In a full-mesh configuration, each PE router creates a multipoint-to-multipoint forwarding relationship with all other PE routers in the VPLS domain using a VFI. An Ethernet or VLAN packet 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.
Figure 3 |
VPLS Configuration Example |
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
This 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
Here the attachment circuit (VLAN) is associated with the VSI.
interface vlan 100
no ip address
xconnect vfi PE1-VPLS-A
This is the 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
This 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
Here the attachment circuit (VLAN) is associated with the VSI.
interface vlan 100
no ip address
xconnect vfi PE2-VPLS-A
This is the 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
This 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
!
Here the attachment circuit (VLAN) is associated with the VSI.
interface vlan 100
no ip address
xconnect vfi PE3-VPLS-A .
!
This is the enablement of the Layer 2 VLAN instance.
vlan 100
state active
The show mpls l2 vc command provides information on the status of the VC.
VPLS1# show mpls l2 vc
Local intf Local circuit Dest address VC ID Status
------------- -------------------- --------------- ---------- ----------
Vi1 VFI 22.22.22.22 100 DOWN
Vi1 VFI 22.22.22.22 200 UP
Vi1 VFI 33.33.33.33 100 UP
Vi1 VFI 44.44.44.44 100 UP
Vi1 VFI 44.44.44.44 200 UP
The show vfi command provides information on the VFI.
PE-1# show vfi PE1-VPLS-A
VFI name: VPLSA, state: up
Local attachment circuits:
Vlan100
Neighbors connected via pseudowires:
2.2.2.2 3.3.3.3
The show mpls 12transport vc command provides information the virtual circuits.
Router# show mpls l2 vc det
Local interface: VFI vfi17 up
Destination address: 1.3.1.1, VC ID: 17, VC status: up
Tunnel label: imp-null, next hop point2point
Output interface: PO3/4, imposed label stack {18}
Create time: 3d15h, last status change time: 1d03h
Signaling protocol: LDP, peer 1.3.1.1:0 up
MPLS VC labels: local 18, remote 18
Group ID: local 0, remote 0
MTU: local 1500, remote 1500
Remote interface description:
Sequencing: receive disabled, send disabled
VC statistics:
packet totals: receive 0, send 0
byte totals: receive 0, send 0
packet drops: receive 0, send 0