# HR-24 Question



## HammerHead001 (Mar 14, 2010)

I saw a post on SatGuys re: the new HR24 and was curious if anyone could help me with a few questions?? 

I wold post the thread link but as new member to this forum, it isnt allowed. I was posted on 3/12



OK.. So with DECA, I understand I dont need my ethernet connection for DVR sharing. But, what about On Demand - won't that connection still be needed?

Also, can I use my Cat6 gigabit network if I want and disable the DECA functionality if I find my network set up is faster?

When can we get these new boxes? I am an existing customer that is bound by contract until October. Honestly, some new HD channels and these new boxes might just be enough to get me to "re-up" - provided they get the VS mess sorted!

Thanks!


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## say-what (Dec 14, 2006)

1) If you want the H/HR24 to communicate with other devices on your home network, including existing HR2x's, or access the internet for On Demand, you would use a DECA adapter w/ a power inserter that would act as a bridge with your home network and insert the network traffic into the coax.

2) The H/HR24 will work on a traditional ethernet network and when the ethernet connection is used, the DECA functionality is disabled

3) There is no word on availability or pricing yet on the H/HR24


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## Stuart Sweet (Jun 19, 2006)

HammerHead001 said:


> OK.. So with DECA, I understand I dont need my ethernet connection for DVR sharing. But, what about On Demand - won't that connection still be needed?


You're correct that the DECA cloud will still need a connection to the internet for On Demand and TV Apps. Click here to read all about DECA and how it connects.



> Also, can I use my Cat6 gigabit network if I want and disable the DECA functionality if I find my network set up is faster?


It's not clear whether or not DIRECTV will allow multi-room viewing over an ethernet connection. That being said, the DECA testers reported that DECA was as fast or faster than any ethernet connection, so you are not missing anything there.



> When can we get these new boxes? I am an existing customer that is bound by contract until October. Honestly, some new HD channels and these new boxes might just be enough to get me to "re-up" - provided they get the VS mess sorted!


Ah, that is the big question isn't it. It's very hard to say what the schedule is there... and even if they are available at Costco, Best Buy or other stores, it may be a while until they're commonly seen on DIRECTV trucks.


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## carl6 (Nov 16, 2005)

There is a lot of information posted here about DECA. A receiver or DVR that has a DECA connection will get all of the ethernet traffic over the DECA. You do not need a separate ethernet connection to that unit for On Demand.

Somewhere in the DECA cloud, you will need a bridge to your ethernet LAN in order for DECA connected units to have external communication.

I believe the HR24 can run with regular ethernet (non-DECA), but DECA puts all the MRV traffic inside the DECA cloud and will absolutely be as good as, or better than, a separate ethernet network.


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## Barry in Conyers (Jan 14, 2008)

I don't recall seeing anything suggesting that DECA is faster than Fast Ethernet (100 Mbps). Unless DirecTV cripples Ethernet, why would DECA have any performance advantage?

I understand the installation advantage, but that is a separate issue.


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## The Merg (Jun 24, 2007)

Barry in Conyers said:


> I don't recall seeing anything suggesting that DECA is faster than Fast Ethernet (100 Mbps). Unless DirecTV cripples Ethernet, why would DECA have any performance advantage?
> 
> I understand the installation advantage, but that is a separate issue.


When using MRV over your LAN, you are then dealing with your router which has to prioritize requests among all of the devices that is connected to it. If you are using DECA, there is no intermediary really. Requests go directly from one box to the other. It's almost as if the boxes are directly connected to each other.

The best analogy in regards to a regular LAN, would be if you happened to have all your receivers hardwired to a switch which was then connected to your router. But even in that case, some traffic still goes back to the router and is not contained exclusively on the switch.

- Merg


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## DogLover (Mar 19, 2007)

Barry in Conyers said:


> I don't recall seeing anything suggesting that DECA is faster than Fast Ethernet (100 Mbps). Unless DirecTV cripples Ethernet, why would DECA have any performance advantage?
> 
> I understand the installation advantage, but that is a separate issue.


I think the advantage is that no other ethernet traffic (from PC's, game systems, VOIP, etc.) would be on the DECA cloud. Therefore, there would be no slow downs in either MRV or the other non-DirecTV network applications from other network traffic. While many installations may not face this problem, DECA eliminates it.


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## Barry in Conyers (Jan 14, 2008)

The statement I responded to was ".....and will absolutely be as good as, or better than, a separate ethernet ". Notice the word "separate". There was no mention of using a network that was loaded with non-MRV traffic.

As far as network congestion is concerned, an inexpensive switch can effectively isolate the MRV traffic from everything else.

IMO, this is a phantom issue.


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## Stuart Sweet (Jun 19, 2006)

To clarify, I did not mean to intimate that DECA is capable of transfer speeds greater than gigabit ethernet. Although, it very well may be, technically. There's a lot of bandwidth available. What I am saying is, that due to the way the DECA cloud is set up, and its being optimized for streaming video (unlike traditional ethernet, which is not) that it should perform as well or better than a wired network when streaming video between receivers. 

We can all agree that even an 802.11g wireless connection "should" be able to stream a 10Mbit/second HD program, as it is nominally performing at 54Mbit/sec. Certainly a wired 100BaseT connection with a nominal perfomance of 100Mbit/sec should have no problem. 

However, the MRV stream needs to be fairly smooth, where a lot of ethernet transfers vary greatly in speed. In the case of wireless, this is due to latency and lost packets, for example, but even in the case of wired networks, inexpensive routers (with inexpensive switches built-in) can contribute to inconsistent speeds. Most routers and switches are simply not optimized for video. 

I'm not going to argue with anyone who has spent thousands of dollars building an enterprise-level network in his home. I will say that you should expect that if you are satisfied with the performance of MRV over your home network, you should expect to be equally satisfied with DECA. If you are less than satisfied, you should expect to be more satisfied. 

With due respect to my colleague from Conyers, I've seen the difference between a cobbled-together network with inexpensive components and a DECA cloud and the DECA cloud is much better. Not only that, the use of DECA technology allows for easier and cleaner installs, with a single coax performing multiple functions on an HR24 receiver.


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## HammerHead001 (Mar 14, 2010)

I guess another question needs to be addressed as well - Are the HR22's and the HR24's equipped with a gigabit nic internally or only the 10/100?

Depending on the answer will determine if I pursue the DECA option.

My network will be gigabit switch & each receiver will have dedicated cat6 run to that switch. 90 % of my current LAN traffic is DTV stuff.

Thanks for all of the input!


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## DogLover (Mar 19, 2007)

Barry in Conyers said:


> The statement I responded to was ".....and will absolutely be as good as, or better than, a separate ethernet ". Notice the word "separate". There was no mention of using a network that was loaded with non-MRV traffic.
> 
> As far as network congestion is concerned, an inexpensive switch can effectively isolate the MRV traffic from everything else.
> 
> IMO, this is a phantom issue.


When you used "separate", I took it to mean "separate from the coax", not "separate from the rest of ethernet network". So yes, if you separate your DVR's onto their own switch that would isolate non-MRV traffic as well.

However, that may not be possible in all configurations. We have a DVR's downstairs and upstairs. We also have an office that needs networking. The router is in a central location with the cable modem and wireless access point. Cat5 cable goes to the various areas of the house, where a switch then connects to the various pieces of equipment in that room. The DVRs could not be on the same switch in this configuration, as well as the fact that there is additional equipment (non-DVRs) on each switch with the DVRs.

DECA can effectively isolate all the DVRs to their own little grouping, that doesn't need to interact with any other traffic for MRV.

DECA may not be the only solution, but it does seem like a very good solution for many (most) customers.


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## say-what (Dec 14, 2006)

HammerHead001 said:


> I guess another question needs to be addressed as well - Are the HR22's and the HR24's equipped with a gigabit nic internally or only the 10/100?
> 
> Depending on the answer will determine if I pursue the DECA option.
> 
> ...


The ethernet ports on all HR2x's are 10/100.

The actual DECA adapter is a 10/100 connection

I don't know what the actual capacity of DECA over coax is other than it delivers results on par with existing hardwired ethernet connections.


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## Stuart Sweet (Jun 19, 2006)

HammerHead001 said:


> I guess another question needs to be addressed as well - Are the HR22's and the HR24's equipped with a gigabit nic internally or only the 10/100?
> 
> Depending on the answer will determine if I pursue the DECA option.
> 
> ...


It's all 10/100 but really that's all you need for a video stream.


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## veryoldschool (Dec 10, 2006)

say-what said:


> I don't know what the actual capacity of DECA over coax is other than it delievers results on par with existing hardwaired ethernet conenctions.


It's somewhere between 2 & 3 times what the DECA input is.


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## BudShark (Aug 11, 2003)

Speed kills  It also is a very bad indicator of "network" performance.

Ethernet is a mutli-purpose data movement network specification. It has layered on top of it things for Quality of Service, etc - but its multi-purpose.

MoCA (which DECA is based off of) was designed specifically to move video packets around a closed loop. It includes packet scheduling, low latency, low error rate as part of its core.

In theory, a 50Mb MoCA/DECA network would move video equally or better than a 100Mb ethernet network.

Ethernet is NOT the holy grail for moving video around the home. It is familiar, it is common, but it is NOT going to be the best solution for a closed system box to box stream. If they want to copy video files around, download files, etc... different story. But for pure MRV implementation, MoCA/DECA has benefits far beyond the installation side of the equation.


