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VPLS basic configurations in MPLS environment: Cisco Routers

Today I am going to tell you about the basic configurations of VPLS on the Cisco routers. Let's take an scenario where i can say that there is a MPLS network where we have PE1, PE2 and PE3 connected at the edges of the MPLS network and beyond that there are customer edge routers.
Let me explain little bit how Layer 2 split horizon enabled in the VPLS scenario. So on the edge of the MPLS PE routers VLAN packets received from the customer network can be forwarded to one or more local interfaces and or emulated VCs in the VPLS domain. To avoid broadcasted packets looping around in the network, no packet received from an emulated VC can be forwarded to any emulated VC of the VPLS domain on a PE router. That is, the Layer 2 split horizon should always be enabled as the default in a full-mesh network. 

Below is the topology showing the VPLS connectivity across the three Service Provider Edge routers that i mentioned above. We have three PE routers and named as PE1, PE2 and PE3 routers. Below the topology we have the configurations on all these PE routers step by step. All these IPs and interfaces are used for demo purposes and has no relevance to any of the live network or topology with any of the enterprise network or Service Providers.

Fig 1.1- VPLS connectivity across the MPLS

Make sure to take an assumption that

  • PE1 is connected to VPLS A via interface FE0/0
  • PE2 is connected to VPLS A via interface FE0/0
  • PE3 is also connected to VPLS A via interface FE0/0
For the above topology of the service provider you have the following VPLS configurations on all the PE Routers one by one. 

Note: VPLS is generally used where customer don't want to share the L3 information with the Service provider, So VPLS is purely a Layer 2 technology with the Virtual circuits end to end which is attached to virtual switch instances.

Below are the steps we need to do on all the PE routers
  • Creation of the virtual switch instances (VSIs) and associated VCs
  • Configures the CE device interface (there can be multiple Layer 2 interfaces in a VLAN)
  • Attachment circuit (VLAN) is associated with the VSI
  • Enablement of the Layer 2 VLAN instance
Lets take on configuration part now.


Configuration on PE 1 
This shows the creation of the virtual switch instances (VSIs) and associated VCs.
!
l2 vfi PE1-VPLS-A manual
  vpn id 100
  neighbor 2.2.2.2 encapsulation mpls
  neighbor 3.3.3.3 encapsulation mpls
!
interface Loopback 0
  ip address 1.1.1.1 255.255.255.255
!
Configures the CE device interface (there can be multiple Layer 2 interfaces in a VLAN). 
!
interface FastEthernet0/0
  switchport
  switchport mode dot1qtunnel
  switchport access vlan 100
!
Attachment circuit (VLAN) is associated with the VSI. 
!
interface vlan 100
  no ip address
 xconnect vfi PE1-VPLS-A
!
Enablement of the Layer 2 VLAN instance. 
!
vlan 100

  state active
!

Configuration on PE 2 
This shows the creation of the virtual switch instances (VSIs) and associated VCs.
! 
l2 vfi PE2-VPLS-A manual
vpn id 100
  neighbor 1.1.1.1 encapsulation mpls
  neighbor 3.3.3.3 encapsulation mpls
!
interface Loopback 0
  ip address 2.2.2.2 255.255.255.255
!
Configures the CE device interface (there can be multiple Layer 2 interfaces in a VLAN). 
!
interface FastEthernet0/0
  switchport
  switchport mode dot1qtunnel
  switchport access vlan 100
!
Attachment circuit (VLAN) is associated with the VSI. 
!
interface vlan 100
  no ip address
 xconnect vfi PE2-VPLS-A
!
Enablement of the Layer 2 VLAN instance. 
!
vlan 100
  state active
!

Configuration on PE 3 
This shows the creation of the virtual switch instances (VSIs) and associated VCs. 
!
l2 vfi PE3-VPLS-A manual
  vpn id 100
  neighbor 1.1.1.1 encapsulation mpls
  neighbor 2.2.2.2 encapsulation mpls
!
interface Loopback 0
  ip address 3.3.3.3 255.255.255.255
!
Configures the CE device interface (there can be multiple Layer 2 interfaces in a VLAN). 
!
interface FastEthernet0/1
  switchport
  switchport mode dot1qtunnel
  switchport access vlan 100
! 
Attachment circuit (VLAN) is associated with the VSI. 
!
interface vlan 100
  no ip address
 xconnect vfi PE3-VPLS-A .
!
Enablement of the Layer 2 VLAN instance. 
vlan 100
  state active
!

Hope now you are very much clear about the configuration of VPLS on the MPLS PE routers.