VLAN Cross-Connect (XC)
Overview
VLAN cross connect creates a L2 bridge between two given endpoints on the same device. Once configured, every packets arriving at one of the endpoints with specific VLAN tag will be sent to another endpoint directly. In current implementation it matches VLAN tag as per configuration in device. If device is configured to match single tag then only outer most tagged will be matched whether packet is double tagged. If device is configured to match double tag then outer tag as well as inner tag will match If the packet is double tagged.
Note:
1. End point or source point could be a physical (Native Ethernet) port or logical port (po, vlan etc).
2. Same Vlan ID cannot be used in 2 cross connects.
3. Different type of L2, L3 and subscriber services are supported over cross.
4. The XC implementation will forward all packets and MAC address learning is disabled.
Topology
Cross-connect topology
Configuration - Single-tagged VLAN
TOR1
#configure terminal | Enter Configure mode. |
(config)#interface ce25/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#interface ce16/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#cross-connect VC1 | Create cross-connect (XC) |
(config-XC)# vlan ep1 ce25/1 ep2 ce16/1 | Add Endpoints to XC |
(config-VXC)# outer-vlan 100 | Outer-vlanId associated with the XC |
(config-VXC)#commit | Commit candidate configuration to be running configuration |
(config-VXC)#end | Return to privilege mode |
TOR2
#configure terminal | Enter Configure mode. |
(config)#interface ce16/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#interface ce26/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#cross-connect VC1 | Create cross-connect (XC) |
(config-XC)# vlan ep1 ce16/1 ep2 ce26/1 | Add Endpoints to XC |
(config-VXC)# outer-vlan 100 | Outer-vlanId associated with the XC |
(config-VXC)#commit | Commit candidate configuration to be running configuration |
(config-VXC)#end | Return to privilege mode |
SW2
#configure terminal | Enter Configure mode. |
(config)#bridge 1 protocol mstp | Add a bridge (1) to the multiple spanning tree table |
(config)#vlan database | Enter the VLAN configuration mode |
(config-vlan)#vlan 100 bridge 1 state enable | Enable the state of VLAN 100 on bridge 1. Specifying an enable state allows forwarding of frames over VLAN 100 on bridge 1 |
(config-vlan)#commit | Commit candidate configuration to be running configuration |
(config-vlan)#exit | Exit the VLAN configuration mode |
(config)#interface xe51/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#bridge-group 1 | Associating the interface to bridge-group 1 |
(config-if)#switchport mode trunk | set the switching characteristics of the Layer 2 interface |
(config-if)#switchport trunk allowed vlan all | Allow all VLANs to transmit and receive through the interface |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#interface xe3 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#bridge-group 1 | Associating the interface to bridge-group 1 |
(config-if)#switchport mode trunk | set the switching characteristics of the Layer 2 interface |
(config-if)#switchport trunk allowed vlan all | Allow all VLANs to transmit and receive through the interface |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
SW1
#configure terminal | Enter Configure mode. |
(config)#bridge 1 protocol mstp | Add a bridge (1) to the multiple spanning tree table |
(config)#vlan database | Enter the VLAN configuration mode |
(config-vlan)#vlan 100 bridge 1 state enable | Enable the state of VLAN 100 on bridge 1. Specifying an enable state allows forwarding of frames over VLAN 100 on bridge 1 |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit the VLAN configuration mode |
(config)#interface xe53/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#bridge-group 1 | Associating the interface to bridge-group 1 |
(config-if)#switchport mode trunk | set the switching characteristics of the Layer 2 interface |
(config-if)#switchport trunk allowed vlan all | Allow all VLANs to transmit and receive through the interface |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#interface xe33 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#bridge-group 1 | Associating the interface to bridge-group 1 |
(config-if)#switchport mode trunk | set the switching characteristics of the Layer 2 interface |
(config-if)#switchport trunk allowed vlan all | Allow all VLANs to transmit and receive through the interface |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
Validation
TOR1
#show cross-connect
Cross-connect name : VC1
EP1:ce25/1 EP2:ce16/1 Admin Status:UP OperStatus:UP
+======================================================================================+
| EP | OVID | IVID | Rx packets | Rx bytes | Tx packets | Tx bytes |
+======================================================================================+
| EP1 |100 | - |6572258 |9858387000 |0 |0 |
| EP2 |100 | - |0 |0 |6572224 |9858336000 | +======================================================================================+
Cross-connect summary Total XC : 1
Admin Up : 1
Admin Down : 0
Total Rules : 1
TOR2
#show cross-connect
Cross-connect name : VC1
EP1:ce16/1 EP2:ce26/1 Admin Status:UP OperStatus:UP
+======================================================================================+
| EP | OVID | IVID | Rx packets | Rx bytes | Tx packets | Tx bytes |
+======================================================================================+
