CompTIA Network+ N10-009

Static Routing

Manually configured routes that don't change automatically. Provides full administrative control but requires manual updates for network changes.

Dynamic Routing

Automatically discovers and maintains routes using routing protocols. Adapts to network changes and provides fault tolerance.

BGP (Border Gateway Protocol)

Type: Exterior Gateway Protocol (EGP)
Use: Internet routing between autonomous systems
Algorithm: Path vector
Metric: Path attributes (AS path, local preference)

EIGRP (Enhanced Interior Gateway Routing Protocol)

Type: Advanced distance vector
Vendor: Cisco proprietary
Algorithm: DUAL (Diffusing Update Algorithm)
Metric: Bandwidth, delay, reliability, load

OSPF (Open Shortest Path First)

Type: Link state protocol
Standard: Open standard (RFC 2328)
Algorithm: Dijkstra's shortest path
Metric: Cost (based on bandwidth)

Administrative Distance

Trustworthiness of routing source (0-255, lower is better)

Prefix Length (Subnet Mask)

More specific routes (longer prefix) preferred over less specific routes

Metric

Protocol-specific path cost calculation

• OSPF: Cost (bandwidth-based)
• EIGRP: Composite metric
• RIP: Hop count
• BGP: Path attributes

NAT (Network Address Translation)

Translates private IP addresses to public IP addresses, typically one-to-one mapping for each connection.

PAT (Port Address Translation)

NAT overload - many private IPs share one public IP using different port numbers. Most common home/business implementation.

FHRP (First Hop Redundancy Protocol)

Provides gateway redundancy using virtual IP addresses

• HSRP: Cisco proprietary
• VRRP: Open standard
• GLBP: Cisco load balancing

Virtual IP (VIP) & Subinterfaces

VIP: Shared IP address for redundancy
Subinterfaces: Multiple logical interfaces on single physical interface for VLAN routing

VLAN Fundamentals

Logical segmentation of Layer 2 networks, creating separate broadcast domains on same physical infrastructure. For advanced security concepts, see our Security+ Network Architecture guide.

VLAN Database

Switch configuration storage containing VLAN information:

• VLAN ID (1-4094)
• VLAN name
• Port assignments
• VLAN state (active/suspended)

SVI (Switch Virtual Interface)

Layer 3 logical interface representing a VLAN, enables inter-VLAN routing and management access.

Native VLAN

Default VLAN for untagged traffic on 802.1Q trunk ports. Default is VLAN 1, but should be changed for security.

Voice VLAN

Dedicated VLAN for VoIP traffic, providing QoS prioritization and separate from data traffic.

802.1Q Tagging

IEEE standard for VLAN tagging, inserts 4-byte tag into Ethernet frame header:

• TPID: Tag Protocol Identifier
• PCP: Priority Code Point (QoS)
• DEI: Drop Eligible Indicator
• VID: VLAN Identifier (12 bits)

Link Aggregation

Combines multiple physical links into single logical link:

• LACP: Link Aggregation Control Protocol (802.3ad)
• PAgP: Port Aggregation Protocol (Cisco)
• Benefits: Increased bandwidth, redundancy

Speed & Duplex

Speed: 10Mbps, 100Mbps, 1Gbps, 10Gbps, etc.
Duplex:

• Half: Send OR receive (collisions possible)
• Full: Send AND receive simultaneously
• Auto: Negotiate best speed/duplex

Spanning Tree Protocol (STP)

Prevents Layer 2 loops by blocking redundant paths:

• STP: Original 802.1D (50 second convergence)
• RSTP: Rapid STP 802.1w (6 second convergence)
• MSTP: Multiple STP 802.1s (per-VLAN)

MTU (Maximum Transmission Unit)

Largest frame size that can be transmitted:

• Standard Ethernet: 1518 bytes
• Jumbo Frames: Up to 9000 bytes
• Benefits: Reduced overhead for large transfers
• Requirement: End-to-end support needed

2.4GHz Band

Channels: 1-14 (varies by region)
Non-overlapping: 1, 6, 11 (North America)
Range: Better penetration, longer range
Issues: More congested, interference

5GHz Band

Channels: Many more available
Non-overlapping: 36, 40, 44, 48, 149, 153, 157, 161
Range: Shorter range, less penetration
Benefits: Less congested, higher speeds

6GHz Band (Wi-Fi 6E)

Channels: 1200MHz of spectrum
Benefits: No legacy device interference
Range: Similar to 5GHz
Requirement: Wi-Fi 6E certified devices

Channel Management

Channel Width: 20MHz, 40MHz, 80MHz, 160MHz
Band Steering: Direct devices to optimal frequency
802.11h: Dynamic Frequency Selection (DFS)

SSID (Service Set Identifier)

Network name broadcasted by access points, up to 32 characters. Can be hidden for basic security.

