Diferencia entre revisiones de «2.6 KM Link Test Downtown Bogota - Guadalupe Hill»

Revisión del 03:35 16 jul 2017

On July 7th, 2017 Network Bogota took part in a so expected long distance Point-to-Point link test. Having already performed links greater than 300 meters, there was no experience on the 1-kilometer mark combining difficulties on technical, geographical and logistic factors.

Geography details

Bogotá landscape with Eastern Hills

Bogota is a city with an average altitude around 2.600 meters above sea level. Therefore, the city grows north and south and is flanked by the Eastern Hills which dominate the landscape over the metropolis, with summits around 3.650 meters. These Eastern Hills have an important role on the city weather and smog, acting as a buffer ecosystem. Moreover, the hills act as home to an extensive wildlife and provide inhabitants leisure and trekking spaces.

Consequently,the first test node or point was Guadalupe Hill, due to its clear line sight over Bogotá, but also one element that helped in the selection was the ease of ascent, possible thanks to a pavimented road that goes almost to the summit.

About the second test node, the chosen point was Torres Blancas complex, thanks to a tenant who allowed Network Bogotá to install temporarily the required equipment.

Torres Blancas complex

Guadalupe Hills

Planning

Planning this test required lots of work on several fields. From space management, working permissions, staff transport, router tweaks and autonomous electrical power system for the Guadalupe node can be counted among all the time invested. Preparing antenna's poles, the design and construction of the electrical autonomous system and software configuration, 15 days were required to fulfill these tasks, with shifts beginning at 9:00 and finishing at 20:00.

Some weeks prior to the job being described here, there was a failed test attempt between Monserrate Hill and a parking lot placed on the " La Rebeca " zone, still Bogotá Downtown. This attempt was a failure due to permissions being denied by the Monserrate Cableway authorities, and also the parking lot manager who revoked a previously granted permission to work in the cited venue. Considering all these obstacles and the appereance of new possibilities (transportation), it was decided to perform a new test in Guadalupe Hill and Torres Blancas complex.

After a site survey involving all Network Bogota team ascending to Guadalupe Hill on July 4th, 2017, they decided to make the link test 3 days after. This date allow more participants to come and help.

Paying a visit to Guadalupe Hill

Link projection

Team

NWBTA transport

• Guadalupe Node
  • Juan Carlos Burgos
  • Leonardo Taborda

• Torres Blancas Node
  • Oscar Prieto
  • Oscar Cruz
  • David Erazo

• Logistic Support
  • Laura Prieto
  • Miguel Sánchez

Hardware employed

The hardware employed in the session was chosen accordingly with the planned link and the physical and geographical conditions of both Guadalupe Hill and Torres Blancas complex.

Building the power bank

Node with Airgrid antenna, ip camera, access point, power bank and wooden pole

Nodo Guadalupe in working position

Guadalupe Node

Acting as access point, in this node was mandatory to build an autonomous power supply. Seeing that, the node received a power bank providing 24v, with voltage converters ranging to 3.5v, 5v and 9v for other devices

• Antenna
  • Ubiquiti Airgrid M5 AG-HP-5G27
• Access Point
  • TP-LINK TL-MR3020
• Camera
  • Camera IP HD 1080 with PTZ
• Power
  • Power bank with outputs to 3.5v, 5v, 9v y 24v
• Radios
  • Motorola y Baofeng
• Laptops
  • Samsung and Lenovo

Torres Blancas Node

In this node was placed a simple server with test services, i.e, asterisk and iperf, because the power supply there came directly from the city grid.

Torres Blancas Node and server

• Antenna
  • Ubiquiti Airgrid M5 AG-HP-5G27
• Access Point
  • TP-LINK TL-WR841N
• Radios
  • Motorola y Baofeng
• Server
  • Lenovo laptop

Weather

The proposed activity was near to cancellation due to the well known Bogotan weather, hardly predictable. On the Guadalupe Hill there was some rain and mist alongside the test time.

Tests performed

• Video streaming with ptz ip camera

On the Guadalupe Node there was an high-definition, PTZ ip camera that could be controlled from Torres Blancas node. On the next video it is possible to see a demo of such activity.

• Asterisk VOIP

On the Torres Blancas node was running a simple Asterisk server, featuring two SIP extensions (1001 and 1002), with uLaw codec. The 1001 extension was assigned to Torres Blancas team and the 1002 extension belonged to Guadalupe team. The preferred softphone app was Zoiper (android). Several calls were done, lasting more than 10 minutes, providing the same audio quality found on comercial VOIP services.

• iPerf bandwith

In order to measure the channel bandwith, iPerf was employed to get measurements on sent and received date. Some capture data is provided.

• Pings

Ping is perhaps the simplest tool to check the status of a network. Here some screenshots of some pings done.

• Signal Strength and antenna alignment

In the next image it is possible to verify signal strength received on the Torres Blancas node coming from Guadalupe.

Conclusions

Se trató de un laboratorio con numerosas dificultades que permitieron aprender más de lo esperado, ya que se pudo realizar un enlace con velocidades superiores a los 15 MB/s en condiciones de lluvia y visibilidad parcial. A nivel logístico la delegación de tareas fue fundamental para realizar con orden las actividades programadas.

Para laboratorios futuros es necesario ir con equipamiento adicional que mejore la experiencia cuando el clima esté lluvioso o nublado (típico en Bogotá).

Entre más personas puedan asistir a actividades de este tipo, más datos se pueden obtener ya que la concentración en una tarea determinada no permite prestar atención a otras pruebas y labores fundamentales, como la documentación visual y sonora del esfuerzo realizado.