• Functionally, the router-on-a-stick model for inter-VLAN routing is the same as using the traditional routing model, but instead of using the physical interfaces to perform the rout[r]
(1)CCNA – Semester1
Chapter
-Inter – VLAN Routing
(2)2 Objectives
• Explain how network traffic is routed between VLANs in a converged network.
• Configure inter-VLAN routing on a router to enable communications between end-user devices on separate VLANs
(3)3
(4)4 Introduction
(5)5 Traditional Inter-VLAN Routing
• In a traditional network that uses multiple VLANs to
(6)6 "Router-on-a-stick" Inter-VLAN Routing
(7)7 Switched-based Inter-VLAN Routing
• Some switches can perform Layer functions, replacing the need for dedicated routers to perform basic routing on a
(8)8
(9)9 Interface
• Traditional routing requires routers to have multiple physical interfaces to facilitate inter-VLAN routing
• Each interface is also configured with an IP address for the subnet associated with the particular VLAN that it is
connected to
• In this configuration, network devices can use the router as a gateway to access the devices connected to the other
(10)(11)11 Subinterface
• To overcome the hardware limitations of inter-VLAN routing based on router physical interfaces, virtual subinterfaces and trunk links are used
• Each subinterface is configured with its own IP address, subnet mask, and unique VLAN assignment, allowing a
single physical interface to simultaneously be part of multiple logical networks
(12)(13)(14)14 Comparison
Features Physical Interface Subinterface
Port Limits One physical interface per VLAN
One physical interface for many VLANs
Performance No bandwidth contention Bandwidth contention
Access Ports and Trunk Ports
Connected to access mode switch port
Connected to trunk mode switch port
Cost More expensive Less expensive
Complexity More complex
connection configuration
(15)15
(16)16
Configure Traditional Inter-VLAN Routing
(17)17
Configure Traditional Inter-VLAN Routing
(18)18
(19)19
Configure Router-on-a-Stick Inter-VLAN Routing
(20)20
Configure Router-on-a-Stick Inter-VLAN Routing
(21)21
(22)22
(23)23 Switch Configuration Issues
• Switch ports are not configured on the correct VLAN
(24)24 Router Configuration Issues
(25)25 Router Configuration Issues
Router R1 has been configured to use the wrong VLAN on subinterface F0/0.10, preventing devices configured on
(26)26 IP Addressing Issues
Router R1 has been configured with an incorrect IP address on interface F0/0 This prevents PC1 from being able to
(27)27 IP Addressing Issues (cont)
PC1 has been configured with an incorrect IP address for the subnet associated with VLAN10 This prevents PC1 from
(28)28 IP Addressing Issues (cont)
(29)