Chapter 6 1 Chap 6 – Implement Inter-VLAN Routing Learning Objectives Explain to the satisfaction of a qualified instructor 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 Troubleshoot common inter-VLAN connectivity issues.

Chapter 6 2 Inter-VLAN Routing Fa0/1 S2 PC /24 (VLAN 10) Fa0/11 PC /24 (VLAN 20) PC /24 (VLAN 30) Fa0/18 S3S1 Fa0/1 Fa0/6 Fa0/2 Fa0/3 Fa0/1 Fa0/4Fa0/3Fa0/4 Fa0/2Fa0/3 Inter-VLAN routing can be performed by connecting different physical router interfaces to different physical switch ports. The switch ports connect to the router in access mode, and different static VLANs are assigned to each port interface. Each switch interface would be assigned to a different static VLAN. Each router interface can then accept traffic from the VLAN associated with the switch interface that it is connected to, and traffic can be routed to the other VLANs connected to the other interfaces. R1 Link to VLAN 20 Link to VLAN 30 Link to VLAN 10

Chapter 6 3 Router-on-a -Stick Fa0/1 S2 PC /24 (VLAN 10) Fa0/11 PC /24 (VLAN 20) PC /24 (VLAN 30) Fa0/18 S3S1 Fa0/1 Fa0/6 Fa0/2 Fa0/3 Fa0/1 Fa0/4Fa0/3Fa0/4 Fa0/2Fa0/3 R1 R1 - Fa0/0 Sub-interfaces Fa0/0.10 – – Default Gateway to VLAN 10 Fa0/0.20 – – Default Gateway to VLAN 20 Fa0/0.30 – – Default Gateway to VLAN 30 Fa0/0 "Router-on-a-stick" is a type of router configuration in which a single physical interface routes traffic between multiple VLANs on a network. Sub-interfaces are configured for different subnets corresponding to their VLAN assignment to allow logical routing before data frames are VLAN tagged and sent back out the physical interface. Sub-interfaces are multiple virtual interfaces, associated with one physical interface. These sub-interfaces are configured with an IP address and VLAN assignment to operate on a specific VLAN.

Chapter 6 4 Layer-3 Switch Fa0/1 S2 PC /24 (VLAN 10) Fa0/11 PC /24 (VLAN 20) PC /24 (VLAN 30) Fa0/18 S3S1 Fa0/1 Fa0/6 Fa0/2 Fa0/3 Fa0/1 Fa0/4Fa0/3 Fa0/4 Fa0/2Fa0/3 S1 VLAN Interfaces – Default Gateway to VLAN – Default Gateway to VLAN – Default Gateway to VLAN 30 Some switches can perform Layer 3 functions, replacing the need for dedicated routers to perform basic routing on a network. Multilayer switches are capable of performing inter-VLAN routing. To enable a multilayer switch to perform routing functions, VLAN interfaces on the switch need to be configured with the appropriate IP addresses that match the subnet that the VLAN is associated with on the network. The multilayer switch also must have IP routing enabled.

Chapter 6 5 Management VLAN /24 Student VLAN /24 Student VLAN /24 Guest VLAN /24 Guest VLAN /24 Fa0/1 Fa0/3 Fa0/18 Fa0/6 Connecting VLANs SVI VLAN20 SVI VLAN30 SVI VLAN99 Layer 3 Switch Switch Virtual Interface (SVI) is a logical interface configured for a specific VLAN, and is used by layer 3 switches to route between VLANs or to provide IP host connectivity to a switch. A Layer 3 switch has the ability to route transmissions between VLANs. The process is the same as when using a separate router, except that the SVIs act as the router interfaces for routing the data between VLANs.

Chapter 6 6 Physical Interface Configuration Fa0/1 S2 PC /24 (VLAN 10) Fa0/11 PC /24 (VLAN 20) PC /24 (VLAN 30) Fa0/18 S3S1 Fa0/1 Fa0/6 Fa0/2 Fa0/3 Fa0/1 Fa0/4Fa0/3Fa0/4 Fa0/2Fa0/3 R1 Fa0/ /24 Fa0/ /24 Configure Router Interfaces Fa0/6Fa0/5

Chapter 6 7 Sub-Interface Configuration Fa0/1 S2 PC /24 (VLAN 10) Fa0/11 PC /24 (VLAN 20) PC /24 (VLAN 30) Fa0/18 S3S1 Fa0/1 Fa0/6 Fa0/2 Fa0/3 Fa0/1 Fa0/4Fa0/3Fa0/4 Fa0/2Fa0/3 R1 Fa0/ /24 Fa0/ /24 Configure Router Interfaces To avoid confusion, name the sub- interface after the VLAN to which it is attached – e.g. Fa0/0.10 is connected to VLAN 10 Fa0/5

Chapter 6 8 Sub-Interface Configuration Fa0/1 S2 PC /24 (VLAN 10) Fa0/11 PC /24 (VLAN 20) PC /24 (VLAN 30) Fa0/18 S3S1 Fa0/1 Fa0/6 Fa0/2 Fa0/3 Fa0/1 Fa0/4Fa0/3Fa0/4 Fa0/2Fa0/3 R1 Fa0/ /24 Fa0/ /24 Fa0/5 S1 Fa0/5 must be configured as a trunk to allow it to carry tagged data from multiple VLANs

Chapter 6 9 Interface and Sub-Interface Comparison

Chapter 6 10 Chap 6 – Implement Inter-VLAN Routing Learning Objectives Explain to the satisfaction of a qualified instructor 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 Troubleshoot common inter-VLAN connectivity issues.

Chapter 6 11 Any Questions?

Chapter 6 12 Lab Topology PC /24 Fa0/11 PC /24 Chap – Basic Inter-VLAN Routing Fa0/8Fa0/5 Fa0/6 R1 Fa0/0Fa0/1

Chapter 6 13 Lab Topology PC /24 Fa0/11 PC /24 Chap – Router- On-A-Stick Inter-VLAN Routing Fa0/5 Fa0/6 R1 Fa0/1

Chapter 6 14 Lab Topology Fa0/1 S2 PC /24 Fa0/11 PC /24 PC /24 Fa0/18 S3S1 Fa0/1 Chap – Basic VLAN Routing Fa0/6 Fa0/2 Fa0/3 Fa0/1 Fa0/4Fa0/3Fa0/4 Fa0/2Fa0/3 R1 Server /24 Fa0/0 Fa0/