Part 3: Placing Nodes and Scaling the Network

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Determining the placement and number of nodes needed

Quick Tip: Let CloudTrax do the work

For large installs, test your environment with CloudTrax and two or three nodes. You’ll be able to see the range and how many walls and floors you can expect to transmit through.

The number of nodes you require depends on five factors:

  1. The size of the area you need to cover.
  2. How many walls and floors you need to penetrate with mesh.
  3. The material of the walls and floors you need to penetrate.
  4. The amount of interference in your environment.
  5. The number of simultaneous users expected on the network.

While every installation is different and the number of nodes you need will vary greatly with the factors above, in general, you shouldn't exceed these parameters when planning:

Device Indoor range Outdoor range Max walls to penetrate
OM2P 75-150' 600' 3-4
OM2P-HS 75-150' 600' 3-4
OM5P-AC 40-75' 100-200' 1-2
MR1750 75-150' 600' 3-4

In CloudTrax, you'll be able to see the speed of each device and signal strength between devices (both of which decrease over distance and through walls and floors). Look for a signal strength (or “RSSI”) of at least 20, where 30+ is desirable. You can add, remove, or reposition nodes as needed at any time.

While we've tested more than 250 users on a single node in the lab, you should aim for no more than 20-50 users per node to give each user an optimal experience. The maximum number of users will vary based on your network environment, ISP connection, and bandwidth to each client device. 

With any model, it is possible to overpower dense indoor networks. However, you can turn the transmit power down through CloudTrax if you experience symptoms such as interference or dropped connections. Setting TX Power to 19 or 21 dBm typically resolves these issues. 

For large installs, test your environment with CloudTrax and two or three nodes before buying all of the nodes. You'll be able to see the range and how many walls and floors you can expect to transmit through in your specific environment. Nodes transmit in a spherical pattern—up, down and side to side—so there's no need to “aim” signals.

Here are some guidelines to help plan how many nodes are needed for your installation.

Nodes: indoors or out?

With the advent of low cost mesh technology, network design is literally turning “outside-in.” Here are some benefits of installing your nodes indoors:

  • It is much less expensive to install inside rather than outside
  • Outdoor nodes often require an electrician to install power
  • Outdoor nodes often involve getting up on ladders or rooftops
  • Outdoor nodes require installation of long Ethernet cables
  • Outdoor nodes can be unsightly and often violate apartment/ condo CC&Rs
  • Outdoor nodes take your strongest signals outdoors, the opposite of what you generally want

 

Hotels and apartments:You will typically need one node for every four to six hotel rooms or apartments. This will vary depending upon the type of construction and layout. If you are in a single-story, single-row concrete/ brick/stone build, you may need one node in every second or third unit. For wood frame multistory buildings with interior hallways and small rooms, one node for every six or seven rooms may be sufficient if placed in a central hallway.

When installing multistory buildings, we recommend placing units on every second floor for both concrete and wood buildings. Copper ceilings, steel plating, cement and adobe-type materials may limit (and even eliminate) signal transmission between floors.

Coffee shops and restaurants: One well-placed node can usually cover an entire coffee shop. For restaurants or large coffee shops, you may need two or three nodes, especially if you want to cover outdoor seating areas.

Small and medium-sized businesses: One well-placed node can usually cover a small retail shop. For larger spaces, use the numbers in the table above to plan the number of access points based on the number of walls to penetrate. 

Residential neighborhoods: In residential neighborhoods, we recommend that each house have at least one node. And if the houses are especially large, you can add multiple nodes to the house to provide better coverage in every room. Wherever possible, place nodes near windows or exterior walls with a direct line of sight to the nodes in other houses. Placing some nodes outside may help extend coverage more efficiently.

Quick Tip: Test with a smartphone

Smartphones are the perfect device for testing. First, they are by far the most popular device on networks today. Second, they have a much weaker antenna than a laptop, so you’ll be able to find holes and weak spots in your network faster. A simple speed test application can show your download and upload speeds in each area of your property.

