terminated.…”