TSPEC-based Admission Control Effects for WMM Clients | CCIE Wireless Exam

Effects of TSPEC-based Admission Control on WMM Clients


Which two effects does TSPEC-based admission control have as it relates to WMM clients? (Choose two.)



Click on the arrows to vote for the correct answer

A. B. C. D. E.


TSPEC-based admission control (TSPEC-AC) is a mechanism used in Wi-Fi networks to ensure efficient allocation of network resources to different types of traffic, including voice traffic. When applied to Wi-Fi multimedia (WMM) clients, TSPEC-AC has the following two effects:

B. Enforce airtime entitlement for wireless voice applications: When a WMM client establishes a session with the access point (AP), it sends a request for network resources to the AP through a TSPEC reservation. The TSPEC reservation specifies the amount of network resources required for the session, including the bandwidth, the data rate, and the maximum delay that can be tolerated. If the AP has sufficient network resources available, it grants the TSPEC reservation and allocates the requested resources to the session. The AP then enforces the airtime entitlement of the session based on the TSPEC reservation, ensuring that the session receives the required network resources and that other sessions do not interfere with it. In the case of voice traffic, this ensures that the voice call maintains a consistent level of quality, without being affected by other traffic on the network.

D. Ensure that call quality does not degrade for existing VoWLAN calls: TSPEC-AC ensures that new sessions are admitted into the network only if sufficient network resources are available to maintain the quality of existing sessions. If a new session requires more network resources than are available, the AP will deny the request and the session will not be established. This prevents the degradation of call quality for existing voice-over-WLAN (VoWLAN) calls due to the introduction of additional traffic into the network.

Therefore, the correct answers are B and D.

The other options are incorrect:

A. Allow access only for VoWLAN traffic when interference is detected: This option is not accurate because TSPEC-AC does not have the capability to detect interference on the network. TSPEC-AC only reserves network resources for sessions based on the TSPEC reservation and enforces the airtime entitlement of the sessions.

C. Deny clients access to the WLAN that do not support WMM: This option is not accurate because TSPEC-AC does not depend on whether a client supports WMM or not. TSPEC-AC works with any WMM-enabled client that can establish a TSPEC reservation with the AP.

E. Deny clients access to the WLAN if they do not comply with the TERP standard: This option is not accurate because TERP (Traffic Engineering Radio Resource Management Plane) is not a standard that is related to TSPEC-AC or WMM. TERP is a mechanism used in Cisco wireless networks to optimize the allocation of radio resources based on network traffic conditions. It does not affect the access of clients to the WLAN.