Which two technologies can be used to tunnel IPv6 traffic over IPv4 networks choose two?

Prerequisite – Differences between IPv4 and IPv6 

In the current scenario, the IPv4 address is exhausted and IPv6 had come to overcome the limit.

Various organization is currently working with IPv4 technology and in one day we can’t switch directly from IPv4 to IPv6. Instead of only using IPv6, we use combination of both and transition means not replacing IPv4 but co-existing of both.

When we want to send a request from an IPv4 address to an IPv6 address, but it isn’t possible because IPv4 and IPv6 transition is not compatible. For a solution to this problem, we use some technologies. These technologies are Dual Stack Routers, Tunneling, and NAT Protocol Translation. These are explained as following below. 

1. Dual-Stack Routers: 
In dual-stack router, A router’s interface is attached with IPv4 and IPv6 addresses configured are used in order to transition from IPv4 to IPv6. 

In this above diagram, A given server with both IPv4 and IPv6 addresses configured can communicate with all hosts of IPv4 and IPv6 via dual-stack router (DSR). The dual stack router (DSR) gives the path for all the hosts to communicate with the server without changing their IP addresses. 

2. Tunneling: 
Tunneling is used as a medium to communicate the transit network with the different IP versions.

In this above diagram, the different IP versions such as IPv4 and IPv6 are present. The IPv4 networks can communicate with the transit or intermediate network on IPv6 with the help of the Tunnel. It’s also possible that the IPv6 network can also communicate with IPv4 networks with the help of a Tunnel. 

3. NAT Protocol Translation: 
With the help of the NAT Protocol Translation technique, the IPv4 and IPv6 networks can also communicate with each other which do not understand the address of different IP version. 

Generally, an IP version doesn’t understand the address of different IP version, for the solution of this problem we use NAT-PT device which removes the header of first (sender) IP version address and add the second (receiver) IP version address so that the Receiver IP version address understand that the request is sent by the same IP version, and its vice-versa is also possible. 

In the above diagram, an IPv4 address communicates with the IPv6 address via a NAT-PT device to communicate easily. In this situation, the IPv6 address understands that the request is sent by the same IP version (IPv6) and it responds.
 

Configuring an IPv4 over IPv6 Tunnel

An IPv4 over IPv6 tunnel functions as a permanent link that connects two IPv4 domains through the IPv6 backbone network. It is a fixed channel for regular and secure communication between border devices. An IPv4 over IPv6 tunnel is a point-to-point tunnel. The source and destination IPv6 addresses of the tunnel interfaces are manually specified, and must be unique on the same device.

Usage Scenario

To enable IPv4 networks to communicate with each other through an IPv6 network, configure an IPv4 over IPv6 tunnel on the devices where IPv4 networks border an IPv6 network.

On the network shown in Figure 7-1, an IPv4 over IPv6 tunnel can be established between two edge devices to provide stable connection for isolated Pv4 networks or between a terminal and an edge device to allow the terminal to access the remote IPv4 network. You can configure multiple IPv4 over IPv6 tunnels on an edge router for communicating with multiple IPv6 networks.

Figure 7-1 Networking diagram of an IPv4 over IPv6 tunnel

Pre-configuration Tasks

Before configuring an IPv4 over IPv6 tunnel, connect interfaces and configure IPv6 addresses for the interfaces so that the route between the interfaces is reachable.

Configuration Procedures

Figure 7-2 Flowchart for configuring an IPv4 over IPv6 tunnel

• Configuring a Source Interface for an IPv4 over IPv6 Tunnel
  You can only specify a loopback interface as the source interface for an IPv4 over IPv6 tunnel interface and use it to communicate with other devices because a loopback interface stays in the Up state after being created.
• Configuring an IPv4 over IPv6 Tunnel Interface
  This section describes how to create an IPv4 over IPv6 tunnel interface to implement communication between IPv4 networks using the tunneling technology.
• Configuring IPv4 over IPv6 Tunnel Routes
  The other configurations of an IPv4 over IPv6 tunnel include the number of times that IPv6 encapsulation is performed for an IPv4 packet, traffic flag, maximum hops, and traffic class.
• (Optional) Configuring Other Parameters of an IPv4 over IPv6 Tunnel
  This section describes how to configure an IPv6 packet header for an IPv4 packet so that the packet can be transmitted over an IPv4 over IPv6 tunnel.
• Checking the Configurations
  After configuring an IPv4 over IPv6 tunnel, you can check the status of the tunnel interfaces and routing information.

