Placing Nodes and Scaling the Network

Topic

This article describes placing nodes and scaling an AP Mesh-enabled network with wireless repeaters.

Environment

  • Datto Access Points
  • Datto Network Manager

Description

The number of nodes needed, and the placement of those nodes depends on a variety of environmental conditions. When planning the placement of your nodes, keep in mind that Datto Access Points are intended for deployment within a LAN environment and should not be directly connected to the internet.

NOTE  Wireless meshing uses a significant amount of air time and is generally not recommended for deployments where maximum throughput is desired.

Determining the placement and number of nodes needed

Environmental variables

The number of nodes you require depends on the following factors:

  • The size of the area you need to cover
  • The number of walls and floors you need to penetrate with mesh
  • The material comprising the walls and floors
  • The amount of interference in your environment
  • The number of simultaneous users expected on the network

Evaluating signal strength

In Network Manager, you can see each device's speed and signal strength (both of which decrease over distance and through walls and floors).

The WiFi speed and strength being reported corresponds to the mesh link between Access Points configured at Manage → Access Points → Status → Neighbors tool → Access Point details flyout. Data will not populate here if:

  1. AP Mesh is disabled.

  2. The Access Points are on different channels.

  3. The Access Points are out of range from each other.

Look for signal strength (or RSSI) to be no higher than -65, where -30 to -50 is desirable. You can add, remove, or reposition nodes at any time.

Users per node

For optimal user experience, aim for no more than 20-50 users per node. The maximum number of users will vary based on your network environment, ISP connection, and bandwidth to each client device.

Transmit power

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

Testing the 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 you need for your installation.

Indoor vs. outdoor node installations

Where possible, install your nodes indoors. In addition to costing more to install, outdoor nodes:

  • often require an electrician to install power.
  • may involve getting up on ladders or rooftops.
  • need installation of long Ethernet cables.
  • can be unsightly and often violate apartment/ condo CC&Rs.
  • take your strongest signals outdoors, the opposite of what you generally want.

Sample node setups

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).

  • In single-story, single-row concrete, brick, or stone buildings, you may need one node in every second or third unit.
  • In 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 hall.
  • When installing multistory buildings, a best practice is to place nodes 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 include outdoor seating areas.

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

Residential neighborhoods: In residential areas, a best practice is to ensure that each house has at least one node. If the houses are large, you can add multiple nodes 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.
Smartphones are preferred test devices; they have less powerful antennas than laptops and are better suited to finding holes and weak spots in your network. A speed test application can show download and upload speeds in each area of your property.

Determining gateway locations

Gateway users on mesh networks will lose half (or more) of their maximum speed for every hop away from the gateway. As a best practice, place the gateways as central to the coverage area as possible.

mceclip0.png
Figure 1: Speed degradation over multiple hops to the gateway

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

mceclip1.png
Figure 2: Optimal gateway placement

Since your repeaters' speed will operate at maximum speed if they have a direct (or single-hop) connection to the gateway, put your DSL/cable/fiber connection as close to the middle of the coverage area as possible.

To position a node using RSSI, click it in Network Manager 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

Datto networks are highly scalable. To build large-scale networks, add additional gateways and repeaters according to the guidelines above.

  • 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 report readability.
  • More extensive networks can be broken up into discrete zones under the same login.

mceclip2.png
Figure 3: Network scalability

Adding additional gateways

There are two primary ways to add additional gateways:

  • Multiple DSLs (cable modems, etc.)
    • Let you avoid running Ethernet cabling
    • Provide built-in failover (if one DSL goes down, your network will switch-over to the others)
    • Somewhat slower than the Ethernet method
    • May cost more due to multiple DSL connections
  • A switch with Ethernet cables distributing gateways evenly through your network.
    • Faster than multiple DSLs
    • Reduced ongoing cost
    • You may need to run Ethernet cabling

Additional tips

Here are some additional network planning suggestions:

  • Ensure the nodes' signal edges overlap so that each node can talk to at least one (and preferably two) other nodes with good signal quality.

  • Don't under-install. Building redundancy into the network by having extra nodes lets Datto Network Manager's self-healing, self-configuring mesh protocol keep users connected and minimize outages.

  • To avoid bottlenecks, don't run more than five repeaters off of any single gateway.

  • Think vertically in multistory buildings. If you have two or three floors to cover, place the nodes on the middle floor so they can provide coverage where they can provide coverage both above and below.

  • Use straight lines when broadcasting through walls and floors. The less material the wireless signal must penetrate, the stronger the signal.

  • If you are installing in an apartment complex or hotel with internal hallways and no in-room Category 5 or 6 Ethernet cabling, consider placing most nodes in the hallways.

    • As this is shared space, you'll have access to them without disturbing residents.

    • The nodes can see each other without having to go through as many walls, maximizing the signal between the routers and minimizes potential “hops” and low signal quality.

    • Add additional nodes as needed (typically in larger units) to boost signals in specific areas.

mceclip3.png
Figure 4: Suggested node placement in larger units

  • If you are installing a building that has Category 5 or 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.
  • 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).

  • Due to the way Datto Networking detects and reports nodes, daisy-chained devices will show up as repeaters. However, each daisy-chained node will still receive the same bandwidth as the gateway it is connected to.