5 ms·

Why is MoCA still so rare and expensive? Is there a technical reason or is it just some combination of business reasons? It seems like it's been the obvious c

by wolrah 7y ago

Why is MoCA still so rare and expensive? Is there a technical reason or is it just some combination of business reasons? It seems like it's been the obvious choice for no-new-wires home networking for years but you basically can't find it at retail and have to look for it even online.

variaga 7y ago
<normal disclaimer about this just being my opinion> I think there were a couple of contributing factors: - WiFi is still easier to install (where you can get a good signal), and built into phones/laptops/etc. so mostly all you have to do to get wireless networking is buy the router. For MoCA, you have to buy & install a box for every endpoint. Also, MoCA is limited to places you have coax, which is usually bedrooms & living rooms. If you need connectivity in the garage/attic/closet/kitchen, MoCA might require new wires anyway. - Lack of interest from MoCA developers. The main "customer" for MoCA chips was cable set-top-box vendors (Scientific Atlanta, etc.) for "multi-room PVR" products. That's where almost all MoCA networking chips made ended up. The cable/satellite vendors needed the deterministic performance of MoCA (vs WiFi) and they were always planning on putting a box in every room with a TV - which generally already aligns with where the cable taps are. They could also pre-configure the MoCA so it wouldn't interfere with some other stuff they might want to put on the cable (Example: DirecTV put its downlink from the dish squarely in the middle of the MoCA frequency band, so you had to configure MoCA to a different channel in DirecTV houses than e.g. Verizon). The market for bare Ethernet-Coax Bridges (ECB) was always tiny in comparison. - The chicken and egg problem. The consumer market for bare Ethernet-Coax gateways was smaller (see above) as it has to compete with both WiFi and "just run some new CAT-5" (as well as niche things like HPNA/G.hn) so it didn't get a lot of focus or advertising. In turn, this means most people have no idea that MoCA even exists, so they don't go looking for it. D.Link, Netgear, Linksys, etc. then decided that lack of demand meant it's not worth developing/advertising new/improved versions of the products, etc. MoCA was a very targeted solution for adding IP connectivity to things which were already wired together on a Coax network, and it did a great job at that. We sold 100s of millions of chips. MoCA was never meant to be all things to all people though, and while I personally use MoCA in my home I never got my own parents to use it - they just have the one computer hooked directly to their router, and WiFi for their iPad.
Unklejoe 7y ago
For what it’s worth, you can buy the DirecTV DECA adapters for like $20 on Amazon. They’re actually just MoCA adapters, but they run at a lower frequency than regular MoCA so they don’t interfere with the DirecTV signal. They work fine by themselves. The only downside is that they’re 100 Mbit/s. That said, they really do give you a rock solid 100 Mbit/s. If you need more bandwidth, I think Verizon sells a MoCA 2.5 adapter for like $60 which should give you GigE.
- rubatuga 7y ago
  They're actually ~91Mbit/s, but yes, very, very stable. They also seem to add about 4ms of latency.
  - variaga 7y ago
    The 4ms of latency is a product of the MOCA protocol. As a fully scheduled network, each packet must wait for a timeslot to send a reservation packet, wait for the schedule to be updated (map packet), and then wait for the actual scheduled time. The reservation timeslots and mail packets are on a fixed schedule (approximately- there are cases where the timing changes if you have a poor link) with a consequence of an unloaded MOCA network having a transit time of ~2ms going from the master node, or ~2.5ms going anywhere else (master node transmit is faster since it gets to skip the reservation step. Times are averages, as the exact time depends on the alignment of the time of arrival to the scheduling period). Round- trip ping times should go up by roughly 4.5ms. Under ideal conditions, it is possible to get 100Mbps UDP throughput on a pair of MoCA nodes (1518 byte packets). The physical media can support up to 110Mbps (MOCA 1.0), 140Mbps (MOCA 1.1) or 450Mbps (MOCA 2.0) user throughput per channel (up to 5 channels in MOCA 2.5), but that's shared bandwidth (all traffic summed together). Throughout will fall off in bad channels (minimum 40Mbps), or if you use smaller packets (higher scheduling requirements per packet) so YMMV

