Dhruv Gupta EEC 273 class project Prof. Chen-Nee Chuah Measurement-based Admission Control for multi-hop Wireless Mesh Networks Dhruv Gupta EEC 273 class project Prof. Chen-Nee Chuah

Wireless Mesh Networks 4/4/2019 Dhruv Gupta, EEC 273

Admission Control Is the simple practice of discriminating which traffic is admitted into a network The network judges whether it has enough resources available to accept a new connection based on the current network status Used to control the amount of traffic in the network and thus provide guaranteed service to end users 4/4/2019 Dhruv Gupta, EEC 273

Background WMN’s have become increasingly prevalent Roofnet, SF, Mountain View, Philadelphia and many others Ease of deployment, increased coverage area and reduced cost have driven the deployment of WMNs At the same time, low bandwidth, interference and high loss rates are some of the problems Network management is of crucial importance to provide guaranteed service to end users 4/4/2019 Dhruv Gupta, EEC 273

YAO: Yet Another Outline Problem statement Related work Motivation Methodology Conclusion 4/4/2019 Dhruv Gupta, EEC 273

Problem Definition I/P : Connectivity graph & measurement data Objective : Perform an AC decision for a given client request by finding a path P from source to destination that satisfies the following constraints Constraints : For each link ‘i’ on path P, we have Buser <= α * ABi 4/4/2019 Dhruv Gupta, EEC 273

Related work Yaling Yang, Robin Kravets, "Contention-Aware Admission Control for Ad Hoc Networks," IEEE Transactions on Mobile Computing ,vol. 04, no. 4,  pp. 363-377, July/August, 2005. Luo, L., Gruteser, M., Liu, H., Raychaudhuri, D., Huang, K., and Chen, S. 2006, “A QoS routing and admission control scheme for 802.11 ad hoc networks,” In Proceedings of the 2006 Workshop on Dependability Issues in Wireless Ad Hoc Networks and Sensor Networks (Los Angeles, CA, USA, September 26 - 29, 2006), DIWANS '06 4/4/2019 Dhruv Gupta, EEC 273

Motivation Most schemes focus on wireless LANs or Adhoc networks Simulation based studies do not capture the underlying interference models accurately No experimental measurement based work yet for wireless mesh networks 4/4/2019 Dhruv Gupta, EEC 273

Assumption Small scale WMNs with single gateway node Single channel for wireless backhaul and separate channels for clients All traffic directed for the internet – no peer to peer communication within the network Client based admission control, not flow-based User resource requirements are assumed to be known 4/4/2019 Dhruv Gupta, EEC 273

Problem components… Connectivity graph Network measurements Centralized admission control algorithm 4/4/2019 Dhruv Gupta, EEC 273

Network Discovery Purpose: Constraint: Advertise node existence/nonexistence Construct connectivity graph Constraint: Achieve node advertisement with minimum resource usage Accurate record of neighboring nodes 4/4/2019 Dhruv Gupta, EEC 273

Hello Message - Types Add - new node being added Delete - node presumed dead Update - “I’m alive” 4/4/2019 Dhruv Gupta, EEC 273

Network measurement Why? What? Centralized controller needs an updated view of the network topology statistics What? Bandwidth of the links in the network (asymmetric) 4/4/2019 Dhruv Gupta, EEC 273

How to get Link Bandwidth? A wireless link is different from a wired link Wireless is a broadcast medium, which means traffic on one link will affect bandwidth on another What is the base variable for bandwidth? Amount of Data/Time 4/4/2019 Dhruv Gupta, EEC 273

Time = Channel Utilization Channel Utilization is used instead of node utilization because CU is the limiting factor (and is affected by other APs) We define channel busy time as the total time a node is busy transmitting, receiving or sensing packets Channel utilization = CBT / tmeasurement 4/4/2019 Dhruv Gupta, EEC 273

Amount of Data = Modulation Rate The maximum bandwidth allowed per link (src to dest) varies based on signal quality and packet loss rate General upper bound for amount of data that can be sent to a certain neighbor 4/4/2019 Dhruv Gupta, EEC 273

Thus, Upper bound bandwidth to a neighbor = Modulation Rate * (1 - Channel Utilization) Monitored data is periodically sent to the central controller 4/4/2019 Dhruv Gupta, EEC 273

The final piece Central Controller Implements the admission control algorithm Takes as input: Connectivity graph Available Bandwidth 4/4/2019 Dhruv Gupta, EEC 273

Path search algorithm Use a uniform cost search algorithm to search for a path From source node, sort the links in decreasing order of available bandwidths Check if first link satisfies the user requirement If not, then request cannot be accepted Else repeat the procedure for subsequent links 4/4/2019 Dhruv Gupta, EEC 273

Centralized Admission Control Client associates to an AP (Wi-Fi assoc req) AP will send a client association request to centralized controller Centralized controller will reply (after running admission control algorithm) with a client association reply AP will receive the reply and send a Wi-Fi assoc reply back to the client If a path is found, send back association reply and setup route If no path is found, send back a reply denying the new request If a new client is accepted or a client leaves the network, the measurements will reflect the same 4/4/2019 Dhruv Gupta, EEC 273

Implemented the network discovery protocol Implemented the central controller algorithm Currently working on estimation of available bandwidth Integrate and test the scheme 4/4/2019 Dhruv Gupta, EEC 273

Hope you all get A’s and I get an A+ Thank You Hope you all get A’s and I get an A+ Q & A 4/4/2019 Dhruv Gupta, EEC 273