Magnets – A Next Generation Access Network

Magnets is a next-generation WiFi-based wireless infrastructure consisting of a wireless mesh with 50 nodes, and a high-speed wireless backbone with a raw end-to-end throughput of 108Mb/sec. The main theme in the design of the Mangets and its key distinguishing characteristic from similar efforts is heterogeneity. It is integrated with cellular networks based on GPRS, UMTS and next-generation wireless technology based on WiMAX. Magnets combines a research environment where new protocols and future architecture ideas can be deployed and experimentally evaluated. It encompasses a production environment where students at the TU Berlin are offered free access to the network. 19% Design Goals Back Bone Magnets is designed with three-fold goal: Provide a combination of semi-production environment and research testbed Traffic created by students of TU Berlin Asses the research outcome suitability w.r.t realistic traffic assumptions Serve as a platform for investigating interoperability issues (stemming from carefully planned, high speed backbone to an untethered, lowcapacity, and extended diameter urban mesh. Leverage and help evaluate the multi-tier design approach in the contexts of mesh environments (a design trend followed in p2p and sensor networks. Magnets WiFi backbone in the heart of Berlin WiFi Mesh and Heterogeneous Nodes Five nodes on top of high-rise with unobstructed line of sight, Unlicensed spectrum (2.4GHz and 5GHz), Workstation support for management and services, 12 WiFi access points (APs) supporting 802.11a/g modes (at 54Mbps) and proprietary Turbo Mode (108Mbps), with outdoor suitability, attached to routers APs are connected to directional antennas, 8 operating at 2.4GHz and 4 operating at 5GHz Shortest link 330 meters and longest link 920 meters Multi-path routing (T-Labs to HHI via 2 separate links (3,4) or via TC (link 2) 50 Mesh Nodes, H/W: RouterBoards with multiple Mini PCI cards, ability to attach external storage attachment. Each node is equipped with 3 to 6 WiFi interfaces Phase I: 15 nodes will be deployed and with operational success, the diameter of the mesh will extended in an ad hoc fashion By taking advantage of multiple Mini PCI slots, GPRS, UMTS and WiMax technologies will provide an opportunity to superimpose multiple network configurations Issues with TCP performance during vertical handovers between multiple access technologies will be explored Investigations will be carried out on operator-driven optimizations for resource management and load-balancing, as well as opportunities for the separation of control and data planes As an extension, few nodes will be furnished with low-range Bluetooth and Zigbee communication interfaces for integrating sensor networks Conclusions Preliminary Measurements on the Backbone Constellation of Mesh Networks in Berlin 150 – 200 150 – 200 8.7 5.2 1.7 -81 -81 Dynamic Frequency Selection 5 6 10 10 2.9 1.6 6.4 4 -76 – -80 -74 – -77 13 2.4 5 3 3 15.7 13.3 16 15.5 -56 -56 13 2.4 4 21 21 15.3 12.3 12.3 -58 -57 1 2.4 3 3 3 12.6 7.7 13.6 13.7 -55 -55 7 2.4 2 2 2 26.3 24 -49 -49 Dynamic Frequency Selection 5 1 RTT [ms] UDP [Mbps] TCP [Mpbs] Level [dBm] Channel Freq [GHz] Link 3 mesh networks in Berlin Magnets (50 nodes) Olsr-experiment (250) Berlin Roofnet (50) Islands under different administrations Interconnect to investigate Routing policies among different meshes Multi-operators/providers (virtualization) Magnets olsr-experiment Berlin Roofnet How shall we deploy wireless access networks? Real experiences: Antenna setup, lightning protection Environmental influence (radar, interferences of APs) How do protocols perform? Planning (raw 54 Mbps) vs measured (TCP 13-16 Mbps) Future: network capacity, end-to-end throughput, latency, influence of routing protocol, SIP and video adaptation How far can / shall we design new protocols? Open router platform for cross-layer optimization Clean-slate approach: information and experimentation www.deutsche-telekom-laboratories.de/~networks/magnets.html {roger.karrer, petros.zerfos, nischal.piratla}@telekom.de Magnets Magenta Networks The world’s most attractive networks!