Basic Description of Wireless ISP System MikroTik Wireless Internet Service Provider Systems

What is WISP ? It is fixed wireless service between the central node and the client direct line of sight required low power radios and high gain antennas are used It IS NOT a mobile service. Under WISP we understand an integrated Metropolitan Area Network (MAN) system of connecting customers to the Internet. High-speed wireless datalinks are used to provide Internet access on a point-to-point and point-to-multipoint basis for companies, governmental organizations, schools, universities and other institutions having Local Area Networks (LAN). 11 May, 2002 MikroTik WISP

RF Information Broadband Technology Spread Spectrum Technology Direct Sequence Spread Spectrum (DSSS) Frequency Hopping Spread Spectrum (FHSS) Frequencies for Unlicensed SS 2400-2483MHz ISM band, or 5725-5875MHz ISM band Narrowband Technology A narrowband radio system transmits and receives user information on a specific radio frequency. Narrowband radio keeps the radio signal frequency as narrow as possible just to pass the information. Undesirable crosstalk between communications channels is avoided by carefully coordinating different users on different channel frequencies. Spread Spectrum Technology Most wireless LAN systems use spread-spectrum technology, a wideband radio frequency technique developed by the military for use in reliable, secure, mission-critical communications systems. Spread-spectrum is designed to trade off bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is consumed than in the case of narrowband transmission, but the tradeoff produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a spread-spectrum signal looks like background noise. There are two types of spread spectrum radio: frequency hopping and direct sequence. 11 May, 2002 MikroTik WISP

DS versus FH Direct Sequence Frequency Hopping (+) Faster (up to 11 Mbps) and Greater Range (+) recently standardization has made this the lowest cost radio Frequency Hopping (-) higher cost per radio (-) Slower (max 3 Mbps) and Limited Range Frequency-Hopping Spread Spectrum Technology Frequency-hopping spread-spectrum (FHSS) uses a narrowband carrier that changes frequency in a pattern known to both transmitter and receiver. Properly synchronized, the net effect is to maintain a single logical channel. To an unintended receiver, FHSS appears to be short-duration impulse noise. Direct-Sequence Spread Spectrum Technology Direct-sequence spread-spectrum (DSSS) generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The longer the chip, the greater the probability that the original data can be recovered (and, of course, the more bandwidth required). Even if one or more bits in the chip are damaged during transmission, statistical techniques embedded in the radio can recover the original data without the need for retransmission. To an unintended receiver, DSSS appears as low-power wideband noise and is rejected (ignored) by most narrowband receivers. 11 May, 2002 MikroTik WISP

2.4GHz Spread Spectrum Channels Interference 1 to 13 depending on the set three non-overlapping ones Interference 11 May, 2002 MikroTik WISP

Antenna Types Directional Sectorial Omnidirectional Parabolic Yagi or Loop Yagi Sectorial Horns Omnidirectional 11 May, 2002 MikroTik WISP

Antenna Polarity Omnidirectional and Sectorial Antennas Vertical E-Plane Directional Antennas Vertical or Horizontal E-Plane depending on the mounting of antenna For communicating radios the antennas should match the polarity 11 May, 2002 MikroTik WISP

Mounting of Antennas Polarity Vertical and Horizontal Alignment Safety Lightning Strikes 11 May, 2002 MikroTik WISP

Cabling Requirements High Quality Cables Low Loss - LMR-400 / Belden 99xx Super Low Loss - LMR-600 Cable Length - as short as possible Recommended 3-5m for omni antennas ~10m for directional antennas, depending on the distances, antenna gains, and radio power 11 May, 2002 MikroTik WISP

Cable Connectors Standard Proprietary N Connectors (male or female) for antennas Proprietary RP-TNC Connectors for Aironet Radio 11 May, 2002 MikroTik WISP

Using Antenna Calculator Distances to be covered Cabling Length Antenna Gains Radio Power Receive Sensitivity 11 May, 2002 MikroTik WISP

WISP Topologies Point to point links Point to multipoint links (+) longer distances (max 30-40km) (-) higher cost/client Point to multipoint links (+) serving multiple clients at lower cost/client (+) larger area of coverage (-) lower range (max 5-12km) 11 May, 2002 MikroTik WISP