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## HammerHead001 (Mar 14, 2010)

Thanks BudShark! Great answer to what I didn't know and needed to!


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## Barry in Conyers (Jan 14, 2008)

Sorry I asked a legitimate question!

*FOR THE RECORD: DECA is undoubtedly the best thing since sliced bread and it is far better than a "cobbled together network with inexpensive components" with poor topology and overloaded with non-MRV traffic.*

All those conditions have nothing to do with what Carl6 stated or my question / response, but maybe a mea culpa will make some people happy.

Thanks to those who responded appropriately to what was intended as a straightforward question about performance.


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## carl6 (Nov 16, 2005)

Barry,
No need for any apologies. We are dealing with new technologies here. DECA that only a very few have had an opportunity to use, and MRV which a few more have had a chance to use. I'm not sure anyone is saying DECA is the holy grail, but it was designed and engineered for the specific task of moving MRV so we would expect it to perform as well as, if not better than, a regular ethernet LAN.

Those of us who have had a chance to use DECA (myself included) have found it to serve the purpose excellently. We have compared it to both wired and wireless LANs of varying quality, and in every instance DECA has proven to be as good as, if not better than, the LAN it was compared with.

That certainly does not mean that you can't have a quality home network that will fully support MRV. You can. But the average customer won't have that and in those cases DECA is the right solution.

The fact remains that we can discuss this and have varying opinions and positions.


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## LameLefty (Sep 29, 2006)

From a practical standpoint, I can have 3 HD streams going through a single DECA connection to my router the way my network is setup currently. I have a small DECA "cloud" consisting of an H24-100 and an HR24-500; this cloud is bridged to my ethernet and wireless LAN by a DECA module. I have served up one HD stream from the HR24 to other boxes in the house which are hardwired to my router. Simultaneously, I have had two streams flowing into the cloud from other boxes (one each to the H24 and HR24). Playback of all three was flawless. Others with more DECA equipment have run even more streams into, out of, and through their clouds with identical performance.


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## Barry in Conyers (Jan 14, 2008)

Carl,

I appreciate your polite response.

I think the word better is being misused; a network either works properly for the application or it does not. If both ethernet and DECA work for MRV, then how can one be called "better" than the other?

I don't doubt that DECA works very well and I certainly agree that DECA will probably be "easier" for most users and all installers, but my original question was specifically about performance. "DECA works" is not better performance than "ethernet works".

Of course, all this discussion is a moot point if DirecTV decides to kill ethernet functionality and I have not seen an authoritative response to that question.


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## Doug Brott (Jul 12, 2006)

Let's just say that DECA is the preferred method of connectivity for MRV. Beyond that I wouldn't worry too much.


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## carl6 (Nov 16, 2005)

Barry in Conyers said:


> Carl,
> 
> I think the word better is being misused; a network either works properly for the application or it does not. If both ethernet and DECA work for MRV, then how can one be called "better" than the other?


Note the comments from Stuart Sweet and BudShark regarding how networks work with regard to video. There are a lot of variables involved, but moving HD video in real time is not the same as sending data. A lost or corrupted packet that is re-sent or recovered via CRC works just fine for data but not for MRV. Latency and jitter are huge factors with regard to video (and are potentially significant factors in almost any wireless implementation).

DECA, being designed specifically for the purpose, is less/not susceptible to the same variables that can cause issues on a regular lan.

In a black and white world with no shades of grey, if I had to choose "works" or "doesn't work" with regard to MRV via LAN (even a very good wired LAN), I would have to pick "doesn't" because there are those occasional glitches that you don't see when you are doing it via DECA. They may be infrequent, and they may not be of concern to you personally, but they are there. In the real world of color and shades of grey, DECA is "better" because it overcomes some of the issues that can manifest themselves with a LAN based MRV system.

My comments and observations are based on my personal experience, using MRV on both LAN and DECA based systems between various H2x/HR2x products. My LAN is completely wired (10/100) with physical separation between units varying from inches to roughly 100 feet (of wire).

In summary, in my opinion, based on my observations, DECA is better than a wired LAN for the purpose of supporting MRV. That does not mean that a wired LAN won't work for you, or for many others. It works for me. But DECA works even better (i.e., I see fewer of the infrequent or occasional glitches).


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## ABQNM (Dec 14, 2006)

Just an FYI... I saw you stating the VS mess... As of 7 pm EST tonight, Versus is back on Directv Channel 603.


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## harsh (Jun 15, 2003)

Stuart Sweet said:


> It's not clear whether or not DIRECTV will allow multi-room viewing over an ethernet connection.


At the same time, it isn't clear how they could disable it nor why they would want to.


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## Doug Brott (Jul 12, 2006)

harsh said:


> At the same time, it isn't clear how they could disable it nor why they would want to.


I still wouldn't worry too much .. and as for how .. uh, they wouldn't let you sign up for MRV if you don't have DECA .. that part is easy, but like I said - it's nothing to worry about now.


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## kokishin (Sep 30, 2006)

If you have your DVR's connected to the same wired LAN switch, I don't believe the router has much to do to support MRV.



The Merg said:


> When using MRV over your LAN, you are then dealing with your router which has to prioritize requests among all of the devices that is connected to it. If you are using DECA, there is no intermediary really. Requests go directly from one box to the other. It's almost as if the boxes are directly connected to each other.
> 
> The best analogy in regards to a regular LAN, would be if you happened to have all your receivers hardwired to a switch which was then connected to your router. But even in that case, some traffic still goes back to the router and is not contained exclusively on the switch.
> 
> - Merg


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## The Merg (Jun 24, 2007)

kokishin said:


> If you have your DVR's connected to the same wired LAN switch, I don't believe the router has much to do to support MRV.


Correct. It doesn't, however, traffic is still sent to and from the switch to the router. Even when you isolate devices on a switch, they are not completely isolated. Within the DECA cloud, the devices do not have to compete with any other traffic on the network and are completely isolated from all other network traffic.

- Merg


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## BattleScott (Aug 29, 2006)

The Merg said:


> Correct. It doesn't, however, traffic is still sent to and from the switch to the router. Even when you isolate devices on a switch, they are not completely isolated. Within the DECA cloud, the devices do not have to compete with any other traffic on the network and are completely isolated from all other network traffic.
> 
> - Merg


But apples to apples, if the switch was not connected to a router, then you have an isolated "ethernet cloud". The reason to connect the MRV switch to a router is to introduce the broadband connectivity to the cloud. 
Once a DECA cloud is bridged to provide the same connectivity, wouldn't those devices would also be exposed to external traffic?


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## Doug Brott (Jul 12, 2006)

BattleScott said:


> Once a DECA cloud is bridged to provide the same connectivity, wouldn't those devices would also be exposed to external traffic?


No .. Well, unless you are in a situation like myself where I do in fact have one device via Ethernet ant the remaining devices on DECA. In my case it will traverse the broadband DECA to reach the rogue receiver.

Either way you look at it, DECA is the preferred path.


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## WestDC (Feb 9, 2008)

BattleScott said:


> But apples to apples, if the switch was not connected to a router, then you have an isolated "ethernet cloud". The reason to connect the MRV switch to a router is to introduce the broadband connectivity to the cloud.
> Once a DECA cloud is bridged to provide the same connectivity, wouldn't those devices would also be exposed to external traffic?


YES, the main reason for DECA is the Installer pool , inorder for D* to support this it was by far eaiser to roll out a RG6 product than try to train a already under paid group of tech's to also try and support any combination of a customers home pc network (paid at the lowest rate), of which most homes do not have to begin with.

The tech's always have been hard pressed to connect phone lines to the receivers-because they do not get paid extra to be the phone company. They will still have to run a RG6 near a Customers router when the DECA rolls out- and that may or may not happen (getting the extra RG6 to that location) just like the phone connection went. That would have to be handled as custom work (adding a outlet) and we all know that most installs are free installation and when you try to sell the customer on paying extra, the customer screams it was supposed to free install, and I'm not paying for that.

There in lies the trouble getting everone else connected that doesn't visit this site or know how to do it yourself.


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## HDinVT (Dec 14, 2006)

Doug Brott said:


> No .. Well, unless you are in a situation like myself where I do in fact have one device via Ethernet ant the remaining devices on DECA. In my case it will traverse the broadband DECA to reach the rogue receiver.
> 
> Either way you look at it, DECA is the preferred path.


Doug, I think what BattleScott was asking once the DECA network is given a path to the internet and maybe the PC LAN, wouldn't that traffic(TVapps, VOD, MediaShare,etc..) interfere with the MRV traffic ?


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## BudShark (Aug 11, 2003)

BattleScott said:


> But apples to apples, if the switch was not connected to a router, then you have an isolated "ethernet cloud". The reason to connect the MRV switch to a router is to introduce the broadband connectivity to the cloud.
> Once a DECA cloud is bridged to provide the same connectivity, wouldn't those devices would also be exposed to external traffic?


Short answer would be yes.

Thats why, IMO, its a mistake to say DECA is better because its an isolated cloud. I can create an isolated cloud in ethernet (which I think is some of the point you guys are making).

