3.3 Wireless
📘CCNP Encore (350-401-ENCORE-v1.1)
1. What Is an Access Point (AP)?
An Access Point (AP) is a network device that allows wireless clients (laptops, phones, tablets, scanners, IoT devices) to connect to a wired network.
In enterprise networks, APs are usually:
- Managed by a Wireless LAN Controller (WLC), or
- Managed by a cloud-based controller, or
- Configured as standalone devices
2. AP Modes (Very Important for Exam)
AP mode defines how the access point operates and what role it plays in the wireless network.
Cisco enterprise APs support multiple modes.
2.1 Local Mode (Default Mode)
What It Is
- The most common AP mode
- AP provides normal wireless access to clients
Key Characteristics
- AP connects clients to the network
- Traffic is usually sent to the WLC (centralized forwarding)
- Supports authentication, encryption, roaming, and QoS
Where It Is Used
- Standard enterprise WLANs
- Office, campus, and data center wireless access
Exam Notes
✔ Default mode for lightweight APs
✔ Clients can connect normally
✔ Most production wireless networks use this mode
2.2 FlexConnect Mode (Previously H-REAP)
What It Is
- AP can operate even if the WLC is unreachable
Key Characteristics
- AP is located at a remote site
- Control traffic goes to the WLC
- Data traffic can be:
- Locally switched at the AP, or
- Centrally switched to the WLC
Important Features
- Supports local authentication
- Supports local switching
- Ideal for branch or remote offices
Exam Notes
✔ Used for remote locations
✔ Can continue working if WAN link fails
✔ Supports local VLAN mapping
2.3 Monitor Mode
What It Is
- AP does not serve clients
- Used only for monitoring the RF environment
Key Characteristics
- Listens to all wireless channels
- Detects:
- Rogue APs
- Interference
- Security threats
- Sends data to the WLC
Exam Notes
✔ No client connectivity
✔ Used for security monitoring
✔ Common in wireless intrusion detection systems (WIDS)
2.4 Sniffer Mode
What It Is
- AP captures raw 802.11 frames
Key Characteristics
- Sends captured packets to a packet analyzer
- Used for:
- Wireless troubleshooting
- Packet-level analysis
Exam Notes
✔ Used for deep wireless analysis
✔ No client connectivity
✔ Requires a packet capture system
2.5 Rogue Detector Mode
What It Is
- AP detects rogue access points on the wired network
Key Characteristics
- AP connects only via Ethernet
- Does not transmit RF signals
- Compares wired MAC addresses with wireless devices
Exam Notes
✔ Focuses on wired rogue detection
✔ No wireless client access
✔ Works with security features on the WLC
2.6 Bridge Mode (Point-to-Point / Point-to-Multipoint)
What It Is
- AP acts as a wireless bridge
Key Characteristics
- Connects two or more wired networks wirelessly
- Does not serve wireless clients
- Common configurations:
- Point-to-Point (P2P)
- Point-to-Multipoint (P2MP)
Exam Notes
✔ Used for wireless backhaul
✔ Often used with directional antennas
✔ No client access
2.7 Mesh Mode
What It Is
- APs connect to each other wirelessly
Key Components
- Root AP (RAP) – connected to the wired network
- Mesh AP (MAP) – connects wirelessly to RAP or another MAP
Key Characteristics
- No Ethernet cable needed for every AP
- Used when cabling is difficult
Exam Notes
✔ Used in outdoor or complex deployments
✔ Uses wireless backhaul
✔ Self-forming and self-healing topology
2.8 Summary of AP Modes (Exam-Friendly)
| AP Mode | Client Access | Purpose |
|---|---|---|
| Local | Yes | Normal wireless access |
| FlexConnect | Yes | Remote site AP |
| Monitor | No | Security monitoring |
| Sniffer | No | Packet analysis |
| Rogue Detector | No | Rogue AP detection |
| Bridge | No | Network bridging |
| Mesh | Sometimes | Wireless backhaul |
3. Antenna Types (Very Important Topic)
An antenna controls how RF signals are sent and received.
Choosing the correct antenna is critical for:
- Coverage
- Performance
- Interference control
3.1 Omnidirectional Antenna
What It Is
- Sends RF signals in all horizontal directions
Radiation Pattern
- 360 degrees horizontally
- Limited vertical coverage
Key Characteristics
- Wide coverage area
- Shorter distance compared to directional antennas
Exam Notes
✔ Most common antenna type
✔ Used for general indoor coverage
✔ Default antenna in many APs
3.2 Directional Antenna
What It Is
- Focuses RF energy in one direction
Radiation Pattern
- Narrow beam
- Longer distance
Key Characteristics
- Stronger signal in one direction
- Reduced interference in other directions
Exam Notes
✔ Used for bridges and mesh links
✔ Provides better range
✔ Requires precise alignment
3.3 Common Directional Antenna Types (Know Names)
Patch Antenna
- Flat and rectangular
- Medium coverage
- Used in wall-mounted APs
Yagi Antenna
- Narrow beam
- Long distance
- Used for point-to-point links
Parabolic Antenna
- Very narrow beam
- Very long distance
- High gain
3.4 Internal vs External Antennas
Internal Antennas
- Built inside the AP
- Fixed radiation pattern
- Easier to deploy
External Antennas
- Connected via antenna ports
- Can be replaced or upgraded
- Flexible design
Exam Notes
✔ Internal = simple deployments
✔ External = specialized coverage needs
3.5 Antenna Gain (Important Concept)
What Is Antenna Gain?
- Measurement of how focused the signal is
- Measured in dBi
Key Points
- Higher gain = narrower beam
- Lower gain = wider coverage
Exam Notes
✔ High gain does not increase power
✔ It focuses energy instead of spreading it
4. Relationship Between AP Mode and Antenna Type
| AP Mode | Common Antenna Type |
|---|---|
| Local | Omnidirectional |
| FlexConnect | Omnidirectional |
| Bridge | Directional |
| Mesh | Directional or Omni |
| Monitor | Omnidirectional |
5. Exam Tips (Very Important)
✔ Know all AP modes and their purpose
✔ Understand which modes allow clients and which do not
✔ Remember omnidirectional vs directional antennas
✔ Understand antenna gain and coverage behavior
✔ Be able to match AP mode + antenna type + use case
6. Key Takeaways (For Students)
- AP modes define behavior, not hardware
- Local and FlexConnect are most common for client access
- Monitor and Sniffer are for security and troubleshooting
- Omnidirectional antennas provide wide coverage
- Directional antennas focus signal for distance and precision
