OcNOS-RON : Multi-Protocol Label Switching Guide : Multi-Protocol Label Switching Configuration Guide : MPLS OAM Configuration : VCCV and BFD for Pseudowires
VCCV and BFD for Pseudowires
The Virtual Circuit Connectivity Verification (VCCV) mechanism is used to facilitate Operations Administration and Maintenance (OAM) in pseudowires (PW). VCCV defines a set of messages that are sent via a PW data stream to enable management functionalities, such as connectivity and verification. Each VCCV packet contains information about its sequence number and the current value of the transmission counter. When a PW receiver receives a VCCV packet, it records the transmission counter contained in the packet. Each PW receiver also has a local received counter, which counts received PW packets. The PW receiver compares the value of the transmission counter with that of the received counter. Packet losses are detected when the count of transmitted packets is greater than the count of received packets.
Bidirectional Forwarding Detection (BFD) is used as one of the connectivity verification mechanisms in VCCV when continuous monitoring is required for a session. BFD VCCV provides a detection mechanism for pseudowires as well as the OAM functions to use over a PW to check its true operational state.
CC Types
• Type 1: PWE3 Control Word with 0001b as first nibble
• Type 2: MPLS Router Alert Label
• Type 3: MPLS PW Label with TTL == 1
VCCV CV Types
• LSP Ping
BFD CV Types
• Type 1: BFD IP/UDP-encapsulated, for PW Fault Detection only
• Type 2: BFD IP/UDP-encapsulated, for PW Fault Detection and AC/PW Fault Status Signaling
• Type 3: BFD PW-ACH-encapsulated, for PW Fault Detection only
• Type 4: BFD PW-ACH-encapsulated, for PW Fault Detection and AC/PW Fault Status Signaling
VC with Control-word, VCCV and BFD Enabled
PE1
 
#configure terminal
Enter configure mode.
(config)#router ldp
Enter the Router LDP mode.
(config-router)#pw-status-tlv
Configure PW status TLV for PW status signaling.
(config-router)#targeted-peer ipv4 3.4.5.6
Configure targeted LDP session to PE2 loopback address.
(config-router)#exit
Exit Router LDP mode and return to Configure mode.
(config)#interface eth2
Enter interface mode.
(config-if)#label-switching
Configure label-switching on provider interface PE1.
(config-if)#enable-ldp ipv4
Enable LDP at provider interface PE1.
(config-if)#exit
Exit interface mode.
(config)#mpls l2-circuit test 100 3.4.5.6
Configure PW named “test” with PW-ID 100.
(config-pseudowire)#control-word
Enable Control-word.
(config-pseudowire)#vccv cc-type type-1
Enable VCCV CC-Type as 1.
(config-pseudowire)#vccv cv-type type-3
Enable VCCV CV-Type as 3.
(config-pseduowire)#exit
Exit pseudowire mode.
(config)#bridge 1 protocol ieee vlan-bridge
Specify VLAN for bridge 1.
(config)#interface eth1
Enter interface mode.
(config-if)#switchport
Switch to Layer-2 mode.
(config-if)#switchport mode access
Set the switching characteristics of this interface to Access mode.
(config-if)#mpls-l2-circuit test
Bind the PW to access interface.
(config-if)#exit
Exit interface mode.
(config)#exit
Exit Configure mode.
P
 
#configure terminal
Enter configure mode.
(config)#router ldp
Enter the Router LDP mode.
(config-router)#pw-status-tlv
Configure PW status TLV for PW status signaling.
(config-router)#exit
Exit Router LDP mode.
(config)#interface eth1
Enter interface mode.
(config-if)#label-switching
Configure label-switching for eth1.
(config-if)#enable-ldp ipv4
Enable LDP for eth1.
(config-if)#exit
Exit interface mode.
(config)#interface eth2
Enter interface mode.
(config-if)#label-switching
Configure label-switching for eth2.
(config-if)#enable-ldp ipv4
Enable LDP for eth2.
(config-if)#exit
Exit interface mode.
(config)#exit
Exit Configure mode.
PE2
 
#configure terminal
Enter configure mode.
(config)#router ldp
Enter the Router LDP mode.
(config-router)#pw-status-tlv
Configure PW status TLV for PW status signaling.
(config-router)#targeted-peer ipv4 1.2.3.4
Configure targeted LDP session to PE1 loopback address.
(config-router)#exit
Exit Router LDP mode.
(config)#interface eth1
Enter interface mode.
(config-if)#label-switching
Configure label-switching on provider interface of PE2.
(config-if)#enable-ldp ipv4
Enable LDP on the provider interface of PE2.
(config-if)#exit
Exit interface mode.
(config)#mpls l2-circuit test 100 1.2.3.4
Configure PW named “test” with PW-ID 100.
(config-pseudowire)#control-word
Enable Control-word.
(config-pseudowire)#vccv cc-type type-1
Enable VCCV CC-Type as 1.
(config-pseudowire)#vccv cv-type type-3
Enable VCCV CV-Type as 3.
(config-pseduowire)#exit
Exit pseudowire mode.
(config)#bridge 1 protocol ieee vlan-bridge
Specify VLAN for bridge 1.
(config)#interface eth1
Enter interface mode.
(config-if)#switchport
Switch to Layer-2 mode.
(config-if)#switchport mode access
Set the switching characteristics of this interface to Access mode.
(config-if)#mpls-l2-circuit test
Bind the PW to access interface.
(config-if)#exit
Exit interface mode.
(config)#exit
Exit Configure mode.
Last modified date: 07/13/2023