3Com Router 3031, Command Reference Manual

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798 C
HAPTER
8: MPLS B
ASIC
C
ONFIGURATION
C
OMMANDS
Description
Using the route-tag command, you can specify a tag value to identify VPN import
route. Using the undo route-tag command, you can restore the default value.
If a VPN site is linked to multiple PEs, when the 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 route loop. To avoid route loop,
you should configure route-tag and it is 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. The route-tag is not transmitted in the extended community
attributes of BGP, but can only be configured and function on the PE router which
receives BGP route 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 with different
commands, but with different priority levels.
■
Those configured with the import-route command are of highest priority level.
■
Those configured with the route-tag command are in the second place in terms
of priority level.
■
Those configure with the default tag command are of the lowest priority level.
If the route-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 take effect until the reset ospf
command is executed.
For the related commands, see import-route and default.
Example
Configure route-tag 100 to OSPF procedure 100.
[3Com-ospf-100] route-tag 100
OSPF: Process 100's route tag has been changed
OSPF: Reload or use 'reset ospf' command for this to take effect
vpn-target Syntax
vpn-target vpn-target-ext-community [ import-extcommunity |
export-extcommunity | both ]
undo vpn-target vpn-target-ext-community [ import-extcommunity |
export-extcommunity | both ]
View
Vpn-instance view
Parameter
import-extcommunity: Ingress route information from the extended community of
target VPN.
export-extcommunity: Egress route information to the extended community of
target VPN.