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Cisco SCE 2000 and SCE 1000 Software Configuration Guide
OL-7827-12
Chapter 6 Configuring the Line Interface
Tunneling Protocols
Options
The following option is available:
•
portnumber
—The port number that the LNS and LAC use for L2TP tunnels.
Default port# = 1701
Step 1
From the SCE(config if)# prompt, type
L2TP identify-by port-number
portnumber
and press
Enter
.
Enables privileged EXEC mode.
Asymmetric L2 Support
You should enable asymmetric layer 2 support in cases where the following conditions apply for any
flows:
•
Each direction of the flow has a different pair of MAC addresses.
•
The routers do not accept packets with the MAC address of the other link.
Note
'Asymmetric routing topology' support and 'asymmetric tunneling support' are two separate features.
Asymmetric routing topology refers to topologies where the SCE platform might see some flows only
in one direction (upstream/downstream). Asymmetric tunneling support (asymmetric L2 support) refers
to the ability to support topologies where the SCE platform sees both directions of all flows, but some
of the flows may have different layer 2 characteristics (like MAC addresses, VLAN tags, MPLS labels
and L2TP headers), which the SCE platform must specifically take into account when injecting packets
into the traffic (such as in block and redirect operations). Note as well, that in order to support
asymmetric layer 2, the SCE platform switches to asymmetric flow open mode, which incurs a certain
performance penalty. This is NOT the case for asymmetric routing topology.
Step 1
From the SCE(config if)# prompt, type
asymmetric-L2-support
and press
Enter
.
Displaying the Tunneling Configuration
Step 1
From the SCE# prompt, type
show interface linecard 0 MPLS|VLAN|L2TP|IP-tunnel
and press
Enter
.
Displays the current configuration for the specified tunnel option.