Interface and Hardware Component Configuration Guide, Cisco IOS XE Release 3S
GRE IPv6 Tunnels
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GRE IPv6 Tunnels

GRE IPv6 Tunnels

The GRE IPv6 Tunnels feature enables the delivery of packets from other protocols through an IPv6 network and allows the routing of IPv6 packets between private networks across public networks with globally routed IPv6 addresses. Generic routing encapsulation (GRE) is a unicast protocol that offers the advantages of encapsulating broadcast and multicast traffic (multicast streaming or routing protocols) or other non-IP protocols and of being protected by IPsec.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Restrictions for GRE IPv6 Tunnels

  • GRE tunnel keepalive packets are not supported.

  • Multipoint GRE (mGRE) IPv6 tunneling is not supported.

  • There is limited support for tunnel transport in virtual routing and forwarding (VRF). The limited support in VRF is applicable to IPv6 point-to-point GRE without tunnel protection.

Information About GRE IPv6 Tunnels

Overview of GRE IPv6 Tunnels

The GRE IPv6 Tunnels feature enables the delivery of packets from other protocols through an IPv6 network and allows the routing of IPv6 packets between private networks across public networks with globally routed IPv6 addresses.

For point-to-point GRE tunnels, each tunnel interface requires a tunnel source IPv6 address and a tunnel destination IPv6 address when being configured. All packets are encapsulated with an outer IPv6 header and a GRE header.

GRE IPv6 Tunnel Protection

GRE IPv6 tunnel protection allows devices to work as security gateways, establish IPsec tunnels between other security gateway devices, and provide crypto IPsec protection for traffic from internal networks when the traffic is sent across the public IPv6 Internet. The GRE IPv6 tunnel protection functionality is similar to the security gateway model that uses GRE IPv4 tunnel protection.

How to Configure GRE IPv6 Tunnels

Configuring GRE IPv6 Tunnels

Perform this task to configure a GRE tunnel on an IPv6 network. GRE tunnels can be configured to run over an IPv6 network layer and transport IPv6 and IPv4 packets through IPv6 tunnels.


Note


You must enable IPv6 or configure IPv6 MTU size more than 1500 on a tunnel's exit interface to avoid receiving warning messages.


Before You Begin

When GRE IPv6 tunnels are configured, IPv6 addresses are assigned to the tunnel source and the tunnel destination. The tunnel interface can have either IPv4 or IPv6 addresses (this is not shown in the task below). The host or device at each end of the configured tunnel must support both IPv4 and IPv6 protocol stacks.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    interface tunnel tunnel-number

    4.    tunnel source {ipv6-address | interface-type interface-number}

    5.    tunnel destination ipv6-address

    6.    tunnel mode gre ipv6

    7.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 interface tunnel tunnel-number


    Example:
    Device(config)# interface tunnel 0
     

    Specifies a tunnel interface and number and enters interface configuration mode.

     
    Step 4 tunnel source {ipv6-address | interface-type interface-number}


    Example:
    Device(config-if)# tunnel source ethernet 0
     

    Specifies the source IPv6 address or the source interface type and number for the tunnel interface.

    • If an interface type and number are specified, the interface must be configured with an IPv6 address.

    Note   

    Only the syntax used in this context is displayed. For more details, see the IPv6 Command Reference.

     
    Step 5 tunnel destination ipv6-address


    Example:
    Device(config-if)# tunnel destination 2001:0DB8:0C18:2::300
     

    Specifies the destination IPv6 address for the tunnel interface.

    Note   

    Only the syntax used in this context is displayed. For more details, see the IPv6 Command Reference.

     
    Step 6 tunnel mode gre ipv6


    Example:
    Device(config-if)# tunnel mode gre ipv6
     

    Specifies a GRE IPv6 tunnel.

    Note   

    The tunnel mode gre ipv6 command specifies GRE as the encapsulation protocol for the tunnel interface. Only the syntax used in this context is displayed. For more details, see the IPv6 Command Reference.

     
    Step 7 end


    Example:
    Device(config-if)# end
     

    Exits interface configuration mode and returns to privileged EXEC mode.