Determining a location for your gateway(s)

Gateway Users on mesh networks will lose half—or more—of their maximum speed for every hop they are away from a gateway. Therefore, you want to place the gateway(s) as central to the area you want to cover as possible. As you can see below, forcing traffic through too many hops quickly leads to very slow network speeds.

By moving the gateway from one end to the center, as shown below, you can improve the maximum potential speed on the outer reaches of the network by a multiple of four.

If most of your repeaters have a direct (or single “hop”) connection to the gateway, their speed is maximized. The easiest way to accomplish this, is to put your DSL/cable/fibre connection as close to the middle of the area you want to cover as possible.

Quick Tip: Using RSSI to position nodes

From the Access Points map view in CloudTrax, click on any node to see its name, throughput and connection to other nodes.

All of your nodes should have an RSSI of at least -70 (the closer to zero the stronger the signal) to one or more nodes. If not, try repositioning them closer or add more nodes.

Scaling your network

CloudTrax networks are highly scalable. To build large-scale networks, simply repeat the model above as needed by adding additional gateways and repeaters. There is virtually no limit to the number of gateways and repeaters you can have on a single network (although we recommend 200 or fewer nodes for readability of reports). Larger networks can simply be broken up into discrete zones under the same login.

There are two primary ways to add additional gateways: you can have multiple DSL's (cable modems, etc.) or have a switch with Ethernet cables, both distributing gateways evenly through your network.

The advantage of multiple DSL's feeding your network is twofold. First, you avoid running any Ethernet cabling. Second, you have a built-in failover: if one DSL were to go down, your network will switch-over to the other DSL(s) keeping your network up, if a bit slower. However, there is typically a higher ongoing cost to providing multiple low-speed DSL's compared to one high-speed DSL. With a switch running Ethernet to multiple gateways, you have a one time investment but a reduced on-going cost because you are only paying for one DSL connection.

Additional tips

Here are some additional network planning suggestions:

  1. Have the edges of the signals from nodes overlap so that each node can talk to at least one (and preferably two) other nodes, with good signal quality.

  2. Don't under install. Having redundancy built into the network by having extra nodes allows CloudTrax's self-healing, self-configuring mesh protocol to keep users connected and minimize outages.

  3. To avoid bottlenecks, don't have more than five repeaters running off of any one gateway.

  4. Think vertically in multistory buildings. If you have two or three floors to cover, place the nodes on the second floor. This keeps them centered between the floors where they can provide coverage both above and below. You get all of the coverage with half of the nodes.

  5. Use straight lines when broadcasting through walls and floors. The less material the wireless signal needs to penetrate, the stronger the signal will be.

  6. If you are installing in an apartment complex or hotel with internal hallways and no in-room cat5/6 Ethernet cabling, consider placing most nodes in the hallways. As this is common space, you'll have access to them without disturbing residents. Secondly, placing the nodes down a long corridor means they can all see each other without having to go through as many walls. This maximizes the signal between the routers and minimizes potential “hops” and low signal quality that will slow down the network. Add additional nodes as needed (typically in larger units) to boost signals in specific areas.

    If you are installing a building that has cat5/6 Ethernet cabling to each room, consider using the indoor Ethernet enclosure to add gateways to as many rooms as needed. In this scenario, you could do without repeaters completely, maximizing your network performance.

  7. If there is no power outlet where you want to place a node, you can power it through an Ethernet cable (power over Ethernet, or PoE). Any OM Series device can be powered through passive PoE; however, only the OM2P-HS, OM5P-AC & MR1750 devices are compatible with PoE switches using 802.3af standard PoE. Two enclosures—the outdoor enclosure and indoor Ethernet enclosure—are best used with PoE, while it is option in the indoor ceiling enclosure and not recommended for the indoor wall plug enclosure.

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Comments

  • Avatar
    Zach Boettner

    This page says... Look for a signal strength (or “RSSI”) of at least 20, where 30+ is desirable. But when I go to my Clients tab in CloudTrax I see in the RSSI column -69, -79, -81, -92, -63, etc. So are these good numbers or ??

