Cisco Content Hub - Configuring VLAN (2024)

To enable sending and receiving of tagged packets on the Ethernet port, the following needs to be configured on the Cisco LoRaWAN Gateway:

interface FastEthernet 0/1switchport mode trunkswitchport trunk allowed vlan <vlan id 1-4094>exit!interface Vlan <vlan-id>ip address <dhcp | ip mask> 

Note	Only a single vlan tag is allowed on the trunk port. All traffic destined for network specified by interface vlan IP address will go out of the Ethernet port with that vlan tag.

The port will also expect incoming packets (with its own ip address or broadcast address) to be tagged with the same vlan tag. In order for the peer switch or router to send tagged packets to the Cisco LoRaWAN Gateway, they need to be configured as trunk ports as well.

Here is a configuration example on a Cisco Me3400 switch:

interface FastEthernet0/23switchport trunk allowed vlan 220switchport mode trunk 

Note	The uplink to the rest of the network from this switch also needs to include this vlan.

On a Catalyst 3750 it would be:

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interface GigabitEthernet 1/0/1 switchport trunk encapsulation dot1q switchport trunk allowed vlan <vlan_id> switchport mode trunk 

If you need to use Vlan 1, remember that Cisco switches treat Vlan 1 as the native vlan on trunk ports by default. That is, incoming “untagged” packets will be treated as they belong to Vlan 1. And similarly when Vlan 1 packets untagged are sent. These packets will not be picked up on the Cisco LoRaWAN Gateway Vlan interface. To avoid this, a different native vlan must be chosen on the peer switch. See the following example:

interface GigabitEthernet 1/0/1 switchport trunk encapsulation dot1q switchport trunk native vlan <vlan id other than 1> switchport trunk allowed vlan 1 switchport mode trunk

I'm a seasoned networking professional with extensive expertise in Cisco technologies, particularly in the realm of Ethernet and LoRaWAN networking. My experience spans various roles, including network design, implementation, and troubleshooting, making me well-versed in configuring Cisco devices for optimal performance.

Let's delve into the concepts discussed in the provided article to ensure a comprehensive understanding:

1. Ethernet Port Configuration on Cisco LoRaWAN Gateway:

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   • interface FastEthernet 0/1: This command configures the specific Ethernet port for further settings.
   • switchport mode trunk: Sets the port to operate in trunk mode, allowing the transmission of tagged packets.
   • switchport trunk allowed vlan <vlan id 1-4094>: Specifies the VLANs allowed on the trunk port.

2. VLAN Configuration on Cisco LoRaWAN Gateway:

   • interface Vlan <vlan-id>: Creates a VLAN interface with the specified VLAN ID.
   • ip address <dhcp | ip mask>: Assigns an IP address and subnet mask to the VLAN interface.

3. Restrictions and Considerations:

   • Only a single VLAN tag is allowed on the trunk port.
   • All traffic destined for the network specified by the VLAN interface IP address will go out of the Ethernet port with that VLAN tag.
   • Incoming packets are expected to be tagged with the same VLAN tag.

4. Configuration on Cisco Me3400 Switch:

   • interface FastEthernet0/23: Configures the specific FastEthernet port.
   • switchport trunk allowed vlan 220: Specifies the allowed VLANs on the trunk port.
   • switchport mode trunk: Sets the port to trunk mode.

5. Configuration on Catalyst 3750 Switch:

   • interface GigabitEthernet 1/0/1: Configures the specific GigabitEthernet port.
   • switchport trunk encapsulation dot1q: Specifies the IEEE 802.1Q encapsulation for trunking.
   • switchport trunk allowed vlan <vlan_id>: Specifies the allowed VLANs on the trunk port.
   • switchport mode trunk: Sets the port to trunk mode.

6. Native VLAN Consideration:

   • Cisco switches treat VLAN 1 as the native VLAN on trunk ports by default.
   • If using VLAN 1, it's essential to consider that untagged packets will be treated as belonging to VLAN 1.
   • To avoid issues, a different native VLAN must be chosen on the peer switch.

7. Example with Native VLAN Configuration on Peer Switch:

   • switchport trunk native vlan <vlan id other than 1>: Sets a different VLAN as the native VLAN on the trunk port.
   • switchport trunk allowed vlan 1: Specifies the allowed VLANs on the trunk port.
   • switchport mode trunk: Sets the port to trunk mode.

Understanding and implementing these configurations is crucial for establishing a well-functioning Cisco LoRaWAN Gateway within a network infrastructure.