# Configuring an MPLS Pseudowire with VCC Cell Relay Encapsulation

The following commands create an ATM layer 2 services over MPLS pseudowire connection between two ATM 1483 subinterfaces on different routers. This procedure uses the aal0 encapsulation keyword for each ATM PVC to indicate that the router receive raw ATM cells on these circuits and forward the cells without performing AAL5 packet reassembly. The procedure also includes optional steps for configuring nondefault values for the ATM Martini cell packing timers and cell concatenation parameters.

| Note: Although this procedure uses AAL0 encapsulation to configure an MPLS pseudowire (tunnel) connection between two ATM VCCs on different routers, you can also use AAL0 encapsulation when you configure a local cross-connect between two ATM 1483 subinterfaces within the same router.

To create an MPLS pseudowire connection with VCC cell relay encapsulation:

1. (Optional) Configure values for the three ATM Martini cell packing timers on the ingress router to define the cell collection time threshold.
   host1(config)#atm mcpt-timers 1500 2500 3500
2. Configure a loopback interface.
   host1(config)#interface loopback 0 host1(config-if)#ip address 5.1.1.1 255.255.255.255 host1(config)#exit
3. Create an ATM 1483 subinterface and ATM PVC with aal0 encapsulation on the ingress interface.
   host1(config)#interface atm 2/0.100 host1(config-subif)#atm pvc 100 0 100 aal0
4. (Optional) Configure the following cell concatenation parameters for the ATM 1483 subinterface:
   - Maximum number of ATM cells that the router can concatenate in a single packet
   - Identifier (1, 2, or 3) of the ATM Martini cell packing timer that you want to use to detect timeout of the cell collection threshold
   host1(config-subif)#atm cell-packing 100 mcpt-timer 2
5. Create an MPLS relay connection to the loopback interface on the egress router. The VC ID (1 in this example) must be the same on both sides of the connection.
   host1(config-subif)#mpls-relay 6.1.1.1 1 host1(config-subif)#exit
6. Repeat Steps 1 through 5 on the egress router, creating an MPLS relay connection to the loopback interface on the ingress router.

   The values you configure for the ATM Martini cell packing timers and cell concatenation parameters need not be the same on the ingress and egress routers, although matching values are permitted. The virtual connection ID (VC ID) value in the mpls-relay command, however, must be the same on the ingress and egress routers.

   host2(config)#atm mcpt-timers 1500 2500 3500 host2(config)#interface loopback 0 host2(config-if)#ip address 6.1.1.1 255.255.255.255 host2(config)#exit host2(config)#interface atm 4/0.101 host2(config-subif)#atm pvc 101 0 101 aal0 host2(config-subif)#atm cell-packing 150 mcpt-timer 3 host2(config-subif)#mpls-relay 5.1.1.1 1 host2(config-subif)#exit
7. (Optional) Use the appropriate show commands to verify your configuration.

       host1#show atm mcpt-timers
       ATM Martini cell aggregation timers:
               Timer1: 1500microseconds
               Timer2: 2500microseconds
               Timer3: 3500microseconds

       host1#show atm subinterface atm 2/0.100
                                        Circuit                           Interface
       Interface   ATM-Prot VCD VPI VCI  Type   Encap MTU      Status       Type
       ---------   -------- --- --- --- ------- ----- ---- -------------- ---------
       ATM 2/0.100 ATM/MPLS 100   0 100 PVC     AAL0  9180 lowerLayerDown Static

       Maximum number of cells per packet: 100
       Cell aggregation timeout timer:     2

       SNMP trap link-status: disabled

       InPackets:                0
       InBytes:                  0
       OutPackets:               0
       OutBytes:                 0
       InErrors:                 0
       OutErrors:                0
       InPacketDiscards:         0
       InPacketsUnknownProtocol: 0
       OutDiscards:              0
       1 interface(s) found

       host2#show atm subinterface atm 4/0.101
                                        Circuit                           Interface
       Interface   ATM-Prot VCD VPI VCI  Type   Encap MTU      Status       Type
       ---------   -------- --- --- --- ------- ----- ---- -------------- ---------
       ATM 4/0.101 ATM/MPLS 101   0 101 PVC     AAL0  9180 lowerLayerDown Static

       Maximum number of cells per packet: 150
       Cell aggregation timeout timer:     3

       SNMP trap link-status: disabled

       InPackets:                0
       InBytes:                  0
       OutPackets:               0
       OutBytes:                 0
       InErrors:                 0
       OutErrors:                0
       InPacketDiscards:         0
       InPacketsUnknownProtocol: 0
       OutDiscards:              0
       1 interface(s) found

#### Related Documentation

- atm cell-packing
- atm mcpt-timers
- atm pvc
- interface atm
- interface loopback
- ip address
- mpls-relay
- show atm mcpt-timers
- show atm subinterface