Manual

Layer 2 Tunnel Protocol Version 3
How to Configure Layer 2 Tunnel Protocol Version 3
51
Cisco IOS Releases 12.0(29)S and 12.2(25)S
Configuring OAM Local Emulation for ATM AAL5 over L2TPv3
If a PE router does not support the transport of OAM cells across an L2TPv3 session, you can use OAM
cell emulation to locally terminate or loopback the OAM cells. You configure OAM cell emulation on
both PE routers. You use the oam-ac emulation-enable command on both PE routers to enable OAM
cell emulation.
After you enable OAM cell emulation on a router, you can configure and manage the ATM VC in the
same manner as you would a terminated VC. A VC that has been configured with OAM cell emulation
can send loopback cells at configured intervals toward the local CE router. The endpoint can be either of
the following:
• End-to-end loopback, which sends OAM cells to the local CE router.
• Segment loopback, which responds to OAM cells to a device along the path between the PE and CE
routers.
The OAM cells have the following information cells:
• Alarm indication signal (AIS)
• Remote defect indication (RDI)
These cells identify and report defects along a VC. When a physical link or interface failure occurs,
intermediate nodes insert OAM AIS cells into all the downstream devices affected by the failure. When
a router receives an AIS cell, it marks the ATM VC as down and sends an RDI cell to let the remote end
know about the failure.
Perform this task to enable OAM local emulation for AAL5 over L2TPv3.
Step 5
encapsulation aal5
Example:
Router(config-atm-vc)#
encapsulation aal5
Specifies ATM AAL5 encapsulation for the PVC.
Step 6
xconnect peer-ip-address vcid
pw-class pw-class-name
Example:
Router(config-atm-vc)# xconnect
10.0.3.201 888 pw-class
atm-xconnect
Specifies the IP address of the peer PE router and the 32-bit VCI shared
between the PE at each end of the control channel.
• The peer router ID (IP address) and virtual circuit ID must be a unique
combination on the router.
• pw-class pw-class-name—The pseudowire class configuration from
which the data encapsulation type (L2TPv3) will be taken. The pw-class
keyword binds the Xconnect statement to a specific pseudowire class. The
pseudowire class then serves as the template configuration for all
attachment circuits bound to it.
Note The L2TPv3 session can also be provisioned manually. See the section
“Manually Configuring L2TPv3 Session Parameters” for information
about manually configuring the L2TPv3 session parameters.
Command or Action Purpose