BSSID (Basic Service Set Identifier)

MAC address of individual access point's radio. Unique identifier for each AP.

ESSID (Extended Service Set Identifier)

Same SSID used across multiple access points to create seamless roaming experience.

Infrastructure Mode

Devices connect through access point to wired network. Most common deployment model.

Ad Hoc (IBSS)

Direct device-to-device communication without access point. Independent Basic Service Set.

Point-to-Point

Direct wireless link between two locations, often using directional antennas for long distances.

Mesh Networks

Multiple APs interconnected wirelessly, providing redundancy and extended coverage.

WPA2 (Wi-Fi Protected Access 2)

Encryption: AES-CCMP
Authentication: PSK or 802.1X
Standard: IEEE 802.11i
Key Management: 4-way handshake

WPA3

Encryption: AES-GCMP
Authentication: SAE (Simultaneous Authentication of Equals)
Benefits: Protection against offline attacks
Enhanced: 192-bit security for enterprise

Authentication Methods

PSK (Pre-Shared Key): Same password for all users
Enterprise (802.1X): Individual user credentials via RADIUS server

Guest Networks & Captive Portals

Guest Network: Isolated SSID for visitors
Captive Portal: Web-based authentication before network access

Antenna Types

Omnidirectional: 360-degree coverage pattern
Directional: Focused coverage (Yagi, parabolic)
Use Cases: Omni for general coverage, directional for point-to-point

Access Point Types

Autonomous (Fat AP): Self-contained with full functionality
Lightweight (Thin AP): Controlled by wireless LAN controller (WLC)

MDF (Main Distribution Frame)

Central wiring point connecting to service provider and housing core network equipment:

• Internet service provider connections
• Core switches and routers
• Server connections
• Building backbone cabling

IDF (Intermediate Distribution Frame)

Secondary wiring closets for floor or area distribution:

• Access layer switches
• Patch panels
• Horizontal cable runs to workstations
• Local networking equipment

Rack Considerations

Standard Sizes: 19" width, 42U height typical
Airflow: Port-side exhaust vs. intake
Security: Lockable doors and side panels
Organization: Cable management and labeling

Patch Panels

Organized termination points for horizontal cabling:

• Purpose: Cable management and organization
• Types: Cat5e, Cat6, Cat6A
• Configuration: 24, 48 port common
• Benefits: Easy changes without re-termination

Fiber Distribution Panels

Fiber optic cable termination and management:

• Splice trays: Fusion splice protection
• Adapter panels: Connector terminations
• Cable management: Bend radius protection
• Testing access: Easy troubleshooting

UPS (Uninterruptible Power Supply)

Backup power for critical network equipment:

• Online: Continuous power conditioning
• Line Interactive: Automatic voltage regulation
• Standby: Basic backup power
• Runtime: Based on load and battery capacity

PDU (Power Distribution Unit)

Intelligent power distribution for rack equipment:

• Basic: Simple power strip
• Monitored: Remote power monitoring
• Switched: Remote on/off control
• Intelligent: Advanced monitoring and control

Power Considerations

Power Load: Calculate total equipment power draw
Voltage Requirements:

• 120V: Standard US outlets
• 208V: Three-phase systems
• 240V: High-power equipment
• Planning: 80% rule for circuit loading

Temperature Control

Operating Range: Typically 64-75°F (18-24°C)
Cooling: HVAC systems for equipment rooms
Hot/Cold Aisles: Efficient airflow management
Monitoring: Temperature sensors and alerts

Humidity Control

Optimal Range: 45-55% relative humidity
Too Low: Static electricity damage
Too High: Corrosion and condensation
Control: Humidifiers and dehumidifiers

Fire Suppression

Specialized systems for equipment protection:

• Clean Agent: FM-200, Novec 1230 (no residue)
• Inert Gas: Nitrogen, argon (oxygen displacement)
• Water Mist: Fine water droplets
• Avoid: Standard sprinklers (water damage)