Equipment
Introduction
The network is built using standard IEEE 802.11 wireless equipment as it is readily available and inexpensive. It also requires no licence to operate within given specifications, even over long distances.
Also I might as well mention I am not affiliated with any of the brands below, this is simply some information on our experiences.
Standards-Based
Obviously standards are established to ensure inter-operability between different equipment vendors. Whilst some people prefer to use proprietary gear such as that from Trango, it is prohibitively expensive and severely restricts the amount of equipment available to expand.
Basing the network on standard IEEE 802.11 wireless gear means additional nodes can be added with less dependency on hardware vendors, using off-the-shelf equipment at relatively low cost.
Why MikroTik?
MikroTik differs from most other brands of wireless network equipment as they go beyond the realms of a traditional wireless to Ethernet bridge. They produce RouterOS, a Linux-based router operating system that includes a vast number of features such as dynamic routing, DNS, NAT, DHCP, wireless, firewalling, VLANs, tunnelling protocols, etc. By using a single OS to do both wireless and routing the amount of equipment needed can be substantially reduced.
Some people tend to frown on the concept of paying for anything based on Linux or GPL software. While I agree with that, as long as source code is supplied where appropriate I don’t think there is a problem with charging for a distribution as long as the cost is reasonable. RouterOS features no direct access to the innards of the OS, but it does provide features and management that would take vast amounts of time and expertise to replicate with a completely open distribution and I feel the price of this justified.
MikroTik also produce a series of embedded platforms called RouterBOARDs. These are inexpensive single board computers designed for low power operation both in and outdoors. Most RouterBOARDs come with a RouterOS licence included at purchase.
To enable wireless functionality, standard miniPCI wireless cards need to be installed into each RouterBOARD. These are the same type as those commonly supplied in laptop computers and a large number of varieties are readily available from many different vendors.
Bear in mind that MikroTik equipment is aimed at experienced network professionals and the documentations tends to reflect this. A good understanding of networking is required to set up the gear correctly, and the documentation does little to explain the concepts behind many of the options that can be configured.
Antennae
We have used Pacific Wireless for all antennae as they are well built without costing a fortune. There are a few cheap Asian antenna suppliers out there but testing reveals a lot of their equipment does not live up to its published specifications.
Backhaul
The backhaul is comprised of RouterBOARD 532s fitted with Compex WLM54G radio cards. The reason for using RB 532s in backhaul is that they can power two cards simultaneously (and up to four with an inexpensive daughterboard). They feature a 266MHz MIPS CPU and 32MB RAM which has proven perfectly adequate for the task. The CPU can be over-clocked to 300MHz without any adverse side effects.
The radio cards are configured to operate in 802.11g mode for best performance and provide 100mW of transmit power. Real world performance is pretty similar to the popular CM9 series from Wistron Neweb, except the Compex cards are noticeably more reliable.
The antennas chosen for coverage to clients are 12dBi sector antennas from Pacific Wireless. These offer an ideal compromise between gain and spread and have proven to be good for up to about 4km of LoS reception.
For medium haul (up to about 6km) point-to-point links, the 16dBi ‘Vagi’ antenna from Pacific Wireless does an excellent job.
Each RouterBOARD fits nicely into a purpose-designed diecast weatherproof case. These cases are extremely rugged and seem to hold up to anything thrown at them. They certainly don’t leak even in the harshest weather conditions. The only problem is that fitting a daughterboard to the 532 makes things get a bit tight.
Clients
The clients are RouterBOARD 112s using the same Compex WLM54G cards housed in a 14dBi ‘RooTenna’ panel antenna. The RooTenna is even more practical than it is ugly, as it allows all the electronics to be housed inside the antenna itself, so the antenna cabling is kept incredibly short for optimal performance. When used with power over Ethernet (PoE), only a single Cat5 cable is required from the CPE into the house.
Adding a weatherproof RJ45 connector greatly simplifies installation as it means the entire unit is self contained and can be install or removed from a roof pre-assembled. Although these have had bad reviews, if installed properly they pose no problems and are well worth the low cost investment.
The lower specifications of the RB 112 (175MHz CPU, 16MB RAM) mean it is much cheaper than a 500-series, but this is reflected by their reduced performance. As a CPE they have proven to work well, however would not be recommended for backhaul use.
48v PoE injectors from Pacific Wireless were originally used as these are compliant with the IEEE 802.3af specification. A direct mains input also means there is no need for an annoying chunky power adapter hanging off the wall socket. The only drawback with these is a large amount of EMI radiated which renders FM radio and VHF TV reception almost useless. Using shielded Cat5 cable fixes this but we are investigating other power supplies for suitability.
Check out our page on installing a RouterBOARD 500 into a slimline RooTenna as an example. Due to the tight fit we now stick with the full-size model of the RooTenna.
Where do I find this stuff?
We originally purchased most of the equipment from WISP Router, however their service has been lacking lately and unfortunately I’d have a hard time recommending them to anyone else.
The radio cards came from PC Engines and arrived very promptly.
We now purchase MikroTik gear locally from The Network Company and although a bit pricier than some overseas suppliers they have been good to deal with.