3Com Switch 8800 Configuration Guide
Chapter 37 BGP/MPLS VPN Configuration
37-72
37.4.9 OSPF Multi-instance sham link Configuration Example
I. Network requirements
As shown in the following picture, a company connects to a WAN through OSPF
multi-instance function of a router. OSPF is bind to VPN1.MPLS VPN backbone runs
between PEs and OSPF runs between PE and CE. Configure a sham link between
PE1 and PE2 to ensure the traffic between CE1 and CE2 does not pass the backdoor
link that directly connects CE1 and CE2.
II. Network diagram
CE1
10.10.10.10
CE2
20.20.20.20
12.1.1.0/24
PE1
PE3
3.3.3.3
PE2
2.2.2.2
VLAN201
10.1.1.1/24
(168.1.1.0/24)
20.2.1.0/24
VLAN202
12.1.1.1/24
MPLS VPN Backbone
LoopBack0: 1.1.1.1
LoopBack0: 2.2.2.2
LoopBack0: 3.3.3.3
VLAN201
10.1.1.2/24
VLAN203
168.1.12.1/24
VLAN202
168.1.13.1/24
(backdoor)
sham link
LoopBack1:
50.1.1.1
LoopBack1:50.1.1.2
LoopBack1:
50.1.1.3
1.1.1.1
VLAN203
168.1.12.2/24
VLAN202
168.1.13.2/24
VLAN202
168.1.23.2/24
VLAN201
168.1.23.1/24
VLAN201
20.1.1.2/24
VLAN201
20.1.1.1/24
VLAN202
12.1.1.2/24
CE1
10.10.10.10
CE2
20.20.20.20
12.1.1.0/24
PE1
PE3
3.3.3.3
PE2
2.2.2.2
VLAN201
10.1.1.1/24
(168.1.1.0/24)
20.2.1.0/24
VLAN202
12.1.1.1/24
MPLS VPN Backbone
LoopBack0: 1.1.1.1
LoopBack0: 2.2.2.2
LoopBack0: 3.3.3.3
VLAN201
10.1.1.2/24
VLAN203
168.1.12.1/24
VLAN202
168.1.13.1/24
(backdoor)
sham link
LoopBack1:
50.1.1.1
LoopBack1:50.1.1.2
LoopBack1:
50.1.1.3
1.1.1.1
VLAN203
168.1.12.2/24
VLAN202
168.1.13.2/24
VLAN202
168.1.23.2/24
VLAN201
168.1.23.1/24
VLAN201
20.1.1.2/24
VLAN201
20.1.1.1/24
VLAN202
12.1.1.2/24
Figure 37-16
Network diagram for OSPF multi-instance
III. Configuration procedure
1) Configure
PE1
Enable MPLS and LDP.
[PE1] mpls lsr-id 50.1.1.1
[PE1] mpls
[PE1-mpls] quit
[PE1] mpls ldp
Configure VPN-instance.
[PE1] ip vpn-instance vpn1
[PE1-vpn-vpn1] route-distinguisher 2:1
[PE1-vpn-vpn1] vpn-target 100:1 export-extcommunity
[PE1-vpn-vpn1] vpn-target 100:1 import-extcommunity
Configure VLAN interface.