Huawei equipment is configured to access the virtual private network through GRE tunnel

1. Configure each interface IP Address
   [CE3-GigabitEthernet0/0/0]ip add 20.1.1.1 24
   [CE3-GigabitEthernet0/0/1]ip add 10.1.1.1 24
   [CE1-GigabitEthernet0/0/0]ip add 20.1.1.2 24
   [CE1-GigabitEthernet0/0/1]ip add 30.1.1.2 24
   [PE1-GigabitEthernet0/0/0]ip add 30.1.1.3 24
   [PE1-GigabitEthernet0/0/1]ip add 40.1.1.3 24
   [PE1-LoopBack0]ip add 3.3.3.3 32
   [PE2-GigabitEthernet0/0/0]ip add 40.1.1.4 24
   [PE2-GigabitEthernet0/0/1]ip add 50.1.1.4 24
   [PE2-LoopBack0]ip add 4.4.4.4 32
   [CE2-GigabitEthernet0/0/0]ip add 50.1.1.5 24
   [CE2-GigabitEthernet0/0/1]ip add 10.2.1.5 24
2. To configure PE Routing and MPLS： Can make MPLS LDP, And use the process as 10 Of OSPF route , send PE The inter route can reach , Auto build LSP
   [PE1]mpls lsr-id 3.3.3.3
   [PE1]mpls
   [PE1-mpls]lsp-trigger all
   [PE1]mpls ldp
   [PE1]ospf 10
   [PE1-ospf-10]area 0
   [PE1-ospf-10-area-0.0.0.0]network 3.3.3.3 0.0.0.0
   [PE1-ospf-10-area-0.0.0.0]network 40.1.1.0 0.0.0.255
   [PE1-GigabitEthernet0/0/1]mpls
   [PE1-GigabitEthernet0/0/1]mpls ldp
   [PE2]mpls lsr-id 4.4.4.4
   [PE2]mpls
   [PE2-mpls]lsp-trigger all
   [PE2]mpls ldp
   [PE2]ospf 10
   [PE2-ospf-10]area 0
   [PE2-ospf-10-area-0.0.0.0]network 4.4.4.4 0.0.0.0
   [PE2-ospf-10-area-0.0.0.0]network 40.1.1.0 0.0.0.255
   [PE2-GigabitEthernet0/0/0]mpls
   [PE2-GigabitEthernet0/0/0]mpls ldp
3. stay PE1 establish VPN example vpn2 And with CE1 Interface binding
   [PE1]ip vpn-instance vpn2
   [PE1-vpn-instance-vpn2]route-distinguisher 100:2
   [PE1-vpn-instance-vpn2-af-ipv4]vpn-target 222:2 export-extcommunity
   [PE1-vpn-instance-vpn2-af-ipv4]vpn-target 222:2 import-extcommunity
   [PE1-GigabitEthernet0/0/0]ip binding vpn-instance vpn2
   [PE1-GigabitEthernet0/0/0]ip add 30.1.1.3 24
4. stay PE1 establish VPN example vpn1 And with GRE Tunnel binding
   [PE1]ip vpn-instance vpn1
   [PE1-vpn-instance-vpn1]route-distinguisher 100:1
   [PE1-vpn-instance-vpn1-af-ipv4]vpn-target 111:1 export-extcommunity
   [PE1-vpn-instance-vpn1-af-ipv4]vpn-target 111:1 import-extcommunity
   [PE1]int Tunnel 0/0/1
   [PE1-Tunnel0/0/1]ip binding vpn-instance vpn1
   [PE1-Tunnel0/0/1]ip add 2.2.2.2 24
5. stay PE2 establish VPN example vpn1 And it is bound with the user side interface
   [PE2]ip vpn-instance vpn1
   [PE2-vpn-instance-vpn1]route-distinguisher 200:1
   [PE2-vpn-instance-vpn1-af-ipv4]vpn-target 111:1 export-extcommunity