by wolrah 7y ago

variaga 7y ago

<normal disclaimer about this just being my opinion> I think there were a couple of contributing factors: - WiFi is still easier to install (where you can get a good signal), and built into phones/laptops/etc. so mostly all you have to do to get wireless networking is buy the router. For MoCA, you have to buy & install a box for every endpoint. Also, MoCA is limited to places you have coax, which is usually bedrooms & living rooms. If you need connectivity in the garage/attic/closet/kitchen, MoCA might require new wires anyway. - Lack of interest from MoCA developers. The main "customer" for MoCA chips was cable set-top-box vendors (Scientific Atlanta, etc.) for "multi-room PVR" products. That's where almost all MoCA networking chips made ended up. The cable/satellite vendors needed the deterministic performance of MoCA (vs WiFi) and they were always planning on putting a box in every room with a TV - which generally already aligns with where the cable taps are. They could also pre-configure the MoCA so it wouldn't interfere with some other stuff they might want to put on the cable (Example: DirecTV put its downlink from the dish squarely in the middle of the MoCA frequency band, so you had to configure MoCA to a different channel in DirecTV houses than e.g. Verizon). The market for bare Ethernet-Coax Bridges (ECB) was always tiny in comparison. - The chicken and egg problem. The consumer market for bare Ethernet-Coax gateways was smaller (see above) as it has to compete with both WiFi and "just run some new CAT-5" (as well as niche things like HPNA/G.hn) so it didn't get a lot of focus or advertising. In turn, this means most people have no idea that MoCA even exists, so they don't go looking for it. D.Link, Netgear, Linksys, etc. then decided that lack of demand meant it's not worth developing/advertising new/improved versions of the products, etc. MoCA was a very targeted solution for adding IP connectivity to things which were already wired together on a Coax network, and it did a great job at that. We sold 100s of millions of chips. MoCA was never meant to be all things to all people though, and while I personally use MoCA in my home I never got my own parents to use it - they just have the one computer hooked directly to their router, and WiFi for their iPad.

Unklejoe 7y ago

For what it’s worth, you can buy the DirecTV DECA adapters for like $20 on Amazon. They’re actually just MoCA adapters, but they run at a lower frequency than regular MoCA so they don’t interfere with the DirecTV signal. They work fine by themselves. The only downside is that they’re 100 Mbit/s. That said, they really do give you a rock solid 100 Mbit/s. If you need more bandwidth, I think Verizon sells a MoCA 2.5 adapter for like $60 which should give you GigE.

rubatuga 7y ago
They're actually ~91Mbit/s, but yes, very, very stable. They also seem to add about 4ms of latency.
- variaga 7y ago
  The 4ms of latency is a product of the MOCA protocol. As a fully scheduled network, each packet must wait for a timeslot to send a reservation packet, wait for the schedule to be updated (map packet), and then wait for the actual scheduled time. The reservation timeslots and mail packets are on a fixed schedule (approximately- there are cases where the timing changes if you have a poor link) with a consequence of an unloaded MOCA network having a transit time of ~2ms going from the master node, or ~2.5ms going anywhere else (master node transmit is faster since it gets to skip the reservation step. Times are averages, as the exact time depends on the alignment of the time of arrival to the scheduling period). Round- trip ping times should go up by roughly 4.5ms. Under ideal conditions, it is possible to get 100Mbps UDP throughput on a pair of MoCA nodes (1518 byte packets). The physical media can support up to 110Mbps (MOCA 1.0), 140Mbps (MOCA 1.1) or 450Mbps (MOCA 2.0) user throughput per channel (up to 5 channels in MOCA 2.5), but that's shared bandwidth (all traffic summed together). Throughout will fall off in bad channels (minimum 40Mbps), or if you use smaller packets (higher scheduling requirements per packet) so YMMV