Multi-Dwelling Unit - Overview

Overview of MDU topology

Multi-Dwelling Unit Network

One possible application of Althea technology is a Multi-Dwelling Unit (MDU) network. This topology works well to provide network access to apartment buildings, townhomes, multi-tenant office buildings, and similar properties. The primary characteristics of an MDU are residents/tenants of a common building, generally sharing interior walls and/or a common roof, but the network can be expanded to accommodate a campus of individual buildings.

This article will explore how Althea technology can be used, and the requirements thereof, in both a simple MDU existing in a single building and a complex MDU, spread amongst a campus of buildings.

Simple MDU

For the purpose of this article, a simple MDU example is a single building with one set of exterior walls, many interior walls, and a single flat roof. This could be an apartment building, a row of townhomes, or a multi-tenant office.

Equipment Requirements

  1. Minimum Point of Entry (MPOE) - This setup first requires an entry point for the service being provided to the building. If feasible, the best option for connecting your building is with a Dedicated Internet Access (DIA) fiber connection. However, the most accessible option for a good connection is an incoming radio mounted to the top of the building. Althea recommends using a 60 GHz radio, like this one, or a 24 GHz radio in this capacity, but a 5 GHz radio may be substituted. Note: A basic CPE radio, like a Litebeam, is not suited to handle a whole building’s worth of traffic. A radio with a fast enough CPU to saturate the link capacity is required.
  2. Router - Connected to the building’s MPOE will be an Althea router called the central relay router. The minimum spec for this would be a Linksys 3200ACM or Linksys 32X. Those routers will smoothly handle the traffic from about 10 downstream users. If the building has more than 10 downstream users (or has very heavy data throughput requirements), we recommend a more powerful router, such as a Protectli with i7 CPU instead. This router will be the bottleneck for the whole building, so you want it to be fast enough to handle the traffic it needs to process and forward. Typically this router does not need WiFi, but there may be some situations where WiFi is useful (such as future maintenance, or connecting wireless security cameras). Note: This router can be configured to earn income as a relay router within the Althea Network.
  3. Switch - For a small network, where the chosen router above has sufficient ports to service your building, a switch is not required. In all other cases, a switch can be used as ‘port expander’ to provide more ports to connect additional downstream users. Both managed and unmanaged switches will work in this context. An unmanaged switch is simpler and less expensive, but may result in slightly slower performance if there are many downstream devices. A managed switch provides more options for segregating traffic, which may be important in some business environments. A managed switch may also provide slightly better performance, but in most cases this is fairly negligible.
  4. Firewall - Since Althea routers encrypt all traffic end-to-end (and operate a firewall at the exit node), no firewall is needed. In fact, adding a firewall is likely to break the network, as it might block the ports that Althea routers need to communicate with each other.
  5. Electrical Grounding - It is vitally important that all of the network equipment have a proper electrical ground. Many older buildings are grounded improperly, so in some cases you may need to install your own grounding solution (i.e. a grounding rod outside, with a ground cable running to the network cabinet). Consult with a local electrician and your local electrical code for grounding requirements. If you install network equipment without a proper ground, it is likely to fail prematurely and suddenly, due to electrical surges and/or buildup of static electricity.
  6. Cabling - With the above pieces in place, cabling to the individual units is the next requirement. Some buildings may require new cabling, but often existing cabling can be used. Shielded CAT6 cabling is the most ideal, but existing CAT5E will likely work as well. However, existing CAT5E should be tested for both speed and continuity before being relied upon for this task. CAT5 and CAT3 will not work in this context. Buildings wired with COAX (tv and internet cables) can be adapted to Althea networks by employing media converters to either end of the cable. However, as these adaptors can be expensive, the use or replacement of COAX should be handled on a case-by-case basis.
  7. Optional UPS - We recommend using a UPS (uninterruptible power supply) system to provide continuous power to networking hardware in the network cabinet. If this hardware goes down for any reason, all service in the MDU will be down as well. Power failures are the most common cause of network outages.
  8. Optional Fan - If the enclosure is outdoors or in a poorly ventilated space, you may also need to add fans or some other climate control system. Typiclly basic 12V DC computer fans are sufficient, and if sound dampening is important, opt for larger 80 - 120mm fans when possible.
  9. End User Routers - Each unit in the building will have one endpoint Althea router. This endpoint router will connect to the cabling ran from the switch or central relay router described above and negotiate an internet connection. The endpoint router will also pay the relay fee to the central relay router (if configured to a non-zero amount) for data usage. The endpoint router should only need a single MESH connection to the building wiring, the rest of the ports can be LAN for the user’s hardwired devices (TV, game system, desktop PC, etc).

WiFi Functionality in a Simple MDU

Because units in an MDU are disposed to close proximity, WiFi interference is likely and can present some challenges. However, Althea Operator Tools can provide useful data for troubleshooting issues. Additionally, Althea routers and other equipment can be optimized to mitigate potential problems.

In some cases, a WiFi mesh may provide a solution that avoids the potential pitfalls of traditional WiFi networks in the MDU.

Building-wide 3rd party WiFi Mesh:

A building-wide 3rd party WiFi mesh could be treated as a single Althea endpoint. This would be especially useful for building monitoring systems like security cameras. In this scenario, the central WiFi mesh node would be plugged into the LAN port of an Althea router (which could be either an endpoint router or the central building router, depending on the billing requirements).

Althea WiFi Mesh:

There is support for an Althea WiFi Mesh, in which each Mesh node operates as a separate Althea endpoint and wirelessly connects to nearby Althea nodes. The benefit to this approach is that each WiFi mesh node has its own separate billing. The downside to this approach is that the overall performance is much slower, as each WiFi mesh node needs to dedicate some of its WiFi time allocation to communicating with other nodes (and not with the user devices). We consider this approach experimental.

Complex MDU

For the purpose of this article, a complex MDU will consist of a ‘campus’ of multiple buildings, each with separate exterior walls, separate roofs, and likely walkways between structures.

Equipment Requirements

A more complex MDU is best approached as a collection of simple MDUs. The above equipment requirements apply to each separate structure in the MDU, but an extra layer of networking is required to interconnect the structures to one another. We recommend one of the three following options.

  1. Wireless bridges - To connect existing buildings, likely the most cost-effective solution is wireless bridges. Assuming the distance between buildings is relatively small (much less than a mile/kilometer), a 60 GHz wireless bridge is an excellent option. They are generally inexpensive and perform very well under short distance and perfect line-of-sight environments. Each building could host one or more 60 GHz radio on a non-penetrating roof mount, or wall mounted as needed. CAT6 or better cabling is highly recommended, as many of these products can exceed 1 Gbps throughput, so you want your cabling to handle 10 Gbps throughput. You can think of a wireless bridge as just a long Ethernet cable, so Althea routers can interconnect with wireless bridges via MESH ports.
  2. Underground cabling - In some situations such as new construction, trenching underground cabling in conduit is a better solution. Note that CAT6 cable has a maximum length of 330 ft / 100 m, so in many situations fiber is needed to cover greater distances between buildings. We recommend keeping CAT6 below 250 ft / 77 m whenever possible. Conduit is highly recommended, so the cabling can be maintained and replaced in the future if needed. Consult your local building codes regarding underground low voltage (CAT6) or non-electrical (fiber) cabling.
  3. Aerial cabling - Aerial cabling is also a possibility, with the same maximum length restrictions. Aerial cabling is generally more exposed to environmental damage, so underground cabling is preferred whenever possible.