The problem is, ethernet is still a contention based packet movement, whereas DECA is a scheduled based packet movement. With ethernet, the more devices I add, the more streams I add to a server, the more video I want to move, the more "hiccups" if you will, I will see. Each device will simply start talking - if it talks at the same time as something else, it has to backoff, and try to talk again. The faster the network, the more chance I have to talk, but I am still "contending" for that time. If I drop a packet, or have pixelation - it makes the scenario worse for everyone.

With DECA, its scheduled. I get a window for my packet. I know its mine, and no one else is talking. And the server is able to equally divide up the time for its streams. So, lets say I have a hiccup - there is no backoff, there is no waiting, the server simply sends the packet at the next scheduled window (which is roughly a millisecond). With this scheduling component, your recovery from glitches becomes nearly imperceptible (an audio blip versus a pixelized screen) and no other streams are affected.

In my personal opinion - and I have no basis other than theory for this - I think when we see the Whole House solution with multiple MRV streams from a single server - Ethernet WILL become non-functioning and a DECA/MoCA solution will be the only stable method to support the multistreams. Again just my opinion - we shall see when multi-streams become a reality. I also think this is the reason for the "change" - about the time DirecTV got MRV working pretty well under ethernet, they began testing the multi-streams and just flat out found it was too susceptible to breakups that would affect all devices whenever one had a problem.


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## veryoldschool (Dec 10, 2006)

Guess I'll put my two cents in.
I have a DECA cloud. It works great, but then it also works just as well as my hardwired LAN did before.
Now just because my LAN worked well, doesn't mean everyone else has their LAN setup the same way. I'd imagine there are many that were simply cobbled together as the needs came along.
I'd say the DECA cloud could be seen as a star topography, with the switched centralized and single runs to each device [one being the run to the router] in a 100 Mb/s network. This may be over simplified, but it was how my LAN was setup.
I read how some are daisy-chaining off the second ports on the DVRs, have wireless links, etc. DECA will simply force the network to be laid out well/correctly, from the start AND be a technology that DirecTV can support/understand.


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## BudShark (Aug 11, 2003)

WestDC said:


> YES, the main reason for DECA is the Installer pool , inorder for D* to support this it was by far eaiser to roll out a RG6 product than try to train a already under paid group of tech's to also try and support any combination of a customers home pc network (paid at the lowest rate), of which most homes do not have to begin with.
> 
> The tech's always have been hard pressed to connect phone lines to the receivers-because they do not get paid extra to be the phone company. They will still have to run a RG6 near a Customers router when the DECA rolls out- and that may or may not happen (getting the extra RG6 to that location) just like the phone connection went. That would have to be handled as custom work (adding a outlet) and we all know that most installs are free installation and when you try to sell the customer on paying extra, the customer screams it was supposed to free install, and I'm not paying for that.
> 
> There in lies the trouble getting everone else connected that doesn't visit this site or know how to do it yourself.


I think installation is a "reason" (none of us know for sure), but everyone is downplaying the fact one of these technologies was designed to stream video and the other not.

DECA is NOT ethernet over coax. It is a different physical layer that was designed for streaming video. Period. Think token ring vs. ethernet. That is a more valid comparison of DECA/MoCA vs. ethernet.

It took me a bit to get my head around it, but as I did a little more testing and research and added in the multi-stream aspects of the Whole House DVR - I think a lot of those with working Ethernet systems will not be quite as happy down the road.

There are a LOT of factors - none are solely responsible for why Doug/Stuart are correctly stating "DECA is the preferred manner" - but at the end of the day, and even more tomorrow - DECA is the preferred method of connecting for MRV.


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## BudShark (Aug 11, 2003)

HDinVT said:


> Doug, I think what BattleScott was asking once the DECA network is given a path to the internet and maybe the PC LAN, wouldn't that traffic(TVapps, VOD, MediaShare,etc..) *interfere with the MRV traffic* ?


Difficult question to answer.

In short, on a switched ethernet (Switch based not hub based, but if you have a Linksys/D-Link/2-Wire/etc router its switched) - the answer is the traffic didn't interfere. Traffic destined for the internet from HR20#1 did not interrupt a stream between your HR20#2 and your H21. That is the purpose of a switched network - traffic destined for a device only goes to that device.

But, you are correct - all things being equal, traffic that in the past went on the same network wire as your MRV stream, would still go down your DECA connection.

The difference *is* on ethernet, that traffic would cause collisions, backoffs, delays, etc on your ethernet stream. Mostly imperciptible, but the design of ethernet was that traffic would "force" its way onto the wire. That same traffic, once it hits the DECA cloud would be held, scheduled, and then transmitted. There would not be the level of interference.


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## Steve (Aug 22, 2006)

BudShark said:


> [...] The problem is, *ethernet is still a contention based packet movement, whereas DECA is a scheduled based packet movement.* With ethernet, the more devices I add, the more streams I add to a server, the more video I want to move, the more "hiccups" if you will, I will see. Each device will simply start talking - if it talks at the same time as something else, it has to backoff, and try to talk again. The faster the network, the more chance I have to talk, but I am still "contending" for that time. If I drop a packet, or have pixelation - it makes the scenario worse for everyone.
> 
> With DECA, its scheduled. I get a window for my packet. I know its mine, and no one else is talking. And the server is able to equally divide up the time for its streams. So, lets say I have a hiccup - there is no backoff, there is no waiting, the server simply sends the packet at the next scheduled window (which is roughly a millisecond). With this scheduling component, your recovery from glitches becomes nearly imperceptible (an audio blip versus a pixelized screen) and no other streams are affected [...]


Great post, *BudShark*!

I wasn't aware of the conceptual difference in packet transfer between DECA and ethernet. I always assumed they functioned identically, and that if I was already Cat-5 hard-wired, it wouldn't make a difference in my particular set-up how a receiver was connected. Like *VOS*, my hard-wired set-up has been generally working flawlessly, except for occasional "choppiness" when multiple OTA streams are in the mix. E.g., when a new OTA recording is starting on either the client or server at the same time I'm watching an OTA recording via MRV. I'm in the NYC DMA, and my OTA channels from the major networks are all very high bandwidth. They're the same feeds that are provided to MSO's on the east coast.

Your post now makes me wonder if DECA's "schedule-based" approach might mitigate those occasional OTA choppiness issues I'm experiencing? :scratchin


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## RAD (Aug 5, 2002)

BudShark said:


> The difference *is* on ethernet, that traffic would cause collisions, backoffs, delays, etc on your ethernet stream. Mostly imperciptible, but the design of ethernet was that traffic would "force" its way onto the wire. That same traffic, once it hits the DECA cloud would be held, scheduled, and then transmitted. There would not be the level of interference.


Sorry, don't get this schedule bit. I put a hub between a DECA and a H21 and then used Wireshark to see what was on the interface. I saw all the usual broadcast type traffic that I see on the straight ethernet network. How would a DECA schedule that type of traffic on the coax?


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## HDinVT (Dec 14, 2006)

BudShark said:


> Difficult question to answer.
> 
> In short, on a switched ethernet (Switch based not hub based, but if you have a Linksys/D-Link/2-Wire/etc router its switched) - the answer is the traffic didn't interfere. Traffic destined for the internet from HR20#1 did not interrupt a stream between your HR20#2 and your H21. That is the purpose of a switched network - traffic destined for a device only goes to that device.
> 
> ...


.... thanks, that makes sense to me. my topology is a whole lot simpler than a lot of folks here. I only have the two HR2x's and they are their own Linksys 10/100 switch, then that switch is on the router to provide access to the internet and VOD.


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## BattleScott (Aug 29, 2006)

RAD said:


> Sorry, don't get this schedule bit. I put a hub between a DECA and a H21 and then used Wireshark to see what was on the interface. I saw all the usual broadcast type traffic that I see on the straight ethernet network.


What your seeing at that point is the conversion back to ethernet. What BudShark is describing is the media access control used on the coax cabling and you would not see as part of the network traffic. The difference he is describing is taking place in the DECA converters. A packet arrives from the HR21 through the ethernet port and is held at the DECA port until the all clear is given to the DECA device to access the media and transmit the packet.


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## RAD (Aug 5, 2002)

BattleScott said:


> What your seeing at that point is the conversion back to ethernet. What BudShark is describing is the media access control used on the coax cabling and you would not see as part of the network traffic. The difference he is describing is taking place in the DECA converters. A packet arrives from the HR21 through the ethernet port and is held at the DECA port until the all clear is given to the DECA device to access the media and transmit the packet.


OK, thanks, I was reading more into it I guess.


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## morphy (Jun 5, 2007)

Same theme, different question. I've had Cat5e in every room in my house previous to even being a DirecTV customer. One way or another, I will have HD content available throughout the house over my IP network. For now, the best option for being able to accomplish this (and still having access to premium content) seems to be through DirecTV's MRV product. When MRV is out of beta, and once my home renovation is finished, my plan is to have a DVR loaded up with a large disk array and considered to be a master content location (with a few occassional exceptions) throughout the house. DECA doesn't seem to have anything to offer me, since it wouldn't offer me any sizeable advantage. Before anyone mentions the flaky performance of consumer-grade network devices, trust me, that's NOT a problem here.  I work in enterprise networking professionally, and I have a 48 port Foundry gig switch. Overkill? Probably. 

So even if DECA isnt necessarily on my radar, would I benefit by waiting for HR24s? I'm planning to attach an external disk array anyways, so I dont need the space. My next DVR purchase will probably go in the network rack so I dont really care about interface speed. Does DirecTV's new RVU initiative have any advantages that would go above and beyond what they do in MRV? 

