InterVLAN is routing between VLANs that enables communication between different virtual networks.

What is InterVLAN?

InterVLAN is the routing process that enables communication between devices in different VLANs, using routers or layer 3 switches.

Concepts

VLANs

  • Segmentation: Logical network segmentation
  • Isolation: Traffic isolation
  • Scalability: Network scalability
  • Management: Simplified management

Routing

  • L3: Layer 3 routing
  • Routing: Routing tables
  • ACLs: Access control lists
  • QoS: Quality of service

InterVLAN Types

Router-on-a-Stick

  • Single Interface: Single physical interface
  • Subinterfaces: Multiple subinterfaces
  • Trunk: Trunk link
  • VLANs: Support for multiple VLANs

L3 Switch

  • Switch: Layer 3 switch
  • Routing: Routing functions
  • Performance: High performance
  • Scalability: Scalability

External Router

  • Router: External router
  • Multiple Interfaces: Multiple interfaces
  • Flexibility: Flexibility
  • Cost: Cost

Configuration

Router-on-a-Stick

# Configure subinterfaces
interface GigabitEthernet0/0.10
 encapsulation dot1Q 10
 ip address 192.168.10.1 255.255.255.0

interface GigabitEthernet0/0.20
 encapsulation dot1Q 20
 ip address 192.168.20.1 255.255.255.0

# Configure trunk
interface GigabitEthernet0/0
 no shutdown

L3 Switch

# Configure VLANs
vlan 10
 name Sales
vlan 20
 name IT

# Configure SVIs
interface Vlan10
 ip address 192.168.10.1 255.255.255.0
 no shutdown

interface Vlan20
 ip address 192.168.20.1 255.255.255.0
 no shutdown

# Configure trunk
interface GigabitEthernet0/1
 switchport mode trunk
 switchport trunk allowed vlan 10,20

Use Cases

Companies

  • Departments: Separation by departments
  • Security: Security by VLANs
  • Management: Simplified management
  • Scalability: Network scalability

Data Centers

  • Servers: Server separation
  • Storage: Storage networks
  • Backup: Backup networks
  • Monitoring: Monitoring networks

Cloud

  • Tenants: Tenant separation
  • Services: Service separation
  • Security: Security by VLANs
  • Scalability: Scalability

Security

Controls

  • ACLs: Access control lists
  • Firewalls: Network firewalls
  • Segmentation: Network segmentation
  • Monitoring: Traffic monitoring

Best Practices

  • Principle of least privilege: Minimum necessary access
  • Segmentation: Segment by function
  • Monitoring: Monitor traffic
  • Documentation: Document configurations

Monitoring

Tools

  • SNMP: Simple Network Management Protocol
  • NetFlow: Flow analysis
  • Packet Capture: Packet capture
  • Logs: Log analysis

Metrics

  • Throughput: Transmission capacity
  • Latency: Network latency
  • Packet Loss: Packet loss
  • Availability: Availability

Best Practices

Design

  • Segmentation: Segment by function
  • Scalability: Scalable design
  • Security: Security by design
  • Monitoring: Implement monitoring

Implementation

  • Phased: Phased implementation
  • Testing: Test before implementing
  • Documentation: Document configuration
  • Training: Train staff

Operation

  • Monitoring: Continuous monitoring
  • Maintenance: Regular maintenance
  • Updates: Regular updates
  • Optimization: Continuous optimization

References