   [PE2-vpn-instance-vpn1-af-ipv4]vpn-target 111:1 import-extcommunity
   [PE2-GigabitEthernet0/0/1]ip binding vpn-instance vpn1
   [PE2-GigabitEthernet0/0/1]ip add 50.1.1.4 24
6. To configure GRE Of the tunnel Tunnel Interface
   [CE3]int Tunnel 0/0/1
   [CE3-Tunnel0/0/1]tunnel-protocol gre
   [CE3-Tunnel0/0/1]source 20.1.1.1
   [CE3-Tunnel0/0/1]destination 30.1.1.3
   [CE3-Tunnel0/0/1]ip add 2.2.2.1 24
   [PE1]int Tunnel 0/0/1
   [PE1-Tunnel0/0/1]tunnel-protocol gre
   [PE1-Tunnel0/0/1]source 30.1.1.3
   [PE1-Tunnel0/0/1]destination vpn-instance vpn2 20.1.1.1
7. To configure CE3、CE1 and PE1 Routing protocol between
   [CE3]ospf 20
   [CE3-ospf-20]area 0
   [CE3-ospf-20-area-0.0.0.0]network 20.1.1.0 0.0.0.255
   [CE1]ospf 20
   [CE1-ospf-20]area 0
   [CE1-ospf-20-area-0.0.0.0]network 20.1.1.0 0.0.0.255
   [CE1-ospf-20-area-0.0.0.0]network 30.1.1.0 0.0.0.255
   [PE1]ospf 20 vpn-instance vpn2
   [PE1-ospf-20]area 0
   [PE1-ospf-20-area-0.0.0.0]network 30.1.1.0 0.0.0.255
8. To configure CE3 And PE1 Between IS-IS route
   [CE3]isis 10
   [CE3-isis-10]network-entity 10.0000.0000.0001.00
   [CE3-GigabitEthernet0/0/0]isis enable 10
   [CE3]int Tunnel 0/0/1
   [CE3-Tunnel0/0/1]isis enable 10
   [PE1]isis 10 vpn-instance vpn1
   [PE1-isis-10]network-entity 10.0000.0000.0003.00
   [PE1]int Tunnel 0/0/1
   [PE1-Tunnel0/0/1]isis enable 10
9. To configure CE2 And PE2 Between IS-IS route
   [CE2]isis 10
   [CE2-isis-10]network-entity 10.0000.0000.0005.00
   [CE2-GigabitEthernet0/0/0]isis enable 10
   [CE2-GigabitEthernet0/0/1]isis enable 10
   [PE2]isis 10 vpn-instance vpn1
   [PE2-isis-10]network-entity 10.0000.0000.0004.00
   [PE2-GigabitEthernet0/0/1]isis enable 10
10. stay PE Establish between MP-IBGP peers
    [PE1]bgp 100
    [PE1-bgp]peer 4.4.4.4 as-number 100
    [PE1-bgp]peer 4.4.4.4 connect-interface LoopBack 0
    [PE1-bgp]ipv4-family vpnv4 // Start peer exchange VPN-IPv4 Routing information
    [PE1-bgp-af-vpnv4]peer 4.4.4.4 enable
    [PE1-bgp]ipv4-family vpn-instance vpn1 // Get into BGP Of vpn1 example
    [PE1-bgp-vpn1]import-route isis 10 // introduce IS-IS route
    [PE2]bgp 100
    [PE2-bgp]peer 3.3.3.3 as-number 100
    [PE2-bgp]peer 3.3.3.3 connect-interface LoopBack 0
    [PE2-bgp]ipv4-family vpnv4
    [PE2-bgp-af-vpnv4]peer 3.3.3.3 enable
    [PE2-bgp]ipv4-family vpn-instance vpn1
    [PE2-bgp-vpn1]import-route isis 10
11. stay IS-IS Introduction in BGP route
    [PE1]isis 10
    [PE1-isis-10]import-route bgp
    [PE2]isis 10
    [PE2-isis-10]import-route bgp
12. Check the configuration