Configuring a Source Interface for an IPv4 over IPv6 Tunnel

You can only specify a loopback interface as the source interface for an IPv4 over IPv6 tunnel interface and use it to communicate with other devices because a loopback interface stays in the Up state after being created.

Procedure

1. Run system-view

   The system view is displayed.

2. Run interface Loopback looback-number

   A loopback interface is created.

3. (Optional) Run ip binding vpn-instance vpn-instance-name

   A VPN instance is bound to the loopback interface.

   In VPN scenarios, the loopback interface must be bound to the VPN instance to which the device belongs.

4. Run ipv6 enable

   IPv6 is enabled on the interface.

5. Run ipv6 address { ipv6-address prefix-length | ipv6-address/prefix-length }

   An IPv6 address is configured for the loopback interface.

6. Run binding tunnel ipv4-ipv6

   IPv4 over IPv6 is enabled on the loopback interface.

7. Run commit

   The configuration is committed.

Configuring an IPv4 over IPv6 Tunnel Interface

This section describes how to create an IPv4 over IPv6 tunnel interface to implement communication between IPv4 networks using the tunneling technology.

Context

An IPv4 over IPv6 tunnel is established on the tunnel interfaces at both ends. Therefore, you need to configure a tunnel interface on the device at each end of the tunnel. You must specify the protocol type, source IPv6 address or source interface, and destination IPv6 address for an IPv4 over IPv6 tunnel interface.

A tunnel interface is a logical interface and its status is Down in the following situations:

• The destination address configured for the tunnel interface is unreachable or is the IPv6 address of the tunnel interface.

• The status of the source interface configured for the tunnel interface is Down.

• The IPv6 address configured on the tunnel interface is invalid.

Perform the following steps on the devices at both ends of a tunnel:

Procedure

1. Run system-view

   The system view is displayed.

2. Run interface tunnel interface-number

   A tunnel interface is created, and the tunnel interface view is displayed.

3. Run tunnel-protocol ipv4-ipv6

   The tunnel protocol is set to IPv4 over IPv6.

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

   A source IPv6 address or source interface is specified for the tunnel interface.

   You can only specify a loopback interface as the source interface for a tunnel interface. Likewise, you can only specify the IPv6 address of a loopback interface as the source IPv6 address for a tunnel interface.

5. Run destination [ vpn-instance vpn-instance-name ] ipv6-address

   A destination IPv6 address is specified for the tunnel interface.

   The destination IPv6 address specified for the tunnel interface can only be the IPv6 address of the loopback interface on the peer end.

   In VPN scenarios, the configured destination IPv6 address must belong to the VPN instance to which the peer device is bound.

6. Run ip address ip-address { mask | mask-length } [ sub ]

   An IPv4 address is configured for the tunnel interface.

7. Run commit

   The configuration is committed.

Configuring IPv4 over IPv6 Tunnel Routes

The other configurations of an IPv4 over IPv6 tunnel include the number of times that IPv6 encapsulation is performed for an IPv4 packet, traffic flag, maximum hops, and traffic class.

Procedure

1. Run system-view

   The system view is displayed.

2. Choose one of the following methods to configure the route with the outgoing interface as the tunnel interface:

   • Run the ip route-static ip-address { mask } tunnel interface-number command to configure static routes.

     When configuring the static routes, you must configure both ends of the tunnel. Note that the destination address is the destination IPv4 address of the packet to be encapsulated with the IPv4 over IPv6 tunnel; the next hop is the tunnel interface at the peer end.

     In VPN scenarios, you must also specify the VPN instance to which the next-hop address belongs.

