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更新于2008-06-25 21:46:44

5.6 Differences between ESS and IBSS LANs

•   In 5.2.1 the concept of the IBSS LAN was introduced. It was noted that an IBSS is often used to support an ad hoc network. In an IBSS network, a STA communicates directly with one or more other STAs. Consider the full IEEE 802.11 architecture as shown in Figure 5-8.

• Only the minimum two STAs are shown in Figure 5-9. An IBSS may have an arbitrary number of members. In an IBSS, only Class 1 and Class 2 frames are allowed because there is no DS in an IBSS.
• The services that apply to an IBSS are the SSs. A QoS IBSS supports operation under the HCF using TXOPs gained through the EDCA mechanism. The parameters that control differentiation of traffic classes using EDCA are fixed. A QoS IBSS has no HC and does not support polled TXOP operation and setting up of TSPEC.
• In an IBSS, each STA must enforce its own security policy. In an ESS, an AP can enforce a uniform security policy across all STAs.

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