  • Avatar
    Ryan Detwiller

    Hi Zach,

    RSSI is reported a bit differently on access points versus client devices. For the purposes of this article and planning your network, you'll want to click on an access point on the map and select the "Neighbors" tab to see the values mentioned above.

  • Avatar
    Irkonst

    Ryan, just done that but nothing appears. I have a single OM2P-LC. How can I test RSSI?
    What seems to be the most suitable position for the access point? What is the cover area and how I can maximize the range of my access point? Also what channel is preferable to use?
    Hope not to tire you!

  • Avatar
    Patrick Cummings

    "Have the edges of the signals from nodes overlap so that each node can talk to at least one (and preferably two) other nodes, with good signal quality."

    It's not super clear, but I assume this means the maximum distance between nodes (OM5p), say in an open field, should be about 400ft then?

  • Avatar
    Ryan Detwiller

    Yes, that's right Patrick.

  • Avatar
    Chris

    Is there a maximum RSSI value between nodes that I should try to stay below by decreasing radio power?

  • Avatar
    Kurt Heinrich

    Hi Guys,
    I have networks across 8 sites that I would like to have setup the same , they will not be visible to each other via any network and there will be around 40 - 50 access points in total. Are there any issues with this design , or are their advantages to using separate networks ?
    Its a common user base and we simply use a splash page to enforce terms and conditions.

  • Avatar
    Michael DeRousse

    In an environment where all nodes are gateways (i.e. connected via ethernet) and there may be some overlap between node coverage areas, is it recommended to change the channel to prevent interference between node radios? And if so, would this have any impact on device roaming between nodes?

  • Avatar
    Ryan Detwiller

    @Kurt - It's up to you. A "Network" is simply shared reporting, clients and configuration, so there's no issue with having multiple sites under one network.

  • Avatar
    Ryan Detwiller

    @Michael - slight overlap isn't an issue, and allows the mesh to act as a fallback in case a wired connection goes down. If you're seeing performance issues then it may be worthwhile to change the channels. We're testing a new feature that will determine this for you and set the channels automatically - looking forward to showing you!

  • Avatar
    Rodolfo Borcena

    hi just to clarify, will adding gateway on the mesh with different internet plan will be the same as adding the bandwith like load balancing? thanks...

  • Avatar
    Ryan Detwiller

    Great question Rodolfo. It's mostly the same. The only difference is in roaming - users will break their connection when roaming from one part of the network connected to one modem to another, as the external IP address will change.

  • Avatar
    David S. Smith

    New guy here, Just want to be clear, if I connect the nodes with cable, from the gateway, will I still run into signal loss for every hop?

  • Avatar
    Ryan Detwiller

    Hi David - no, hard-wiring access points with a cable eliminates the hop-loss.

  • Avatar
    Sadiq Mundi

    hi i would like to know if i can use this product to an offline e-library server without internet connection thanks in advance

  • Avatar
    Bryan Patterson

    Sadiq, our devices require an internet connection in order to be configured. They can be used offline by using the Disable Internet Check option but the internet check is used to find paths through the mesh so it is recommended not to disable it.

  • Avatar
    David Dunagan

    If I have an 850 seat auditorium and I want coverage plus 75% subscribership (638 users), how many MR900's would I want to use, and how many of them hard-wired? I have the ability to hard-wire all of them and bandwidth will be throttled down.

  • Avatar
    Bryan Patterson

    The MR900 can handle about 50-100 users depending on usage. If you're throttling bandwidth then 10 MR900s all hard wired should be able to handle the load. Just be sure to adjust the Tx power is turned down and you are using the Auto channel feature so that they aren't interfering with each other.

  • Avatar
    Carlos Aleman

    Hello everyone, the OM5P-AN are dual band, so do the mesh using the 5 Ghz band and leave the 2.4 Ghz band for the devices? or they use both bands to handle devices more efficiently? Also, when they mesh they do it automatically selecting the nearest point in order to heal the network? or this can be configured? What would you say is a safe distance for a hop?

