Powerline Networking with the Western Digital Livewire

The main issue with powerline networking is that it is heavily dependent on the usage environment. The other issue with powerline networking products is that most of them are based on the same chipset, and offer similar performance. It is not the case for a consumer that one powerline networking product performs better than the other. Ideally, we would have liked to benchmark the WD Livewire against a product based on a chipset from Gigle Networks. Unfortunately, we are not in possession of a Belkin Gigabit unit. On the other hand, we did manage to lay our hands on a couple of other Atheros/Intellon based powerline adapters. As expected, they gave similar sort of benchmark figures as the WD Livewire.

We decided to do nothing fancy in our benchmarking methodology for the WD Livewire. The kits were connected to the two power outlets to be tested and two notebooks with GbE ports were connected to them to set up a P2P network. Both machines were running Windows 7 and the hard disks had more than enough performance to surpass the 100 Mbps rate at which the interfaces were capped by the powerline kit. It is quite well known that nothing can be as inefficient as the Windows SMB network sharing protocol. We set up 5 files of varying sizes (5 MB, 700 MB, 1.4 GB, 4.37 GB and 16 GB), and transferred them from one computer to the other four times. The average of the time taken to transfer each file was recorded. The experiments were repeated across one outlet in each room of the house, and transfer rates corresponding to the worst performance are reproduced in the table below. The experiments were conducted in two houses, the first of which (Location 1 in the table) was a 23 year old single bedroom apartment of approximately 700 sq. ft. The other house (Location 2 in the table) was a 10 year old five bedroom single family dwelling spread across two floors, with an approximate area of 2800 sq. ft.

Surprisingly, better results were obtained in the bigger house, but this can probably be explained away by the fact that there is probably too much noise in the power lines in an apartment setting. Also, note that the figures quoted above are probably the worst case bandwidth measurements. That said, it is probably what an user would encounter while trying to use the powerline network for file transfers within the home network. As the figures indicate, it is not quite possible to stream Blu-Ray bitrate movies from a PC or NAS to a media streamer with this generation of powerline networking products. Compressed 720p copies work reliably (and this was confirmed to be without issues in both our test locations). Netflix and YouTube streaming, which used to stutter on a Wireless-N network in Location 2, was managed without breaking a sweat, once the WD Livewire units were set up. In this respect, the WD Livewire achieves what it was intended/advertised to do by Western Digital.

Readers contemplating powerline networking must remember that the usage scenario heavily influences perceived performance. There are a number of good resources on the Internet about how to make the best of your powerline network. SmallNetBuilder has one such excellent piece. Also, it must be remembered that capacitive loads close to the routing unit result in reduced performance, while inductive loads improve performance. Also, the topology of the electrical wiring in the house heavily influences effective bandwidth. In places such as the UK, where the electrical wiring has a ring topology, the wires almost act equivalent to running an Ethernet cable around the house. In places such as the US, a ring / mesh topology is often seen. The performance does go down in such cases. Physical separation between the locations of the units often doesn't matter. It is often characteristics such as electrical distance, and whether the units are on opposite sides of a circuit breaker which matter more. All in all, it is best to try out a powerline adapter kit and see whether it fits the intended requirements in one's own place of usage, rather than relying on the advertising.