R3303-HP HSR6800 Routers MPLS Command Reference

343
3489661028, which equals the decimal value of 0xD0000000 (3489660928) + 100. If the BGP's AS
number is greater than 65535 or the MPLS backbone does not use BGP, the default external route tag is
0.
Views
OSPF view
Default command level
2: System level
Parameters
tag-value: Specifies the external route tag for imported VPN routes, in the range of 0 to 4294967295.
Usage guidelines
If PE-CE routing protocol is OSPF, the local PE redistributes the BGP VPNv4 routes received from the peer
PE into the OSPF routing table, and advertises these routes to the locally connected CE through OSPF. If
the routes are advertised to the CE through Type 5 or 7 LSAs, Type 5/7 LSAs must contain the external
route tag. An external route tag can be configured by different commands and has different priorities.
The following lists the commands used to configure the external route tag (in the descending order of tag
priority):
• import-route
• route-tag
• default tag
The external route tag is used to avoid routing loops. If the external route tag carried in a Type 5 or 7 LSA
received by a PE is the same as the locally configured external route tag, the PE neglects the LSA in route
calculation to avoid routing loops.
HP recommends that you configure the same external route tag for PEs in the same area.
An external route tag is not transferred in any BGP extended community attribute. It is only locally
significant and takes effect only on the PEs that receive BGP routes and generate OSPF Type 5 or 7 LSAs.
You can configure the same external route tag for different OSPF processes.
Examples
# In OSPF process 100, set the external route tag for imported VPN routes to 100.
<Sysname> system-view
[Sysname] ospf 100
[Sysname-ospf-100] route-tag 100
Related commands
• import-route
• default (Layer 3—IP Routing Command Reference)
routing-table limit (VPN instance view/IPv4 VPN view)
Use routing-table limit to limit the maximum number of routes in a VPN instance, preventing too many
routes from being accepted by a PE.
Use undo routing-table limit to restore the default.