Cross-Connect (XC) Resiliency
This Chapter contains the cross-connect resiliency configuration example.
This feature provides resiliency support for port level cross connect when primary link goes down. Whenever, any of the endpoint (EP) of cross-connect goes down, pre-configured backup EP will be chosen and cross-connect will be up with backup EP. Same backup EP cannot be used in another cross-connect link.
This following are the types of EPs supported as backup EPs. 
1.	Native Ethernet interface
2.	LAG interface
Topology
 
 
Figure 2-3: Cross-connect Resiliency Topology
 
LFPT (Link-Fault-Pass-Through) 
If one endpoint goes down, other endpoint of the link is notified and port status is shown as DOWN.
Example: If po100 interface of Node-1 goes down, then Node-2 will inform to Node-3 via LFPT to down the po300 interface.
Revertive
When primary EP comes up, then traffic need to switch from backup EP to Primary EP.
Example: Suppose po100 is down on Node-1, the traffic flow is send to backup EP po300. Whenever the po100 comes up on Node-1 then the traffic flow is switched from backup EP po300  to primary EP po100.
Node-1
 
#configure terminal  | Enter configure mode  | 
(config)#hostname Node-1  | Configure the hostname  | 
(config)#interface po100  | Create port channel interface   | 
(config-if)#switchport  | Configure switchport on LAG port  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce29  | Enter interface level  | 
(config-if)#channel-group 100 mode active  | Add  member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce30  | Enter interface level  | 
(config-if)#channel-group 100 mode active  | Add member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface po300  | Create port channel interface   | 
(config-if)#switchport  | Configure switchport on LAG interface  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce6/1  | Enter interface level  | 
(config-if)#channel-group 300 mode active  | Add  member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce15/1  | Enter interface level  | 
(config-if)#channel-group 300 mode active  | Add member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce2/1  | Enter interface level  | 
(config-if)#switchport  | Configure switchport  | 
(config)#interface ce4/1  | Enter interface level  | 
(config-if)#switchport  | Configure switchport  | 
(config-if)#exit  | Exit the interface level  | 
(config)#cross-connect sample  | Create cross-connect by providing the name  | 
(config-XC)#ep1 po100 ep2 ce2/1  | Add end-points end-point1 and end-point2  | 
(config-XC)#backup ep1 po300  | Add backup end-point1  | 
(config-XC)#backup ep2 ce4/1  | Add backup  end-point2  | 
(config-XC)#cross-connect switchover type revertive  | Configure revertive mode  | 
(config-XC)#link-fault-pass-through enable  | Configure LFPT   | 
Node-2
 
#configure terminal  | Enter configure mode  | 
(config)#hostname Node-2  | Configure the hostname  | 
(config)#interface po100  | Create port channel interface   | 
(config-if)#switchport  | Configure switchport on LAG port  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce23  | Enter interface level  | 
(config-if)#channel-group 100 mode active  | Add  member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce24  | Enter interface level  | 
(config-if)#channel-group 100 mode active  | Add member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface po300  | Create port channel interface   | 
(config-if)#switchport  | Configure switchport on LAG interface  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce21  | Enter interface level  | 
(config-if)#channel-group 300 mode active  | Add  member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce22  | Enter interface level  | 
(config-if)#channel-group 300 mode active  | Add member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#cross-connect sample2  | Create cross-connect by providing the name  | 
(config-XC)#ep1 po100 ep2 po300  | Add end-points end-point1 and end-point2  | 
(config-XC)#link-fault-pass-through enable  | Configure LFPT   | 
Node-3
 
#configure terminal  | Enter configure mode  | 
(config)#hostname Node-3  | Configure the hostname  | 
(config)#interface po300  | Create port channel interface   | 
(config-if)#switchport  | Configure switchport on LAG port  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce13  | Enter interface level  | 
(config-if)#channel-group 300 mode active  | Add  member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce14  | Enter interface level  | 
(config-if)#channel-group 300 mode active  | Add member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface po100  | Create port channel interface   | 
(config-if)#switchport  | Configure switchport on LAG interface  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce1/1  | Enter interface level  | 
(config-if)#channel-group 100 mode active  | Add  member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce2/1  | Enter interface level  | 
(config-if)#channel-group 100 mode active  | Add member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce4/1  | Enter interface level  | 
(config-if)#switchport  | Configure switchport  | 
(config)#interface ce5/1  | Enter interface level  | 
(config-if)#switchport  | Configure switchport  | 
(config-if)#exit  | Exit the interface level  | 
(config)#cross-connect sample3  | Create cross-connect by providing the name  | 
(config-XC)#ep1 po300 ep2 ce4/1  | Add end-points end-point1 and end-point2  | 
(config-XC)#backup ep1 po100  | Add backup end-point1  | 
(config-XC)#backup ep2 ce5/1  | Add backup  end-point2  | 
(config-XC)#cross-connect switchover type revertive  | Configure revertive mode  | 
(config-XC)#link-fault-pass-through enable  | Configure LFPT   | 
Node-4
 
