wireless bridges, tivos, and networks and subnets, oh my!

Discussion in 'TiVo Roamio DVRs' started by CrashHD, Jan 28, 2020.

  1. CrashHD

    CrashHD I am the me.

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    I'm considering building a wireless network bridge link to connect my home and my farm office. The farm and office is about a mile and a half away. I'll be able to get line of sight from an existing antenna tower at one location, and a tall rooftop at the other (question doesn't actually pertain to wireless bridge, just including it for context).

    The purpose is to get internet to my farm office, *BUT* if I could also get a tivo mini, that would be great.

    Will tivos work across different subnets? I was going to route this with my home as one class D subnet, and my farm as another. For example, tivos in my home might be 192.168.1.xxx addresses, and tivo minis at my farm might be 192.168.2.xxx addresses.

    Will that work?
     
  2. HerronScott

    HerronScott Well-Known Member

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    I'm pretty sure that you need to be on the same subnet.

    Scott
     
  3. CrashHD

    CrashHD I am the me.

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    Furthering discusion on that, is there a subnet size limitation? Subnet mask 255.255.128.0 is twice as large as 255.255.255.0.

    I'm reasonably certain I don't have to route the wireless bridge, and both sides can be on one subnet.
     
  4. HerronScott

    HerronScott Well-Known Member

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    Someone has reported issues with the mobile app using a larger than class C subnet. Not sure if I've seen any reports regarding the Mini with this kind of configuration (but if you use the mobile app it could be an issue for you anyway).

    Scott
     
  5. Diana Collins

    Diana Collins Well-Known Member TCF Club

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    Any given subnet is limited to a max of 254 devices, including the gateway. However, you can run multiple subnets on the same physical wire by using a subnet mask of 255.255.0.0. That would make addresses like 192.168.1.25 and 192.168.2.50 appear on the same LAN. I haven't tried it with TiVos, but that should work. I can't speak to the issue of the mobile app, since I hardly ever use it and never locally. I seriously doubt TiVo to TiVo connections will work through a router - bridging is what you want to do.

    This is all under IP4...if every device supports IP6 the rules are different, but I don't think TiVos support IP6.
     
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  6. nt40lanman

    nt40lanman Member

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    In Diana's example above, 192.168.1.xxx and 192.168.2.xxx are on the same subnet with a 255.255.0.0 subnet mask. A 255.255.255.0 mask allows 254 clients. A subnet mask of 255.255.0.0 will give you 65,534 clients on the same subnet. More reasonable would be a 255.255.254.0 giving 510 clients. I can't see why a Tivo and a mini wouldn't work on a more custom subnet like that as long as they are configured properly. I think the communication between the twois a broadcast announcement, which wouldn't go through a standard router.
     
  7. HDRyder9

    HDRyder9 Member

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    I have a customer that, due to the large number of home automation devices, needs to use multiple subnets. As long as its configured properly there are no issues.

    Why over complicate things? Just use a single subnet both places and there will be no issues.
     
  8. Time_Lord

    Time_Lord Member

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    The simple answer is no you cannot use TiVO's across different subnets. In your subnet example you show Class C networks not Class D, the reason I point this out is Class D subnets are used for Multi-cast traffic which then brings me to what the TiVO's are doing in the background.

    This is all from a very foggy memory as I don't have any notes readily available to me so some of the information maybe blatantly wrong but as I recall.... When I looked closely at the traffic generated by the TiVO's about 6+ months ago I found that there were several different (3 or 4?) multi-cast groups used to allow the TiVO's to find each other and pass certain data to each other on the network, in addition the TiVO's also used a network broadcast to exchange some additional data.

    With the exception of the network broadcast you can route/forward multi-cast traffic if your router is capable of doing so, that being said in theory you should be able to make your TiVo's visible across subnets, the only problem is what to do about the broadcast traffic and at this point I don't remember what the TiVO's uses it for.

