300-110 Sample Questions Answers

In a Cisco Catalyst 9800 SSO deployment using Link Aggregation Group (LAG) for network interface redundancy, the SSO pair — WLC1 (active) and WLC2 (standby) — must both have their physical interfaces connected to the network infrastructure as part of the LAG bundle. LAG on the 9800 in an SSO configuration is implemented as a multi-chassis LAG across both the active and standby controllers. This means both WLC1 and WLC2 contribute physical member links to the port channel, and the connected switches must have LACP or PAgP bundle members from both controllers in the same port channel group. When an SSO failover occurs — WLC1 fails and WLC2 takes over as active — the LAG remains operational because WLC2 ' s physical links are already established members of the bundle and continue forwarding traffic without any link renegotiation. If only WLC1 had LAG connectivity and WLC2 had independent links, an SSO failover would cause a LAG topology change requiring re-convergence, introducing downtime. WLC3 is a separate N+1 backup controller joined via a mobility tunnel — not part of the SSO pair and its LAG configuration is independent. Reference: WLSD Study Guide — Catalyst 9800 SSO with LAG, Multi-Chassis Link Aggregation, High Availability Network Redundancy Design.

In an N+1 redundancy deployment, an AP ' s ability to return to its designated primary WLC after that controller recovers depends on two distinct configuration requirements working in concert. First, the AP Fallback feature (Option C) must be enabled on the WLC. AP Fallback instructs APs to monitor the availability of their configured primary controller and automatically reconnect to it when it becomes available again, rather than remaining permanently joined to the N+1 backup controller. Without AP Fallback enabled, APs stay connected to whichever controller they most recently joined. Second, the APs must have their primary WLC information correctly configured (Option D). If an AP does not have the primary controller ' s name, IP address, or FQDN correctly set, it cannot identify when its designated primary has recovered and therefore cannot initiate a return fallback. DHCP Option 43 (Option A) is used for initial AP discovery only. Secondary WLC configuration (Option B) addresses failover direction but not the return path. AP failover priority (Option E) controls which APs are moved first during a failover event, not whether fallback occurs. Reference: WLSD Study Guide — N+1 Redundancy Design, AP Fallback Configuration, Controller Primary, Secondary and Tertiary Assignment.

To focus the coverage heat map on the desired coverage threshold, the engineer should use the RSSI slider to set the heat map to the desired cutoff filter. This action adjusts the display to show only the signal levels that meet or exceed the specified RSSI value, effectively filtering out weaker signals and highlighting areas with sufficient coverage. In Ekahau and similar survey tools, the RSSI slider provides a dynamic way to set minimum signal thresholds, allowing the engineer to quickly validate whether coverage meets design targets such as -67 dBm for voice or -70 dBm for data. Changing the color scheme (Option A) only modifies the visual representation without filtering data. The RSSI calibration tool (Option B) adjusts how the tool perceives signal levels, not the display filter. Filtering by AP (Option D) would remove APs from the view, potentially hiding coverage gaps. Reference: WLSD Study Guide — Post-Deployment Survey, Ekahau Heat Map Tools, RSSI Coverage Filtering.

For a network supporting both data and voice over wireless, two key Cisco design recommendations apply. First, the 5 GHz radio band is recommended for voice over wireless due to its wider channel bandwidths, allowing for higher data rates and better quality of service for latency-sensitive applications. 40 MHz channels in the 5 GHz band provide significantly higher throughput than 20 MHz channels in 2.4 GHz, making Option B correct for the bandwidth reason stated. Second, setting the cell boundary to -67 dBm ensures sufficient signal strength for reliable voice communication at the cell edge, which is the Cisco standard threshold for VoWLAN coverage. Options C and E are partially correct (24 non-overlapping channels is accurate, 15-20% overlap is standard) but B and D are the primary Cisco recommendations that define the design targets for a predictive survey supporting voice. Reference: WLSD Study Guide — VoWLAN Design Requirements, Predictive Survey Design Criteria, 5 GHz Band Selection.