#configure terminal  | Enter configure mode  | 
(config)#hostname Node-4  | Configure the hostname  | 
(config)#interface po100  | Create port channel interface   | 
(config-if)#switchport  | Configure switchport on LAG port  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce1/1  | Enter interface level  | 
(config-if)#channel-group 100 mode active  | Add  member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce2/1  | Enter interface level  | 
(config-if)#channel-group 100 mode active  | Add member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface po300  | Create port channel interface   | 
(config-if)#switchport  | Configure switchport on LAG interface  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce8/1  | Enter interface level  | 
(config-if)#channel-group 300 mode active  | Add  member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#interface ce15/1  | Enter interface level  | 
(config-if)#channel-group 300 mode active  | Add member port to the port channel interface  | 
(config-if)#lacp timeout short  | Configure LACP timeout as short  | 
(config-if)#exit  | Exit the interface level  | 
(config)#cross-connect sample4  | Create cross-connect by providing the name  | 
(config-XC)#ep1 po300 ep2 po100  | Add end-points end-point1 and end-point2  | 
(config-XC)#link-fault-pass-through enable  | Configure LFPT   | 
Validation
Cross-connect using Dynamic LAG on Node-1
Node-1#sh etherchannel summary
  Aggregator po100 100100
  Aggregator Type: LayeNode-2
  Admin Key: 0100 - Oper Key 0100
     Link: ce29 (5073) sync: 1
     Link: ce30 (5074) sync: 1
--------------------------------------
  Aggregator po300 100300
  Aggregator Type: LayeNode-2
  Admin Key: 0300 - Oper Key 0300
     Link: ce6/1 (5005) sync: 1
     Link: ce15/1 (5006) sync: 1
 
Node-1#sh running-config cross-connect
!
cross-connect sample
 ep1 po100 ep2 ce2/1
 cross-connect switchover type revertive
 link-fault-pass-through enable
 backup ep1 po300
 backup ep2 ce4/1
!
 
Node-1#sh cross-connect
Codes: EP - Endpoint, Bkp_EP - Backup endpoint
       *  - Active Endpoint, none - not configured
Cross-connect name : sample
EP1:po100      EP2:ce2/1       Revertive:Yes        Bkp_EP1:po300      Bkp_EP2:ce4/1      Admin Status:UP         Oper Status:UP
+==================================================================================================================+
| EP       | OVID     | IVID     | Rx packets    | Rx bytes      | Tx packets    |Tx bytes       |Interface Status|
+==================================================================================================================+
| EP1*     |     -    |     -    |0              |0              |5974137342     |764688374912   |UP             |
| EP2*     |     -    |     -    |5973605019     |764619747456   |0              |0              |UP             |
| bkp_EP1  |     -    |     -    |5973879754     |764654827904   |0              |0              |UP             |
| bkp_EP2  |     -    |     -    |0              |0              |0              |0              |UP             |
+==================================================================================================================+
 
cross-connect summary
Total XC    : 1
Admin Up    : 1
Admin Down  : 0
Total Rules : 1
Cross-connect using Dynamic LAG on Node-2
Node-2#sh etherchannel summary
  Aggregator po100 100100
  Aggregator Type: LayeNode-2
  Admin Key: 0100 - Oper Key 0100
     Link: ce23 (5067) sync: 1
     Link: ce24 (5068) sync: 1
--------------------------------------
  Aggregator po300 100300
  Aggregator Type: LayeNode-2
  Admin Key: 0300 - Oper Key 0300
     Link: ce21 (5063) sync: 1
     Link: ce22 (5064) sync: 1
 
Node-2#show running-config cross-connect
!
cross-connect sample2
!
cross-connect sample2
 ep1 po100 ep2 po300
 link-fault-pass-through enable
!
 
Node-2#sh cross-connect
Codes: EP - Endpoint, Bkp_EP - Backup endpoint
       *  - Active Endpoint, none - not configured
Cross-connect name : sample2
EP1:po100      EP2:po300       Revertive:No         Bkp_EP1:None       Bkp_EP2:None       Admin Status:UP         Oper Status:UP
+==================================================================================================================+
| EP       | OVID     | IVID     | Rx packets    | Rx bytes      | Tx packets    |Tx bytes       |Interface Status|
+==================================================================================================================+
| EP1*     |     -    |     -    |3710           |470780         |723            |90626          |UP             |
| EP2*     |     -    |     -    |72             |6468           |14             |1548           |UP             |
+==================================================================================================================+
 
cross-connect summary
Total XC    : 1
Admin Up    : 1
Admin Down  : 0
Total Rules : 1
 
Cross-connect using Dynamic LAG on Node-3
Node-3#sh etherchannel summary
  Aggregator po100 100100
  Aggregator Type: LayeNode-2
  Admin Key: 0100 - Oper Key 0100
     Link: ce1/1 (5005) sync: 1
     Link: ce2/1 (5006) sync: 1
--------------------------------------
  Aggregator po300 100300
  Aggregator Type: LayeNode-2
  Admin Key: 0300 - Oper Key 0300
     Link: ce13 (5011) sync: 1
     Link: ce14 (5012) sync: 1
 
Node-3#sh running-config cross-connect
!
cross-connect sample3
 ep1 po300 ep2 ce4/1
 cross-connect switchover type revertive
 link-fault-pass-through enable
 backup ep1 po100
 backup ep2 ce5/1
!
 