Thanks for your help guys!


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## BudShark (Aug 11, 2003)

RAD said:


> OK, thanks, I was reading more into it I guess.


Scott is correct. Here's a good white paper if you're into that: http://www.mocalliance.org/industry/white_papers/PQoS_White_Paper.pdf

Basically, what MoCA does is embed Quality of Service into its lower layer (layer 1 and 2). In the past ethernet used QoS at higher levels - it was up to the application and the routers to handle it at the TCP and/or IP levels.

Granted, 802.11 now includes specs for layer 1 and 2 QoS that would equal or rival what MoCA has done (such as Wireless MultiMedia) *BUT* for that to work, DirecTV would have to specify EXACT hardware requirements for ethernet networks down to the model and firmware of routers, wireless adapters, etc. Something they can't do. And once you break that with a single device (like AT&Ts provided 2-Wire router for example), 802.11 can't use the low level QoS and DirecTV can no longer ensure the multimedia packet scheduling that ensures smoother video and trickplay that we see on DECA.

Also, of note - in the MoCA 1.1 specs is some throughput numbers for those who are curious. 175Mbps with 16 nodes at real world throughput. So its roughly 3x the real world throughput of a 100Mbps ethernet network.


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## BudShark (Aug 11, 2003)

morphy said:


> Same theme, different question. I've had Cat5e in every room in my house previous to even being a DirecTV customer. One way or another, I will have HD content available throughout the house over my IP network. For now, the best option for being able to accomplish this (and still having access to premium content) seems to be through DirecTV's MRV product. When MRV is out of beta, and once my home renovation is finished, my plan is to have a DVR loaded up with a large disk array and considered to be a master content location (with a few occassional exceptions) throughout the house. DECA doesn't seem to have anything to offer me, since it wouldn't offer me any sizeable advantage. Before anyone mentions the flaky performance of consumer-grade network devices, trust me, that's NOT a problem here.  I work in enterprise networking professionally, and I have a 48 port Foundry gig switch. Overkill? Probably.
> 
> So even if DECA isnt necessarily on my radar, would I benefit by waiting for HR24s? I'm planning to attach an external disk array anyways, so I dont need the space. My next DVR purchase will probably go in the network rack so I dont really care about interface speed. Does DirecTV's new RVU initiative have any advantages that would go above and beyond what they do in MRV?
> 
> Thanks for your help guys!


1) HR24s offer you excellent speed improvement in guides, channel changes, etc. They seem to be worth the upgrade outside of DECA.

2) If you are familiar with enterprise networks, than the white paper about PQoS on MoCA and the conversation about multimedia packet scheduling and non-contention based networks should be enough to convince you DECA DOES provide benefit especially once you go to multiple simultaneous streams.

3) The RVU initiative is probably heavily dependent on DECA/packet scheduling since it involves the painting of the interface on top of streaming of the video. The advantage over the existing MRV initiative is cheaper end devices, and potentially even the elimination of set top boxes completely with compatible displays.


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## carl6 (Nov 16, 2005)

morphy said:


> DECA doesn't seem to have anything to offer me, since it wouldn't offer me any sizeable advantage. Before anyone mentions the flaky performance of consumer-grade network devices, trust me, that's NOT a problem here.


Having read some of the excellent discussions regarding how DECA works versus ethernet, there does appear to be some qualitative and quantitative differences, and the indications are that DECA is in fact the preferred solution.

So my question for you is, why not use DECA? Your excellent ethernet infrastructure is still there and available for anything/everything else, but you would lose nothing by using DECA for networking DirecTV products and MRV.


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## Beerstalker (Feb 9, 2009)

carl6 said:


> Having read some of the excellent discussions regarding how DECA works versus ethernet, there does appear to be some qualitative and quantitative differences, and the indications are that DECA is in fact the preferred solution.
> 
> So my question for you is, why not use DECA? Your excellent ethernet infrastructure is still there and available for anything/everything else, but you would lose nothing by using DECA for networking DirecTV products and MRV.


I don't want to use it because I don't really want to have to tear stuff apart and add the DECA adapters everywhere, and deal with powering yet another device. I'm sure they don't take too much power, but if I don't need them why waste that power.

Now if D* wants to come in and swap all my DVRs for HR24s and my H21 for an H24 at no cost to me then sure I'll switch to DECA. I'd only need 1 DECA adapter to bridge between the SWM system and my home network instead of the 5 DECA adapters I would need now.


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## BattleScott (Aug 29, 2006)

Beerstalker said:


> Now if D* wants to come in and swap all my DVRs for HR24s and my H21 for an H24 at no cost to me then sure I'll switch to DECA. I'd only need 1 DECA adapter to bridge between the SWM system and my home network instead of the 5 DECA adapters I would need now.


This is exactly what they are doing in the 4 test markets (well not upgrading, but only all new installations) and I suspect that this is exactly what the "special offer" referred to in the public MRV BETA announcement will be in order to move to the full fledged, supported MRV system.


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## harsh (Jun 15, 2003)

The Merg said:


> Even when you isolate devices on a switch, they are not completely isolated.


UDP traffic notwithstanding, real switches very effectively isolate traffic in such a way that normal data transfer is restricted to a channel between exactly two devices.


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## Sixto (Nov 18, 2005)

This DECA/Ethernet discussion is a very valuable read. Thanks.

It makes me think long and hard about the long-term plan for my 7 receivers.

Thinking I want them all-in or all-out, trying to avoid a bottle neck or single point-of-failure at the network-DECA.

Previously all 7 have had hard-wire 10/100 Cat5e access to a Switch.

Keep up the great comments.


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## Beerstalker (Feb 9, 2009)

BattleScott said:


> This is exactly what they are doing in the 4 test markets (well not upgrading, but only all new installations) and I suspect that this is exactly what the "special offer" referred to in the public MRV BETA announcement will be in order to move to the full fledged, supported MRV system.


Yeah, I assumed they would be doing that in the test markets for new installs, but I don't know if they are really going to go and do that for anyone that wants update to get SWM. That would mean replacing a lot of receivers that are out their working fine right now as it is, or it would require a ton of DECA adapter installs.

I did just realize that I was a little off in my original comment though. It appears the DECA adapters are powered by the receivers themselves so I wouldn't have to worry about powering them, but they still would make more of a mess out of my current wiring, and be a hassle I don't need since my Gigabit network is working great for MRV already.


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## TomCat (Aug 31, 2002)

Barry in Conyers said:


> ...As far as network congestion is concerned, an inexpensive switch can effectively isolate the MRV traffic from everything else...


"Isolate" implies that there will not be collisions with other traffic where there should not be. That's all well and good, but isn't how the traffic is prioritized more important than whether there are collisions? Isolation would seem not to be a full solution to congestion. It's still TCP/IP traffic, and it still is all going through the same funnel. Can an inexepensive switch maintain the sustained throughput needed for MRV or streaming video in the face of congestion? I don't see how it would be smart enough to prioritize the data in a mission-critical video stream over my daughter's tweets or downloads.

It seems like DECA could completely isolate it from congestion better, simply because it is a private channel and therefore does not even see congestion from other traffic. That does not seem like a non-issue to me, but I am certainly willing to hear an explanation that could convice me otherwise.


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## Barry in Conyers (Jan 14, 2008)

I did not say "isolate"; what I said was "...effectively isolate..." and others have addressed that fact.

Not that it matters; it has been definitively indicated that ethernet cannot work acceptably for MRV.


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## LameLefty (Sep 29, 2006)

Barry in Conyers said:


> Not that it matters; it has been definitively stated that ethernet cannot work acceptably for MRV.


I don't believe that is the consensus. Rather, the consensus seems to be that a good ethernet network may well be fine for MRV as it is used now: discrete boxes sending and receiving individual streams. Several such streams seem to still work just fine between nodes of a well-built network.

However, the Whole-Home solution Directv is building towards will likely involve a server box with multiple tuners (in the range of 4 - 8 probably) and must be able to stream out several of those (perhaps all 8) to client devices at once. In addition, the RVU Alliance (of which Directv is a member) is working toward a thin-client solution such that the client boxes don't even have tuners of their own; they basically simply overlay the GUI elements served up from the central box as if they were being generated locally. This type of arrangement, plus the overhead of trickplay, has a bigger likelihood of overwhelming the typical home LAN. DECA thus has advantages in "future proofing" a present home MRV setup.


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## RAD (Aug 5, 2002)

Barry in Conyers said:


> Not that it matters; it has been definitively indicated that ethernet cannot work acceptably for MRV.


Works fine for me, I've had a max of three client and four server streams going over a single 100Mbps uplink without any issues while also handling my internet access (surfing) from a PC.

Will everyones ethernet network work, maybe not if they've done a poor design on their network.


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## Steve (Aug 22, 2006)

Barry in Conyers said:


> [...] Not that it matters; it has been definitively indicated that ethernet cannot work acceptably for MRV.


Well there's theory and there's practice.  If I take OTA out of the equation, as currently implemented, I'd have to say that SAT MPEG-4 MRV works flawlessly between my 5 networked H/HR's, all CAT-5.

Whether or not my rare OTA MRV issues are related to higher than average OTA recording bit rates, a need for further MRV tuning, or no DECA QOS to smooth things out remains to be seen. I'm currently unable to test that last part.


