We are preparing to install Verizon's FIOS. They expect you to have coaxial cable distribution from a central point to each room where TV or Internet service is wanted. The fiber terminates at the ONT (Optical Network Terminal), which rebroadcasts TV content on your coax in the frequency range 55 to 860 MHz. Voice chat is converted to and from analog form. Internet service is handled over MoCA (Multimedia over CoAx Alliance) and is sent on the coax in the 1150 to 1500 MHz band. If the subscriber is not getting TV Verizon are willing to install Cat5 wire from the ONT to a suitable location, but we have the cable and plan to use MoCA even though we are declining TV service.
MoCA channels are centered at multiples of 25 MHz in 800 to 1000 MHz and multiples of 50 MHz in 1150 to 1500 MHz. They are numbered 1 to 29 (not all numbers are used). Nearby channels overlap quite a bit and should not be configured thus. The 800 to 1000 MHz range overlaps higher TV channels and should not be configured if TV is required. There is probably a practical limit of 2 channels in 1150-1500MHz at 250 Mbit/sec, but more can be accomodated at 50 Mbit/sec.
In the standard configuration for FIOS, the ONT bridges one of Verizon's numerous subnets to the router (currently, in California, USA, the Westell 9100EM) on one of the MoCA channels, referred to as the WAN (Wide Area Network) channel. The router acts as a DHCP client on the WAN, a NAT box, and a DHCP server for its LAN. This router simultaneously serves LAN clients via 802.11b/g wireless, 802.3 wired Ethernet at 100MHz, and MoCA on the LAN channel, the one not used by the WAN. It can also do USB networking to one client, which precludes wired Ethernet, according to the documentation.
It is [said to be] possible to place one client in the router's DMZ, which means that the router bridges traffic to it, except for router-specific traffic.
Since we are soon going to be dealing with MoCA, we upgraded our home network to use it. Looking at various options, we decided to get the Netgear MCAB1001 MoCA Coax-Ethernet Adapter Kit (two stations), $180 from Amazon. This is a summary of its technical specifications:
Type F connectors, 75 ohms, includes an internal splitter and RF Out port as well as RF In.
One RJ45 port, IEEE 802.3 100baseT
Can be set to use 800 to 1500 MHz (precluding TV) or 1150 to 1500 MHz (the default). Can be set to fixate on any of the channels in 1..29, or to auto-negotiate with discovered partners (the default).
250 Mbit/sec if attenuation is less than 50 dB; 50 Mbit/sec if less than 75 dB. The Ethernet port is limited to 100 Mbit/sec.
8 for MoCA 1.0; 16 for MoCA 1.1. As with wired Ethernet, stations are not addressable individually; a packet sent by one is received by all the others and the client is responsible to ignore irrelevant packets, e.g. by looking for its MAC address.
DES (optional)
100 to 240 VAC 50/60Hz.
Under 10 W
, measured 6W (each).
The sales package contains two of each of these: channel station, power
converter, Ethernet cable (about 1 meter), co-ax cable (about 1 meter), and
feet so in theory the channel station can stand on its side. Also there is a
printed instruction sheet and a resource CD
. This contains Windows XP
and Vista device drivers, a setup program (Windows only), a PDF of the
instruction sheet, and a page of links to the vendor's website, where you can
find a PDF of the users guide.
As noted in many purchasers' reviews, the instruction sheet is not all that informative. It describes a common user scenario but if you aren't using MoCA to connect an Xbox-360 to a cable modem, you could find the instructions to be confusing. The basic principles are:
The rooms having the equipment that will communicate via MoCA need to be connected to a splitter at the head end (where cable TV coax comes in). This splitter must pass MoCA frequencies. The 900 MHz splitter typically provided by the cable company will not do; a passband up to 2000 MHz is recommended.
The room's coax connector goes to the RF In port of the channel station.
In the common case that there is non-MoCA equipment such as a TV or a cable modem, it attaches to the channel station's RF Out port. It is sub-optimal to put your own splitter upstream of both the channel station and the other equipment -- use the internal splitter. On the other hand, MoCA-capable equipment such as a set-top box for FIOS will need to be connected with the upstream splitter, because the RF Out port does not pass MoCA frequencies.
Use 802.3 wired Ethernet to connect the data equipment (computer, etc.) to the channel station's RJ45 port. In many cases you will want to connect a hub or router so multiple data equipment can share the channel station: desktop computer, game console, video recorder, etc. If you have a cable modem, this is where you connect its data output.
Setup was a piece of cake: connect the cables, turn it on, and it works. My head-end splitter was obsolete, and I purchased (and installed in advance) a Dynex DX-AD114 4-way splitter, $12.99 at Best Buy.
If you need to set configuration options or see statistics (such as channel assignments and data rates), the resource CD has a program that runs only on Windows. The procedure is to connect the channel station directly to one of your computers (not through a router), and press the Configure button on the back of the station. Then run the program. Likely there is actually a webserver on the channel station, but I have not yet tried to make it work on Linux.
Data rate speed test: A directory full of images was packaged in a tar file and was retrieved from the webserver using wget, a command line web client for downloading files. The test file ended up with 7.04e7 bytes. Data rates are reported in bits/sec (multiply bytes/sec by 8). The test procedure was:
tar cf ~jimc/public_html/images04.tar ./images04 #Preparation
time wget -O /dev/null http://jacinth/~jimc/images04.tar #Test on each client
The results:
| Host | Time | Rate | Comments |
|---|---|---|---|
| Secs | Bit/sec | ||
| Jacinth | 1.0 | 5.50e8 | Local disc and webserver |
| Aurora | 6.7 | 8.24e7 | MoCA via 100 Mbit/sec ether |
| Diamond | 6.1 | 8.8e7 | 802.3 wired ether, 100 Mbit/sec |
| Piki | 13.7 | 4.2e7 | Power line networking |
| Xena | 27.2 | 2.19e7 | 802.11g wireless |
These MoCA channel stations are performing as advertised, with the data rate being limited by the 100 Mbit/sec wired Ethernet link.
MoCA is performing well on my network and I seem to have avoided the pitfalls which troubled some purchasers. This success bodes well for FIOS over MoCA when I get it installed. The only negative issue I've found so far is the power of 6 watts per station; I would prefer to use less power for a device that will be on all the time.