The design requirements specify a multi-LAG configuration where each LAG connects to a single switch, different VLANs are assigned to different LAGs, the controller must dynamically learn partner LAG capabilities per port, and standby ports provide redundancy upon active port failure. These requirements collectively point to IEEE 802.3ad LACP (Link Aggregation Control Protocol) as the correct protocol. LACP is the industry-standard IEEE protocol that enables dynamic negotiation of LAG membership between endpoints — the WLC and each Catalyst 9300 switch exchange LACP PDUs (LACPDUs) to discover port capabilities, negotiate bundle membership, and monitor link status. LACP supports active and passive port states where active ports initiate negotiation and passive ports respond, and it provides the standby port mechanism through its hot-standby capability for link redundancy within the bundle. The requirement to ' learn the identity of partners that can support LAG capabilities ' is the defining characteristic of LACP ' s standardized PDU exchange mechanism. PAgP (Option C) is a Cisco proprietary port aggregation protocol that, while functionally similar, is not the IEEE standard and is incompatible with non-Cisco equipment in mixed environments. OSPF (Option B) and BGP (Option D) are Layer 3 routing protocols entirely unrelated to port channel negotiation. Reference: WLSD Study Guide — Catalyst 9800 LAG Configuration, LACP IEEE 802.3ad, Multi-LAG High Availability Design.

Cisco ' s mobility group architecture enables seamless client roaming between WLCs by establishing a trusted peer relationship and shared mobility domain. When two Cisco Catalyst 9800-80 WLCs are placed in the same mobility group, they establish CAPWAP mobility tunnels enabling both Layer 2 and Layer 3 roaming with session continuity including IP address preservation. Within the same mobility group, WLCs exchange client state information, allowing 802.11r Fast BSS Transition, 802.11k neighbor reports, and 802.11v BSS Transition Management to function across controller boundaries. No specific primary or secondary roles are assigned within a mobility group — all members are peers with equal standing for roaming purposes, which is precisely what Option D describes. Option A incorrectly implies a hierarchical structure that does not exist in mobility group peer relationships. Option B separating the WLCs into different groups would break inter-building roaming since clients would experience a full re-authentication cycle. Option C imposing an anchor relationship is appropriate only for guest WLANs. Reference: WLSD Study Guide — Mobility Group Architecture, Inter-Controller Roaming, 802.11r/k/v Fast Roaming Design.

In a high-availability configuration with multiple WLCs in a mobility group, when APs that only have a primary controller configured become orphaned (their primary WLC fails), they will by default join the controller with the lowest percentage of associated APs per license capacity. This load-based selection mechanism ensures a balanced distribution of APs across the remaining controllers in the mobility group. The WLC with the lowest percentage of AP capacity utilized is chosen because it has the most headroom to accept additional APs without becoming overloaded. This prevents a single backup controller from becoming overwhelmed while others remain underutilized. The selection is not based on absolute number of APs (Option D), available free licenses in absolute terms (Option A), or CPU utilization (Option C) — it specifically uses the percentage of license capacity occupied, which normalizes across controllers with different total AP capacities. Reference: WLSD Study Guide — N+1 Redundancy Default Behavior, AP Orphan Failover Logic, WLC Load-Based AP Assignment.

After creating a new predictive survey project and importing the floor plan, the next mandatory step is to set the scale of the floor plan. Setting the scale is critical because all subsequent measurements — AP coverage radius, cell overlap calculations, and distance-based attenuation modeling — depend on the accuracy of the floor plan ' s physical dimensions. If the scale is incorrect, the predictive model will place APs at incorrect distances relative to each other and produce inaccurate coverage predictions. The scale is typically set by the engineer clicking on two known points on the floor plan and entering the real-world distance between them, calibrating the software ' s measurement system. Analyzing the network (Option A) and placing APs (Option C) come after the scale is established. Identifying the coverage area (Option B) is often done simultaneously with scale setting or immediately after. Setting the scale first ensures all subsequent work is based on accurate physical dimensions. Reference: WLSD Study Guide — Ekahau Predictive Survey Workflow, Floor Plan Import and Scale Setting, Pre-Deployment Survey Methodology.

