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DECA support?

Discussion in 'DIRECTV Connected Home' started by Hoggy, Dec 3, 2010.

  1. gg80108

    gg80108 New Member

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    think its coming to me now,, I dont have a phone line so the HD receivers registered on the router so I can do pay per view and see HD on my DirectTVtoPC .... The mac on the deca must just be for the private network of hd receivers so the dvr can go from room to room ..
     

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  2. The Merg

    The Merg 1*

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    I'll hafta do some more research as the DECA, considering its function, should not need a MAC address at all. The only thing I can see is it is technically acting as a switch, which while having a MAC address, as you mentioned above regarding the DECAs, it does not require a IP address.

    - Merg
     
  3. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    Seriously .. 50? .. Something's not sounding right with that number.

    That being said, each DVR can see 10 DVRs (again, not sure if that is 10 total or 11 total, but I think it's 10 total, including the one you're on).

    So even if you found a way to hook all of them up (Ethernet switch, whatever) .. You'd find that you're severely limited by not having 40 DVRs on your playlist at all. Double that by the fact that I THINK the DVR selection will change each time. It would make for a lot of WTF moments I think.
     
  4. Barry in Conyers

    Barry in Conyers Godfather

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    My DECA1MR0-01 module has the MAC address printed on the bottom of the front green label.
     
  5. bobnielsen

    bobnielsen Éminence grise

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    Bainbridge...
    I think that the term "bridge" is a better fit than switch.
     
  6. The Merg

    The Merg 1*

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    Could be... :)

    Was just making the point that while a switch has MAC, it doesn't need an IP address... Might be similar to how the DECAs are working. Generally, a bridge will have it's own IP address, even if it is not used for anything other than acting as a bridge.

    - Merg
     
  7. Barry in Conyers

    Barry in Conyers Godfather

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    As currently utilized, a DECA module is neither a switch nor a bridge; it is simply a bi-directional converter that goes between an Ethernet cable and a coax cable. A MAC address is not needed for that use, so perhaps there are other potential applications.
     
  8. HoTat2

    HoTat2 Hall Of Fame

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    But don't DECA adapters still act like an ethernet bridge by only allowing the data packet streams intended for destinations on its opposite ends (ethernet cable<--->coax) to traverse it while blocking all others?
     
  9. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    Well technically it is a bridge. It bridges the DECA network with the Ethernet network. TCP/IP runs on top of each network.
     
  10. HoTat2

    HoTat2 Hall Of Fame

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    Yes, and in fact that was the main reason I thought a DECA adapter needs a MAC address so it would know what data packets to actually allow over its "bridge" and what not to and block.

    If the data packet has a particular DECA's MAC address embedded in its header it allows the packet to cross, if not it ignores it which effectively blocks the data traffic from passing.
     
  11. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    I'm not sure exactly what is going on there as certainly non DECA connected DVRs can traverse the bridge.
     
  12. Barry in Conyers

    Barry in Conyers Godfather

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    Being TCP/IP on both sides does not mean something is a bridge. If the DECA unit is not blocking packets based on MAC addresses, what bridging function is it performing?
     
  13. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    It's a bridge because both Ethernet and DECA are operating on Layer 2 .. and the DECA module connects the two distinct physical networks.

    TCP/IP is Layer 3.

    If there were switching/routing on the DECA module (there's not), then the module would be a switch.
     
  14. Barry in Conyers

    Barry in Conyers Godfather

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    I know what a switch and router do. The still unanswered question is what bridge function does the DECA module perform?
     
  15. bobnielsen

    bobnielsen Éminence grise

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    Bainbridge...
    http://en.wikipedia.org/wiki/Bridging_(networking):

    Bridging and routing are both ways of performing data control, but work through different methods. Bridging takes place at OSI Model Layer 2 (data-link layer) while routing takes place at the OSI Model Layer 3 (network layer). This difference means that a bridge directs frames according to hardware assigned MAC addresses while a router makes its decisions according to arbitrarily assigned IP Addresses. As a result of this, bridges are not concerned with and are unable to distinguish networks while routers can.
     
  16. The Merg

    The Merg 1*

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    Which makes perfect sense. As you would normally use a switch on a network with a router, any traffic that is destined for that network would already be directed onto it by the router. The switch at that point is just looking for the device on that network to send the data to and does so by looking for the particular MAC address.

    Of course, the interesting thing here is that a switch will not have a MAC address, yet the DECAs do. And bridges generally have MAC addresses and IP addresses, but DECAs do not have IP addresses. So, what exactly is the purpose of the MAC address of the DECA?

    - Merg
     
  17. Doug Brott

    Doug Brott Lifetime Achiever DBSTalk Club

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    The same function any network bridge does .. transports data packets between two different networks. In this case, the bus/token topology on the DECA side and the bus/broadcast topology on the Ethernet side. Physically the two types of networks work differently .. The DECA module connects these two distinct networks to make them appear as one network .. bobnielsen gives an apt description above.
     
  18. hdtvfan0001

    hdtvfan0001 Well-Known Member

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    I think some of this DECA network technical information would be a valuable addition to the FAQ section....just my $0.02.
     
  19. Barry in Conyers

    Barry in Conyers Godfather

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    hdtvfan0001 and I have been known to disagree, but I'll throw in two bits if it will help convince someone that technical documentation is a good idea and is not "too complicated".
     
  20. HoTat2

    HoTat2 Hall Of Fame

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    Yeah ...

    I certainly would not consider myself among the ethernet savvy myself and have a tough time getting my mind wrapped around some of this ethernet IP/TCP protocol stuff. :)

    However, in the assortment of intermediary networking ethernet switches, PowerLine adapters, and of course DECA adapters on my home network I notice none of them show up on my Network Magic topology map or under the "Network" category of any PC here running Windows Vista or 7 as devices with assigned IP addresses.

    Only the end terminal equipment. PCs, my NAS, networked printer, the DirecTV receivers (as "media adapters," "servers," or "renderers" ), etc.

    But can't we still assume as with all other bridges where after powering up the DECA adapter bridges likely build up then store a list of MAC addresses (a forwarding or filtering database) on the two LAN segments it joins?

    Then when a DECA receives a frame with a MAC destination address on the same LAN segment it ignores it, but if the MAC destination address is on the other segment it passes it over to that segment as the Wikipedia link bobnielson refers to describes?
     

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