Command Reference Guide
3Com Router 5000 Family and Router 6000 Family route-tag ● 81
Command Reference
route-tag
Purpose 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.
Syntax route-tag tag-number
undo route-tag
Parameters tag-number
Tag value to identify VPN import route, in range of 0 to
4294967295. By default, its first two fields are fixed to
0xD000, while the last two fields are the ASN of local
BGP. For example, if local BGP ASN is 100, then the
default tag value in decimal is 3489661028.
Example Configure route-tag 100 to OSPF process 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
View This command can be used in the following views:
■ OSPF Protocol view
Description 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 levels.
1. Those configured with the import-route command are of the highest priority
level.
2. Those configured with the route-tag command are in the second place in terms
of priority level.
3. Those configure with the default tag command are of the lowest priority level.