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## Barry in Conyers (Jan 14, 2008)

LameLefty said:


> I don't believe that is the consensus. Rather, the consensus seems to be that a good ethernet network may well be fine for MRV as it is used now: discrete boxes sending and receiving individual streams. Several such streams seem to still work just fine between nodes of a well-built network.
> 
> However, the Whole-Home solution Directv is building towards will likely involve a server box with multiple tuners (in the range of 4 - 8 probably) and must be able to stream out several of those (perhaps all 8) to client devices at once. In addition, the RVU Alliance (of which Directv is a member) is working toward a thin-client solution such that the client boxes don't even have tuners of their own; they basically simply overlay the GUI elements served up from the central box as if they were being generated locally. This type of arrangement, plus the overhead of trickplay, has a bigger likelihood of overwhelming the typical home LAN. DECA thus has advantages in "future proofing" a present home MRV setup.


Lefty,

I don't disagree with anything in your second paragraph, but those conditions were not included when the DECA enthusiasts attacked every remotely positive comment about using ethernet for MRV. There were lots of reasons given for why ethernet is not acceptable for MRV, not reasons for why ethernet might not be acceptable for MRV at some point in the future.

When I raised the issue of a network either working or not for an application, strong statements were made to the effect that ethernet does not / cannot work acceptably for MRV. I can provide specific examples if you want them.

Again, it does not really matter. Ethernet was fine for MRV until DECA appeared and now ethernet is not acceptable.


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## harsh (Jun 15, 2003)

TomCat said:


> "Isolate" implies that there will not be collisions with other traffic where there should not be.


There isn't congestion unless two devices are both trying to talk to a third device with high throughput streams. MRV in its current incarnation is defined as exclusive exchanges between pairs of receivers. A third receiver will get a simple "not now" from any receiver engaged in an MRV session.

QoS between VOD downloads and other Internet traffic may be important, but a switch (or a router) will insure that MRV traffic never sees the Internet proper because it is destined for local machines and the router doesn't route local traffic. Until the speed of your broadband connection gets to be a lot higher than it is today, the router is the least of your worries.


> That's all well and good, but isn't how the traffic is prioritized more important than whether there are collisions?


If you're talking about MRV, there are pairs of receivers talking to each other with an occasional network announcement or query. In MRV, there typically won't be many surprises outside of a trick play request.


> It's still TCP/IP traffic, and it still is all going through the same funnel.


Not on a switch. Communications between devices is channeled directly between the two devices and the rest of the network is blissfully ignorant.


> Can an inexepensive switch maintain the sustained throughput needed for MRV or streaming video in the face of congestion?


Absolutely. There is no congestion in a modern switch of up to eight ports or so even with the lowliest hardware.


> I don't see how it would be smart enough to prioritize the data in a mission-critical video stream over my daughter's tweets or downloads.


MRV isn't headed out onto the Internet so it has absolutely *nothing* to do with your daughter's Internet activity. Of course I'm assuming that everything is hardwired to a switch and/or router. If you're using a wireless connection, all bets are off as every wireless device (or wireless subnet if you've wirelessly connected DECA to your router) must share the available bandwidth with all other wireless devices).


> It seems like DECA could completely isolate it from congestion better, simply because it is a private channel and therefore does not even see congestion from other traffic.


DECA represents a hub-like scenario where all traffic in the cloud is seen by all devices in the cloud. It perfectly represents the bottleneck that you feared a switch or router was. In the case of a switch connected to the cloud, it knows what IP addresses are in the cloud and essentially ignores their packets. DECA cannot ignore anything and in fact, it must pass everything out to the switch that, in turn, promptly ignores it.


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## veryoldschool (Dec 10, 2006)

harsh said:


> DECA represents a hub-like scenario where all traffic in the cloud is seen by all devices in the cloud.


No it doesn't. While the RF signal may be "hub like", going to all the DECAs, at the outputs of the DECAs, they and the whole cloud is acting like one large switch.


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## harsh (Jun 15, 2003)

veryoldschool said:


> No it doesn't. While the RF signal may be "hub like", going to all the DECAs, at the outputs of the DECAs, they and the whole cloud is acting like one large switch.


If all nodes share bandwidth with all other nodes, it isn't following a switch model. Switches are point to point (like a telephone switch) while hubs (and DECA) are not.

Don't be fooled by the PQoS (Parameterized Quality of Service) terminology. That simply means that the transmissions of each device are scheduled by one of the nodes (network coordinator, chosen by highest signal quality) to avoid collision.


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## veryoldschool (Dec 10, 2006)

harsh said:


> If all nodes share bandwidth with all other nodes, it isn't following a switch model. Switches are point to point (like a telephone switch) while hubs (and DECA) are not.
> 
> Don't be fooled by the PQoS (Parameterized Quality of Service) terminology. That simply means that the transmissions of each device are scheduled by one of the nodes (network coordinator, chosen by highest signal quality) to avoid collision.


Too bad you've never used/seen these, as you seem to be clueless.
If [as I said] you look at the DECA outputs, they are point to point.
The internal [cloud] bandwidth is much greater than a 100 Mb switch, since it is 50 MHz @ 550 MHz.
To say DECA is a hub, or even works like a hub, is simply wrong/incorrect.
Since I have a DECA network, I can monitor activity and know that the traffic is point to point.


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## BudShark (Aug 11, 2003)

harsh said:


> If all nodes share bandwidth with all other nodes, it isn't following a switch model. Switches are point to point (like a telephone switch) while hubs (and DECA) are not.
> 
> Don't be fooled by the PQoS (Parameterized Quality of Service) terminology. That simply means that the transmissions of each device are scheduled by one of the nodes (network coordinator, chosen by highest signal quality) to avoid collision.


In the scenario described, VOS is right.

The DECA cloud is a hub - the cloud sees everything. However, because in this particular case the DECA is bridging between the cloud and ethernet - the end devices are ONLY seeing what is destined for them. The DECA sees everything - but only passes what is slated for the end device. So in that respect, the DECA and ethernet port on an HR20 are creating a switched environment.

So if node = DECA everything sees everything.
If node = HR20 then it only sees what is destined for it.

In terms of PQoS you are incorrect. PQoS allows me to place a priority on a particular packet type or data transmission. Either by device or content. The scheduling aspect you are referring to is a different component of the physical layer of MoCA. But, yes, the scheduling is done to avoid collisions and other traffic flow problems.


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## TomCat (Aug 31, 2002)

harsh said:


> ...DECA represents a hub-like scenario where all traffic in the cloud is seen by all devices in the cloud. It perfectly represents the bottleneck that you feared a switch or router was. In the case of a switch connected to the cloud, it knows what IP addresses are in the cloud and essentially ignores their packets. DECA cannot ignore anything and in fact, it must pass everything out to the switch that, in turn, promptly ignores it.


Thanks for taking the time to answer (even if you did get slammed). Maybe I do not understand TCP/IP traffic as well as I would like to. I understand that a switch can isolate traffic and destinations do not see traffic not intended for them, but I still don't see how that prevents collisions or does not threaten throughput.

Are you saying that the throughput is so significantly beyond that that incidental traffic on other ports will not make a difference to the actual streaming path?

Best networking pratices always seem to try to imply that throughput is best when you can limit the number of hops. IOW, if you design the network with the goal of probable traffic patterns not piling up on each other, that is good design in that it prevents colisions. But maybe that is hub-style obsolete thinking. It would seem that if packets arrive at the switch at the same time, that there must be prioritization, even if they arrive on separate ports bound for separate destinations. Are these paths isolated completely from each other as well? IOW, do the separate paths share anything, such as do they time-divide the capability of the switch, or does a separate event such as an internet download remain absolutely separate?


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## evan_s (Mar 4, 2008)

TomCat said:


> Thanks for taking the time to answer (even if you did get slammed). Maybe I do not understand TCP/IP traffic as well as I would like to. I understand that a switch can isolate traffic and destinations do not see traffic not intended for them, but I still don't see how that prevents collisions or does not threaten throughput.
> 
> Are you saying that the throughput is so significantly beyond that that incidental traffic on other ports will not make a difference to the actual streaming path?
> 
> Best networking pratices always seem to try to imply that throughput is best when you can limit the number of hops. IOW, if you design the network with the goal of probable traffic patterns not piling up on each other, that is good design in that it prevents colisions. But maybe that is hub-style obsolete thinking. It would seem that if packets arrive at the switch at the same time, that there must be prioritization, even if they arrive on separate ports bound for separate destinations. Are these paths isolated completely from each other as well? IOW, do the separate paths share anything, such as do they time-divide the capability of the switch, or does a separate event such as an internet download remain absolutely separate?


A collision is 2 devices trying to talk at the same time. If the communication from one device to another is never seen by 2 other devices communicating then by definition a collision can't occur. A switch does generally have internal bandwidth higher than the speed of the ports it supports for the exact same reason you mention. They have to be able to move information from port a to port b and from port c to d with out interfering with each other. Now there is a limit to this so theoretically with enough traffic floating around you can max out this internal bandwidth but it is pretty unlikely in most home configurations.

BTW this is not a TCPIP thing at all. This is occurring at level 1 and 2 of the OSI layer (data link and physical layer) and TCPIP is layers 4 and 5 (transport and session)


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## harsh (Jun 15, 2003)

TomCat said:


> I understand that a switch can isolate traffic and destinations do not see traffic not intended for them, but I still don't see how that prevents collisions or does not threaten throughput.


