Configuring L2Vpn Pseudowire Redundancy - Cisco 3845 - Security Bundle Router Software Manual

Chapter 34 Configuring MPLS, MPLS VPN, MPLS OAM, and EoMPLS
Figure 34-5 Sample EoMPLS Packet Flow
Customer
Host
switch
A
A
Host MAC
address: 1 address: 2
Assume that Host A is connected to the customer switch on VLAN 3 that has a trunk port connected to
PE1 configured for IEEE 802.1Q tagging. Host A sends a packet to Host B, using the specific values of
MAC addresses, labels, and VLANs shown in the figure. The customer switch tags the host packet and
forwards it over the trunk port to switch PE1.
The tagged packet is received on the customer-edge port that is configured for per-port EoMPLS
tunneling. The PE1 switch examines the packet headers and looks at the tables stored in the switch to
determine what to do with the packet. Because the port is configured for per-port EoMPLS tunneling,
the switch does not remove any VLAN tags that are in the packet, but assigns the packet to an internal
VLAN. Only the customer port and the PE1 port are configured with that internal VLAN, which makes
the PE1 port the only possible destination for the packet.
The PE1 port encapsulates the packet header with the tunnel label and the virtual-connection label and
forwards the packet to the next hop, in this case Router A, to send it across the MPLS network.
The router receives the packet and forwards it over the MPLS network to the remote PE2 switch. PE2
removes the MPLS encapsulation and sends the packet out the port associated with the
virtual-connection label. Customer Switch B removes the final VLAN tag and forwards the packet to the
remote host B.
VLAN-based EoMPLS packet flow is basically the same as port-based EoMPLS, except that the
customer VLAN is used instead of an internal VLAN. The PE1 switch looks up the customer VLAN ID
to determine that the packet is forwarded to the designated port, where the packet is again examined and
encapsulated with the tunnel label and virtual-connection label based on the EoMPLS for that VLAN.

Configuring L2VPN Pseudowire Redundancy

Successful transmission of Layer 2 frames between PE routers requires a connection, called a
pseudowire, between the routers. You can use the L2VPN pseudowire redundancy feature to configure
your network to detect a failure in the network and reroute the Layer 2 service to another endpoint that
can continue to provide service. This feature provides the ability to recover from a failure of either the
remote provider edge (PE) router or of the link between the PE and customer edge (CE) routers.
For more information see this URL:
http://www.cisco.com/en/US/docs/ios/wan/configuration/guide/wan_l2vpn_pw_red_ps6441_TSD_Pro
ducts_Configuration_Guide_Chapter.html
OL-23400-01
EoMPLS Tunnel
Tunnel
Label
VLAN 7
PE1 Router
A
SVI MAC Router MAC
address: 3
VC Label
MPLS
PE2
Router B
Cisco ME 3800X and 3600X Switch Software Configuration Guide
Enabling EoMPLS
Remote Site
Customer
Host
switch
B
B
Host MAC
address: 4
34-37