Ip routing command

As explained in Acing the CCNA Exam: Volume 1 Fundamentals and Protocols

ip routing is a Cisco IOS global-configuration command that enables Layer 3 packet forwarding on a multilayer switch.

The Cisco IOS global-configuration command ip routing enables Layer 3 packet forwarding on a multilayer switch. Without it, the switch cannot route packets between VLANs or subnets. section 12.4.2

Use ip routing as the foundation for multilayer-switch routing:

• Configure an SVI for each VLAN with interface vlan vlan-id and an IP address; hosts use the SVI address as their default gateway. section 12.4.2

Basic multilayer-switch configuration

SW1(config)# ip routing SW1(config)# interface vlan 10 SW1(config-if)# ip address 172.16.1.1 255.255.255.192 SW1(config-if)# interface vlan 20 SW1(config-if)# ip address 172.16.1.65 255.255.255.192 SW1(config-if)# interface vlan 30 SW1(config-if)# ip address 172.16.1.129 255.255.255.192

Figure 12.11 SW1, a multilayer switch, routes a packet from PC1 to PC5. SW1 has three SVIs: VLAN 10 (172.16.1.1), VLAN 20 (172.16.1.65), and VLAN 30 (172.16.1.129), allowing SW1 to route packets internally, without relying on an external router.

Trace how SW1 routes traffic between VLAN 10 and VLAN 30 through its SVIs without relying on an external router. section 12.4.2

How Acing the CCNA Exam: Volume 1 Fundamentals and Protocols covers it

How deep it goes

Explains command placement, SVI dependencies, route verification, and up/up requirements, but not forwarding internals.

Examples

Uses SW1 with VLAN 10, VLAN 20, and VLAN 30 SVIs, show ip route output, and an internal PC1-to-PC5 packet path.

What it assumes

Assumes VLANs and IP addressing, while demonstrating SVI configuration and default-gateway use.

What you can do after

Operate/configure a multilayer switch for inter-VLAN routing and verify its SVIs and connected routes.

How it connects

Connects ip routing with multilayer switching, switched virtual interfaces, inter-VLAN routing, routing tables, and default routes.

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This explainer was generated by Manning's knowledge graph from the text of Acing the CCNA Exam: Volume 1 Fundamentals and Protocols. The section links point to the parts of the book it draws on.