Network Technology & Programming LaboratoryCS-435spring semester 2014
Stefanos Papadakis & Manolis SpanakisUniversity of Crete
Computer Science Department
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
CS-435
• Lecture preview
• Ad-Hoc Networks
• Mesh Networking
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Ad-Hoc? vs.
Mesh?
I can hear u, Lisa.
The Simpson's
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Mobile Ad Hoc Networks
• May need to traverse multiple links to reach a
destination
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Mobile Ad Hoc Networks (MANET)
• Mobility causes route changes
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Why Ad Hoc Networks ?
• Ease and Speed in deployment
• Decreased dependence on infrastructure
• Only possible solution to interconnect a group of
nodes
• Many Commercial Products available today
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Introduction• In the past the Ad hoc Networking paradigm absorbed a lot
of research effort.
• Most of the work is focused on isolated military or
specialized civilian application multi-hop ad hoc networks.
• Turning ad-hoc networks into a commodity takes a few
changes
• Make multi-hop flexible low cost last mile-extensions of
wired infrastructure:
Turn them into MESH NETWORKS!
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
MANET Applications
• Body Area Networking
• body sensors network,
• Personal area Networking
• cell phone, laptop, ear
phone, wrist watch
• Emergency operations
• search-and-rescue
(earthquakes, boats,
airplanes…)
• policing and fire fighting
Military environments
soldiers, tanks,
planes, battlefield
Civilian environments
taxi cab network
meeting rooms
sports stadiums
boats, small aircraft
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Variations
• Traffic characteristics may differ in different ad hoc
networks
• bit rate, reliability requirements, unicast, multicast, host-based
addressing, content-based addressing, capability-based
addressing
• Adhoc networks may co-exist and co-operate with
infrastructure-based networks
• Mobility characteristics may be different
• speed, direction of movement, pattern of movement
• Symmetric vs. Asymmetric
• nodes’ capabilities and responsibilities
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Issues in Mobile Ad-hoc
Networks• Limited wireless transmission range
• Broadcast nature of the wireless medium• Hidden terminal problem
• Packet losses due to transmission errors
• Mobility-induced route changes
• Mobility-induced packet losses
• Battery constraints
• Potentially frequent network partitions
• Ease of snooping on wireless transmissions (security hazard)
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
What’s unique about a
MANET ?• Moving nodes
ever changing topology
• Wireless links
various and volatile link quality
• Pervasive (cheap) devices
Power constraints
• Security
Confidentiality, other attacks
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Ad-hoc & p2p a Comparison
• P2P is based on an IP network
• Ad-hoc is based on a mobile radio network
• Mobile Ad-hoc and Peer-to-Peer Networks
hold many similarities concerning their
• routing algorithms and
• network management principles
• Both have to provide networking functionalities
in a completely unmanaged and decentralized
environment
• ie. To determine how queries (packets) are guided
through the network
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Ad-hoc & p2p a Comparison
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Ad-hoc & p2p - Differences
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Ad-hoc & p2p - Similarities
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Is the ad-hoc paradigm failed?
• An ad-hoc network is a collection of mobile nodes that
connect over the wireless medium without the need of any
pre-deployed infrastructure.
• Nodes in a MANET can dynamically self-organize into
temporary and arbitrary and network topologies
✓ No pre-existing infrastructure required:
• Many supporting application scenarios:
• Disaster Recovery Areas
• Battlefields
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Is the ad-hoc paradigm failed?
• Key Research drivers
• Bluetooth and WiFi
• mass market deployment
• ZigBee
• IETF “MANET” WG standardizations
Main problem:
• Users want:
• affordable devices
• Internet access
• Is high quality connectivity during mobility such an important issue?
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Making ad-hoc networks a
commodity
• Pass down research from the MANET field to a more market-
viable networking paradigm.
• Relax the main constraint of MANETS:
• Accept the existence of wired infrastructure
• Wireless Mesh Networks (WMNs) are build by interconnecting
internet egress points with end-user devices can act as terminals
and as routers.
• Community Networks being the earliest form of Meshes, relaxed a
second MANET feature:
• Mesh nodes are practically stationary
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Wireless Mesh Networks
• Wireless Mesh Networks (WMN) are the networks in which each node can communicate directly with one or more peer nodes.
• Different from traditional wireless networks (e.g. 802.11 WLANs) requiring centralized access points to mediate the wireless connection.
• Each node operates not only as a host but also as a router, forwarding packets on behalf of other nodes that may not be within direct wireless transmission range of their destinations.
• It is dynamically self-organized and self-configured, nodes can automatically establishing and maintaining mesh connectivity among nodes
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Network ArchitectureWMNs consist of two types of nodes: Mesh Routers and Mesh
Clients
• Mesh router • Additional routing functions to support mesh networking.
