Inter VLAN routing

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Inter VLAN routing

• W.lilakiatsakun

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What is inter VLAN routing
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Traditional Inter VLAN Routing (1)
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Traditional Inter VLAN Routing (2)
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Traditional Inter VLAN Routing (3)
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Traditional Inter VLAN Routing (4)
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Traditional Inter VLAN Routing (5)
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Traditional Inter VLAN Routing (6)
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Traditional Inter VLAN Routing (7)
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Traditional Inter VLAN Routing (8)
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Router on a stick Inter VLAN Routing (1)
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Router on a stick Inter VLAN Routing (2)
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Router on a stick Inter VLAN Routing (3)
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Router on a stick Inter VLAN Routing (4)

• Router-on-a-stick is a type of router
  configuration in which a single physical
  interface routes traffic between multiple VLANs
  on a network.
• The router interface is configured to operate as
  a trunk link and is connected to a switch port
  configured in trunk mode.
• The router performs the inter-VLAN routing by
  accepting VLAN tagged traffic on the trunk
  interface coming from the adjacent switch and
  internally routing between the VLANs using
  subinterfaces.

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Router on a stick Inter VLAN Routing (5)

• Subinterfaces are multiple virtual interfaces,
  associated with one physical interface.
• These subinterfaces are configured independently
  configured with an IP address and VLAN assignment
  to operate on a specific VLAN.

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Router on a stick Inter VLAN Routing (6)
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Router on a stick Inter VLAN Routing (7)
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Switch Layer 3 inter VLAN routing (1)
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Switch Layer 3 inter VLAN routing (2)
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Switch Layer 3 inter VLAN routing (3)
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Switch Layer 3 inter VLAN routing (4)
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Traditional Vs Router-on-stick (1)

• Port Limits
• Physical interfaces are configured to have one
  interface per VLAN on the network.
• On networks with many VLANs, using a single
  router to perform inter-VLAN routing is not
  possible.
• Instead, you could use multiple routers to
  perform inter-VLAN routing for all VLANs if
  avoiding the use of subinterfaces is a priority.
• Subinterfaces allow a router to scale to
  accommodate more VLANs than the physical
  interfaces permit..

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Traditional Vs Router-on-stick (2)

• Performance
• Because there is no contention for bandwidth on
  separate physical interfaces, physical interfaces
  have better performance when compared to using
  subinterfaces.
• When subinterfaces are used for inter-VLAN
  routing, the traffic being routed competes for
  bandwidth on the single physical interface.

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Traditional Vs Router-on-stick (3)

• Access Ports and Trunk Ports
• Connecting physical interfaces for inter-VLAN
  routing requires that the switch ports be
  configured as access ports.
• Subinterfaces require the switch port to be
  configured as a trunk port so that it can accept
  VLAN tagged traffic on the trunk link.

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Traditional Vs Router-on-stick (4)

• Cost
• Financially, it is more cost-effective to use
  subinterfaces over separate physical interfaces.
• Routers that have many physical interfaces cost
  more than routers with a single interface.
• Switch ports are an expensive resource on high
  performance switches.

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Traditional Vs Router-on-stick (5)

• Complexity
• Using subinterfaces for inter-VLAN routing
  results in a less complex physical configuration
  than using separate physical interfaces, because
  there are fewer physical network cables
  interconnecting the router to the switch.
• On the other hand, using subinterfaces with a
  trunk port results in a more complex software
  configuration, which can be difficult to
  troubleshoot.

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Traditional Vs Router-on-stick (6)
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Configuring Traditional Inter VLAN routing (1)
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Configuring Traditional Inter VLAN routing (2)
Switch configuration
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Configuring Traditional Inter VLAN routing (3)
Router configuration
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Configuring Traditional Inter VLAN routing (4)
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Configure router-on-a-stick inter VLAN routing (1)
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Configure router-on-a-stick inter VLAN routing (2)
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Configure router-on-a-stick inter VLAN routing (3)
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Troubleshooting inter VLAN routing switch
issues (1)
Incorrect VLAN
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Troubleshooting inter VLAN routing switch
issues (2)
Not configure as a trunk
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Troubleshooting inter VLAN routing switch
issues (3)
No Redundant link
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Troubleshooting inter VLAN routing router
issues
Incorrect VLAN on a stick
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Troubleshooting inter VLAN routing IP
addressing issues (1)
Incorrect IP Addressing
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Troubleshooting inter VLAN routing IP
addressing issues (2)
Incorrect subnet mask