1. Emerging Technologies in Wireless LANs

2. Replacement for traditional Ethernet LANs Several Municipalities Portland, OR Philadelphia, PA San Francisco, CA Thornton, CA Rockville, MA New Orleans, LA Anaheim, CA Built-out Plan of the Network

3. Virtual Private Network (VPN) Technology Network Security Mechanisms 802.11-based Device Support QoS Capabilities Access Levels Free Premium Business Network Operations Centers(NOC) & Authentication, Authorization and Accounting (AAA)

4. Access Tier Client Connection Tier 802.11 b/g Ad-hoc Mode Infrastructure Mode Handoff Delay 1. Offering an AP for potential handoff. 2. Continuously update routing information to the client device’s point of attachment. VoIP Latency Limit of 50ms

5. Mesh Tier Path Redundancy Inefficiencies Hidden Station Phenomenon CSMA/CA MAC Protocol at high capacity Injection Tier Extends existing wired network at low cost. Connects Mesh Tier to Backhaul Tier Backhaul Tier

6. Aggregates user traffic and responsible for routing, subscriber-related administration functions. Access Controller (AC) acts as the layer 3 router. AAA Operates on a per-subscriber QoS policies. Network performance monitoring. Bottleneck Possibilities Access Controller Backhaul PoP

7. Design Problems Coverage, RF propagation, and interference require detailed site surveying. AP placement dependant on scale and cost. Must interoperate with existing 802.11 devices. Authentication Encryption 802.11 b/g Compatibility Handoff and Dynamic IP Addressing Multi-story buildings require AP cells that extend into the third dimension.

8. Operate in Ad-Hoc Mode. Efficient Path Selection 1. It maximizes the throughput for the current flow as well as the aggregate throughput of the mesh. 2. It minimizes the delay and jitter imposed on packets of the current flow as well as other flows in the mesh. Throughput issues Hidden Station Phenomenon Transmission Range < Interference Range

9. Connects wireless mesh network to a wired backhaul. Drastically reduces throughput. 1.544 MBps down to 3 Mbps (T1) Potentially a bottleneck. Opportunity for high cost.

10. 900 MHz Preferred in areas with high foliage. Long Ranges and/or no LOS Low Data Rates 2.4 GHz Co-channel Interference the access tier third-party 802.11 b/g devices non-802.11 interferers 5 GHz Preferred when no subject to obstructions.

11. 802.11r Standard Alternative for existing cellular networks Needed capability of efficient handoffs. Low signaling overhead, packet loss and latency. Principle Problems Custom protocols not on standard 802.11 devices. Non-standard software needed. RFC 2002 standards designed with low mobility in mind. Inefficient bandwidth usage.

12. Conclusion