In a separate white paper titled Home Networking for Service Providers, we had reached the conclusion that a Broadband IPTV operator will achieve a better margin when using powerline adapters with embedded remote control and configuration due to:
This white paper describes the technical aspects of how the support team will preempt support calls and prevent lost revenue by data mining the powerline link statistics that are gathered from the millions of adapters installed at homes across the country. A side benefit of using smart adapters is that the number of transactions with the hosting server is greatly reduced since the adapter can store the link information across various points during the day then upload all in a single transaction as opposed to multiple transactions at each sampling period. The current failures and potential future failures for all links are all present in the collected data. One can examine the history of each link one at a time to determine the health of that installation. In general, 95% of all links will have the required minimum throughput for a satisfactory operation. It is the remaining 5% that generates the support load and lost revenue. There are multiple known reasons to why the throughput of a link may be lower than the required minimum rate. The stored performance data along with the stored configuration and networked machine types hold all that is required to pinpoint the type of failure and hence the remedy. Before going through the technical analysis of various failure case types one by one, we need to look at the tools and data set we have at hand to detect and analyze these failures.
The physical rate from every node to every other node in the powerline network is stored locally then reported to the hosting server on regular basis. The so called "phy" rate is then used to determine the maximum rate for Ethernet packets over each link in each of the transmit and receive directions. A scan of these rates will immediately isolate the links that can not reliably carry IPTV or allow web browsing and email.  The history of the performance gives the support team the necessary background to resolve all intermittent issues. b- Link Traffic: The traffic is reported in packets per second. The history plot clearly shows whether the link is running near saturation or within acceptable conditions.  c- MAC Address / Device Manufacturer: Each Ethernet port normally has a universal unique MAC address. This universally administered address is uniquely assigned to a device by its manufacturer. The first three octets identify the organization that issued the identifier and are known as the Organizationally Unique Identifier (OUI). The following three are assigned by that organization in nearly any manner they please, subject to the constraint of uniqueness. The following IEEE web page will lookup the company name given the first three octets. Sometimes the resulting company is that of component supplier as opposed to the company shipping the final product. http://standards.ieee.org/regauth/oui/index.shtml For example, a device with a MAC address of 0024E70015D9 has an OUI of 0024E7 A lookup in the OUI database for 0024E7 yields: Plaster Networks. This device was then built by the company Plaster Networks. In this case a smart powerline network adapter. The hosting server stores the MAC addresses of all boxes seen by the adapter. A simple lookup yields the box manufacturer. The reason why this data is important is that there are some units from certain companies that have very low cost electrically noisy power supplies. A support person can then pin point the exact source of the noise impacting the throughput just by knowing the MAC address.
What follows is an analysis of a list of known failure cases with the explanation of the failure, its signature and the proposed resolution. Real network statistics are used in each case. 1- Low throughput in one direction only
The throughput in one direction is half that in the other direction. Probable Cause: Noise from an electrical appliance plugged in an adjacent socket at the receiving end. It is known in the industry that the power supplies of many electronic equipment are of very poor quality since they contain the minimum possible of components to control the cost to a maximum. When such a power adapter is plugged into a power strip or in an adjacent socket then electric noise will interfere within the immediate zone which will then reduce the quality of the signal at the powerline receiver. Hence the reduced throughput. Potential Fix: IX2 Isolator Noise on the receiving end results in a low throughput for the link. (For more information, please see the white paper titled Powerline Network Isolators.) If the noisy appliance is plugged into the IX2 isolator then the noise will be removed from the power line and the performance will go back to its normal level. 2- Low throughput in both directions
Probable Cause: Noise from an electrical appliance plugged in an adjacent socket OR attenuation OR both The impact of noise was discussed in the case above. The electric wiring inside the home may sometimes cause a strong attenuation of the powerline signal. The two conditions are sometimes present at the same time. Potential Fix: Isolator or firmware upgrade In certain cases where a powerline adapter may be running an earlier version of the HomePlug firmware, a remote firmware upgrade will fix the attenuation issue by increasing the transmit level. If that change alone does not fix the low throughput then an isolator is required at each end to get the performance back to its normal level. Below is the graph of a real network where the noise was causing low throughput in both directions. Once an isolator was installed at both ends, the throughput reached its normal expected level.  3- Throughput stuck at 4Mbps Probable Cause: Firmware bug Earlier versions of the HomePlug firmware contain a known bug which infrequently may cause the adapter to fall back into safe mode where the throughput is capped at 4Mbps. Potential Fix: Firmware upgrade A remote firmware upgrade with the latest version will fix the issue. 4- Occasional drop in throughput in either direction (or windows of low throughput) Probable Cause: Noise from an electrical appliance plugged in an adjacent socket that is turned on intermittently. Without the hosting server and the performance history, this would be the most difficult problem for the support team to handle. The issue is reported usually as a random event. Sometimes the setup works, sometimes it does not. The end user does not correlate the event of turning on an electric appliance to the change in the throughput. Given a graphical view of the history of the link, the problem becomes immediately obvious to the support team. Potential Fix: Isolator Use an isolator at the source of the noise. When an operator has a few million IPTV users then 1% or 5% of bad links will result in a huge amount of support calls from unsatisfied customers. These calls can be prevented since the technology exists today to detect and resolve a majority of the issues by remote. The key is to simply use smart powerline adapters and a hosting server. About Plaster Networks Plaster Networks was founded by Paul Baran, a Silicon Valley entrepreneur widely known as the inventor of packet switching, the foundation technology for the Internet. For more information, visit www.plasternetworks.com. Plaster Networks, LLC Copyright © 2010 Plaster Networks, LLC. All rights reserved. Plaster Networks is a trademark of Plaster Networks, LLC. |
|
|
Technical Analysis of Powerline Networks |