R2600 Enabling Multi-Interface Causes L2 Forwarding

Configuring a full mesh architecture with F5 devices, particularly the R2600 series, can be challenging, especially when dealing with VLAN assignments and L2 forwarding. Your observations about the F5 devices behaving unexpectedly when VLANs are assigned to multiple interfaces are accurate, as this can lead to unintended Layer 2 (L2) forwarding loops and other issues.

Here’s an example of how you might configure the F5 devices and switches to avoid L2 forwarding issues:

1. Switch Configuration:
   • Configure trunk ports on the switches to carry multiple VLANs.
   • Ensure that each VLAN is properly tagged and isolated.

interface Ethernet1/1

switchport mode trunk

switchport trunk allowed vlan 10,20,30

1. F5 Configuration:
   • Assign a single VLAN to each interface on the F5 devices.
   • Use VLAN tagging if necessary to separate traffic.

config
net vlan VLAN10 {
    interfaces add { 1.1 }
    tag 10
}
net vlan VLAN20 {
    interfaces add { 1.2 }
    tag 20
}

Floating IP Configuration:

• Configure floating IP addresses for the virtual servers and services.

tmsh create net self self_floating {
    address 192.168.10.2/24
    vlan VLAN10
    traffic-group traffic-group-1
}

By following these guidelines, you should be able to avoid the L2 forwarding issues you're experiencing with the R2600 series devices. Ensure that VLANs are correctly assigned and isolated, use VLAN tagging and trunking where applicable, and leverage floating IP addresses for HA configurations. If issues persist, consulting with F5 support for more specific guidance tailored to your deployment is highly recommended.

Here are some article related.

https://my.f5.com/manage/s/article/K000132544

https://my.f5.com/manage/s/article/K000133283