Intra-mesh Connectivity

Each location where NYC Mesh offers connectivity is called a node and part of the purpose of each node is to connect individual NYC Mesh members to as many other nodes that are also participating in the NYC Mesh network as possible. That’s what makes NYC Mesh a mesh network!

To do this, we install an outdoor router somewhere in the building or, more commonly, on the roof of the building to which we are offering NYC Mesh connectivity. Since these routers and antennas are physically installed at individual member’s apartments or rooftops, we sometimes also refer to these hardware components as Customer-Premises Equipment (CPE).

If a node’s outdoor router connects to more than one other outdoor router, we call it a hub or a hub node simply to distinguish it from singly-connected nodes. In general, the more connections a node has to other nodes, the more important it is in our network because more traffic is likely to be transported through multiply-connected nodes than singly-connected nodes. This is very much like the way a busy intersection will have more cars traveling through it than an intersection at the edge of town will. We call our most well-connected nodes supernodes, as these nodes usually have very high-power routers installed. (Refer to our Node Reference for details about any given node installation.)

Each node’s outdoor router has at least two connections: a downstream connection and an upstream connection. These terms refer to the direction in which messages (network traffic) are carried towards or away from end-user connections. The outdoor router’s downstream connection usually connects to an indoor router, which lives inside the individual member’s house or apartment. In contrast, the upstream connection always connects to other NYC Mesh outdoor routers, which are usually located on the roofs of nearby buildings in the neighborhood.

We use a number of different hardware devices as outdoor routers. One of the major differences between each type of hardware device is the kind of antenna attached to it. Some outdoor routers have omni-directional antennas, which are like souped-up versions of an indoor router’s Wi-Fi antenna and can emit or receive a signal in a full 360° circle. Other outdoor routers have directional antennas, which point in a specific direction and can only send or receive a radio signal in that specific direction. Thanks to their more focused radio beam, directional antennas can often connect outdoor routers to other nodes over much longer distances than omni-directional antennas can.

Since late 2016 and early 2017, NYC Mesh has preferred two hardware brands for its outdoor routers. These are Ubiquiti Networks and MicroTik, which both manufacture several different models of outdoor router and antenna equipment that we use for different nodes. One of the reasons we like these brands is because they are specifically made for outdoor use and can withstand inclement weather reasonably well. Before 2017, we also built our own custom outdoor router software that was based on OpenWrt. While some of these older devices are still in use at some nodes throughout NYC Mesh, they are being phased out in favor of the more robust and easier-to-manage proprietary Ubiquiti and MicroTik devices. (See our Hardware Reference for full specifications on each of these devices.)

In order to connect to other nodes, each outdoor router must “mesh with” (that is, speak to and understand) other outdoor routers. Due to the split in our hardware choices, there are a couple of different meshing protocols that we commonly use to connect outdoor routers to each other:

• Ubiquiti equipment uses a proprietary radio network protocol called airMAX®. A Ubiquiti outdoor router will “speak” airMAX to other Ubiquiti outdoor routers that are within its radio range.
• MicroTik equipment uses more standard protocols, such as Wireless Distribution System (WDS) and so MicroTik outdoor routers can “speak” to both other MicroTik-branded hardware as well as other hardware that supports these same protocols.

In both cases, the purpose of these connections between one outdoor router and another is to create a “rooftop-to-rooftop” computer network. Put simply, these radio antennas and outdoor router combinations replace the need to run physical cabling from one building to another, since the physical connectivity is accomplished entirely with radios (wirelessly!) on rooftops. These outdoor routers are what makes it possible for a given member’s traffic to “hop” across New York City buildings in order to reach the rest of the NYC Mesh network and, eventually, to be connected to the Internet.