Lesson 1 of hubs versus switches: Hubs are half-duplex devices. Only one device can be "talking" at a time and all other devices must shut up and wait for an opening (or have the traffic administered as DECA does).

Switches are full duplex devices (simultaneously bidirectional). The "fabric" of the switch has much greater capacity than each port and as I said earlier, most consumer level switches can support two-way traffic at full speed with four pairs of devices gabbing up a storm.


> Are you saying that the throughput is so significantly beyond that that incidental traffic on other ports will not make a difference to the actual streaming path?


The streaming path is between two machines. In the case of MRV, the only "incidental traffic" will be transport control requests (pause, skip, etc). These can travel unfettered in a full duplex scenario, but in a hub scenario, the playback device has to shout out for its turn. MoCA improves on this by reserving some capacity for non-streaming traffic.


> Best networking pratices always seem to try to imply that throughput is best when you can limit the number of hops.


Hops is a term usually reserved for very large networks with routers and firewalls like the Internet itself. It doesn't come into play as much in a home LAN as switched traffic doesn't have to contend with narrow pipes or other traffic.

If you're running multiple switches, you do end up sharing the path between uplink ports, but it is still a full duplex connection.

Lesson 2 involves terms like "store and forward" and "buffering" that don't apply as readily to hubs but are used to great effect in switches.


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## harsh (Jun 15, 2003)

veryoldschool said:


> The internal [cloud] bandwidth is much greater than a 100 Mb switch, since it is 50 MHz @ 550 MHz.


The Nyquist Rate formula says that f (bits per second) < 2B (bandwidth). The ability of a frequency band to carry data is no more than twice the bandwidth and has _nothing_ to do with the center frequency of the band.

Modulation schemes within the band can improve on the throughput and error rates but DECA has no less capacity than MoCA that operates more than double the center frequency.

Have you connected a hub to a DECA adapter to see if the adapter actually prevents intra-cloud traffic from leaving the cloud?


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## tag (Mar 18, 2010)

Came across this thread by chance and was rather surprised at the amount of FUD there is against your typical modern network. I thought I was having flashbacks to 10 Mbit half-duplex hub days. So just some real-world data FWIW. I happen to handle the networking for a university department (amongst a bunch of other hats I wear). Looking at one of our uplinks to campus I see:


```
[email protected]>show int e 2/1
GigabitEthernet2/1 is up, line protocol is up 
  STP Root Guard is disabled, STP BPDU Guard is disabled
  Hardware is GigabitEthernet, address is 001b.edae.9800 (bia 001b.edae.9830)
  Configured speed auto, actual 1Gbit, configured duplex fdx, actual fdx
  Member of VLAN 201 (untagged), port is in untagged mode, port state is Forwarding
  STP configured to ON, Priority is level0, flow control enabled
  Priority force disabled, Drop precedence level 0, Drop precedence force disabled
  dhcp-snooping-trust configured to OFF
  mirror disabled, monitor disabled
  Not member of any active trunks
  Not member of any configured trunks
  Port name is link-dx2-eng
  MTU 1548 bytes, encapsulation ethernet
  300 second input rate: 7069508 bits/sec, 11845 packets/sec, 0.89% utilization
  300 second output rate: 240447404 bits/sec, 21065 packets/sec, 24.38% utilization
  24816547910 packets input, 2266586380758 bytes, 0 no buffer
  Received 3 broadcasts, 2373436 multicasts, 24814174471 unicasts
  0 input errors, 0 CRC, 0 frame, 0 ignored
  0 runts, 0 giants
  NP received 24816547929 packets, Sent to TM 24809184466 packets
  NP Ingress dropped 7363467 packets
  51867718352 packets output, 73486522306442 bytes, 0 underruns
  Transmitted 19619 broadcasts, 382086 multicasts, 51867316647 unicasts
  0 output errors, 0 collisions                                   
  NP transmitted 51867718392 packets, Received from TM 51867892777 packets
```
So we're doing over 32,000 packets every second and over 26 *billion* total logged since the interface was brought up and not a single collision.

Ah, but you say that is really expensive Foundry equipment. Honestly it doesn't matter that much. I have an el-cheapo (~$70 8-port) Netgear gig-e switch for my house and one server with a lowly Atom processor and other with an old P4. Do a ping flood test between them and you see:


```
ping -fc 5000 <host>
PING <edit> 56(84) bytes of data.
 
--- <edit> ping statistics ---
5000 packets transmitted, 5000 received, 0% packet loss, time 3112ms
rtt min/avg/max/mdev = 0.051/0.082/0.316/0.016 ms, ipg/ewma 0.622/0.080 ms
```
So 5K packets in ~3 seconds with imperceptible jitter. Let's bump up to ~1K packets:


```
ping -fc 5000 -s 1000 <host>
PING <edit> 1000(1028) bytes of data.
 
---<edit> ping statistics ---
5000 packets transmitted, 5000 received, 0% packet loss, time 4262ms
rtt min/avg/max/mdev = 0.273/0.324/0.654/0.029 ms, ipg/ewma 0.852/0.324 ms
```
Observe the RTT and jitter. It'll be fine for a few video streams (quite a few depending on the bitrate of the streams). Also this isn't an idle network. There are http/smtp/dns servers as well as several users on it. And yes icmp isn't the same as streaming video, but the point was just to load the network quickly.

Look at the interface on the server:


```
RX packets:148813738 errors:0 dropped:0 overruns:0 frame:0
          TX packets:199800741 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
```
So only 34 million packets, but still no collisions.

Whether or not you want to use DECA is a whole other ball of wax.


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## LameLefty (Sep 29, 2006)

tag said:


> So only 34 million packets, but still no collisions.
> 
> Whether or not you want to use DECA is a whole other ball of wax.


Try the test again while streaming three or four 1080i OTA MPEG2 HD video streams.


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## tag (Mar 18, 2010)

LameLefty said:


> Try the test again while streaming three or four 1080i OTA MPEG2 HD video streams.


It won't make a (significant) difference. You should have seen that in the first example I gave. But, as a quick test, I ran iperf between the two servers while also running the flood ping:


```
0.0-10.0 sec  1.03 GBytes    878 Mbits/sec
```


```
5000 packets transmitted, 5000 received, 0% packet loss, time 6596ms
rtt min/avg/max/mdev = 0.062/0.412/3.808/0.191 ms, ipg/ewma 1.319/0.422 ms
```
3 OTA streams are not going to push anywhere near 878 Mbps, probably not even 10%.


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## TomCat (Aug 31, 2002)

harsh said:


> Lesson 1 of hubs versus switches: Hubs are half-duplex devices. Only one device can be "talking" at a time and all other devices must shut up and wait for an opening (or have the traffic administered as DECA does).
> 
> Switches are full duplex devices (simultaneously bidirectional). The "fabric" of the switch has much greater capacity than each port and as I said earlier, most consumer level switches can support two-way traffic at full speed with four pairs of devices gabbing up a storm.The streaming path is between two machines. In the case of MRV, the only "incidental traffic" will be transport control requests (pause, skip, etc). These can travel unfettered in a full duplex scenario, but in a hub scenario, the playback device has to shout out for its turn. MoCA improves on this by reserving some capacity for non-streaming traffic.Hops is a term usually reserved for very large networks with routers and firewalls like the Internet itself. It doesn't come into play as much in a home LAN as switched traffic doesn't have to contend with narrow pipes or other traffic.
> 
> ...


Terrific info, which I actually understood (meaning the presentation gets high marks). Thanks so much.


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## LameLefty (Sep 29, 2006)

tag said:


> It won't make a (significant) difference. You should have seen that in the first example I gave. But, as a quick test, I ran iperf between the two servers while also running the flood ping:
> 
> 
> ```
> ...


Your HOME network routinely handles 878 Mbps, does it?


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## harsh (Jun 15, 2003)

LameLefty said:


> Your HOME network routinely handles 878 Mbps, does it?


That is the point, isn't it? You too can have a Gigabit network at home without too much expense (8 port switches regularly go for under $50).

For those who can't get the wires run and the HomePlug solution isn't fast enough, DECA is a handy (if not inexpensive) fall-back to bring your SWiM connected DIRECTV receivers (and maybe a handful of other devices) onto a network.


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## LameLefty (Sep 29, 2006)

harsh said:


> That is the point, isn't it? You too can have a Gigabit network at home without too much expense (8 port switches regularly go for under $50).
> 
> For those who can't get the wires run and the HomePlug solution isn't fast enough, DECA is a handy (if not inexpensive) fall-back to bring your SWiM connected DIRECTV receivers (and maybe a handful of other devices) onto a network.


No, that's not the point at all. Just because you have a consumer-grade gigabit switch and some Cat5e/Cat6 wiring doesn't mean your home LAN can handle sustained throughputs like that. It depends on what devices are used all over the LAN and what each of them is trying to do. Which is MY point here, and the point Budshark is making in his thread.

And as for DECA being "not inexpensive" in your terms, how do you know? Have you priced it? The $99 being batted around is on the high end for a two room situation, but if that price holds for me, great! For that $99 I'd expect my two SWM8's to be replaced with an SWM16 and the addition of four DECA modules. That's a hell of a great deal, especially since I can sell my SWM8's and recoup all or more of that $99. In other words, the pricing being discussed for DECA is clearly not a money-maker for Directv - it's just an average, to cover most situations without losing money, while future-proofing them for the next steps in their technology roadmap.