   • Configure dynamic routes. You can use the Border Gateway Protocol (BGP) or the Interior Gateway Protocol (IGP), excluding Intermediate System-to-Intermediate System (IS-IS). Detailed configurations are not mentioned here.

     When configuring a dynamic routing protocol, you must enable the dynamic routing protocol on tunnel interfaces and the IPv4 network-side interfaces.

3. Run commit

   The configuration is committed.

(Optional) Configuring Other Parameters of an IPv4 over IPv6 Tunnel

This section describes how to configure an IPv6 packet header for an IPv4 packet so that the packet can be transmitted over an IPv4 over IPv6 tunnel.

Procedure

1. Run system-view

   The system view is displayed.

   NOTE:

   The configuration in the tunnel interface view is similar to that in the system view, and therefore is not described here.

   The configurations in the system view take effect for all IPv4 over IPv6 tunnels configured on a node. The configurations in the tunnel interface view take effect only for the current tunnel interface and override the configurations in the system view.

2. Run tunnel ipv4-ipv6 encapsulation-limit encapsulation-limit

   The maximum number of IPv6 encapsulations that can be performed on embedded tunnel nodes is configured.

3. Run tunnel ipv4-ipv6 flow-label label-value

   A flow label value is set for the IPv4 over IPv6 tunnel so that the device can recognize and provide special handling of packets in a specified flow.

4. Run tunnel ipv4-ipv6 hop-limit hop-limit

   The maximum number of hops along the IPv4 over IPv6 tunnel is configured so that packet transmission can be terminated when routing loops occur on the tunnel.

5. Run tunnel ipv4-ipv6 traffic-class { original | class-value }

   A traffic class value of the IPv4 over IPv6 tunnel is set.

6. Run commit

   The configuration is committed.

Checking the Configurations

After configuring an IPv4 over IPv6 tunnel, you can check the status of the tunnel interfaces and routing information.

Prerequisites

All configurations of an IPv4 over IPv6 tunnel are complete.

Procedure

• Run the display interface tunnel [ interface-number ] command to check the status of tunnel interfaces.
• Run the display ip routing-table command to check IPv6 routing table information.
• Run the ping { -a source-ip-address dest-ip-address | -vpn-instance vpn-instance-name } command to check whether the two ends of the tunnel are reachable.

Example

After completing the configuration, run the display interface tunnel command on both ends of a tunnel. The command output shows that the status of the tunnel interface is Up.

<HUAWEI> display interface Tunnel1
Tunnel1 current state : UP (ifindex: 24)
Line protocol current state : UP
Last line protocol up time : 2017-08-03 08:52:51
Description:  
Route Port,The Maximum Transmit Unit is 1460
Internet Address is 192.168.1.2/24
Encapsulation is TUNNEL, loopback not set
Tunnel protocol/transport (IPv6 or IPv4) over IPv6
Tunnel Source 2001:DB8:300::2  (LoopBack1)
Tunnel Destination 2001:DB8:200::1
Tunnel Encapsulation limit 4
Tunnel Traffic class not set
Tunnel Flow label not set
Tunnel Hop limit 64

Run the ping { -a source-ip-address dest-ip-address | -vpn-instance vpn-instance-name } command. The command output shows that the local tunnel interface can ping the destination tunnel interface.

<HUAWEI> ping 192.168.1.1
  PING 192.168.1.1: 56  data bytes, press CTRL_C to break
    Reply from 192.168.1.1: bytes=56 Sequence=1 ttl=255 time=21 ms
    Reply from 192.168.1.1: bytes=56 Sequence=2 ttl=255 time=3 ms
    Reply from 192.168.1.1: bytes=56 Sequence=3 ttl=255 time=2 ms
    Reply from 192.168.1.1: bytes=56 Sequence=4 ttl=255 time=3 ms
    Reply from 192.168.1.1: bytes=56 Sequence=5 ttl=255 time=3 ms

  --- 192.168.1.1 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 2/6/21 ms

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How do I tunnel IPv6 over IPv4?

Which technique can you use to route IPv6 traffic over an IPv4 infrastructure?

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