Module 4 Flashcards
What is the main objective of the module on Inter-VLAN Routing?
Troubleshoot inter-VLAN routing on Layer 3 devices.
What are the three options for inter-VLAN routing?
- Legacy Inter-VLAN routing
- Router-on-a-Stick
- Layer 3 switch using switched virtual interfaces (SVIs)
What is required for Router-on-a-Stick inter-VLAN routing?
Create a subinterface for each VLAN to be routed.
What command is used to create a subinterface in Router-on-a-Stick configuration?
interface interface_id.subinterface_id
What does the command ‘encapsulation dot1q vlan_id’ do?
Configures the subinterface to respond to 802.1Q encapsulated traffic from the specified VLAN.
What command assigns an IP address to a subinterface in Router-on-a-Stick?
ip address ip-address subnet-mask
What must be done after creating all subinterfaces in Router-on-a-Stick?
Enable the physical interface using the ‘no shutdown’ command.
How do you verify connectivity between two hosts in different VLANs?
Use the ‘ping’ command.
List the commands used to verify and troubleshoot Router-on-a-Stick configuration.
- show ip route
- show ip interface brief
- show interfaces
- show interfaces trunk
What are the advantages of using Layer 3 switches for inter-VLAN routing?
- Faster processing rates
- No need for external links to a router
- Not limited to one link due to EtherChannels
- Lower latency
- Commonly deployed in campus LANs
What is an SVI?
A switched virtual interface configured on a Layer 3 switch.
What command is used to enable IP routing on a Layer 3 switch?
ip routing
What is the limitation of the legacy inter-VLAN routing method?
Not reasonably scalable due to the limited number of physical interfaces on routers.
Is the router-on-a-stick method scalable beyond 50 VLANs?
False.
What is the first step in configuring a Layer 3 switch for inter-VLAN routing?
Create the VLANs.
Fill in the blank: The router-on-a-stick method requires a ______ for each VLAN to be routed.
subinterface
True or False: Layer 3 switches operate only at Layer 2.
False.
What is the primary function of an SVI?
Provides Layer 3 processing for packets sent to or from switch ports associated with that VLAN.
What command is used to create an SVI for a VLAN?
interface vlan vlan-id
What is required to configure trunking ports on a switch?
Configure trunking ports after creating VLANs and access ports.
What is the primary function of Layer 3 switches in enterprise campus LANs?
To provide inter-VLAN routing
How do Layer 3 switches achieve higher packet processing rates than routers?
By using hardware-based switching
What command is used to create a switched virtual interface (SVI) on a Layer 3 switch?
interface vlan vlan-id
What must be configured on a Layer 3 switch to enable routing?
A routed port must be configured
What command disables the switchport feature on a Layer 2 port?
no switchport
What are the steps to configure a Layer 3 switch to route with a router?
- Configure the routed port
- Enable routing
- Configure routing
- Verify routing
- Verify connectivity
What are common reasons for inter-VLAN configuration failures?
- Missing VLANs
- Switch trunk port issues
- Switch access port issues
- Router configuration issues
What is a common cause of issues in a router-on-a-stick configuration?
Misconfigured trunk port
Which command can be used to verify the subinterface status in a router-on-a-stick configuration?
show ip interface brief
When troubleshooting switch access port issues, which command can help verify interface VLAN assignment?
show vlan brief
What command is used to enable routing on a Layer 3 switch?
ip routing
What is the command to verify the routing table on a Layer 3 switch?
show ip route
What is the purpose of the command ‘encapsulation dot1q X [native]’?
To configure subinterfaces for VLANs on a router
Fill in the blank: A _______ is created on a Layer 3 switch by disabling the switchport feature on a Layer 2 port.
routed port
True or False: In a legacy inter-VLAN solution, a misconfigured switch port could be caused when the connecting router port is not assigned to the correct VLAN.
True
What command can be used to verify VLAN membership of a port?
show interfaces switchport
What is the first step to troubleshoot inter-VLAN routing issues?
Check the physical layer for cable connections
What happens to ports assigned to a VLAN when that VLAN is deleted?
They become inactive until reassigned to a new VLAN
What should be checked if the port connecting to the router is missing from the trunk output?
Examine the configuration of the port using show running-config interface X
What is required for VLANs to be reachable by other Layer 3 devices?
They must be advertised using static or dynamic routing
