Huawei Quidway S8500 Series Command Manual page 790

Command Manual – MPLS
Quidway S8500 Series Routing Switches
local BGP. For example, if the local BGP ASN is 100, then the default tag value in
decimal is 3489661028. The value is an integer from 0 to 4294967295.
Description
Use the route-tag command to specify a tag value to identify VPN import route.
Use the undo route-tag command to restore the default value.
If a VPN Site is linked to multiple PEs, when a route learned from MPLS/BGP is
advertised by a PE router via its type-5 or type-7 LSA to the VPN Site, the route may be
received by another PE router. This will result in routing loop. To avoid routing loop, you
should configure Route-tag and you are recommended to configure the same route-tag
for the PEs in the same VPN domain. The Route-tag is included in the type-5/-7 LSA. It
is not transmitted in the extended community attributes of BGP, and thus it is limited in
the local area. Therefore, it can only be configured and function on the PE router which
receives BGP routes and generates OSPF LSA.
Configure Route-tag in OSPF protocol view. Different processes can be configured with
a same Route-tag. You can configure the same Route-tag using different commands,
but they are different in priority.
Those configured with the import-route command are of the highest priority.
Those configured with the route-tag command are in the second place in terms of
priority.
Those configure with the default tag command are of the lowest priority.
If the Tag included in the type-5/-7 LSA is identical with its existing Tag, the LSA
received will be neglected in route calculation.
Caution:
The Route-tag configured will not be validated until the reset ospf command is
executed.
Related command: import-route and default.
Example
# Configure Route-tag 100 to OSPF process 100.
[Quidway-ospf-100] route-tag 100
OSPF: Process 100's route tag has been changed
OSPF: Reboot the system or use the 'reset ospf ID' command for this to take
effect
Huawei Technologies Proprietary
Chapter 2 BGP/MPLS VPN Configuration Commands
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