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## David MacLeod (Jan 29, 2008)

deca pricing is for d* customers so he would not know anyway...
the 99 is a good deal for some existing people as it will bring non swm units up to swm albeit maintaining previous programming capabilities.


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## harsh (Jun 15, 2003)

David MacLeod said:


> deca pricing is for d* customers so he would not know anyway...


Nor would D* customers as the product hasn't been made available for general release yet.

As LarryFlowers points out, things are just being "batted around" at this time and little is known of the cost of upgrading an existing installation (which would be the case for most all current D* customers).


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## veryoldschool (Dec 10, 2006)

harsh said:


> Nor would D* customers as the product hasn't been made available for general release yet.
> 
> As LarryFlowers points out, things are just being "batted around" at this time and little is known of *the cost of upgrading an existing installation *(which would be the case for most all current D* customers).


$99 for SWiM + DECA + receivers swaps, as needed,
+$49 service call,
+ 1 year commitment


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## harsh (Jun 15, 2003)

LameLefty said:


> No, that's not the point at all. Just because you have a consumer-grade gigabit switch and some Cat5e/Cat6 wiring doesn't mean your home LAN can handle sustained throughputs like that.


While it is easy to reason that consumer grade equipment can't do what industrial grade equipment can, I've found that the speed isn't directly related to the price.


> And as for DECA being "not inexpensive" in your terms, how do you know?


MoCA kits go for just under $200 per pair. It is "easy to reason" that the retail price of DECA adapters won't be a small fraction of that figure. You suggest that this is going to be a money-making proposition for DIRECTV if they sell you a new and, as yet, unpriced multiswitch and two adapters. I submit (without any DIRECTV or insight) that the $99 price will be for new installs with new HR24 receivers only. I suspect upgrade installs will cost much more as it will take a very long time to recover the costs at $3/month.

When the product is released for general availability, we'll see how well we did and whether or not there is a different cost for upgrades.


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## harsh (Jun 15, 2003)

veryoldschool said:


> $99 for SWiM + DECA + receivers swaps, as needed,
> +$49 service call,
> + 1 year commitment


Source?


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## veryoldschool (Dec 10, 2006)

harsh said:


> Source?


DirecTV.


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## harsh (Jun 15, 2003)

veryoldschool said:


> DirecTV.


Press release? Printed on your bill? Rumored among beta testers?


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## David MacLeod (Jan 29, 2008)

harsh said:


> Press release? Printed on your bill? Rumored among beta testers?


none of the above, try again. or better yet....don't.


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## BudShark (Aug 11, 2003)

harsh said:


> Press release? Printed on your bill? Rumored among beta testers?


http://www.dbstalk.com/showthread.php?t=174322

Actually if you had a DirecTV account you could probably call and talk to them yourself. I'm sure they'd be glad to let you know the details if you don't believe that thread or DirecTVs press release regarding the release to the 4 markets.


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## texasboy1022 (Feb 23, 2010)

I am not a DirecTV customer yet, but will be very soon. I almost pulled the trigger about 6 weeks ago until I stumbled across this site (amazing BTW) and found out about the HR24 coming out. I will be getting 2 HD DVRs and 1 HD receiver, but I want the best equipment I can get after putting up with TWC for years and their prehistoric garbage. My question, is it worth waiting to try and get the HR24 and H24 or is the probability that I would be able to get one at initial installation very slim? Past experiences regarding new receiver launches and availability are appreciated.

Thanks
C


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## veryoldschool (Dec 10, 2006)

texasboy1022 said:


> I am not a DirecTV customer yet, but will be very soon. I almost pulled the trigger about 6 weeks ago until I stumbled across this site (amazing BTW) and found out about the HR24 coming out. I will be getting 2 HD DVRs and 1 HD receiver, but I want the best equipment I can get after putting up with TWC for years and their prehistoric garbage. My question, is it worth waiting to try and get the HR24 and H24 or is the probability that I would be able to get one at initial installation very slim? Past experiences regarding new receiver launches and availability are appreciated.
> 
> Thanks
> C


As a new customer, I'd wait until your area has become part of the DECA/MRV upgrade/install, as this would get you the 24s.


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## texasboy1022 (Feb 23, 2010)

veryoldschool said:


> As a new customer, I'd wait until your area has become part of the DECA/MRV upgrade/install, as this would get you the 24s.


Thanks for the advice. I see you have the HR24, worth the wait? Big improvement over your prior receivers?


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## veryoldschool (Dec 10, 2006)

texasboy1022 said:


> Thanks for the advice. I see you have the HR24, worth the wait? Big improvement over your prior receivers?


As the first look pointed out, it's FAST/responsive and works great for MRV. 
Since it is a big change, if I signed up now and didn't get one/them, I'd be pissed later when they did come out, and I found I "missed it by that much". :lol:


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## texasboy1022 (Feb 23, 2010)

veryoldschool said:


> As the first look pointed out, it's FAST/responsive and works great for MRV.
> Since it is a big change, if I signed up now and didn't get one/them, I'd be pissed later when they did come out, and I found I "missed it by that much". :lol:


I see, I know all too well how that feels, I'm waiting!


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## tag (Mar 18, 2010)

LameLefty said:


> Your HOME network routinely handles 878 Mbps, does it?


No, but it can.


```
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-600.0 sec  61.1 GBytes    874 Mbits/sec
```
10 minutes sustained. The speed of my disks are usually the bottleneck anyway. It routinely sees 600+ Mbps during nightly backups and when I'm shuffling large video files around.

But the point was that you made the claim that a home network wouldn't be able to handle ~60 Mbps of traffic and still have acceptable latency/jitter/throughput for video. I showed you that it can be fine with 14x that amount of traffic.


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## LameLefty (Sep 29, 2006)

tag said:


> No, but it can.
> 
> 
> ```
> ...


Great! Have a cookie! 

Now, after you eat that cookie, go to Directv and writeup a detailed implementation plan for them to create that very same infrastructure in every one of their 18,000,000 customers' locations that can maintain that throughput for hours on end, 24 hours a day, seven days a week. Further, your implementation plan must have a detailed parts list and come in so that it can be installed in those locations for a flat fee of about a hundred bucks without Directv losing their shirt, AND do so in a way that is guaranteed not to interfere with the customer's possible VOIP service, internet and LAN media streaming, misbehaving DLNA or other devices on the local network, and can be installed by a minimally-trained technician in less than an hour.

Or you can realize what Budshark and others have been telling you: YOUR network is not EVERYONE'S network. YOUR network (*) is obviously great. You're a pro. Most customers aren't. Heck, my brother-in-law doesn't even remember how to setup 30 Sec Skip on his receivers and I've done it for him about three times in three years. :lol:

Real world networks are mishmashes of Cat5, Cat5e, Cat6, 802.11b/g/n, powerline, etc. Most customers don't even change the default admin passwords on wireless routers for heaven's sake. Get real. THOSE networks are the ones that Directv is bypassing with DECA.

(*) My hardwired network has decent performance too and works great for MRV. I'm not a networking pro, but I do have an engineering degree, know how to troubleshoot, and can tell one end of a cable from another.


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## tag (Mar 18, 2010)

LameLefty said:


> Great! Have a cookie!


Apparently you missed this part in my original post:



> Whether or not you want to use DECA is a whole other ball of wax.


No cookie for you.


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## LameLefty (Sep 29, 2006)

tag said:


> Apparently you missed this part in my original post:
> 
> (snipped)


You still haven't addressed the key point: your network is not everyone's. :nono:

And since you won't even acknowledge that, welcome to my Ignore list. You're in some stellar company, I assure you.


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## BattleScott (Aug 29, 2006)

LameLefty said:


> You still haven't addressed the key point: your network is not everyone's. :nono:
> 
> And since you won't even acknowledge that, welcome to my Ignore list. You're in some stellar company, I assure you.


He already addressed it in his original post.



> Ah, but you say that is really expensive Foundry equipment. Honestly it doesn't matter that much. I have an el-cheapo (~$70 8-port) Netgear gig-e switch for my house and one server with a lowly Atom processor and other with an old P4. Do a ping flood test between them and you see:


Any decent quality GB switch costs less than what the DECA upgrade costs and will provide more than 4x the bandwidth of DECA *IF* you could run at gig speeds. Unfortunately, having a nice GB switch in place does not help when the MRV devices are only 100MB. You can really only compare DECA to the throughput of a 100MB network, since the receivers aren't GB capable.


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## DogLover (Mar 19, 2007)

BattleScott said:


> He already addressed it in his original post.
> 
> Any decent quality GB switch costs less than what the DECA upgrade costs and will provide more than 4x the bandwidth of DECA *IF* you could run at gig speeds. Unfortunately, having a nice GB switch in place does not help when the MRV devices are only 100MB. You can really only compare DECA to the throughput of a 100MB network, since the receivers aren't GB capable.


I'm thinking that the key point that LameLefty is talking about is that not everyone is going to have GB switch. (Sorry if I'm putting words in your mouth LL.)

In fact, the average Joe is not going to have a switch. The averge Joe is going to know that when he wants to have lots of USB devices he gets a USB hub. He's going to go into the store, know he needs to support several ethernet devices and he is going to pick up a network hub.


