While reviewing data gathered during a passive RF site survey for an existing network of Cisco Aironet 1260 Series Access Points, you discover a high amount of potential co-channel interference throughout the network.
Which two of these are potential causes? (Choose two.)
Co-channel interference occurs when two or more access points (APs) are operating on the same channel in the same area. This interference can cause poor network performance and can make it difficult for clients to connect to the network. In the given scenario, the passive RF site survey has identified a high amount of potential co-channel interference throughout the existing network of Cisco Aironet 1260 Series Access Points. Let's discuss the potential causes:
A. Inconsistent beacon interval: A beacon is a packet sent by an AP to broadcast its presence and to provide information about the network. The beacon interval is the time between two consecutive beacons sent by an AP. If the beacon interval is inconsistent across APs, it can cause co-channel interference because APs may transmit on the same channel at the same time, leading to collisions. Therefore, inconsistent beacon intervals can be a potential cause of co-channel interference.
B. EDRRM not enabled: Enhanced Distributed Channel Access (EDCA) with Request to Send/Clear to Send (RTS/CTS) and Receiver Directed Transmit (RDT) for Multicast (EDRRM) is a feature that helps reduce co-channel interference by coordinating access to the channel. If EDRRM is not enabled, APs may transmit on the same channel at the same time, leading to collisions and co-channel interference.
C. APs placed too close together: When APs are placed too close together, they can interfere with each other by transmitting on the same channel at the same time. Therefore, AP placement should be carefully considered to avoid co-channel interference.
D. Static channel plan: A static channel plan is a configuration where APs are set to operate on specific channels. If the same channel is used in adjacent areas, it can cause co-channel interference. Therefore, a dynamic channel plan that takes into account the neighboring channels should be used to avoid co-channel interference.
E. Inadvertently set radio policy: The radio policy is a configuration that determines which 802.11 standards (a, b, g, n, ac, etc.) are supported on the AP's radio. If the radio policy is set identically for all SSIDs, it can cause co-channel interference because APs may transmit on the same channel at the same time, leading to collisions. Therefore, the radio policy should be configured based on the requirements of each SSID to avoid co-channel interference.
Based on the above discussion, the potential causes of co-channel interference in the given scenario are inconsistent beacon interval (A) and inadvertently set radio policy (E).