    -TL
     
  9. Time_Lord

    Time_Lord Member

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    This is not an example of multiple subnets, when you specify the mask of 255.255.0.0 and an address of 192.168.1.25, the subnet actually covers 192.168.0.0 through 192.168.255.255 as the complete subnet which puts both of your hosts on the same subnet/network. in addition the subnet mask provides you roughly 65,000 hosts on the subnet, this type of subnet is referred to as a CIDR subnet (Classless Inter-Domain Routing) since you are taking a class C subnet and defining it as something larger, in your case what would be equivalent to a Class B, this type of subnetting is quite common today.

    nah many of the same subnetting rules remain, they are just MUCH larger subnets, for example the smallest recommended subnet is a /64. IPv6 does offer a bunch of other things that IPv4 doesn't but it's not relevant to the discussion.

    Oh and the TiVO's don't support IPv6 yet.
     
  10. kdmorse

    kdmorse Well-Known Member

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    Standard issue Tivo VPN (or other site in general) rules:

    (Yes, all of this applies to tivo's at multiple sites connected via a VPN, which is not what you're doing. However, the rules should be the same (You will more likely be building either an overlay network with a fake subnet, or two separate subnets locally with a limited access bridge in between)).

    1) The units must *believe* they are on the same subnet.
    2) The units must be able to receive each others broadcasts freely.
    3) The units must be able to receive each others multicast packets freely.
    4) The units must be able to receive directed unicast packets sent between any two units freely and without molestation.

    How you satisfy the above rules, is up to you. The most common way is to VPN them is to create one bridged supernet that contains all the different site's subnets, and limit that bridge to Tivo traffic.

    Site A: 192.168.1.0 / 24 (255.255.255.0) - Default router - 192.168.1.1
    Site B: 192.168.2.0 / 24 (255.255.255.0) - Default router - 192.168.2.1
    Site C: 192.168.3.0 / 24 (255.255.255.0) - Default router - 192.168.3.1

    Tivo A: 192.168.1.200 / 16 (255.255.0.0) - Default router - 192.168.1.1.
    Tivo B: 192.168.2.200 / 16 (255.255.0.0) - Default router - 192.168.2.1.
    Tivo C: 192.168.3.200 / 16 (255.255.0.0) - Default router - 192.168.3.1.

    Note, in the above case, all Tivo's believe they are on 192.168.0.0/16 (255.255.0.0). Usually we rig the DHCP server to lie with a static reservation. This is a lie, but it's a functional lie.

    And then build a bridged VPN between all three sites that permits all traffic FROM the MAC address of the local tivo at that site into the bridge. (OpenVPN in bridge mode, with EBTables to limit what enters the bridge is common)

    Special note for Mini's:

    I have never managed to pair a mini to it's parent remotely. Static it, pair it sitting right next to it's parent, make sure it works, *then* carry it to the other location.

    Mini's do not tolerate packet loss. At all. They assume a perfect, wired equivalent network. They even have trouble on some peoples normal wired etherenets if they're not 100% perfect. Whatever you do, it is up to you to ensure perfection on the underlying network, or you will have a miserable experience. People have gone as far as to use a dedicated VPN with FEC enabled to smooth out the bumps.

    ----------

    This is not the only solution, people have come up with custom man-in-the-middle forwarding solutions that shepherd the packets from one network to another in the way that the Tivo likes. I'm told it works, never done it in person.

    Also, the rules may have changed (become more lax?), if so, maybe you can do it easier than the above. I always do some flavor of the above, and it's never failed me.
     
  11. Diana Collins

    Diana Collins Well-Known Member TCF Club

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    Yeah...I know all that - just seemed like overkill for the question. Most non-professionals think of the mask 255.255.255.0 as the definition of a subnet, since they never deal with anything but a Class C subnet. But hey, thanks for mansplaning!
     