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## LameLefty (Sep 29, 2006)

DogLover said:


> I'm thinking that the key point that LameLefty is talking about is that not everyone is going to have GB switch. (Sorry if I'm putting words in your mouth LL.)
> 
> In fact, the average Joe is not going to have a switch. The averge Joe is going to know that when he wants to have lots of USB devices he gets a USB hub. He's going to go into the store, know he needs to support several ethernet devices and he is going to pick up a network hub.


Yes, exactly! This thread is full of nitpicky 'Net-Know-It-Alls, all trying to compare the sizes of their sliderules. Or as my wife abbreviates, "Nerdfight!" :lol:










WE are not the ones that have to worry about performance of MRV over our LANs, by and large. And rather than worry about all those infinite combinations of router, firmware, cabling, etc., and whether or not it'll work, Directv joined MoCA and picked an architecture which is designed from the ground up to do the job, period.

This is really not that hard to grasp except for those who just want a nerdfight.


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## tag (Mar 18, 2010)

LameLefty said:


> You still haven't addressed the key point: your network is not everyone's. :nono:


Actually I have, and so have others. I have a cheap, unmanaged switch that anyone can pick up at Best Buy or Newegg etc.

Instead of DECA they could have rebranded a switch and used gig-e NICs in their devices. and sold that package to you. So everyone could easily have "my network" for less than the proposed cost of DECA. They could easily just provide a specified list of approved devices (plenty of companies take this route). Those that already have a (qualified) network need not spend a dime.

You (and others) kept saying that you'd have collisions and dropped packets on a switch using tcp/ip. I think that is a disservice to the less-technical readers here when it is clearly not the case.

And again, I never said that this was the solution for them (there are issues with setting up and managing a tcp/ip network). Hence my "ball of wax" comment. Anyway this "nerd" needs to get his butt in gear to go rock climbing. The snow is finally melting around here and I'd much rather be doing that than comparing sliderules.


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## Sixto (Nov 18, 2005)

tag said:


> Actually I have, and so have others. I have a cheap, unmanaged switch that anyone can pick up at Best Buy or Newegg etc. ...


Welcome to DBSTalk.

Yep, there may have been several options, but DirecTV partnered with Entropic and developed a nice solution that utilizes the existing SWM standard and Coax infrastructure, and that's easy for mainstream America.

Those with robust Ethernet networks also have the option to utilize MRV over their existing infrastructure (without technical support).

All is fine for both camps.

Yes, we can debate the possible benefits of DECA, but the net is everyone should be happy.

Have fun rock climbing!


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## David MacLeod (Jan 29, 2008)

tag said:


> Actually I have, and so have others. I have a cheap, unmanaged switch that anyone can pick up at Best Buy or Newegg etc.
> 
> Instead of DECA they could have rebranded a switch and used gig-e NICs in their devices. and sold that package to you. So everyone could easily have "my network" for less than the proposed cost of DECA. They could easily just provide a specified list of approved devices (plenty of companies take this route). Those that already have a (qualified) network need not spend a dime.
> 
> ...


but, and this is the BIGGEST reason for deca, installers will NOT set up a network. they will not run wire, they will not enter your router to do anything needed there. would you want them?
this is why they did not go with a branded tcp/ip solution.


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## Steve (Aug 22, 2006)

David MacLeod said:


> but, and this is the BIGGEST reason for deca, installers will NOT set up a network. they will not run wire, they will not enter your router to do anything needed there. would you want them?
> this is why they did not go with a branded tcp/ip solution.


I totally agree.

Same as how building MoCA into their set top boxes allows Verizon to be able to use the existing "POTS" (copper phone wire) installer workforce to do sophisticated FiOS TV and internet installs. It's all co-ax and splitters back to the optical network interface box. Extremely simplified, both conceptually and mechanically.


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## harsh (Jun 15, 2003)

Steve said:


> Same as how building MoCA into their set top boxes allows Verizon to be able to use the existing "POTS" (copper phone wire) installer workforce to do sophisticated FiOS TV and internet installs.


I thought FIOS was FTTP and U-Verse was the one using copper for the "last mile". Was this not true or has it changed?


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## Steve (Aug 22, 2006)

harsh said:


> I thought FIOS was FTTP and U-Verse was the one using copper for the "last mile". Was this not true or has it changed?


I'm referring to inside the home networking for MRV to the ONT, which interfaces with the fiber optic network. The QIP set-top boxes are all MoCA enabled, like the H/HR24's, allowing "phone installers" to install your MRV solution.


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## harsh (Jun 15, 2003)

Steve said:


> The QIP set-top boxes are all MoCA enabled, like the H/HR24's, allowing "phone installers" to install your MRV solution.


Your mention of POTS threw me off seemingly suggesting that twisted pair came into play in a FIOS installation.

In my experience, phone system installers generally fetch a higher pay grade than DBS dish installers.


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## Steve (Aug 22, 2006)

harsh said:


> [...] In my experience, phone system installers generally fetch a higher pay grade than DBS dish installers.


True. Whether or not they are more skillful depends on the individual, based on my experience dealing with both.

That aside, Verizon (rightfully) wants all installs done the same way, for maintenance simplicity. Can't fault DirecTV for wanting the same.


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## Kapeman (Dec 22, 2003)

This may be a bit off topic, but I thought that I read somewhere that the HR24 would have an Ethernet port that could be used to bridge another device to the LAN via the DECA system.

Search didn't reveal anything.

Did I miss remember?


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## Sixto (Nov 18, 2005)

Kapeman said:


> This may be a bit off topic, but I thought that I read somewhere that the HR24 would have an Ethernet port that could be used to bridge another device to the LAN via the DECA system.
> 
> Search didn't reveal anything.
> 
> Did I miss remember?


The HR24 has one Ethernet port, and it's either DECA or Ethernet, not both.

There is a separate DECA for the home network connection.


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## Kapeman (Dec 22, 2003)

Sixto said:


> The HR24 has one Ethernet port, and it's either DECA or Ethernet, not both.
> 
> There is a separate DECA for the home network connection.


Maybe I didn't word my question properly.

Will the DECA setup allow you to plug a device into the DTV receiver and use the DECA network to get to the Ethernet network?


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## RAD (Aug 5, 2002)

Kapeman said:


> Maybe I didn't word my question properly.
> 
> Will the DECA setup allow you to plug a device into the DTV receiver and use the DECA network to get to the Ethernet network?


No, when you plug an ethernet cable in to the 24's the built in DECA adapter is disabled, it's one way or the other but not both. To get from your ethernet to DECA network you need another DECA adapter to interconnect the two.


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## Kapeman (Dec 22, 2003)

RAD said:


> No, when you plug an ethernet cable in to the 24's the built in DECA adapter is disabled, it's one way or the other but not both. To get from your ethernet to DECA network you need another DECA adapter to interconnect the two.


Thanks.

It looks like I melded the fact that A. the DECA can link to the Ethernet via the adapter and B. that some receivers have extra Ethernet ports that other devices can use (when the receiver is using Ethernet). I think I got that last one correct.

Oh well.


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## RAD (Aug 5, 2002)

Kapeman said:


> Thanks.
> 
> It looks like I melded the fact that A. the DECA can link to the Ethernet via the adapter and B. that some receivers have extra Ethernet ports that other devices can use (when the receiver is using Ethernet). I think I got that last one correct.
> 
> Oh well.


BTW, it's been said here a number of times, it's highly recommended that you don't use the 2nd port on the STB's that have them as a passthough, it will effect the boxes performance.


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## INTC (Dec 15, 2006)

I had a HR20 swapped with a HR24 last week but now I'm unable to schedule recordings on the HR24 with the iphone app. The app sees my HR21 but not the HR24. Is there a known bug with the HR24 and the iphone app? I'm able to use the web to schedeule recordings on the HR24 without issues.


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## LameLefty (Sep 29, 2006)

INTC said:


> I had a HR20 swapped with a HR24 last week but now I'm unable to schedule recordings on the HR24 with the iphone app. The app sees my HR21 but not the HR24. Is there a known bug with the HR24 and the iphone app? I'm able to use the web to schedeule recordings on the HR24 without issues.


No, it's probably a glitch on Directv's end with regard to their servers that interface with the mobile apps. I've been scheduling recordings on my HR24 since the Field Trials began.


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## Smuuth (Oct 4, 2005)

INTC said:


> I had a HR20 swapped with a HR24 last week but now I'm unable to schedule recordings on the HR24 with the iphone app. The app sees my HR21 but not the HR24. Is there a known bug with the HR24 and the iphone app? I'm able to use the web to schedeule recordings on the HR24 without issues.


Go to your account equipment listing on the DirecTV website and make sure your HR24 has a location listed. I don't know if it has to be a unique location, but when I changed the location for my HR24 on the website, it showed up on my Android app the next day.


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## Doug Brott (Jul 12, 2006)

INTC said:


> I had a HR20 swapped with a HR24 last week but now I'm unable to schedule recordings on the HR24 with the iphone app. The app sees my HR21 but not the HR24. Is there a known bug with the HR24 and the iphone app? I'm able to use the web to schedeule recordings on the HR24 without issues.


You might want to double check and see if this has been fixed


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## INTC (Dec 15, 2006)

Yes, it has been fixed. My app is now showing my HR21 AND HR24.


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