• Multiple wireless interfaces with same or different wireless access technologies.
• The gateway/bridge functionalities enable the integration of WMNs with existing wireless networks(cellular, sensornet, Wi-Fi, WiMAX).
• Mesh Clients • Conventional nodes (e.g., desktops, laptops, PDAs, PocketPCs,
phones, etc.) equipped with wireless network interface cards (NICs), and can connect directly to wireless mesh routers.
• Customers without wireless NICs can access WMNs by connecting to wireless mesh routers through, e.g., Ethernet
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
WMN Architecture Classifications• Infrastructure Meshing
• Mesh routers form an mesh infrastructure among themselves.
• Provides backbone for clients and enables integration of WMNs with existing wireless networks
and Internet through gateway/bridge functionalities.
• Clients connect to mesh router with wireless link or Ethernet
• Client Mesh Networking• Client nodes constitute peer-to-peer network, and perform routing and configuration
functionalities as well as provide end-user applications to customers, mesh routers are not
required.
• Multi-hop routing.
• Client nodes have to perform additional functions such as routing and self-configuration.
• Hybrid Mesh Networking• A combination of infrastructure and client meshing.
• Infrastructure provides connectivity to other networks such as the Internet, Wi-Fi, WiMAX, cellular, and sensor networks;
• Mesh clients can access the network through mesh routers as well as directly meshing with other mesh clients.
• The routing capabilities of clients provide better connectivity and coverage
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
WMNs Characteristics
• Multi-hop wireless networks
• Support for Ad Hoc networking, and capability of self-forming, self-healing, and self-organization
• Mobility dependence on the type of mesh nodes
• Multiple types of network access
• Dependence of power-consumption constraints on the type of mesh nodes
• Compatibility and interoperability with existing wireless networks
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Protocol Design
• Physical Layer
• Mac Layer
• Network Layer
• Transport Layer
• Application Layer
• Network Management
• Security
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
A Wireless Mobile Ad hoc
Network• A 10-node MANET at time t0
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
A Wireless Mobile Ad hoc
Network• A 10-node MANET at time t1
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
How does this change look like?
• A wireless mesh
network of 3 tiers
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Ad-hoc – WMN, what is
different ?• The WMN concept is similar to ad-hoc networks concept
but has four important differences:
1. (practically) fixed nodes => Topology changes are infrequent
• Addition of nodes
• Node failure or maintenance
2. Traffic distribution is skewed (to/from the wired network)
3. Traffic characteristics aggregated from large numbers of flows
=> network optimization based on profiling
4. Reactive discovery of multi-hop paths is not efficient for an
effective backbone and not fit under (1).
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Mesh Networking - Overview
Wireless routers
Gateways
Printers, servers
Mobile clients
Stationary clients
Intra-mesh wireless links
Stationary client access
Mobile client access
Internet access links
Node Types Link Types
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
How it Works
• User-Internet Data Flows
• In most applications the
main data flows
• User-User Data Flows
• In most applications a small
percentage of data flows
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Taxonomy (example)Wireless
Networking
Multi-hop
Infrastructure-less
(ad-hoc)
Infrastructure-based
(Hybrid)Infrastructure-less
(MANET)
Single
Hop
Cellular
Networks Wireless Sensor
NetworksWireless Mesh
Networks
Car-to-car
Networks
(VANETs)
Infrastructure-based
(hub&spoke)
802.11 802.16 Bluetooth802.11
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Mesh vs. Ad-Hoc Networks
Multi-hop
Nodes are wireless, possibly mobile
Do not rely on infrastructure
Most traffic is user-to-user
Ad-Hoc Networks Wireless Mesh Networks
Multi-hop
Nodes are wireless,
some mobile, some
fixed
It relies on
infrastructure
Most traffic is user-to-
gateway
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Mesh vs. Sensor Networks
Bandwidth is limited
(tens of kbps)
In most applications, fixed
nodes
Energy efficiency is an
issue
Resource constrained
Most traffic is user-to-
gateway
Wireless Sensor Networks Wireless Mesh Networks
Bandwidth is generous
(>1Mbps)
Some nodes mobile,
some fixed
Normally not energy
limited
Resources are not an
issue
Most traffic is user-to-
gateway
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Application domain• Broadband Internet Access
• Extend WLAN Coverage
• Mobile Internet Access• Direct competition
with cellular systems
• Emergency Response
• Layer 2 Connectivity• entire wireless mesh cloud becomes
one (giant) Ethernet switch
• Military Communications
• Community Networks
• Other: • Remote monitoring and control
• Public transportation Internet access
• Multimedia home networking
Internet
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Research Topics
• Physical Layer
• Smart Antennas
• Transmission Power
Control
• MAC Layer
• Multiple Channels
• Network Layer
• Routing
• Fairness and QoS
• Transport Layer
• Provisioning
• Security
• Network Management
• Geo-location
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
QoS requirements• Physical Layer
• Robust modulation
• Link adaptation
• MAC Layer
• Offer priorities
• Offer guarantees
(bandwidth, delay)
• Network Layer
• Select “good” routes
• Offer priorities
• Reserve resources (for
guarantees)
• Transport
• Attempt end-to-end
recovery when
possible
• Application
• Negotiate end-to-end
and with lower layers
• Adapt to changes in
QoS
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
A key research decision that
made a big difference• Test-beds were used in WMN research from the start.