Node-3#sh cross-connect
Codes: EP - Endpoint, Bkp_EP - Backup endpoint
       *  - Active Endpoint, none - not configured
Cross-connect name : sample3
EP1:po300     EP2:ce4/1      Revertive:Yes        Bkp_EP1:po100     Bkp_EP2:ce5/1      Admin Status:UP         Oper Status:UP
+==================================================================================================================+
| EP       | OVID     | IVID     | Rx packets    | Rx bytes      | Tx packets    |Tx bytes       |Interface Status|
+==================================================================================================================+
| EP1*     |     -    |     -    |201            |13536          |83318167485    |10664725404928 |UP             |
| EP2*     |     -    |     -    |93501105144    |11968141426060 |2              |128            |UP             |
| bkp_EP1  |     -    |     -    |0              |0              |10171776397    |1301987373312  |UP             |
| bkp_EP2  |     -    |     -    |93501187674    |11968152089344 |0              |0              |UP             |
+==================================================================================================================+
 
cross-connect summary
Total XC    : 1
Admin Up    : 1
Admin Down  : 0
Total Rules : 1
Cross-connect using Dynamic LAG on Node-4
Node-4#sh etherchannel summary
  Aggregator po100 100100
  Aggregator Type: LayeNode-2
  Admin Key: 0100 - Oper Key 0100
     Link: ce1/1 (5005) sync: 1
     Link: ce2/1 (5006) sync: 1
--------------------------------------
  Aggregator po300 100300
  Aggregator Type: LayeNode-2
  Admin Key: 0300 - Oper Key 0300
     Link: ce8/1 (5009) sync: 1
     Link: ce15/1 (5012) sync: 1
 
Node-4#sh running-config cross-connect
!
 cross-connect sample4
 ep1 po300 ep2 po100
 link-fault-pass-through enable
!
Disable the Cross-connect on Node-1
 
#configure terminal  | Enter configure mode  | 
(config)#cross-connect sample  | Enter into cross-connect mode  | 
(config-XC)#disable  | Disabling the cross-connect   | 
(config-XC)#exit  | Exit the cross-connect  | 
Validation
Disable the cross-connect on Node-1
Node-1#sh cross-connect
Codes: EP - Endpoint, Bkp_EP - Backup endpoint
       *  - Active Endpoint, none - not configured
Cross-connect name : sample
EP1:po100      EP2:ce2/1       Revertive:Yes        Bkp_EP1:po300      Bkp_EP2:ce4/1      Admin Status:DOWN         Oper Status:DOWN
+==================================================================================================================+
| EP       | OVID     | IVID     | Rx packets    | Rx bytes      | Tx packets    |Tx bytes       |Interface Status|
+==================================================================================================================+
| EP1*     |     -    |     -    |0              |0              |5974137342     |764688374912   |UP             |
| EP2*     |     -    |     -    |5973605019     |764619747456   |0              |0              |UP             |
| bkp_EP1  |     -    |     -    |5973879754     |764654827904   |0              |0              |UP             |
| bkp_EP2  |     -    |     -    |0              |0              |0              |0              |UP             |
+==================================================================================================================+
 
cross-connect summary
Total XC    : 1
Admin Up    : 0
Admin Down  : 1
Total Rules : 0
Enable the Cross-connect Node-1
 
#configure terminal  | Enter configure mode  | 
(config)#cross-connect sample  | Enter into cross-connect mode  | 
(config-XC)#no disable  | Enable the cross-connect   | 
(config-XC)#exit  | Exit the cross-connect  | 
Validation
Cross-connect after enable on Node-1
Node-1#sh cross-connect
Codes: EP - Endpoint, Bkp_EP - Backup endpoint
       *  - Active Endpoint, none - not configured
Cross-connect name : sample
EP1:po100      EP2:ce2/1       Revertive:Yes        Bkp_EP1:po300      Bkp_EP2:ce4/1      Admin Status:UP         Oper Status:UP
+==================================================================================================================+
| EP       | OVID     | IVID     | Rx packets    | Rx bytes      | Tx packets    |Tx bytes       |Interface Status|
+==================================================================================================================+
| EP1*     |     -    |     -    |0              |0              |5974137342     |764688374912   |UP             |
| EP2*     |     -    |     -    |5973605019     |764619747456   |0              |0              |UP             |
| bkp_EP1  |     -    |     -    |5973879754     |764654827904   |0              |0              |UP             |
| bkp_EP2  |     -    |     -    |0              |0              |0              |0              |UP             |
+==================================================================================================================+
 
cross-connect summary
Total XC    : 1
Admin Up    : 1
Admin Down  : 0
Total Rules : 1