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This article mainly explains "how to configure OSPF pseudo-link". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "how to configure OSPF pseudo-link".

Deep understanding of ospf

Understand the complementary supper backbone area to OSPF hierarchical design in MPLS VPN

2: understand the regional design concept of OSPF in MPLS VPN

3: understand the importance of OSPF process id and router-id in MPLS VPN

4: understand the extended community attributes of MP BGP in MPLS VPN for OSPF, and understand how to control OSPF LSA types

Domain-id

Extended Community: RT:1:1 OSPF DOMAIN ID:0x0005:0x000000020200

OSPF RT:0.0.0.0:2:0 OSPF ROUTER ID:11.1.1.1:0

Mpls labels in/out nolabel/23

5: understand that OSPF uses down bit domain tag to prevent loops in MPLS VPN

DownBit (vrf related) LSA 3

All are looked up in LSA.

OSPF Tag Fied

6: understand back door route in MPSL VPN, and understand OSPF shame-link (pseudo-link) mechanism

Extended Community: RT:1:1 OSPF DOMAIN ID:0x0005:0x000000020200 (calculated by the associated process of the ospf vrf on the PE side) domain ID is consistent and sees category 3 (OIA)

OSPF RT:0.0.0.1 (area ID): 2 (LSA type): 0

2 (intra-regional or inter-regional)

4 (four categories)

5 (five categories) external

0 oe1

1 oe2

OSPF ROUTER ID:11.1.1.1:0

Mpls labels in/out 19/nolabel

OSPF pseudo-link configuration

1. Enable loopback interface on both ends of PE, (32-bit) lo1

(cannot be declared in OSPF) put interface lo1 into the relevant vrf

Interface Loopback1

Ip vrf forwarding a (put into the corresponding vrf)

Ip address 100.1.1.1 255.255.255.255 (32 bit)

2. Originate (or redistribute) in BGP

Network (redistribute)

Router bgp 100

Address-family ipv4 vrf a

Redistribute connected route-map A

Route-map A permit 10

Match interface Loopback1

Precise redistribution of lo1

Learn the corresponding routes in the vrf routing tables at both ends, and can ping each other.

VPN classroom Notes 2 ">

3. Create ospf sham-link

Enter the process of associating ospf with vrf a

Router ospf 2 vrf a

Area 0 sham-link 100.1.1.1 100.1.1.2

The ospf area between ce and PE (the area between PE and CE at both ends must be consistent)

VPN classroom Notes 2 ">

When you see that the adjacency is full state, the hello packet is suppressed, the shamlink is established successfully, and a new neighbor relationship is formed.

VPN classroom Notes 2 ">

At this point, check whether the ospf route on the CE side is an O table item.

VPN classroom Notes 2 ">

If the O item is completely established successfully

4. Check the backup link (the backup cost value is higher than the primary link (via MPLSVPN)

Interface Serial0/3

Ip ospf cost 131

Directly connected interfaces at both ends of the backup link need to be modified

Static state

Ip route 37.1.1.7 255.255.255.255 Serial0/0

Ip route vrf a 0.0.0.0 0.0.0.0 11.1.1.2 global

Router bgp 100

Bgp router-id 2.2.2.2

Address-family ipv4

Redistribute static

Ip route 37.1.1.7 255.255.255.255 Serial0/0

Write static routes globally (the next hop is unreachable)

Ip route vrf a 0.0.0.0 0.0.0.0 11.1.1.2 global

Write static route under VRF next hop is global

Tunnel

VPN classroom Notes 2 ">

Enable the tunnel interface on both R7 and R3

R7:interface Tunnel0

Ip address 100.1.1.2 255.255.255.0

It must be in the same network segment.

Tunnel source 37.1.1.7

Tunnel destination 37.1.1.3

R3

Interface Tunnel0

Ip address 100.1.1.1 255.255.255.0

Tunnel source 37.1.1.3

Tunnel destination 37.1.1.7

Tunnel vrf a (tunnel Associated vrf)

Best of the game!

Enable the tunnel interface on both R7 and R3

R7:interface Tunnel0

Ip address 100.1.1.2 255.255.255.0

It must be in the same network segment.

Tunnel source 37.1.1.7

Tunnel destination 37.1.1.3

R3

Interface Tunnel0

Ip address 100.1.1.1 255.255.255.0

Tunnel source 37.1.1.3

Tunnel destination 37.1.1.7

Tunnel vrf a (tunnel Associated vrf)

Routing reflector

Non-customer routes are not reflected to non-customer

The rest of the reflection

Thank you for your reading, the above is the content of "how to configure OSPF pseudo-links". After the study of this article, I believe you have a deeper understanding of how to configure OSPF pseudo-links, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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