MoCA effectively operates at half-duplex internally? Performance using 3+ devices?

[WhiteZero]

I'm preparing to buy a new house and planning out my network. It was built in 2003 and has coax outlets in just about every room, so I'm thinking MoCA will be a good solution for me, at least until I can evaluate the possibility of running CAT6 everywhere.

I've been spending the past week researching MoCA and have found woefully limited technical documentation on how it really works. What I'm wanting to find out at this point, is how bandwidth might degrade once you start adding more than 2 MoCA nodes to the network.

For instance, if I use all MoCA 2.5 equipment, that means I have 2.5Gbits available within the MoCA network itself. Now does that mean that bandwidth is available on demand to all nodes, or is it always divided by the number of nodes? I would guess the former, but I want to make sure I'm not missing any "gotchas" here with MoCA.

I've been reading that MoCA itself, much like Wifi, can only really operate at half-duplex (can only send or recieve, not both at the same time). So if I only had one client wanting to transfer at 1Gbps up and down simultaneously, that should be fine because the MoCA backbone effectively can do that at 1.25Gbps?

 

[degrub]

Somewhere here, i think in the GoCoax thread, they stated that their modems operate in half duplex, thus they can provide full Gbit each way.

the moca nodes contend for time on the common coax. Most use cases this will not make a difference, just like for ethernet. If you need guaranteed bandwidth , you should do the moca nodes in pairs on a straight run of coax and connect them all at a central point with a Gbit switch in a physical star layout.

 

[krkaufman]

For instance, if I use all MoCA 2.5 equipment, that means I have 2.5Gbits available within the MoCA network itself. Now does that mean that bandwidth is available on demand to all nodes, or is it always divided by the number of nodes? I would guess the former, but I want to make sure I'm not missing any "gotchas" here with MoCA.

I've been reading that MoCA itself, much like Wifi, can only really operate at half-duplex (can only send or recieve, not both at the same time). So if I only had one client wanting to transfer at 1Gbps up and down simultaneously, that should be fine because the MoCA backbone effectively can do that at 1.25Gbps?

Mostly correct, except the 2500 Mbps (2.5 Gbps) shared bandwidth applies to the special case of just 2 MoCA nodes (TURBO mode, effected by allowing elimination of some overhead). Once you increment to a 3+ node MoCA setup, the 25% TURBO efficiency bonus is eliminated and the effective throughput shared is 2000 Mbps ... still approximating full-duplex GigE. (Basically, throughput is 400 Mbps per channel for MoCA 2.0/2.5, with total throughput then dependent on the number of channels bonded -- 1x for standard MoCA 2.0, 2x for bonded MoCA 2.0, and up to 5x for MoCA 2.5 -- and whether the 25% TURBO mode bump is applicable.)

 

[WhiteZero]

Very informative answers, thanks everyone! I'm really wishing MoCA 3.0 was finally out by now, but it seems to have hit delays. But I think a MoCA 2.5 setup will work well for me, at least to maybe get Wifi Access Points on all 3 floors of my house if thats what I need.

 

[degrub]

i have 4 cisco 371s running off of point to point moca2 bonded runs. 200-500 Mbits/s with no issues. Works as a poor mans QOS without burdening the router.