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Converting MRV from Home Network to "Supported", and from legacy to SWiM

Discussion in 'DIRECTV Connected Home' started by GregAmy, Oct 18, 2011.

  1. GregAmy

    GregAmy AllStar

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    Thanks for the bumps on this; I'm still pondering what I want to do.

    I'm leaning toward going with the existing dish and a SWM8, for reasons posted above. Last week we direct-buried a pair each of RG6 and CAT5e (a spare each in case something happens to one of them). So I can double-connect the new receiver in the garage without SWM. However, for some inexplicable reason, we neglected to run Cat5e up to the second floor where the receiver is going to be before sheetrocking. Just kicking myself...but all is not lost, and I can snake it up there with some effort.

    So, I have no immediate need for SWM or DECA, but I'm thinking it might be the better way to go long-term, and fairly easy to implement.

    GA
     
  2. RunnerFL

    RunnerFL Well-Known Member

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    Professional installation is not required at all.
     
  3. RunnerFL

    RunnerFL Well-Known Member

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    Yes, an actual DirecTV subscriber would know this. A Dish subscriber sticking his nose in a DirecTV thread would not.
     
  4. GregAmy

    GregAmy AllStar

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    Just as a reference/side note, "no bueno" on the gigabit. I bought a small 5-port 10/100/1000 Netgear switch and all H21/22s connected 100MBit only.

    GA
     
  5. DarkLogix

    DarkLogix Godfather

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    From what I can tell all the recivers only have a 10/100 eth port
    so I don't seewhy deca would be better than just eth as its going to eth to reach teh deca.

    and if you use a switch not a hub then its not going to slow the network as data on a switch only goes from source to destination not over all ports like a hub (ie OSI model layer 2 the MAC address table should be able to coordanate properly)

    but it's D* "supported" so be it

    the only thing a gig switch could help with is possible more memory and faster MAC table lookup (but you won't see that as it'll be in the nanoseconds)
     
  6. RunnerFL

    RunnerFL Well-Known Member

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    That is correct.

    If you go with DECA on all of your units you are setting up a second network just for your DirecTV units. The DECA network won't interfere with your "regular" network and your "regular" network won't interfere with your DECA network. No collisions, no dropped packets, no bandwidth problems, etc.
     
  7. DarkLogix

    DarkLogix Godfather

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    If you use a switch not a hub then you won't have any collisions

    http://en.wikipedia.org/wiki/Collision_domain

    with a switch each port is a collision domain and is full duplex
    if you use a hub then yes you'll have collisions which is why you should use switches

    if your switch is functioning properly then they won't interfere anyway and if they were to then adding a BB deca would allow just as much interfereance

    trust me on this I work with networks (I may be new to learing about SWM and deca but networks are what I do)

    if anything you're expanding the collision domain with the use of deca so that you can have collisions between recivers
     
  8. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "Nope" as all DECAs communicate in the RF domain.

    "Now" if all DirecTV receivers are connected to the same switch, and things are working correctly, this won't be any different than the DECA cloud, with a BB DECA bridging to your home network.

    The only real difference would be when things aren't working correctly.
     
  9. DarkLogix

    DarkLogix Godfather

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    Oct 20, 2011
    What I ment by that is does the Deca RF domain act as a Hub or a switch?

    do the the deca's have frequencies that each picks to send on and then listen on all the others or is there a common send frenquency such that if 2 send at the same time they could have a collision?

    I don't know the details of the frequencies the deca's use for send and recive but
    if they all just send on the same range then they would also be reciving on that smae range and thus colliding
    though if they then piece out the full rand to listen to all the channels that they aren't using then it would put a limit on the max number of deca's

    or do they use one of the methods that cell/cablemodems use of TDMA
     
  10. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    Looks like I may start needing a translator here. :confused:
    The DECA center frequency is 550 MHz, and has a bandwidth of 50 MHz.
    Other than these, it really isn't known how they communicate. There is a 16 node limit, and a bit-rate exceeding 250 Mb/s.
    It's fairly hard [impossible] for RF to "collide", since it is directional.
    The whole DECA cloud needs to be seen as one device, and then it's outputs are very much like a switch.
     