Receive Start of Packet (RxSOP) is a Cisco proprietary mechanism that defines the minimum received signal threshold at which an access point will acknowledge an 802.11 frame and begin processing it. In a high-density lecture hall environment with 16 APs and directional antennas on a constrained channel plan, rogue APs operating on the same or adjacent channels contribute directly to elevated channel utilization by causing unnecessary medium contention, virtual carrier sensing via NAV, and clear channel assessment deferral. By raising the RxSOP threshold on the legitimate APs, the engineer creates a higher signal floor requirement — only signals above the configured RxSOP level are processed. Signals from distant rogue APs, arriving below this threshold, are silently discarded rather than processed, preventing them from consuming airtime through CCA deferral and NAV mechanisms. Band select (Option A) encourages dual-band clients to move to 5 GHz but does not address rogue interference. 802.11w (Option B) is a management frame protection standard, not an interference mitigation tool. DFS detection (Option D) is for radar avoidance on UNII-2 channels, not rogue AP mitigation. Reference: WLSD Study Guide — High-Density WLAN Design, RxSOP Configuration, Channel Utilization Management.

An oil terminal presents specific wireless design constraints: the requirement is pervasive coverage (maximum geographic coverage) for low-bandwidth applications (casual web and email). These requirements prioritize coverage reach over throughput optimization. The correct approach is to keep all data rates enabled, including lower rates such as 6, 9, 12, and 18 Mbps — because in an industrial environment with challenging RF propagation paths, reflective surfaces, and potential obstructions, lower data rates extend the functional coverage range of each AP. Web and email traffic does not require high data rates; even 1-6 Mbps is sufficient for these applications. Disabling rates below 54 Mbps (Option A) would dramatically shrink each AP ' s effective coverage area, requiring many more APs for pervasive coverage and failing the primary design objective. Assigning static maximum power without RRM auto-adjustment creates excessive co-channel interference. Disabling rates below 24 Mbps (Option C) still reduces coverage reach unnecessarily. Disabling 802.11n and 802.11ac MCS rates (Option D) prevents the AP from using high-efficiency modulation for nearby clients without coverage benefit. Auto power assignment combined with all rates enabled provides the optimal balance for pervasive industrial deployment. Reference: WLSD Study Guide — Industrial WLAN Design, Coverage vs. Capacity Trade-offs, Data Rate Configuration for Pervasive Coverage.

Raising the minimum data rate to 24 Mbps reduces the effective coverage range of each AP because clients at the cell edge operating at low data rates are effectively excluded from the cell. This shrinks cell size, reducing channel overlap between neighboring APs on the same channel. Using directional antennas limits the coverage area of some APs by focusing RF energy in specific directions rather than radiating omnidirectionally, which directly reduces the lateral overlap between adjacent APs. Increasing AP transmit power (Option B) would worsen overlap, not reduce it. Allowing UNII-2e channels (Option C) provides more channel options but does not reduce the physical cell overlap — it only provides more channels to avoid co-channel interference. Power saving mode (Option E) is a client-side power management feature unrelated to AP cell sizing during a survey. Reference: WLSD Study Guide — Channel Overlap Mitigation, Data Rate Configuration, Directional Antenna Use Cases.

When a data path mobility tunnel fails to come up between WLCs, one of the key troubleshooting steps is to verify whether the necessary ports are open through firewalls in the path. Cisco AireOS mobility tunnels use UDP port 16666 for mobility control traffic and IP Protocol 97 (EtherIP) for mobility data traffic in legacy mode. Establishing a Telnet connection from a local PC to the firewall on port 16666 tests whether the control path port is reachable and not being blocked by the firewall. If the Telnet connection fails, it confirms that the firewall is blocking port 16666, which would prevent the mobility control tunnel from establishing — a prerequisite for the data tunnel. While a Telnet test to port 16666 specifically tests the control path, in practice this is the first verification performed when the data path cannot establish (since the data path depends on the control path being operational). IP Protocol 97 cannot be tested via Telnet (which is TCP). The mping command (Option D, not ' mapping ' ) tests mobility tunnel connectivity from the WLC itself after the tunnel is established. Reference: WLSD Study Guide — Mobility Tunnel Troubleshooting, Firewall Port Requirements, UDP 16666 and IP Protocol 97.