| EP1 |100 | - |616588 |924882000 |0 |0 |
| EP2 |100 | - |0 |0 |618615 |927922500 | +======================================================================================+
Cross-connect summary Total XC : 1
Admin Up : 1
Admin Down : 0
Total Rules : 1
Double-tagged VLAN
TOR1
#configure terminal | Enter Configure mode. |
(config)#interface ce25/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#interface ce16/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#cross-connect VC2 | Create cross-connect (XC) |
(config-XC)# vlan ep1 ce25/1 ep2 ce16/1 | Add Endpoints to XC |
(config-VXC)# outer-vlan 200-300 inner-vlan 20-30 | Outer-vlanId and Inner-vlanId with range associated with the XC |
(config-VXC)#commit | Commit candidate configuration to be running configuration |
(config-VXC)#end | Return to privilege mode |
TOR2
#configure terminal | Enter Configure mode. |
(config)#interface ce16/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#interface ce26/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#cross-connect VC2 | Create cross-connect (XC) |
(config-XC)# vlan ep1 ce16/1 ep2 ce26/1 | Add Endpoints to XC |
(config-VXC)# outer-vlan 200-300 inner-vlan 20-30 | Outer-vlanId and Inner-vlanId with range associated with the XC |
(config-VXC)#commit | Commit candidate configuration to be running configuration |
(config-VXC)#end | Return to privilege mode |
SW2
#configure terminal | Enter Configure mode. |
(config)#bridge 1 protocol mstp | Add a bridge (1) to the multiple spanning tree table |
(config)#vlan database | Enter the VLAN configuration mode |
(config-vlan)#vlan 200-300 bridge 1 state enable | Enable the state of VLANs 200-300 on bridge 1. Specifying an enable state allows forwarding of frames over VLANs 200-300 on bridge 1 |
(config-vlan)#commit | Commit candidate configuration to be running configuration |
(config-vlan)#exit | Exit the VLAN configuration mode |
(config)#interface xe51/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#bridge-group 1 | Associating the interface to bridge-group 1 |
(config-if)#switchport mode trunk | set the switching characteristics of the Layer 2 interface |
(config-if)#switchport trunk allowed vlan all | Allow all VLANs to transmit and receive through the interface |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
(config)#interface xe3 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#bridge-group 1 | Associating the interface to bridge-group 1 |
(config-if)#switchport mode trunk | set the switching characteristics of the Layer 2 interface |
(config-if)#switchport trunk allowed vlan all | Allow all VLANs to transmit and receive through the interface |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
SW1
#configure terminal | Enter Configure mode. |
(config)#bridge 1 protocol mstp | Add a bridge (1) to the multiple spanning tree table |
(config)#vlan database | Enter the VLAN configuration mode |
(config-vlan)#vlan 200-300 bridge 1 state enable | Enable the state of VLANs 200-300 on bridge 1. Specifying an enable state allows forwarding of frames over VLANs 200-300 on bridge 1 |
(config-vlan)#commit | Commit candidate configuration to be running configuration |
(config-vlan)#exit | Exit the VLAN configuration mode |
(config)#interface xe53/1 | Enter Interface mode |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#bridge-group 1 | Associating the interface to bridge-group 1 |
(config-if)#switchport mode trunk | Set the switching characteristics of the Layer 2 interface |
(config-if)#switchport trunk allowed vlan all | Allow all VLANs to transmit and receive through the interface |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit nterface mode |
(config)#interface xe33 | Enter Interface mode |
(config-if)#no shutdown | Bring interface up |
(config-if)#switchport | Configure interface as a layer 2 port |
(config-if)#bridge-group 1 | Associating the interface to bridge-group 1 |
(config-if)#switchport mode trunk | Set the switching characteristics of the Layer 2 interface |
(config-if)#switchport trunk allowed vlan all | Allow all VLANs to transmit and receive through the interface |
(config-if)#commit | Commit candidate configuration to be running configuration |
(config-if)#exit | Exit interface mode |
Validation
TOR1
#show cross-connect
Cross-connect name : VC2
EP1:ce25/1 EP2:ce16/1 Admin Status:UP OperStatus:UP
+======================================================================================+
| EP | OVID | IVID | Rx packets | Rx bytes | Tx packets | Tx bytes |
+======================================================================================+
| EP1 |200-300 |20-30 |442089 |663133500 |0 |0 |
| EP2 |200-300 |20-30 |0 |0 |444123 |666184500 | +======================================================================================+
Cross-connect summary
Total XC : 1
Admin Up : 1
Admin Down : 0
Total Rules : 1
TOR2
#show cross-connect
Cross-connect name : VC2
EP1:ce16/1 EP2:ce26/1 Admin Status:UP OperStatus:UP
+======================================================================================+
| EP | OVID | IVID | Rx packets | Rx bytes | Tx packets | Tx bytes |
+======================================================================================+
| EP1 |200-300 |20-30 |267607 |401410500 |0 |0 |
| EP2 |200-300 |20-30 |0 |0 |269640 |404460000 | +======================================================================================+
Cross-connect summary
Total XC : 1
Admin Up : 1
Admin Down : 0
Total Rules : 1