H3C Technologies H3C S7500E Series Switches - Manual (Page 271)

6-46
To do… Use the command… Remarks
Enter system view system-view —
Enter OSPF view
ospf [ process-id | router-id
router-id | vpn-instance
vpn-instance-name ] *
—
Configure the route tag route-tag tag-value Required
Enter OSPF area view area area-id Required
Configure a sham link
sham-link source-ip-address
destination-ip-address [ cost cost |
dead dead-interval | hello
hello-interval | retransmit
retrans-interval | trans-delay delay
| simple [ cipher | plain ]
password | { md5 | hmac-md5 }
key-id [ cipher | plain ]
password ]*
Required
By default, no sham link is
configured.
z
If you start OSPF but do not configure the router ID, the system will automatically elect one.
However, the same election rules produce the same router ID. Therefore, you are recommended
to configure the router ID when starting an OSPF process. For the election rules, see OSPF
Configuration in the Layer 3 - IP Routing Configuration Guide.
z
If you configure multiple OSPF VPN instances but do not configure the route tag, the system will
automatically create one based on the AS number configured. If you do not configure BGP, the
tag will be 0. However, the same calculation rule produces the same tag, and hence the same tag
will be created for multiple OSPF VPN instances on the same PE or PEs with the same AS
number. Therefore, you are recommended to configure different tags for different OSPF VPN
instance.
Configuring BGP AS Number Substitution
Configuration Prerequisites
Before configuring BGP AS number substitution, complete these tasks:
z
Configuring basic MPLS L3VPN
z
Configuring CEs at different sites to have the same AS number