This design scenario requires careful interpretation of the SSO pair function and AP priority semantics. The SSO requirement for Campus1 zero downtime means Campus1 ' s WLC must be paired in an SSO relationship — SSO provides hitless failover with no AP disassociation and no client reauthentication. The data center WLC, which must always remain available as N+1 backup for all campuses, is the logical SSO partner for Campus1 WLC. The SSO pair presents as a single logical entity, ensuring the data center WLC remains active and capable of serving as N+1 backup while simultaneously providing SSO for Campus1. The AP priority for the N+1 backup scenario defines the recovery order when the backup controller must simultaneously handle APs from multiple campuses. In Cisco WLC AP failover priority, priority 1 is Critical (highest). The stated recovery order — Campus3 first, Campus2 second, Campus1 last — maps to: Campus3 APs assigned priority 4 (Cisco ' s highest numeric value in the 4-tier system, equating to the highest service recovery priority in this context), Campus2 APs priority 2, and Campus1 APs priority 1 (lowest, recovered last). Option C correctly pairs the data center WLC with Campus1 WLC for SSO and assigns AP priorities in the correct descending recovery order. Reference: WLSD Study Guide — SSO High Availability, N+1 Redundancy, AP Failover Priority Design.

In a warehouse setting, two elements with a significant negative effect on wireless performance are AP height and absorption. AP height (Option B) is critical because warehouses often have very high ceilings (25-45 feet). When APs with internal (omnidirectional) antennas are mounted too high, the signal propagates primarily in the horizontal plane and the path loss to floor-level worker devices becomes excessive. Additionally, metal shelving between the AP and users further attenuates the already weak signal at high mounting heights. Absorption (Option E) is a major challenge in warehouses because the inventory stored on metal racks, particularly liquid goods, dry goods in cardboard, and dense materials, absorbs RF energy significantly. Metal racking causes both absorption and reflection, creating RF shadows and multipath environments that degrade connection quality. Wireless channels (Option A) are a design parameter, not an environmental impediment. Client authentication (Option C) and authorization (Option D) are network security processes unrelated to RF propagation quality. Reference: WLSD Study Guide — Warehouse Wireless Design, AP Height Considerations, RF Absorption in Industrial Environments.

Cisco Catalyst Center uses a tiered licensing model — Essentials and Advantage — applied to both switching and wireless infrastructure. To enable a fully fabric-enabled (SD-Access) deployment with centralized management, the Cisco Catalyst Advantage license is required across all device types. The Advantage tier unlocks Software-Defined Access fabric capabilities including macro and micro-segmentation, integration with Cisco ISE for policy enforcement, AI/ML-driven analytics via DNA Spaces and Assurance, and automated provisioning. The Essentials license provides only basic device management, inventory, and software image management — it does not unlock SD-Access fabric functionality. Since the branch design specifically extends an existing fabric-enabled network, the Essentials tier for either the switch or APs would create a licensing gap preventing full fabric participation. Options B, C, and D all create asymmetric licensing that would partially disable fabric capabilities. The correct design mandates Catalyst Advantage for the Catalyst 9300 switch and all 25 APs. Reference: WLSD Study Guide — Cisco Catalyst Center Licensing, SD-Access Design, Fabric-Enabled Wireless Architecture.

Voice over WLAN (VoWLAN) deployments require a minimum SNR threshold to maintain acceptable Mean Opinion Score (MOS) values for call quality. Cisco ' s 300-110 WLSD curriculum specifies that VoWLAN requires a minimum SNR of 25 dB throughout the coverage area. In an Ekahau post-deployment survey SNR heatmap, when the heatmap displays a consistent color indicating SNR at or above this threshold across the entire surveyed area — including all rooms, corridors, and common areas such as the lobby — the conclusion is that voice service is supported in all locations. The color coding in Ekahau ' s SNR heatmap uses green tones to indicate adequate SNR (typically ≥25 dB) and shifts toward yellow and red for degraded conditions. When the exhibit heatmap shows uniform adequate coverage across all surveyed areas without yellow or red zones, it confirms the SNR requirement for VoWLAN is universally met. Options A, B, and C suggest partial or no coverage, which would be indicated by mixed or poor SNR values — conditions not present in this scenario. The post-deployment survey with Ekahau is the validation step confirming that the predictive design was accurately realized in the physical environment. Reference: WLSD Study Guide — VoWLAN Design Requirements, SNR Thresholds, Post-Deployment Survey Validation with Ekahau.

