3Com Switch 8800 Configuration Guide Chapter 37 BGP/MPLS VPN Configuration

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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.