Command Reference Guide

3Com Router 3000 Ethernet Family
Command Reference Guide
Chapter 2 BGP/MPLS VPN Configuration
Commands
3Com Corporation
2-20
32-bit IP address (can be 0.0.0.0 here): a 16-bit number defined by user, for example,
192.168.122.15:1.
Example
# Configure RD for an MPLS VPN instance.
[3Com ] ip vpn-instance vpn_blue
[3Com -vpn-vpn_blue] route-distinguisher 100:3
[3Com ] ip vpn-instance vpn_red
[3Com -vpn-vpn_red] route-distinguisher 173.13.0.12:200
2.1.24 route-tag
Syntax
route-tag tag-number
undo route-tag
View
OSPF protocol view
Parameter
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.
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 levels.
1) Those configured with the import-route command are of the highest priority level.