Link Aggregation Group (LAG) is the correct design approach for a single Cisco 9800-40 WLC that requires high availability between the WLC and the core switch in the event of a cable failure. LAG combines multiple physical ports on the WLC into a single logical channel, providing both redundancy (traffic automatically redistributes across remaining links when one fails) and load balancing (traffic is distributed across all active links). Importantly, LAG operates transparently to AP management — APs see a single logical uplink regardless of which physical port their traffic traverses. With a single WLC, Multi-LAG (Option B) is not applicable — Multi-LAG is a feature of the Catalyst 9800 that allows multiple separate LAG bundles for different network connections, typically used with SSO pairs. LACP (Option C) is the protocol used to negotiate LAG member links — it is the mechanism within LAG, not an independent design approach. PAgP (Option D) is a Cisco proprietary alternative to LACP for port aggregation but the question asks for the design approach, which is LAG. Reference: WLSD Study Guide — Catalyst 9800 LAG Design, Port Redundancy and Load Balancing, Single-Controller High Availability.

The design requirements — optimized performance, interference avoidance, high-density support, and roaming capability — collectively point to a dual-band strategy using narrow channel widths. For 5 GHz operation (Option A), 20 MHz channels are the correct choice for high-density and campus-scale deployments. The 5 GHz band has a significantly greater number of non-overlapping channels compared to 2.4 GHz (up to 24 non-overlapping 20 MHz channels in UNII-1, UNII-2, and UNII-3), enabling a robust channel reuse plan with minimal co-channel interference. Wider 5 GHz channels (Options C and E — 80 MHz and 40 MHz) would consume multiple channel blocks, dramatically reducing the number of available non-overlapping channels and increasing co-channel interference in dense deployments. For 2.4 GHz operation (Option B), 20 MHz channels are mandatory — there are only three non-overlapping 20 MHz channels (1, 6, 11) in the 2.4 GHz band. Using 40 MHz channels in 2.4 GHz (Option D) eliminates all non-overlapping channel separation, causing massive co-channel interference and is universally contraindicated in enterprise designs. Reference: WLSD Study Guide — Channel Planning, High-Density Design, Frequency Band Selection.

In the Cisco Catalyst 9800 IOS XE WLC configuration framework, the site tag serves as the primary organizational and functional grouping element for FlexConnect APs at a given physical location. The site tag defines the FlexConnect site — a logical boundary within which APs can perform local switching and local inter-AP roaming without requiring CAPWAP tunnel traversal to the WLC for every client handoff. Within a FlexConnect site defined by the site tag, APs can exchange client roaming context information directly with each other (peer-to-peer), enabling fast Layer 2 roaming for clients moving between APs that share the same site tag — effectively defining the roaming domain for FlexConnect APs at that site. The site tag also references the flex profile (which defines VLAN mappings, local auth settings, and split tunneling parameters) and the AP join profile. Switch port configuration (Option A) is performed on the infrastructure switches, not through the WLC site tag. IP address assignment (Option B) is a DHCP function. Firewall policies (Option C) are applied through ACLs and policy tags, not site tags. Reference: WLSD Study Guide — Catalyst 9800 Tag Architecture, FlexConnect Site Tag Role, Local Roaming in FlexConnect Deployments.

During a client roaming event in a Cisco SD-Access fabric deployment, the Wireless LAN Controller (WLC) is responsible for communicating the new Layer 2 Endpoint ID (EID) mapping of a wireless supplicant to the fabric domain. In the SD-Access architecture, the WLC acts as a mobility orchestrator and serves as the interface between the wireless domain and the wired fabric. When a client roams from one AP to another, the WLC detects the roaming event and updates the fabric control plane with the new EID-to-RLOC (Routing Locator) mapping by notifying the fabric control plane node (CP). This ensures that the fabric knows the client ' s new location and can route traffic correctly without interruption. The Border Node (BN) handles traffic between the fabric and external networks. CP1 and CP2 are control plane nodes that maintain the mapping database but receive EID update notifications from the WLC — they do not initiate the EID mapping communication themselves. Reference: WLSD Study Guide — SD-Access Wireless Architecture, Client Roaming in Fabric Deployments, EID Mapping and Control Plane Notifications.

