OSPF - detailed explanation of GRE tunnel (including configuration command)

Catalog

One 、GRE Technology is introduced ：

Two 、GRE Tunnel Introduction diagram

3、 ... and 、GRE Tunnel Basic configuration ：

（1） Establishment of tunnel ：

（2） Configure customs clearance Tunnel The routing —— Static routing ​​

 （2） Configure customs clearance Tunnel The routing —— Dynamic routing OSPF

Four 、**GRE tunnel Data transfer process ：！！！

  5、 ... and 、 Application scenario II ：

One 、GRE Technology is introduced ：

• GRE VPN（Generic Routing Encapsulation） namely General routing encapsulation protocol , For some network layer protocols （ Such as IP and IPX） To encapsulate the datagram , Make these encapsulated datagrams available in another network layer protocol （ Such as IP） Transmission of .
• GRE yes VPN（Virtual Private Network） The third layer tunnel protocol , That is, a method called Tunnel（ Tunnel ） Technology .
• Tunnel It's a virtual point-to-point connection , A path is provided to enable the encapsulated data message to be transmitted on this path , And in one Tunnel The two ends of the datagram are respectively encapsulated and unpacked .
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Two 、GRE Tunnel Introduction diagram

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3、 ... and 、GRE Tunnel Basic configuration ：

（1） Establishment of tunnel ：

（2） Configure customs clearance Tunnel The routing —— Static routing

—— test ：

—— Be careful ： But at this time I R2 There are no static routes on the configuration 【 Through virtual VPN】：

 （2） Configure customs clearance Tunnel The routing —— Dynamic routing OSPF

  Be careful ： When it was announced , Cannot declare its own physical interface IP, It can only be declared tunnel Interface and its own intranet segment IP, The negative side will affect the neighborhood relationship .

Tunnel Next enable ospf： Just an announcement tunnel Interface IP Address , Analyze two levels IP Head

：tunnel The source is its own physical interface , The destination is usually the physical interface of the other party IP Address （ End to end connection to the public network interface IP Address ）, Used to encapsulate the outer layer IP Head , In the use of a default only want each other physical IP Address ,tunnel Interface to use , And then tunnel The interface runs the dynamic routing protocol

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Four 、**GRE tunnel Data transfer process ：！！！

 

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  5、 ... and 、 Application scenario II ：