    Thank you so much in advance, I've never worked with these APs and I'm designing my first network where we will be using them.

  • Avatar
    Bryan Patterson

    Hi Carlos - the OM5P-AN will mesh and serve clients on both 2.4 and 5GHz.

    Meshing happens automatically by selecting the best path based on signal strength and connection speed. It is not user configurable.

    The OM5P-AN is a relatively low power device so hops should be around 100-150 feet.

  • Avatar
    Brett Sizemore

    This page says... Look for a signal strength (or “RSSI”) of at least 20, where 30+ is desirable (I remember in CT3 this was valid, the AP RSSI #s were positive, numbers below 20 were in red). But in CT4 when I look at each AP and the neighbors tab, RSSI shows -56 to -73. Does the article need to be updated? Should it be at least -70 but -60 is desirable? Or what are the correct RSSI #s in the AP neighbors tab?

  • Avatar
    Bryan Patterson

    Hi Brett - On CT4 we aren't converting the RSSI to positive numbers anymore. The calculation in CT3 was basically just adding 90 to the negative RSSI value so a good signal strength for mesh in CT4 is -70 and closer to zero is better.

  • Avatar
    Phil Buhler

    Hi, on another page i read that both Ethernet ports on the OM2P can be either WAN or LAN. Can i use both ports as LANs to feed two rooms with a wired connection (thereby not needing to use an extra switch) ? Thx

  • Avatar
    Phil Buhler

    Ok so i've answered my last question but trial and error - yes you can use both ports as LANs for PCs etc but the two wired clients can't see each other ( I have SSID #2 in bridge mode) Also ive discovered a printer connected directly to one of the wired ports cant be printed-to, even though the printer happily enough goes out and picks up an IP address from the upstream dhcp. Not sure why that is - permanent neighbour isolation on wired ports ?

  • Avatar
    Ryan Detwiller

    @Phil - you'll need to allow access to LAN resources in order to print.

  • Avatar
    Alex Goven

    Earlier someone asked about load balancing, but the answer doesn't seem so clear to me.

    1. Do multiple modems add together to create a higher total bandwidth available to a client or will the speed be the same as having one modem? My neighborhood is stuck on 5Mb/s per household and I'd like to bond/team/load balance as many modems as my neighbors will volunteer. You can barely stream HD video on 5Mb/s, so I want to add these speeds together. I know this is possible with other equipment, but that would add a great deal of cost vs Cloudtrax+Open-Mesh doing the work.

    2. Is it more about guaranteeing the best speed by selecting the best modem for the client? So if a 3Mb/s and a 5Mb/s modem were equal as far as number of hops away and signal strength for a given client, that client would get 5Mb/s, not 8Mb/S (5Mb/s+3Mb/s) assuming other clients aren't currently adding internet connection load to the mesh network?

  • Avatar
    Bryan Patterson

    @Alex Having multiple modems will not combine the speed of both modems but having multiple modems will help spread the load of a busy network across multiple connections so that one node/modem won't get overloaded.

  • Avatar
    Patrick Cummings

    @Bryan, @Alex - Correct me if I'm wrong, but I believe it should also be noted per Alex's second question that with two gateways at equal distance/hops from the client but with different internet connection speeds, the client wont necessarily be working across the faster of the two as the nodes don't currently have a way of knowing how fast their hard-line connection actually is.

  • Avatar
    Bryan Patterson

    @Patrick - Yes, that is true. We don't currently have a speed test for the internet connection, just from repeaters to gateways.

  • Avatar
    Dave Duchesneau

    @Patrick: "... the nodes don't currently have a way of knowing how fast their hard-line connection actually is."
    @Bryan: "We don't currently have a speed test for the internet connection..."

