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Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Self Forming Self Healing Networks
Peter Stanforth & Vann Hasty
MeshNetworks Inc.
11-03-216r0-w-meshnetworks_tutorial.ppt
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Contact Information
• Peter Stanforth [email protected]
• Vann Hasty [email protected]
• www.meshnetworks.com
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Beyond peer to peer
802.11 MAC “ad hoc” a network composed solely of stations within mutual communication range of each other.
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Self Forming, A.K.A.
• Ad hoc networks
• Multi hop networks
• Mesh networks
• Viral networks
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Nothing New!• DARPA and the US Military has
a long history of ad hoc networking dating back to Packet Radio experimentsover 20 years ago
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
• Potentially no infrastructure• Communities (Schools, clubs,
social groups)• Location for parents?• Generation that readily accepts
technology• Multi player games, chat, IM
Applications: Kids & Games
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
• Instant Deployment• Accurate and fast
Location• Voice, Data and Video• 802.11a based 4.9Ghz
band solutions
Applications: Emergency Service
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
• Rapid deployment• High bandwidth• No LOS requirement• Little RF and
infrastructure planning• No Right Of Way issues• All you can eat billing
options
Applications: Last Mile
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Based on 802.11b,or 802.11a,Short rangeHigh data rateFixed or portableSelf deploying &Self organizing -Zigbee initiative
BroadBand backbone (cable, DSL, Utility)
The BroadBand Home
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Future: Intelligent Highways
802.11a based DSRC plusAd hoc networking
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Why an ad hoc network?• The belief in its ability to significantly improve
the capability of any RF modulation scheme by:
Requiring less power Having the ability to be rapidly deployed and reconfigured Providing better frequency reuse Not requiring Lines of Sight (LOS) Being able to load balance around congestion Providing redundancy to deal with failure Requiring less centralized infrastructure Providing capacity and scalability improvements
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
802.11 and ad hoc networking
Many companies today are providing ad hoc networking for standard 802.11 devices. Implementing routing at layer 2.5 or 3
Demonstrable advantages to adding ad hoc routing including range, capacity and scalability improvements.
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Client Meshing Example
•Extends range between 802.11 devices•Off-loads traffic from APs via peer-to-peer links •Increases data rates to distant clients •Reduces number of APs and associated costs
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Infrastructure Meshing Example
•Backhaul is minimized•Increased AP location flexibility•Can create Hot Zones not just Hot Spots•Deployment costs are reduced•Leverages 802.11 standards •No new client software
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Implications for 802.11
There is no Silver Bullet!
ONESIZEFITSALL
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Implications for 802.11
There is no Silver Bullet!
General class of routing algorithmsProactiveLow latency not scalable
ReactiveHighly scalable unpredictable latency
ONESIZEFITSALL
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Implications for 802.11
There is no Silver Bullet!
Type of NetworkPAN, LAN, WAN ONE
SIZEFITSALL
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Some lessons learned
• Feedback from MAC/LLC to RoutingImmediate feedback of TX/RX status is critical in developing a reliable network.
• Feedback from the PHYA normalized measure of the number of corrected error bits in a received message can be used to predict a degrading link
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Some lessons learned
• MAC layer Management entity controlFine grained control of the data rate selection on a per packet basis is needed to select routes with the highest end to end throughput. Transmit power control allows optimal frequency reuse
• Basic MAC FunctionsPower Save mode needs enhancement to minimize timing delays in terminals more than 1 hop from an AP. Group traffic needs to be able to be extended beyond basic data rates for routing protocols that build and distribute topology information
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Some lessons learned
• SecurityAlmost everything today is focused on infrastructure mode of operation, access control, link layer (node to node) and higher layer (IPSEC) considerations
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Some lessons learned
• Routing metricsinformation about other nodes including their congestion status, battery status and is needed to allow
• Location Based ServicesNeed to be more robust than RSSI measurement as this is too easily attenuated. To use TOF/TOA the timing becomes critical, the turn around time must be deterministic
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Implications for 802.11
There are many enhancements that can be made to the existing standards efforts to improve the capability and interoperability of ad hoc networks.
Do this before being drawn into holy wars on different routing protocols!
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Implications for 802.11
• Step 1 Define a better interface between the MAC and higher layers
• The capabilities include standard definition of, and access to, the radio link measurements, not only RSSI but number of retransmissions and error correction done on received packets
• A standard way of controlling power/data rate of the transmitter is also needed to allow the option of multi-hopping at high data rates or single hopping at lower rates
• Some of this is ongoing in 802.11k
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Implications for 802.11
• Step 2 Extend the existing MAC to allow information pertinent to ad hoc networks to be pass across the network efficiently
• The key information needed relates to neighbor discovery, identification of APs (and other network resources), battery awareness - crucial in mobile ad hoc networks, the ability to support location awareness
• This would provide common basic building blocks for ad hoc routing protocols
Peter Stanforth, Vann Hasty, MeshNetworks
doc.: IEEE 802.11-03/216
Submission
Implications for 802.11
• Step 3 Define interoperability between multiple ad hoc protocols/networks
• This will not be easy!• There are as many protocols as companies and
solutions today and the trick is to get them all to co-exist peacefully
