PDF 300-110 Study Guide

In Cisco ' s guest anchor WLC deployment model, multiple anchor controllers can be configured in a DMZ to provide redundancy for guest WLAN traffic. The anchor priority value determines which anchor controller is preferred for establishing the guest mobility tunnel from the foreign WLC. Cisco ' s anchor priority system assigns the highest preference to the lowest numerical priority value. Priority 1 is the highest priority, meaning the foreign WLC will prefer Anchor1 when establishing the CAPWAP mobility tunnel for anchoring guest client traffic. Priority 2 would be assigned to Anchor2, and Priority 3 to Anchor3, creating a deterministic failover hierarchy. If Anchor1 becomes unreachable, the foreign controller automatically falls over to Anchor2, then to Anchor3. Priority 0 is not a valid anchor priority value in the Cisco WLC configuration. This design pattern is critical for enterprise guest deployments where DMZ anchor redundancy must be maintained without manual intervention. Reference: WLSD Study Guide — Guest Wireless Architecture, Anchor WLC Configuration, Mobility and DMZ Design.

In an anchored WLAN deployment, client traffic is encapsulated within CAPWAP mobility tunnels between the foreign WLC (where the AP joins) and the anchor WLC (in the DMZ or designated network segment). This tunneling adds encapsulation overhead — CAPWAP/mobility tunnel headers consume a portion of the available MTU on the transport path. When video streaming clients generate large TCP segments, these segments may exceed the effective MTU of the mobility tunnel path, causing IP fragmentation at the WLC or along the path to the anchor. Fragmentation significantly degrades throughput and increases CPU overhead for high-volume video traffic. The correct solution is TCP MSS Clamping — reducing the Maximum Segment Size value advertised in TCP SYN packets so that TCP endpoints negotiate a segment size remaining below the fragmentation threshold. The Cisco 9800 WLC supports TCP MSS adjustment, which intercepts TCP handshake packets and rewrites the MSS option to a value accounting for CAPWAP tunnel overhead. Setting matching MTUs (Option A) does not prevent fragmentation if the effective tunnel MTU is lower than the client segment size. Increasing the MTU (Option B) is often constrained by physical infrastructure. Setting the DF bit (Option D) would cause packets to be dropped rather than fragmented. Reference: WLSD Study Guide — Anchored WLAN Design, CAPWAP Mobility Tunnel MTU, TCP MSS Clamping.

When designing a wireless network to support diverse services — including data, voice, video, and location tracking — across a distributed enterprise with a main office and 10 branch locations, the two primary design factors directly shaping the RF and capacity architecture are the number of wireless devices requiring access and the type of site where the survey will be performed. The device count (Option B) drives AP density, channel reuse planning, capacity modeling, and controller licensing requirements. Each service type — particularly VoWLAN and video — imposes strict per-client throughput and latency constraints that must be multiplied across the concurrent device population. The type of site (Option C) determines the survey approach, attenuation characteristics, coverage requirements, and antenna selection. A warehouse, hospital, or open-plan office each demands a fundamentally different RF design. Options A and D are organizational considerations, not technical RF design inputs. Option E (power sockets) is an installation logistics concern, not a wireless design factor. Reference: WLSD Study Guide — Requirements Gathering, Site Survey Planning, Capacity and Coverage Design Methodology.

To optimize roaming in a wireless network with multiple controllers, it is essential to use the same WLAN name (SSID) across all controllers. When SSIDs differ between controllers, clients perceive them as different networks and must perform a full re-association and re-authentication when roaming between APs managed by different controllers. This causes a roaming disruption equivalent to connecting to an entirely new network. By using identical SSID names on both controllers, clients can seamlessly roam between APs on different controllers within the same mobility group — the controllers exchange client state information via the mobility tunnel, enabling seamless handoff. In the scenario described, ' Copr-NET390595865WLC-1 ' and ' Copr-NET6837l638WLC-2 ' are different SSIDs, meaning clients cannot roam transparently between them. Making both controllers broadcast the same SSID name (and using a mobility group to connect the controllers) resolves this. Reference: WLSD Study Guide — SSID Consistency Across Controllers, Inter-Controller Roaming, Mobility Group Configuration.