    The underlying BATMAN/adv mesh protocol advertises the bandwidth available to each gateway node, and this advertised bandwidth is used -- in conjunction with the link quality between nodes (based on a weighting factor) -- by each repeater node to determine the gateway it should use.

    The problem is that there is currently no way to specify or edit a node's local gateway bandwidth information in CloudTrax, so a default value is used for all nodes. Since the default is the same for all nodes, there is no way to distinguish between nodes with fast or slow gateways. There's another complication also, which is that there are likely to be relatively fast gateways that have low data caps (e.g., a LTE or satellite modem with a 10GB cap). These low-data-cap gateways can easily have their caps exceeded, which is a serious issue that keeps them from being enabled and/or added to the network in the first place.

    Because the BATMAN/adv protocol only advertises a single 16-bit integer describing the gateway bandwidth (and changing the protocol is not feasible), CloudTrax should expose this integer and make the default value specifiable, with a specifiable per-node override value. Even in the simplest-possible STATIC solution, the single integer value used must merge two different gateway constraints: 1) data cap, and 2) speed. The most straightforward way to incorporate both is to encode the data cap in the MSB (most significant byte) because it is also the MOST IMPORTANT constraint, and to encode the speed in the LSB (least significant byte).

    The most obvious benefit of this STATIC (fixed) encoding is that gateways advertising high data caps (e.g., DSL or cable with 200 GB to 500 GB caps) will be preferred over all gateways with lower data caps (e.g., 3G, 4G LTE or satellite), even if the low-data-cap gateways offer faster speeds.

    By using the MSB and LSB to encode the data cap and speed, respectively, it has the very beneficial effect of creating "classes" of data caps and speeds, since there are only 256 values for each byte. A good encoding should at least encompass the order of magnitude, which would require only 4 bits to cover the entire range of possibilities. These 4 order-of-magnitude bits should occupy the most significant "nibble" of the MSB (data cap) or LSB (speed). Any additional bits in the least significant nibble will only come into play when the dominating order of magnitude changes.

    With this approach of statically merging data caps and speeds into the same constraint variable, many more gateway nodes can have alternative provisions for uplinks (e.g., 3G, LTE, satellite) while minimizing the risk of exceeding data caps.

    Consider emergency communications: This same data cap/speed technique would even allow dial-up modems to be distributed around a network (a 24x7 "unlimited" dialup modem would have a maximum data cap north of 140 MB monthly), and their "speed" constraint would normally keep them from being used if cable and DSL modems were available and had the same order-of-magnitude data cap (but cable and DSL would normally be higher). Of course, a dialup plan's data cap could also be much lower, so that they might be on par with 3G modems or some such, so as to prefer 4G LTE over dialup. The point is that minor mods to CloudTrax now would enable a network manager to take advantage of all available gateway uplink technologies.

    Later on, when the capability is eventually added for gateway nodes to determine Internet uplink speed (which could be relatively soon), then that speed value should be DYNAMICALLY encoded into the LSB in the same algorithmic way that the STATIC value was set. Keep in mind that speed-based decisions would still be subordinate to data caps (which should be controlling).

    A future, more advanced CloudTrax capability would be add "gateway vouchers" that specify the monthly data caps and speeds of a gateway device, with the actual usage tracked by CloudTrax. When multiple gateway nodes are connected to the same gateway device (e.g., via a switch), then CloudTrax would need to aggregate their usage. The monthly data cap remaining (tracked by CloudTrax on a per-gateway device basis) should be DYNAMICALLY encoded into the MSB in the same algorithmic way that the STATIC data cap value was set. Likewise, the current uplink speed value should be DYNAMICALLY encoded into the LSB in the same algorithmic way that the STATIC speed value was set.

    It is important to note that with DYNAMIC updates, CloudTrax would need to update the local nodes only when there is a change in the ORDER of MAGNITUDE of the monthly data cap remaining, or the available uplink speed. In the interest of mesh autonomy (and minimizing CloudTrax costs), it would be advisable for the mesh firmware to be updated to track the data caps and speeds locally, and simply report them to CloudTrax.

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