TAILIEUCHUNG - Scalable voip mobility intedration and deployment- P26

Scalable voip mobility intedration and deployment- P26: The term voice mobility can mean a number of different things to different people. Two words that can be quite trendy by themselves, but stuck together as if forgotten at a bus station long past the last ride of the night, the phrase rings a number of different, and at times discordant, bells. | 250 Chapter 6 3. At this point if the new access point is on a different channel the client will change the channel of its receiver. 4. If the new channel is a DFS channel the client is required to wait until it receives a beacon frame from the access point unless it has recently heard one as a part of a passive scanning procedure. 5. The client will send an Authentication message to the new access point establishing the beginnings of a relationship with this new access point but not yet enabling data services. 6. The access point will respond with its own Authentication message accepting the client. A rejection can occur if load balancing is enabled and the access point decides that it is oversubscribed or if key state tables in the access point are full. 7. The client will send a Reassociation Request message to the access point requesting data services. 8. The access point will send a Reassociation Response message to the access point. If the message has a status code for success the client is now associated with and connected to this access point and only this access point. Controller-based wireless architectures will usually ensure this by immediately destroying any connection that may have been left over if step 2 has not been performed. The access point may reject the association if it is oversubscribed or if the additional services the client requests mostly security or quality-of-service in the Reassociation Request will not be supported. At this point the client is associated and data services are available. Usually the access point or controller behind it will send a broadcast frame spoofed to appear as if it were sent by the client to the connected Ethernet switch informing it of the client s presence on that particular link and not on any one that may have been used previously. If no security is employed skip ahead to the admission control mechanisms towards the end of the list. If PSK security is employed skip ahead to the four-way handshake. .

• Phần cứng
• lắp ráp máy tính
• sửa chữa máy tính
• sổ tay phần cứng
• MainBoard
• thiết bị máy tính
• thiết bị mạng
• Lắp ráp bảo trì máy tính
• Lắp ráp bảo trì máy tính phần 2
• Cài đặt phần mềm cho máy tính
• Bảo trì máy tính
• Cài đặt máy tính
• Phần cứng máy tính
• lỗi máy tính
• hệ thống mạch máy tính
• điện máy tính
• Tài liệu máy tính