13.4. Layer-2 Switch

The layer-2 switch is the access switching layer inside the pod.

It should trunk all VLANs into every computing host.
It should switch traffic for the management network containing computing and storage hosts. The layer-3 switch will serve as the gateway for the management network.

Example Configurations

This section contains example configurations for specific switch models for pod-level layer-2 switching. It assumes VLAN management protocols such as VTP or GVRP have been disabled. The scripts must be changed appropriately if you choose to use VTP or GVRP.

13.4.1. Dell 62xx

The following steps show how a Dell 62xx is configured for pod-level layer-2 switching.

Configure all the VLANs in the database.
```
vlan database
vlan 300-999
exit
```
VLAN 201 is used to route untagged private IP addresses for pod 1, and pod 1 is connected to this layer-2 switch.
```
interface range ethernet all
switchport mode general
switchport general allowed vlan add 300-999 tagged
exit
```

The statements configure all Ethernet ports to function as follows:

All ports are configured the same way.
All VLANs (300-999) are passed through all the ports of the layer-2 switch.

13.4.2. Cisco 3750

The following steps show how a Cisco 3750 is configured for pod-level layer-2 switching.

Setting VTP mode to transparent allows us to utilize VLAN IDs above 1000. Since we only use VLANs up to 999, vtp transparent mode is not strictly required.
```
vtp mode transparent
vlan 300-999
exit
```

Configure all ports to dot1q and set 201 as the native VLAN.

interface range GigabitEthernet 1/0/1-24
switchport trunk encapsulation dot1q
switchport mode trunk
switchport trunk native vlan 201
exit

By default, Cisco passes all VLANs. Cisco switches complain of the native VLAN IDs are different when 2 ports are connected together. That’s why you must specify VLAN 201 as the native VLAN on the layer-2 switch.