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  12. kdmorse

    kdmorse Well-Known Member

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    The problem was the above sentences. It makes anyone in networking twitch just reading it. We know what you're getting at in the threads context - but the words themselves are so wrong as written that I've been spending all afternoon resisting the urge to correct them. ;)
     
  13. Diana Collins

    Diana Collins Well-Known Member TCF Club

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    VPN is overkill. All he really needs is a wireless bridge. Unless he's got more than 254 devices that can all be the same logical network. Easy-peasy, but wireless bridges are not exactly cheap (hundreds to thousands) and require absolutely clear LOS. AT 3 miles capacity, this should do the job: Extended Long Range WiFi Bridge System
     
  14. Diana Collins

    Diana Collins Well-Known Member TCF Club

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    Trust me, I tried to write a response that used all the correct terminology, but the need to explain thinks like MAC vs IP address quickly turned into a treatise on local area networking pretty quickly. So I used the same terminology that most laymen around here use.

    I would suggest that my post directly before this one is the sort of answer the OP was really seeking. But that's just my opinion.
     
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  15. kdmorse

    kdmorse Well-Known Member

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    The original post included a desire for multiple subnets*. If multiple subnets are involved, shenanigans are required.

    Edit: *Or at least, a query about how Tivo's interact with multiple subnets, which is why I went there

    I think we all agree a flat network would eliminate all requirements for shenanigans. As long as the OP is happy with a flat network, and as long as the Mini was happy with the latency and any packet loss (which is distance and wireless related, not topology related), then everyone's happy.
     
    Last edited: Jan 30, 2020
  16. Diana Collins

    Diana Collins Well-Known Member TCF Club

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    Sure...I had a client that had offices on both side of the New Jersey Turnpike and they used a wireless bridge to link the two offices. Latency and packet loss wasn't bad - unless it was raining. :) That was years ago...wireless radios are a lot better now.
     
  17. CrashHD

    CrashHD I am the me.

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    Agreed, VPN will be unnecessary. This will all be one network. I was considering having a dhcp server on both sides of the wireless bridge, but that that doesn't have to mean different subnets, it can just be dhcp servers assigned non-overlapping address ranges.
    Latency issues in streaming were going to be my next concern. LOS might be scraping a few treetops unless I put up bigger towers. As to budget, thousand dollar equipment will not be a dealbreaker if it works. Decent internet costing $100/month per location, serving these both from a single location means a $1200 investment pays off in a year, and $2400 in two. If my hardware investment can break even inside of two years, this plan is go.
     
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  18. rpiotro

    rpiotro Member

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    Why have you not considered burying a fiber cable? A mile and a half is not that great of distance. Fiber is getting cheaper and easy to do these days. The reliability and speed are much better than wireless. I was at a training session recently on the new fiber. As part of the training they offered a kit for $450.00 that included the necessary tools and a small number of connectors. The process is so simple a caveman could do it. Put ethernet to fiber convertor on both ends and done.

    I question the ability for a mini to work at all over wireless. Is this something new with the current generation? I have the old stuff and they are specifically not supported. I tried it anyway and no joy.
     
  19. kdmorse

    kdmorse Well-Known Member

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    From a technical point of view, that's an excellent idea, and would be the best solution. From a geographical point of view, depends on the topology involved.

    But I just played with fiber prices, and from a pricing point of view, the cost could probably drive one back to trying wireless first pretty quickly.

    It's not supported at all. But it's always worked as long as your wireless was equivalent in quality to a wireless network (low latency, *no* packet drops, multicast supported sanely) For some, no interference, good equipment, this is easy. For others, the mini looses its brains every time you microwave soup. And many wireless access points don't handle multicasts in a useful manor. So, it's an unsupported crapshoot.
     
  20. CrashHD

    CrashHD I am the me.

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    I don't own the ground between point A and point B.
    Within my own house, I've used a mini just fine on wireless. The thing about a wireless bridge is if done correctly, the fact it is wireless is irrelevant to the devices. The question will be if it introduces too much latency or not.
     

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