Cisco-CompatibleExtensionsCCX无线客户端进步的标准超过90.PPTVIP

* So here is the actual algorithm under the hood to make this happen. First we will identify what clients are dual band capable by listening to the probe responses. If the client is seen to be probing on both bands, we will suppress the response on the 2.4gHz radio. Now there is a bit of a learning curve here, as we need to make sure the client is dual band capable before we block it. Sometimes when you turn the client on for the first time, it might goto 2.4GHz, but after we see it probe for a couple cycles, it’s next association, or roam will be to the 5GHz radio. For 2.4GHz only clients we will essentially timeout their suppression, and allow a probe response on the 2.4GHz radio so that they can associate. 加一个干扰对无线用户的影响 加上大连理工的干扰源 * Additionally, managing the spectrum has increased in complexity over time with the influx of more and more devices that operate in the frequency. Wireless LANs operate in the unlicensed frequencies (2.4GHz and 5GHz), but so do many other devices. The problem is this spectrum is a finite resource and with each new device that is using that spectrum, the ability to deliver continual 802.11n performance becomes more challenging. At the same time, the cost of supporting the network increases as more and more users call the helpdesk with wireless connectivity issues. * * * 干扰源的侦测和分类是AP内置频谱分析芯片的一个功能，凭借高精度的频谱分析，AP可以在30秒内准确快速识别包括微波炉、蓝牙、无绳电话、无线摄像头等二十几种干扰，在多达10个干扰同时存在时，同样可以快速准确识别。 Cisco clean air根据干扰所在的频点，以及干扰对无线信道的影响程度包括信号强度以及占用无线信道的时间来对干扰进行严重级别评估，并且根据无线干扰所影响的信道对每个AP的无线网络性能进行评估,对于每个AP都有一个非常直观的空口质量的显示。 * * * 加上一页高清视频的重要性 加上一页multicast vlan 等相应的PPT * * * 802.11通用安全PPT 加一个ROUGE检测特性 * 现实的问题 * 在传统的组播点播方式下，当属于不同VLAN的主机Host A、Host B和Host C同时点播同一组播组时，三层设备（Router A）需要把组播数据在每个用户VLAN（即主机所属的VLAN）内都复制一份发送给二层设备（Switch A）。这样既造成了带宽的浪费，也给三层设备增加了额外的负担。 可以使用组播VLAN功能解决这个问题。在二层设备上配置了组播VLAN后，三层设备只需把组播数据在组播VLAN内复制一份发送给二层设备，而不必在每个用户VLAN内都复制一份，从而节省了网络带宽，也减轻了三层设备的负担 Multicast at present is based on the grouping of the multicast address and the VLAN as one entity, mgi