About the Dharamsala Wireless-Mesh Community Network

Dharamsala Wireless-Mesh Community Network

The Dharamsala Wireless-Mesh community network came to life in February 2005, following the deregulation for outdoor use of WiFi in India (28, January 2005). By the end of February 2005, the mesh had already connected 8 campuses. Extensive tests during February showed that the hard mountainous terrain is most suitable for Mesh networking, as conventional point-to-multipoint networks, cannot overcome the line-of sight limitations presented by the mountains. Mesh topology also offered much larger area coverage, while the “self healing” nature of Mesh routing, proved to be essential in places where electricity supply is very erratic at best.

At present day (October 2005), the Mesh backbone includes over 30 nodes, all sharing a single radio channel. From October 2nd, broadband Internet services are provided to all mesh members. The total upstream Internet bandwidth available is 6Mbps. There are over 2000 computers connected to the Mesh, and about 500 have Internet access. The broadband internet connection, is putting the mesh under great load. At present it seems to handle the load fine without any increase in neither latency nor packet-loss. It is clear however that it’s not going to offer much more scalability if continue to use a single radio channel. New Mesh routers, with multiple radio channel support, are being developed and tested here in Dharamsala. Results are very good, while the main objective of keeping the manufacturing costs very low is met.

Apart from Internet access, the mesh members are using the network for extensive file-sharing applications, off-site backups, playback of high quality video from remote archives and extensive VoIP telephony. A central VoIP, software-based PBX is installed (Asterisk) and it provides advance telephony services to members. The Asterisk PBX is also interfacing the PSTN telephone network, yet due to legal issues it is used at present only for incoming calls into the Mesh. Subscribers use a large variety of software-phones, as well as numerous ATAs (Analog Telephone Adaptors) and full-blown, fancy, IP-Phones.

As the encrypted Mesh back-bone does not allow access to roaming mobile devices (notebooks and PDAs) we have placed multiple 802.11b access-points at many of the same locations where Mesh-routers are installed. The Mesh provides the back-bone infrastructure while these APs provide access to mobile roaming devices, where needed.

The Mesh network is based on recurring deployments of a hardware device, which is designed, and build locally, known as the Himalayan-Mesh-Router. The same Mesh-routers are installed at every location, with only different antennas, depending on the geographical locations and needs. We use a wide range of antennas, from 8 - 11dBi Omni-directional, to 12 - 24dBi directional antennas and occasionally some high-gain (and cost) sector antennas.

Access to the Mesh back-bone is only possible by Mesh-routers. Simple wireless clients lake the intelligence needed to “speak” the Mesh routing protocols and strict access policies. The Mesh channel is therefore encrypted (WPA), and also “hidden” to prevent mobile devices from finding it or attempting to access it. Allowing access to the mesh only by Mesh-routers allows for strict access control policies and limitations to be enforced at the CPE (Client Premises Equipment) which is a crucial element needed to achieve end-to-end security, traffic-shaping, and quality-of-service.

Power consumption of a Mesh-Router is less then 4watt making them ideal devices to be solar powered, and indeed many of our units in Dharamsala are power solely by small solar panels. Solar power in combination with small antennas, suggest that such a network is ideal for disaster areas, as it very likely to survive when all other communication infrastructure is damaged.