Virtual Circuit Connection Verification On L2Vpn; Ethernet Over Mpls; Ethernet Port Mode - Cisco CRS Configuration Manual

Virtual Circuit Connection Verification on L2VPN

Virtual Circuit Connection Verification on L2VPN
Virtual Circuit Connection Verification (VCCV) is an L2VPN Operations, Administration, and Maintenance
(OAM) feature that allows network operators to run IP-based provider edge-to-provider edge (PE-to-PE)
keepalive protocol across a specified pseudowire to ensure that the pseudowire data path forwarding does not
contain any faults. The disposition PE receives VCCV packets on a control channel, which is associated with
the specified pseudowire. The control channel type and connectivity verification type, which are used for
VCCV, are negotiated when the pseudowire is established between the PEs for each direction.
Two types of packets can arrive at the disposition egress:
• Type 1—Specifies normal Ethernet-over-MPLS (EoMPLS) data packets.
• Type 2—Specifies VCCV packets.
Cisco CRS Router supports Label Switched Path (LSP) VCCV Type 1, which uses an inband control word
if enabled during signaling. The VCCV echo reply is sent as IPv4 that is the reply mode in IPv4. The reply
is forwarded as IP, MPLS, or a combination of both.
VCCV pings counters that are counted in MPLS forwarding on the egress side. However, on the ingress side,
they are sourced by the route processor and do not count as MPLS forwarding counters.

Ethernet over MPLS

Ethernet-over-MPLS (EoMPLS) provides a tunneling mechanism for Ethernet traffic through an MPLS-enabled
L3 core and encapsulates Ethernet protocol data units (PDUs) inside MPLS packets (using label stacking) to
forward them across the MPLS network.
EoMPLS features are described in these subsections:

Ethernet Port Mode

In Ethernet port mode, both ends of a pseudowire are connected to Ethernet ports. In this mode, the port is
tunneled over the pseudowire or, using local switching (also known as an attachment circuit-to-attachment
circuit cross-connect) switches packets or frames from one attachment circuit (AC) to another AC attached
to the same PE node.
L2VPN forwarding using GRE tunnels is supported in the Ethernet port mode.
Note
Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router, Release 6.1.x
8
Implementing Point to Point Layer 2 services