• MIT Roofnet (http://pdos.csail.mit.edu/roofnet/design/)
• Proof of existence of good enough solution for civilian
applications has stimulated the users’ interest to adopt this
technology.
• Two main solutions classes:
1. “off-the-shelf” => “community” networks
• Roofnet
• AWMN
• FORTH
• BAWUG
• Seattle Wireless
2. proprietary => MeshNetworks, Tropos Networks, Radiant…
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Companies
State of the art• Aerial Broadband
• BelAir Networks
• Firetide
• Intel
• Kiyon
• LamTech (ex.
Radiant)
• Locust World
• Mesh Dynamics
• Microsoft
• Motorola (ex. Mesh
Networks)
• Nokia Rooftop
• Nortel Networks
• Packet Hop
• Ricochet Networks
• SkyPilot Networks
• Strix Systems
• Telabria
• Tropos Networks
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
University Testbeds
• Georgia Tech - BWN-Mesh
• MIT - Roofnet
• Rutgers WinLab – Orbit
• SUNY Stonybrook – Hyacinth
• University of Utah – Emulab
• FORTH (eu - MESH)
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Georgia Institute of Technology
BWN-Mesh
• 15 IEEE 802.11b/g
nodes
• Flexible configuration
and topology
• Can evaluate routing
and transport protocols
for WMNs.
• Integrated with the
existing wireless sensor
network testbed Source: http://users.ece.gatech.edu/~ismailhk/mesh/work.html
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
MIT Roofnet• Experimental testbed
• More than 40 nodes at
the present
• Real users (volunteers)
• Focus on link layer
measurements and
routing protocols
• Open source software
runs on Intersil Prism
2.5 or Atheros AR521X
based hardware Source: http://pdos.csail.mit.edu/roofnet/doku.php
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Rutgers Winlab
ORBIT• Collaborative NSF project
(Rutgers, Columbia,
Princeton, Lucent Bell Labs,
Thomson and IBM Research)
• Start date: September 2003
• Emulator/field trial wireless
system
• 400 nodes radio grid
supporting 802.11x
• Software downloaded for
MAC, routing, etc.
• Outdoor field trialSource: www.winlab.rutgers.edu
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
SUNY Stonybrook
Hyacinth
• Multichannel test-bed
based on stock PCs
with two 802.11a
NICs.
• Research focus on:
• interface channel
assignment
• routing protocol
Source: http://www.ecsl.cs.sunysb.edu/multichannel/
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
University of Utah
Emulab
• Three experimental environments
• Simulated and Emulated
• hundreds of PCs (168 PCs in racks)
• Several with wireless NICs (802.11
a/b/g)
• wide-area network
• 50-60 nodes geographically distributed
across approximately 30 sites
• Smaller brothers at
• U. of Kentucky
• Georgia Tech
Source: www.emulab.net
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
FORTH’s metropolitan mesh
network testbedFORTH’s metropolitan
mesh network testbed
• 14 nodes: 6 multi-radio / PC-based
• independent management network
• 1.6 - 5.2km links
• 60sq.km. coverage
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Extended testing
capabilities
• cross layer data acquisition
• parallel processing
• remote management
• remote & local storage
• high computing power
• 4+1 wireless interfaces per
node
• UPS & remote power
management
• Linux operating system
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Features - Advantages -
Flexibility - Adaptability• real life environment
• city wide deployment
• high density population
coverage
• over 9 years of
experience
• off-the-self hardware
• highly customizable &
expandable
• multiple Internet
gateways
• service-driven network
virtualization
• mobile social networking
• location based services
• emergency services
• rapid deployment
scenarios
• ubiquitous wireless
access
• future technologies proof
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
Standards & Committees
• IEEE standards groups actively working to define specifications for
wireless mesh networking techniques
• Special groups established to define the requirements for mesh networking
in WPANs, WLANs, and WMANs.
• The following standards amendments are considering WMNs:
• 802.15.5 (bluetooth - WPAN)
• 802.11s (wi-fi - WLAN)
• 802.16a (wi-max - WMAN)
• Also 802.20 (wireless mobile broadband access -WMBA) is to support the
Mesh Networking paradigm from the first spec.
