HomeNet Technologies MoCA 1.1 Part I (revised 0817)

MOCA 1.1

MULTIMEDIA OVER COAX

	TECHNOLOGY OVERVIEW The Multimedia Over Coax Alliance (MoCA) provides a standard that satisfies the need for this new IP-enabled coaxial network in the home. According to ABI Research, “In homes receiving cable television, MoCA, one of the most widely supported home media networking technologies, will be supported by some 15 million next-generation set-top boxes by 2014.” Multi-room DVR is first application being deployed but, as consumer demand grows, such services as high-speed data and voice also will be delivered over this next generation “whole home”-enabling technology. BASIC MOCA MoCA provides an IP network over a coaxial in-home plant, and it operates over the hierarchical (branching tree) physical topology of the existing home coaxial cable plant. The maximum cable distance supported between the root and the last outlet is 300 feet, with a maximum attenuation of 25 dB. The MoCA 1.1 standard allows 16 nodes ( e.g., STBs, mDVRs, PCs, etc.) to communicate using the same network with a theoretical maximum physical-layer bit rate of 270 Mb/s. Because the characteristics of the physical paths between various nodes will differ, the MoCA standard specifies a logical, fully meshed, point-to-point network in which each of the nodes establishes a bi-directional connection with all other nodes. Figure 1 illustrates the physical and logical aspects of MoCA networks. The controller node in the network allocates a 50-megahertz channel between 850 MHz-1,525 MHz, in which all other nodes communicate. MoCA operates in a variety of bands that can be used by satellite providers, cablecos and telcos worldwide because it does not interfere with their current frequency plans for traditional broadcast TV service. In addition, multiple MoCA networks can operate on different bands on the same coaxial network

BASIC MOCA con't

ASYMMETRIC DATA RATES BETWEEN NODES

One of the objectives of MoCA is the guarantee of sufficient capacity to support DVR sharing, VoD and other high-bandwidth applications. The capacity of a MoCA network is not uniform throughout due to a variety of conditions. Variations in the MoCA communications path and frequency response of the MoCA channel typically result in data-rate asymmetry, where the capacity between the connected MoCA nodes will differ. The effects of splitter jumping, attenuation and reflections can result in significant differences in the MoCA channel characteristics and in the corresponding MoCA data rates.

INFRASTRUCTURE

Current service MoCa turn-up procedures typically involve rating the cable segments from the demarc to the STBs being installed. Because MoCA supports a full-mesh network between all nodes, procedures must be modified to rate all segments, not just from the initial splitter to outlets but also STB-to-STB segments that may not include the initial splitter.

Procedure changes should include validating throughput between all nodes in the home and not just from the initial splitter to each STB location. When a specific problem is identified, such as excessive attenuation or a coaxial cable fault, sectionalizing the home network to isolate the source can be problematic. Any number of components could be the cause, including bad connectors and splitters, amplifiers, band pass filters, un-terminated cables or excessive noise, distortion or interference that affects the MoCA channel.

MOCA TESTING PART 2>>>