In a Layer 1 passive wireless site survey using a channel analyzer tool (such as Metageek Chanalyzer or Cisco Spectrum Expert) in the 2.4 GHz spectrum, the chart that indicates the ratio of interference present during the capture duration is the Duty Cycle chart. The duty cycle chart displays the percentage of time that detected energy — including both Wi-Fi and non-Wi-Fi signals — is present on each channel. A high duty cycle on a channel indicates that the channel is occupied by transmissions for a significant portion of time, reducing available airtime for Wi-Fi clients. This chart directly communicates the ratio of interference because it shows what fraction of the observation period had detectable RF energy above the noise floor. Signal strength charts show amplitude (how strong), while duty cycle charts show temporal occupancy (how often) — the latter is the correct metric for quantifying interference ratio. Reference: WLSD Study Guide — Layer 1 Spectrum Analysis, Duty Cycle Chart Interpretation, Spectrum Analyzer Methodology.

A brownfield deployment scenario involves an existing operational wireless network where a physical remodel will change the RF environment. The engineer ' s task is to assess the impact of new furniture and wall materials on the existing AP placement — a scenario requiring a predictive re-analysis of how changed materials will alter propagation from the existing AP locations. Using a survey tool such as Ekahau with the known AP positions superimposed on updated floor plans, the engineer can reconfigure material attenuation properties to reflect new construction materials and re-run the predictive propagation model. This produces a before/after comparison identifying coverage gaps or interference hotspots introduced by the remodel without requiring physical downtime or temporary infrastructure changes. Option A (sweep analysis) measures existing signal strength but does not model future material changes. Option B (neighbor AP statistics) evaluates the current RF environment using WLC data, not future conditions. Option C (throughput measurements) tests current performance, not future RF impact. Reference: WLSD Study Guide — Brownfield Survey Methodology, Material Attenuation Modeling, Post-Remodel RF Impact Analysis.

Devices that can tolerate at most 100 ms of delay when roaming are voice devices. The 100 ms maximum roaming delay threshold is the Cisco-specified design criterion for VoWLAN implementations — it defines the maximum time a handset can tolerate being disconnected from the wireless network during a roam event before the voice call is degraded or dropped. This threshold drives specific design requirements: 15-20% cell overlap at -67 dBm, fast roaming mechanisms (802.11r, CCKM, or OKC), and AP placement along user movement paths. Location services (Option A) have flexible latency requirements. Data applications (Option B) can tolerate much higher latency — typically several hundred milliseconds. Video (Option C) streaming has buffering mechanisms that allow for higher latency tolerance than real-time voice. Only voice applications have the strict 100 ms roaming delay requirement that directly influences the predictive design criteria. Reference: WLSD Study Guide — VoWLAN Roaming Design, Roaming Delay Requirements, Predictive Survey Criteria.

In a Cisco wireless mobility group, all Wireless LAN Controllers (WLCs) must be configured with the same virtual IP address to ensure proper roaming. The virtual IP address is a Layer 3 construct used by wireless clients during the DHCP renewal process when roaming between subnets managed by different WLCs. All WLCs in the same mobility group use the same virtual IP (typically from the unused 1.1.1.0/24 or similar non-routable space) so that clients receive consistent DHCP server responses regardless of which controller they are associated with. If different virtual IP addresses were used (Option B), clients roaming between controllers would experience DHCP failures during inter-controller roaming because the DHCP server address seen by the client would change. Options A and C relate to DNS hostname configuration, which is useful for AP discovery but does not affect the roaming behavior of client devices. The virtual IP address consistency across all mobility group members is a fundamental requirement for seamless inter-controller roaming. Reference: WLSD Study Guide — Mobility Group Configuration, Virtual IP Address, Inter-Controller Roaming Requirements.

In Ekahau Site Survey ' s multi-floor predictive modeling workflow, alignment points are the critical mechanism that allows the software to understand the precise vertical spatial relationship between floors in a multi-story building. Once floor plans are imported with their scale correctly defined, alignment points must be placed on each floor at the same real-world physical location — such as a stairwell corner, elevator shaft, or structural column — so that Ekahau can accurately calculate vertical signal propagation and inter-floor RF bleed. Without alignment points, the software has no spatial reference to determine which area on Floor 2 is directly above a given point on Floor 1, making floor-to-floor signal bleed calculations geometrically impossible. Drawing coverage areas (Option A) is a post-AP-placement activity. Starting the auto planner (Option B) would attempt to place APs without the required spatial reference. Choosing AP models (Option D) is a subsequent step. Alignment points are a fundamental requirement for any predictive survey involving multi-floor buildings. Reference: WLSD Study Guide — Ekahau Predictive Survey Methodology, Multi-Floor Building Configuration, Signal Propagation Modeling.