Ali Nezhad

Routing and Switching

CNET 311

Centennial College

Inter-VLAN Routing Week #11

Ch6. Wayne Lewis

Ali Nezhad

Routing and Switching

CNET 311

2

One-router-interface-per-VLAN Method#1

Traditional way

Multiple router interfaces connected to

Multiple physical switch ports.

Switch ports in access mode

Each switch port connected to the router

assigned to a different static VLAN

A router interface assigned to each VLAN.

Ali Nezhad

Routing and Switching

CNET 311

3

One-router-interface-per-VLAN

Ali Nezhad

Routing and Switching

CNET 311

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Router-on-a-stick Method#2

Our focus

Uses only one router interface and one

switch port.

The switch-router link is a trunk.

Router uses virtual subinterfaces.

S/W entities associated with an interface .

Ali Nezhad

Routing and Switching

CNET 311

5

Router-on-a-stick

Ali Nezhad

Routing and Switching

CNET 311

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L3 Switch Method#3

A L3 switch acting as a switch as

well as a router.

Explained in CH3 as SVI.

Switch must have IP routing enabled.

Modern way but beyond our scope.

Ali Nezhad

Routing and Switching

CNET 311

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L3 Switch

Ali Nezhad

Routing and Switching

CNET 311

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Configuring InterVLAN Routing

Ali Nezhad

Routing and Switching

CNET 311

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One-router-interface-per-VLAN

Ali Nezhad

Routing and Switching

CNET 311

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One-router-interface-per-VLAN 1- Configure the switch

Create VLANs.

Configure interfaces as access ports.

Assign ports to VLANs.

Ali Nezhad

Routing and Switching

CNET 311

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One-router-interface-per-VLAN 2- Configure the router

Each router interface in use will be the default gateway for all devices in the corresponding VLAN.

Assign an IP-add in the appropriate VLAN to each router-connected interface .

Activate the interface.

Ali Nezhad

Routing and Switching

CNET 311

12

One-router-interface-per-VLAN

3- Verify

Examine routing table

Examine IP addresses

on the router

command: show run

Verify interVLAN

connectivity.

Ping PC to PC.

Ali Nezhad

Routing and Switching

CNET 311

13

Router-on-a-stick

Similar to previous method but with sub-if’s.

Enable/disable the physical interface on the

router to enable/disable subinterfaces.

Ali Nezhad

Routing and Switching

CNET 311

14

Router-on-a-stick

Ali Nezhad

Routing and Switching

CNET 311

15

Router-on-a-stick 1- Configure the switch

Create VLANs.

Configure the interface as a trunk.

Note: The router does not use DTP. therefore, you cannot use the commands: sw mode dynamic auto or sw mode dynamic desirable.

Ali Nezhad

Routing and Switching

CNET 311

16

Router-on-a-stick 2- Configure the router

Create a sub-if for each VLAN.

Configure encapsulation for that sub-if.

Assign it an IP-add in its VLAN.

Activate the physical interface.

Ali Nezhad

Routing and Switching

CNET 311

17

Router-on-a-stick 3- Verify

Examine routing table

Examine IP addresses

on the router

command: show run

Verify interVLAN

connectivity.

Ping PC to PC.

Ali Nezhad

Routing and Switching

CNET 311

18

Troubleshooting Switch Config Issues

Switch port and router-if: must be in the same VLAN

Switch port mode

Access for method#1

Trunk for method#2

Inactive trunk for method#2

show int <interface> switchport

Router Config Issues

Wrong interface-VLAN association

encap dot1q <vlan-id>

sh int and sh run

IP Addressing Issues

Ali Nezhad

Routing and Switching

CNET 311

19

Questions?