Configuring Virtual Link Extension

The vLE configuration revolves around the creation and transport over VXLAN of one or more transparent VLANs using the transparent option of the vlan-create vxlan-mode standard|transparent command. To explain how that is implemented, let’s first refer to Figure A+4 below which shows an example with port 10 and 17 as ingress/egress vLE ports on two fabric leaf switches that are supposed to be connected transparently through a vLE pseudo-wire:

Figure 9-4. Two Ports Interconnected Through a vLE Pseudo-wire

Establishing such vLE pseudo-wire transport requires multiple configuration steps:

Configuration of jumbo frames on all the required ports (ingress and egress ports, as well as all inter-switch ports that are used to transport vLE traffic)
Creation of Layer 3 VLANs (or of routed ports) that are used as tunnel end points (with an MTU configuration suitable to route jumbo frames)
Set up of dedicated VXLAN connections. Typically, manual tunnels are created and set aside for vLE use.
Creation of a VXLAN-mapped transparent VLAN to transport the traffic over vLE
Addition of the transparent VLAN’s VXLAN ID to the allocated tunnels.

Let us look at one configuration example for each of the above steps.

Step 1 requires adding the jumbo option as part of the port configuration with the following command(s):

CLI (network-admin@leaf-1) > port-config-modify port 10 jumbo

In this example, as shown in the figure above, port 10 on leaf-1 is a vLE port. Jumbo (i.e., oversized) frame support should be enabled if mirroring of ingress frames with a (typical) MTU of 9216 bytes is required.

This option is usually already configured end-to-end on inter-switch links if a VXLAN transport is used in the fabric (refer to the Configuring VXLAN section).

Otherwise, the following commands can be used to enable the transport of oversized frames on inter-switch links (individual ports or trunks):

CLI (network-admin@leaf-1) > port-config-modify port <inter-switch port-list> jumbo

CLI (network-admin@leaf-1) > trunk-modify name <trunkname> jumbo

Step 2 requires the creation of the Layer 3 routing endpoints, in this case VLAN interfaces (a.k.a. SVIs), on the switches where the ingress and egress vLE ports are located:

CLI (network-admin@leaf-1)> vlan-create id 1021 scope local description VLE-VTEP ports none

CLI (network-admin@leaf-1)> vrouter-interface-add vrouter-name Leaf-1 vlan 1021 ip 10.21.1.1/30 mtu 9398

CLI (network-admin@leaf-5)> vlan-create id 1021 scope local description VLE-VTEP ports none

CLI (network-admin@leaf-5)> vrouter-interface-add vrouter-name Leaf-5 vlan 1021 ip 10.21.7.1/30 mtu 9398

Then the VLAN(s) can be checked with the following command:

CLI (network-admin@leaf-1)> vlan-show id 1021

switch id scope description active

---------- ---- ------ ----------- -----

leaf-1 1021 local VLE-VTEP yes

leaf-5 1021 local VLE-VTEP yes

Step 3 involves the creation of the VXLAN tunnels:

CLI (network-admin@leaf-1)> tunnel-create name VLE_L1_to_L5 scope local local-ip 10.21.1.1 remote-ip 10.21.7.1 vrouter-name Leaf-1

CLI (network-admin@leaf-5)> tunnel-create name VLE_L5_to_L1 scope local local-ip 10.21.7.1 remote-ip 10.21.1.1 vrouter-name Leaf-5

The tunnel creation can be checked with the following commands:

CLI (network-admin@leaf-1) > tunnel-show local-ip 10.21.1.1 format switch,scope,name,type,vrouter-name,local-ip,remote-ip

switch scope name type vrouter-name local-ip remote-ip

---------- ----- ------------ ----- ------------ --------- ---------

leaf-1 local VLE_L1_to_L5 vxlan Leaf-1 10.21.1.1 10.21.7.1

CLI (network-admin@leaf-5) > tunnel-show local-ip 10.21.7.1 format switch,scope,name,type,vrouter-name,local-ip,remote-ip

switch scope name type vrouter-name local-ip remote-ip

---------- ----- ------------ ----- ------------ --------- ---------

leaf-5 local VLE_L5_to_L1 vxlan Leaf-5 10.21.7.1 10.21.1.1

Step 4 requires the creation of a transparent VLAN per vLE:

CLI (network-admin@leaf-1)> vlan-create id 3001 scope local description VLE-1 vxlan-mode transparent vxlan 3001000 ports 10

CLI (network-admin@leaf-5)> vlan-create id 3001 scope local description VLE-1 vxlan-mode transparent vxlan 3001000 ports 17

The VLAN’s creation can be checked with the following command:

CLI (network-admin@leaf-1)> vlan-show id 3001 format switch,id,type,vxlan,scope,description,active,ports

switch id type vxlan scope description active ports

---------- ---- ------ ------- ----- ----------- ------ -----

leaf-1 3001 public 3001000 local VLE-1 yes 10

leaf-5 3001 public 3001000 local VLE-1 yes 17

Finally, in step 5 the above VXLAN ID(s) of the transparent VLAN(s) are mapped to the tunnel(s):

CLI (network-admin@leaf-1)> tunnel-vxlan-add name VLE_L1_to_L5 vxlan 3001000

CLI (network-admin@leaf-5)> tunnel-vxlan-add name VLE_L5_to_L1 vxlan 3001000

The VXLAN tunnels and their mappings can be checked with the following command:

CLI (network-admin@leaf-1)> tunnel-vxlan-show vxlan 3001000

switch name vxlan

---------- ------------ -------

leaf-1 VLE_L1_to_L5 3001000

leaf-5 VLE_L5_to_L1 3001000