CCNP Exam Prep Tips and Must Knows

Things You Need to Know About Routing between VLANs

Inter-VLAN  routing using an external router

• Provide a single trunk link from switch to router
• Router physical interface is divided into logical subinterfaces
• Each router of interface acts as a gateway for one VLAN
• Inter-VLAN in routing using a switched virtual interface (SVI)
• Multilayer switches use SVI’s for routing between VLANs new line

SVI configuration

• switch (config) #ip routing
• switch (config) # interface vlan10
• switch (config-if) # ip address 10. 1.10.1 255.255.255.0
• switch (config-if) # no shutdown
• switch (config) # interface vlan20
• switch (config-if) # ip address 10.1.20.1 255.255.255.0
• switch (config-if) # no shutdown

Routed ports on a multilayer switch

• Physical switch port with layer 3 capability
• Not associated with any VLAN
• Requires removal of layer 2 port functionality
• Configured like a router interface but does not support VLAN subinterfaces
• Used when a switch has one port per VLAN or subnet only
• Useful for point-to-point layer 3 switch links

Configuration of the routed interface

• switch (config) # ip routing
• switch (config) # interface fastethernet 0/24
• switch (config-if) # no switchport
• switch (config-if) # ip address 10.1.10.1 255.255.255.0

Routing protocol configuration

• switch (config) # ip routing
• switch (config) # router EIGRP 100
• switch (config-router) #no auto-summary
• switch (config-router) #passive-interface default
• switch (config-router) #no passive-interface fa0/24
• switch (config) # interface fa0/24
• switch (config-if) #description uplink
• switch (config-if) #IP summary-address eigrp 100 10.1.0.0 255.255.244.0

Make sure you can configure:

• A routed port
• A routing protocol
• An SVI

Make sure you are familiar with:

• Show ip route
• Show ip interface brief