  11. poppo

    poppo Hall Of Fame

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    People do have other devices that they connect to their switch that can take advantage of the speed.

    I have my 3 DVRs and namad connected to 4 ports, and all traffic between them runs along happily between themselves And I have my computer, server, etc. connected to it too, and they are gigabit and running happily between themselves at high speed.
     
  12. DarkLogix

    DarkLogix Godfather

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    well I know in cable internet they have to use TDMA/UCDMA to ensure that they don't send data in overlaping time segments

    and that they can't send and recive on the same channels
    DOCSIS uses the low channels (48Mhz and below, might be 64Mhz, for upstream and uses much higher channels for downstream)

    in DOCSIS each 38Mbps channel is upto 6Mhz wide (older ones can be 3Mhz)
    so if Deca's are all sending without some control mechanism to ether issue time slots to each or channels to each then it'll interfere with each other

    if RF is directional then DOCSIS would be able to use the same for sending and reciving which would greatly up the bandwidth as the low channels tend to have noise issues

    With that limit of 16 that tells me it likely has a control mechanism that ether pieces out the 50Mhz space or makes 1/16th second time slots (possibily goes through 16 time slots in some very short amount of time)
     
  13. DarkLogix

    DarkLogix Godfather

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    Yes I was talking from a benefit to the reciver's angle
     
  14. RunnerFL

    RunnerFL Well-Known Member

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    As do I...

    You should read up on SWiM and DECA before assuming you know how they work.
     
  15. DarkLogix

    DarkLogix Godfather

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    Well if you're using plain ethernet with switches you won't have any collisions, dropped packets, ect

    now if you use a HUB (which shouldn't even be sold anymore) then you can

    I didn't assume how DECA's work but I know the issues you list will not occue in a network using switches
    Please provide links to info on DECA's and SWiM so that I can read about it and see why its supposidly better
     
  16. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    For the same reason I don't profess to know networking, networking folks shouldn't try to grasp RF. Each has their own "rules/principals", but few are the same between them.
     
  17. DarkLogix

    DarkLogix Godfather

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    Read the rest of the sentance

    I Know ethernet networking and I learn all I can about other forms
    so I know that what he claimed about ethernet is wrong unless he's using gear which I wouldn't allow to touch any network I use

    now on Deca I want to learn more but so far it seems like its similer to wifi but over a cable and wifi is one big collision domain (ie bad) I hope I'm wrong so I want to learn more

    I do know quite abit about DOCSIS which is RF over coax (enough that I got board with that section of a forum) so RF isn't out of my grasp

    so far
    Its RF in the 550Mhz range with a 50Mhz width
    it has over 250mbps of bandwidth

    Now with what I know about Docsis there needs to be some method to avoid collisions as RF over Coax is not directional and will interfere with other signals in the same frequency

    so I want to know what is the method to avoid colisions?

    Docsis uses 2 very differant frequency ranges for send and receive and only the CMTS sends on the High frequencies and the CM's send on the low then via time slices it sections out which CM can speak to avoid multiple CM's from sending at the same time as that will cause collisions.

    From what I've read so far Deca is very similer to Docsis but simpiler
    so Please inform me of what I don't know.
     
  18. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    "I'm bored".
    You seem to have a mindset based on networking that doesn't work well in the RF domain.
    Perhaps others may be able to help you make some sense out of this. :)
     
  19. DarkLogix

    DarkLogix Godfather

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    well the knowledge I know has enabled me to trace a great many RF issues
    from a faulty barrel connecter to a wet connection to a bad GB and many more

    Sorry but I prefer to know more about how any networking device works
    Networking is networking not just ethernet
    Just because i say I know networking don't assume that I mean just RJ45 ethernet
     
  20. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

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    So do you know how to use this?

    [​IMG]
     

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