无线网络·10无线mesh网络.ppt

Wireless worksChallenges and Opportunities
Yi Ping
School of Information Security Engineering,
Shanghai Jiao Tong University
© 2005,2006
1
Outline
Overview of the technology
Opportunities
(Research) Challenges
Current state of the art
Conclusion
2
Wireless routers
Gateways
Printers, servers
Mobile clients
Stationary clients
Intra-mesh wireless links
Stationary client access
Mobile client access
access links
Node Types
Link Types
Overview
3
Gateways
Multiple interfaces (wired & wireless)
Mobility
Stationary (. rooftop) – mon case
Mobile (., airplane, busses/subway)
Serve as (multi-hop) “access points” to user nodes
Relatively few are needed, (can be expensive)
GW
4
Wireless Routers
At least one wireless interface.
Mobility
Stationary (. rooftop)
Mobile (., airplane, busses/subway).
Provide coverage (acts as a mini-cell-tower).
Do not originate/terminate data flows
Many needed for wide areas, hence, cost can be an issue.
5
Users
Typically one interface.
Mobility
Stationary
Mobile
Connected to the work through wireless routers (or directly to gateways)
The only sources/destinations for data traffic flows in work.
6
User – Wireless Router Links
Wired
Bus (PCI, PCMCIA, USB)
, Firewire, etc.
Wireless

Bluetooth
Proprietary
Point-to-Point or Point-to-Multipoint
If properly designed is not a bottleneck.
If different from router-to-router links we’ll call them access links
7
Router to Router Links
Wireless

Proprietary
Usually multipoint to multipoint
Sometimes a collection of point to point
Often the bottleneck
If different from router-to-user links we’ll call them backbone links
8
Gateway to Links
Wired
, TV Cable, Power Lines
Wireless

Proprietary
Point to Point or Point-to-Multipoint
We’ll call them backhaul links
If properly designed, not the bottleneck
9
How it Works
User- Data Flows
In most applications the main data flows

User-User Data Flows
In most applications a small percentage of d