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Specifying the VPN label processing mode
The VPN label processing mode of an egress PE can be either of the following:
•
POPGO forwarding: Pop the label, and then search for the outbound interface according to the
label and forward the packet out the interface.
•
POP forwarding: Pop the label, and then search the FIB to find the outbound interface and forward
the packet out the interface.
To specify the VPN label processing mode on an egress PE:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Specify the VPN label processing
mode as POPGO forwarding
vpn popgo
Required
POP forwarding by default
NOTE:
•
To add two switches to an IRF fabric, configure the same VPN label processing mode (POPGO by using
vpn popgo
or POP by using
undo vpn popgo
) for the two switches. Otherwise, the two switches cannot
form an IRF fabric. For more information about IRF, see
IRF Configuration Guide.
•
After you execute the
vpn popgo
command, you must reboot the switch to validate the configuration.
After the command is executed successfully, the switch does not inform you of the current VPN label
processing mode. You can use the
display vpn label operation
command to view the current VPN label
processing mode.
Configuring BGP AS number substitution and SoO
Configuration prerequisites
Before configuring BGP AS number substitution and SoO, complete the following tasks:
•
Configure basic MPLS L3VPN
•
Ensure CEs at different sites to have the same AS number
Configuration procedure
When CEs at different sites have the same AS number, you need to configure the BGP AS number
substitution function to avoid route loss.
With the BGP AS number substitution function, when a PE advertises a route to the specified peer (CE),
if an AS number identical to that of the CE exist in the AS_PATH of the route, it will be replaced with that
of the PE before the route is advertised.
If the PE connects to multiple CEs in the same site, use a routing policy to add the SoO attribute to the
routes received from the CEs.
