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Subnet playlist seperation question

Discussion in 'DIRECTV Connected Home' started by brett_the_bomb, Jan 11, 2013.

  1. The Merg

    The Merg 1*

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    Northern VA
    You guys are picking up on this. The big thing to remember is that whatever IP address that you pick for a device will determine what other devices it can see. Also, most routers as a standard will only handle DHCP cleanly/easily for one subnet. What that means is that you would want to set the DHCP range so that it covers only one of the subnets. If you want the router to handle DHCP addresses for multiple subnets, you need to use something like IP-Helper Address so the client can find the DHCP server if it is on a different subnet and so that the DHCP server can assign an IP address to the correct subnet. If you are going to use subnets, it is easiest to use static IP addresses on all of the secondary subnets and leave DHCP to the primary subnet.

    - Merg
     
  2. dennisj00

    dennisj00 Hall Of Fame

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    Nobody should feel bad about this or their posts. Subnetting is probably the trickiest part of networking and unless you're good at flipping bits and turning a binary sequence of 32 bits into four octets, it can be baffling. It's been a few years since I've done any of this in practice and most high end commercial routers help you avoid it by allowing vlans.

    For a group of 20 dvrs, you're going to have to use a group of 32, which allows 30 active devices and needs a mask of 255.255.255.224. You also want to keep the router mask at 255.255.255.0 so it will see everything on the lan.

    So for the first group, set the first dvr to 192.168.1.225 with the above mask. You continue the first group up to .254.

    I'd also avoid DHCP and as Merg says set the DHCP range away from any of your groups. Also put a DNS entry for either your ISPs DNS (you can generally see those in your routers WAN setting or use the OPENDNS servers.

    Happy segmenting!! Back to football!

    Edit: Rereading, I see the OP wanted groups of 8 which means using a group of 16 and will waste 6 addresses. So a mask of 255.255.255.240 and start the group at 192.168.1.241 to .254.
     
  3. The Merg

    The Merg 1*

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    Northern VA
    And I'll second what Dennis said about understanding all of this. I still need to look on-line when doing the calculations for subnetting as it's just that much easier for me.

    - Metg
     
  4. carl6

    carl6 Moderator Staff Member DBSTalk Club

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    Seattle, WA
    I've been trying to follow this and understand at least a little of it. So as an example, if I wanted to set up 8 groups of IP addresses with 30 clients in each subnet, I would use a mask of .224, and would end up with (assuming I'm using 192.168.0.xxx):
    192.168.0.1 through 192.168.0.30
    192.168.0.33 through 192.168.0.62
    192.168.0.65 through 192.168.0.94
    192.168.0.97 through 192.168.0.126
    192.168.0.129 through 192.168.0.158
    192.168.0.161 through 192.168.0.190
    192.168.0.193 through 192.168.0.222
    192.168.0.225 through 192.168.0.255

    So how would I set up a single router (consumer class, not a high end Cisco) to handle everyone? If I assign it the "typical" 192.168.0.1 address it would be in the first group. Or do I give it a subnet mask of .000 and by doing that it can then see/communicate with all of the groups? Then would I set the gateway the same in all the groups (.1)?

    But if I then program a client in the second group (.33 through .62) with a subnet mask of .224, it shouldn't recognize the router/gateway with an IP of .1 should it? Or will it because the subnet mask in the router is .000?

    Let's stretch this question a bit farther. Let's say I want one computer in each of the groups to have access to all 255 clients, but the remainder to only have access within their individual groups. I would give the one computer (in each group) a subnet mask of .000 and that takes care of it?

    Sorry to turn this into a network class, but my questions seem to be a logical follow-on to what has been posted so far.
     
  5. brett_the_bomb

    brett_the_bomb Legend

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    Oct 24, 2009
    +1

    I wouldn't mind a little extra info
     
  6. dennisj00

    dennisj00 Hall Of Fame

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    Carl, here's a short answer. . . while I haven't tested this with all brands of home routers, you should be able to set your router to 192.168.0.1 with a mask of 255.255.255.0 but of course you can't use the .1 in your first group of clients.

    I remember having a 'management' pc with a mask of 255.255.255.0 being able to see all the clients, but I don't think the masked clients (something less than .0 as the last octet) being able to see those pcs.

    I think that goes under the 'other problems' I mentioned earlier.
     
  7. The Merg

    The Merg 1*

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    Northern VA
    Correct. The router being set with the subnet mask of 255.255.255.0 allows it to see all clients connected to it. It shouldn't matter what the IP address of the router is.

    Here's a pretty good doc that shows how computers/router communicate depending on their IP address and subnet mask. Start at page 4 where it shows the examples.

    http://www.mission-systems-inc.com/How Subnets Work in Practice.pdf

    - Merg
     
  8. HoTat2

    HoTat2 Hall Of Fame

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    Hey, nice easy to read and understand document.

    But to be clear from the doc., the (typically 4 or 5) LAN ports on a router are more than just an integrated ethernet switch, but can actually route packets between different LAN sub-networks (if the router's LAN interface is configured to cover both subnets of course)?
     
  9. The Merg

    The Merg 1*

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    Northern VA
    Mmmmm... Not exactly. The router is still routing packets within the same network, just a different subnet. As far as the router sees it, all the devices are on the same network.

    - Merg
     
  10. HoTat2

    HoTat2 Hall Of Fame

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    Los...
    OK, but from the doc., the router changes the packet header information from its own LAN address set by the source on one subnet (under the "Next Hop" category in the doc.) to the actual destination address of the packet on another subnet when the router places the packet on the particular LAN port the destination host on the other subnet is connected to?

    Just want to be clear that the LAN ports of a router are more than just an ethernet switch that can "switch" packets between physical ports, but only for hosts on the same network. Not between networks which falls into the area of "routing."
     
  11. BAHitman

    BAHitman Godfather

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    Austin Texas
    It is not a wise idea to break up a subnet on some devices and not others with overlapping IP addressess...

    This can cause erroneous broadcasts to be seen by some devices on addressess other than the correct address, and I have seen this crash some consumer level devices, including routers...

    it will NOT net you internet access on those devices that cannot "see" the router.
     
  12. BAHitman

    BAHitman Godfather

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    Oct 23, 2007
    Austin Texas
    If host1 talks to host2 through the switch of the router, the router has no involvement whatsoever in the communication, except that the switch fabric simply sends the data to the destination port... only in cases where host1 has to talk to google which is on the other side of the router, that's where the translation and hop count comes into play
     

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