1、Wireless LANs,Describing WLAN Topologies,WLAN Topologies,Wireless client access Mobile user connectivity Wireless bridging LAN-to-LAN connectivity Wireless mesh networking Combination of bridging and user connectivity,WLAN and LAN,Service Set Identifier (SSID),SSID is used to logically separate WLAN
2、s. The SSID must match on client and access point. Access point broadcasts one SSID in beacon. Client can be configured without SSID. Client association steps: Client sends probe request. A point sends probe response. Client initiates association. A point accepts association. A point adds client MAC
3、 address to association table.,WLAN Access Topology,Wireless Repeater Topology,Workgroup Bridge Topology,Alternative Peer-to-Peer Topology,Service Sets and Modes,Ad hoc mode Independent Basic Service Set (IBSS) Mobile clients connect directly without an intermediate access point.Infrastructure mode
4、Basic Service Set Mobile clients use a single access point for connecting to each other or to wired network resources.Extended Services Set Two or more Basic Service Sets are connected by a common distribution system.,Roaming Through Wireless Cells,Roaming Through Wireless Cells,Client Roaming,Roami
5、ng without interruption requires the same SSID on all access points.,Maximum data retry count exceeded Too many beacons missed Data rate shifted Periodic intervals,Layer 2 vs. Layer 3 Roaming,Wireless VLAN Support,Multiple SSIDs Multiple security types Support for multiple VLANs from switches 802.1Q
6、 trunking protocol,Wireless VLAN Support (Cont.),VLANs propagate across access points. VLAN numbers are unique. Access points handle up to 16 VLANs.,Enterprise Voice Architecture,Wireless Mesh Networking,In a mesh network topology, devices are connected with redundant connections between nodes.,Wire
7、less Mesh Networking,Mesh access points automatically establish connection to controller. Rooftop access points (RAP) connect via wired connection. Mesh access points (MAP) connect via self-configuring backhaul connection. Cisco uses mesh access points. Adaptive Wireless Path (AWP) protocol establis
8、hes best path to root. Access point authenticates to controller and downloads configuration and radio parameters.,Adaptive Wireless Path Protocol (AWP),AWP protocol establishes an optimal path to root. Each access point carries a feasible successor or successors if topology or link health changes. AWP uses a “parent sticky” value to mitigate route flaps.,