• On 12 June 2008, the IEEE approved the new standard
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
The 802.11s ideas• The 802.11 group had set up the “TG s” to discuss proposals for a specs
amendment in the 2nd quarter of ’05 and reach a final document no sooner than
2007.
…And still is at the drafting stage
• Scope of the Project: An IEEE 802.11 Extended Service Set (ESS) Mesh is a collection of APs
interconnected with wireless links that enable automatic topology learning and dynamic path
configuration.
• The proposed amendment shall be an extension to the IEEE 802.11 MAC.
• The amendment will define an architecture and protocol for providing an IEEE 802.11 ESS Mesh
using the IEEE 802.11 MAC to create an IEEE 802.11 Wireless Distribution System that supports
both broadcast/multicast and unicast delivery at the MAC layer using radio-aware metrics over self-
configuring multi-hop topologies.
• An ESS Mesh is functionally equivalent to a wired ESS, with respect to the STAs relationship with
the BSS and ESS.
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
The 802.11s ideas
The amendment shall:
• Enable interoperable formation and operation of an ESS Mesh
• extensible to allow for alternative path selection metrics and/or
protocols based on application requirements.
• target configuration of up to 32 devices participating as AP
forwarders in the ESS Mesh. Larger configurations may also be
contemplated by the standard.
• The architecture defined by the amendment shall allow an ESS Mesh
to interface with higher layers and to connect with other networks using
higher layer protocols.
• Utilize IEEE 802.11i security mechanisms, or an extension thereof, for the
purpose of securing an ESS Mesh in which all of the APs are controlled by
a single logical administrative entity for security.
• Allow the use of one or more IEEE 802.11 radios on each AP in the ESS
Mesh.”
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
802.11s timeline
802.11s started as a Study Group of IEEE 802.11 in September 2003.
Became a Task Group in July 2004.
A call for proposals was issued in May 2005, which resulted in the submission of 15
proposals submitted to a vote in July 2005.
After a series of eliminations and mergers, the proposals dwindled to two (the "SEE-
Mesh" and "Wi-Mesh" proposals), which became a joint proposal in January 2006.
This merged proposal was accepted as draft D0.01 after a unanimous confirmation
vote in March 2006.
The draft evolved through informal comment resolution until it was submitted for a
Letter Ballot in November 2006 as Draft D1.00.
Draft D2.00 was submitted in March 2008 which failed with only 61% approval.
A year was spent clarifying and pruning until Draft D3.00 was created which reached
WG approval with 79% in March 2009.
The Task Groups stated goal for the May 2009 802.11 meeting is to start resolving
comments from its new Letter Ballot
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
IEEE 802.15.1- Bluetooth
• Low data rate (1Mbps bit-
rate) BAN/PAN technology
• Targets wire replacement
• Has provisions for multi-hop
scatter-nets
• Not a popular wireless mesh
network platform due to:
• the low bandwidth and
• limited hardware support for
scatter-nets.
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
IEEE 802.15.4 - Zigbee
• Lower data rate BAN/PAN (250,40,20kbps)
• Multi-months – years lifetime on small batteries
• Supports mesh topology – one coordinator is responsible for setting up the network
• Characteristics suitable for wireless sensor networks rather than wireless mesh networks
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
IEEE 802.15.5
Mesh Topology Capability in (WPANs).
• Standard applicable to all other WPANs
• Mesh networks have the capability to provide:
• Extension of network coverage without
increasing transmit power or receive sensitivity
• Enhanced reliability via route redundancy
• Easier network configuration
• Better device battery life due to fewer
retransmissions
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
The 802.16a• 802.16 is a point to multipoint first-mile/last-mile WMAN connection
standard
• data rate up to 120Mbps @ 30miles
• great for gateway to internet links
• A base station serves a number of subscriber stations
• BS uses a broadcast channel to transmit to all SSs.
• 802.16 approved in 2001
(10-66GHz operation – TDMA, TDD&FDD)
• 802.16a approved in Jan. 2003
(2-11 GHz operation added -ODFM)
• The extensions specifies user-user links using:
• either centralized schedules,
• or distributed schedules.
• Already obsolete and part of the 802.16-2004 doc
• Stations may have direct links to each other - control can be
distributed.
• WiMax forum formed later in 2003 (just like the 802.11 Wi-Fi forum) to
promote IEEE standards for interoperability)
• Certifications began as late as 2006
<CS-435> Network Technology and Programming Laboratory
CSD.UoC Stefanos Papadakis & Manolis Spanakis spring 2014
More references….
• http://research.microsoft.com/mesh
• Roofnet
• Seattle Wireless
• Locust World
• Kingsbride Link
• Mesh Networks Inc
• FireTide Inc.
• Strix Networks Inc
• Telabria Inc
• Tropos Inc
• Cowave Inc