     

    Configuring GRE IPv6 Tunnel Protection

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    interface tunnel tunnel-number

      4.    tunnel source {ipv6-address | interface-type interface-number}

      5.    tunnel destination ipv6-address

      6.    tunnel mode gre ipv6

      7.    tunnel protection ipsec profile profile-name

      8.    end


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.

       
      Step 2 configure terminal


      Example:
      Device# configure terminal
       

      Enters global configuration mode.

       
      Step 3 interface tunnel tunnel-number


      Example:
      Device(config)# interface tunnel 0
       

      Specifies a tunnel interface and number and enters interface configuration mode.

       
      Step 4 tunnel source {ipv6-address | interface-type interface-number}


      Example:
      Device(config-if)# tunnel source ethernet 0
       

      Specifies the source IPv6 address or the source interface type and number for the tunnel interface.

      • If an interface type and number are specified, the interface must be configured with an IPv6 address.

      Note   

      Only the syntax used in this context is displayed. For more details, see the IPv6 Command Reference.

       
      Step 5 tunnel destination ipv6-address


      Example:
      Device(config-if)# tunnel destination 2001:0DB8:0C18:2::300
       

      Specifies the destination IPv6 address for the tunnel interface.

      Note   

      Only the syntax used in this context is displayed. For more details, see the IPv6 Command Reference.

       
      Step 6 tunnel mode gre ipv6


      Example:
      Device(config-if)# tunnel mode gre ipv6
       

      Specifies a GRE IPv6 tunnel.

      Note   

      The tunnel mode gre ipv6 command specifies GRE as the encapsulation protocol for the tunnel interface. Only the syntax used in this context is displayed. For more details, see the IPv6 Command Reference.

       
      Step 7 tunnel protection ipsec profile profile-name


      Example:
      Device(config-if)# tunnel protection ipsec profile ipsec-profile
       

      Associates the tunnel interface with an IPsec profile.

      Note   

      For the profile-name argument, specify the IPsec profile configured in global configuration mode.

       
      Step 8 end


      Example:
      Device(config-if)# end
       

      Exits interface configuration mode and returns to privileged EXEC mode.

       

      Configuration Examples for GRE IPv6 Tunnels

      Example: Configuring GRE IPv6 Tunnels

      The following example shows how to configure a GRE tunnel over an IPv6 transport. In this example, Ethernet0/0 has an IPv6 address, and this is the source address used by the tunnel interface. The destination IPv6 address of the tunnel is specified directly. In this example, the tunnel carries both IPv4 and IS-IS traffic.

      interface Tunnel0
       ip address 10.1.1.1 255.255.255.0
       ip router isis 
       tunnel source Ethernet0/0
       tunnel destination 2001:DB8:1111:2222::1
       tunnel mode gre ipv6
      !
      interface Ethernet0/0
       no ip address
       ipv6 address 2001:DB8:1111:1111::1/64
      !
      router isis 
       net 49.0001.0000.0000.000a.00

      Example: Configuring GRE IPv6 Tunnel Protection

      The following example shows how to associate the IPsec profile “ipsec-profile” with a GRE IPv6 tunnel interface. The IPsec profile is configured using the crypto ipsec profile command.

      crypto ipsec profile ipsec-profile
       set transform-set ipsec-profile
      !
      interface Tunnel1
       ip address 192.168.1.1 255.255.255.252
       tunnel source FastEthernet2/0
       tunnel destination 10.13.7.67
       tunnel protection ipsec profile ipsec-profile

      Additional References

      Related Documents

      Related Topic

      Document Title

      Cisco IOS commands

      Master Commands List, All Releases

      Tunnel commands: complete command syntax, command mode, defaults, command history, usage guidelines, and examples

      Interface and Hardware Component Command Reference

      IPv6 commands: complete command syntax, command mode, defaults, command history, usage guidelines, and examples

      IPv6 Command Reference

      Technical Assistance

      Description

      Link

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      http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

      Feature Information for GRE IPv6 Tunnels

      The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

      Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

      Table 1 Feature Information for GRE IPv6 Tunnels

      Feature Name

      Releases

      Feature Information

      GRE IPv6 Tunnels

      Cisco IOS XE Release 3.7S

      The GRE IPv6 Tunnels feature enables the delivery of packets from other protocols through an IPv6 network and allows the routing of IPv6 packets between private networks across public networks with globally routed IPv6 addresses.