What can be connected? Internet Connectivity Client’s LAN to the ISP Client LAN uses a Wireless Gateway Router which connects to the Base Station of the ISP Client's Computer to the ISP Client’s Computer with a Wireless NIC connects to the Base Station of the ISP 11 May, 2002 MikroTik WISP

What can be connected? Intranet Connectivity Client’s LAN1 to Client’s LAN2 Client’s LAN at a remote location uses a Wireless Router which connects to the Wireless Router at the main office Client's Computer to the Client’s LAN Client’s Computer at a remote location connects to the Wireless Router at the main office 11 May, 2002 MikroTik WISP

Wireless Setup Diagrams Used conventions 11 May, 2002 MikroTik WISP

Base Setup All customers are using the same 11Mb/s channel. This configuration can be used for unlimited number of clients. The link between the Base Site and the clients is 11 Mb/s. If additional Ethernet NIC is installed in the wireless router located in a building, then more than one client network can be connected to the wireless router. Each of the client networks are separated from each other since they are connected to different interfaces of the router. The bandwidth management can be done at at the Ethernet/Ethernet router located at the ISP. 11 May, 2002 MikroTik WISP

Repeater Setup All customers are using the same 11Mb/s channel. The Internet Service Provider is also using this channel. This means that there is no "backbone" to the Base Unit. This configuration can be used for five to ten LANs from 5 to 50 computers each. The link between the Repeater Site and the clients is 5.5 Mb/s. It is possible to connect one more MikroTik router (so one more LAN) to the Base Unit on the building using Ethernet Cable. The link between the ISP and the client located at the repeater site is 11 Mb/s. 11 May, 2002 MikroTik WISP

Advanced Repeater Setup All customers are using the same 11Mb/s channel. The Internet Service Provider is also using this channel. This means that there is no "backbone" to the Base Unit. This configuration can be used for five to ten LANs from 5 to 50 computers each. The link between the ISP and the wireless clients is 5.5 Mb/s. It is possible to connect one more MikroTik router (so one more LAN) to the Base Unit on the building using Ethernet Cable. The link between the ISP and the client located at the repeater site is 11 Mb/s. 11 May, 2002 MikroTik WISP

Base Setup with Backbone Base Unit has 11Mb/s channel. Internet Service Provider has a separate backbone link going to the Base Unit. All customers are using the same 11Mb/s channel. This configuration can be used for unlimited number of clients. The link between the Base Site and the clients is 11 Mb/s. 11 May, 2002 MikroTik WISP

Point-to-Point Setup You can connect two Local Area Networks using two MikroTik routers and point-to-point link. So there will be 11 Mb/s channel between two LANs. This configuration is used in the Backbone Setup. There is a point-to-point link between the ISP and the Base Site. 11 May, 2002 MikroTik WISP

IP Questionnaire Type of cable used What IP addresses are used 10 Base 2, 10 Base T, 10/100 Mbps? If fiber optic - get a transceiver to 10BaseT… What IP addresses are used what network, network mask? Get one address for the router as the gateway for the LAN. No addresses used yet. Assign a private network, e.g., 192.168…. Use addresses given by the ISP 11 May, 2002 MikroTik WISP

RF Network Configuration System Identificator Should be unique Channel / Frequency Should have minimal interference with other systems Data Rates 11 May, 2002 MikroTik WISP

Base Unit Configuration Connect the Antenna Connect the Ethernet Cable Connect the RS-232 Console Cable Use Terminal Emulation Program on your Laptop or Desktop PC Connect the Power Supply Power the unit on 11 May, 2002 MikroTik WISP

Basic Configuration Configure RF Parameters System Identifier Frequency Data Rates Configure the Identification Parameters Name IP Address / Mask / Default Gateway 11 May, 2002 MikroTik WISP

Things to Remember Association Restriction Passwords for the Unit Maintain a list of controlled nodes Turn Autoregistration off Passwords for the Unit Write - View and Change the Configuration, perform Diagnostics Read - View Configuration 11 May, 2002 MikroTik WISP

IP Network Configuration Global Addresses use routing configuration Local Addresses, no server use masquerading Local Addresses, local server use masquerading and NAT 11 May, 2002 MikroTik WISP

System Diagnostics Check the RF Communication Registration/Association Signal Strength and Quality Link Speed Check the IP Configuration Network Address/Mask Routing, Default Gateway Ping, Traceroute 11 May, 2002 MikroTik WISP