Dual stack is the most direct transition approach. A network node that supports both IPv4 and IPv6 is a dual-stack node. A dual-stack node configured with an IPv4 address and an IPv6 address can forward both IPv4 and IPv6 packets. An application that supports both IPv4 and IPv6 prefers IPv6 at the network layer.

Dual stack is suitable for communication between IPv4 nodes or between IPv6 nodes. It is the basis of all transition technologies. However, it does not solve the IPv4 address depletion issue because each dual-stack node must have a globally unique IPv4 address.

NAT-PT

Network Address Translation – Protocol Translation (NAT-PT) enables communication between IPv4 and IPv6 nodes by translating between IPv4 and IPv6 packets. It performs IP address translation, and according to different protocols, performs semantic translation for packets. This technology is only suitable for communication between a pure IPv4 node and a pure IPv6 node.

6PE

6PE enables communication between isolated IPv6 networks over an IPv4 backbone network.

6PE adds labels to the IPv6 routing information about customer networks and advertises the information into the IPv4 backbone network over internal Border Gateway Protocol (IBGP) sessions. IPv6 packets are labeled and forwarded over tunnels on the backbone network. The tunnels can be GRE tunnels or MPLS LSPs.

Figure 1 Network diagram

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6PE is a highly efficient solution. When an ISP wants to utilize the existing IPv4/MPLS network to provide IPv6 traffic switching, it only needs to upgrade the PE routers. In addition, the operation risk of 6PE is very low. For more information about 6PE, see extended BGP feature configuration in Layer 3—IP Routing Configuration Guide.

Tunneling

Tunneling uses one network protocol to encapsulate the packets of another network protocol and transfers them over the network. For example, IPv6 over IPv4 tunneling and IPv4 over IPv6 tunneling are IPv6 transition technologies.

NOTE:

This document describes only IPv6 over IPv4 tunneling and IPv4 over IPv6 tunneling. Unless otherwise stated, the term "tunneling" in this document refers to IPv6 over IPv4 tunneling and IPv4 over IPv6 tunneling.

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IPv6 over IPv4 tunneling

Implementation

IPv6 over IPv4 tunneling enables isolated IPv6 networks to communicate, as shown in Figure 2.

NOTE:

The devices at both ends of an IPv6 over IPv4 tunnel must support the IPv4/IPv6 dual stack.

Figure 2 IPv6 over IPv4 tunnel

The IPv6 over IPv4 tunnel processes packets by using the following steps:

1. A host in the IPv6 network sends an IPv6 packet to Device A at the tunnel source.

2. After Device A receives the IPv6 packet, it processes the packet as follows:

a. Searches the routing table to identify the outgoing interface for the IPv6 packet.

The outgoing interface is the tunnel interface, so Device A knows that the packet needs to be forwarded through the tunnel.

b. Adds an IPv4 header to the IPv6 packet and forwards the packet through the physical interface of the tunnel.

In the IPv4 header, the source IPv4 address is the IPv4 address of the tunnel source, and the destination IPv4 address is the IPv4 address of the tunnel destination.

3. Upon receiving the packet, Device B de-encapsulates the packet.

4. If the destination address of the IPv6 packet is itself, Device B forwards it to the upper-layer protocol. If it is not, Device B forwards it according to the routing table.

Tunnel modes

IPv6 over IPv4 tunnels include manually configured tunnels and automatic tunnels, depending on how the IPv4 address of the tunnel destination is obtained.

· Manually configured tunnel—The destination IPv4 address of the tunnel cannot be automatically obtained from the destination IPv6 address of an IPv6 packet at the tunnel source. It must be manually configured.

· Automatic tunnel—The destination IPv4 address of the tunnel can be automatically obtained from the destination IPv6 address (with an IPv4 address embedded) of an IPv6 packet at the tunnel source.

The source IPv4 addresses for all IPv6 over IPv4 tunnels are manually configured.

According to the way an IPv6 packet is encapsulated, IPv6 over IPv4 tunnels are divided into the modes shown in the following sections.

IPv6 over IPv4 manual tunneling

An IPv6 over IPv4 manual tunnel is a point-to-point link. To establish a manual tunnel, you must manually configure the source and destination addresses of the tunnel at both ends of the tunnel.

Manual tunneling provides the following solutions:

· Connects isolated IPv6 networks over an IPv4 network.

· Connects an IPv6 network and an IPv4/IPv6 dual-stack host over an IPv4 network.

Automatic IPv4-compatible IPv6 tunneling

An automatic IPv4-compatible IPv6 tunnel is a point-to-multipoint link. The ends of an automatic IPv4-compatible IPv6 tunnel are IPv4-compatible IPv6 addresses. The address format is 0:0:0:0:0:0:a.b.c.d/96, where a.b.c.d is an IPv4 address. The destination IPv4 address of an automatic IPv4-compatible IPv6 tunnel is embedded in the destination IPv4-compatible IPv6 address. This mechanism enables the device to automatically obtain the tunnel destination address.

Automatic IPv4-compatible IPv6 tunnels have limitations because IPv4-compatible IPv6 addresses must use globally unique IPv4 addresses.

6to4 tunneling

A 6to4 tunnel is a point-to-multipoint automatic tunnel. It is used to connect multiple isolated IPv6 networks over an IPv4 network.

The ends of a 6to4 tunnel are 6to4 addresses. The address format is 2002:abcd:efgh:subnet number::interface ID/48.

· 2002 is the fixed IPv6 address prefix.

· abcd:efgh represents a 32-bit globally unique IPv4 address in hexadecimal notation.

For example, 1.1.1.1 can be represented by 0101:0101. The IPv4 address identifies a 6to4 network (an IPv6 network where all hosts use 6to4 addresses). The border router of a 6to4 network must have the IPv4 address abcd:efgh configured on the interface connected to the IPv4 network.

· The subnet number identifies a subnet in the 6to4 network.

· The subnet number::interface ID uniquely identifies a host in the 6to4 network.

The destination IPv4 address of a 6to4 tunnel is embedded in the destination 6to4 address. This mechanism enables the device to automatically obtain the tunnel destination address.

6to4 tunneling uses an IPv4 address to identify a 6to4 network. This method overcomes the limitations of automatic IPv4-compatible IPv6 tunneling.

Figure 3 Principle of 6to4 tunneling

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ISATAP tunneling

An ISATAP tunnel is a point-to-multipoint automatic tunnel. It provides a solution to connect an IPv6 host and an IPv6 network over an IPv4 network.

The destination address of an ISATAP tunnel is an ISATAP address. The address format is prefix:0:5EFE:abcd:efgh/64.

· The 64-bit prefix is a valid IPv6 unicast address prefix.

· The abcd:efgh/64 segments represent a 32-bit IPv4 address in hexadecimal notation, which identifies the tunnel destination but does not require global uniqueness.

ISATAP tunnels are mainly used for communication between IPv6 routers or between an IPv6 host and an IPv6 router over an IPv4 network.

Figure 4 Principle of ISATAP tunneling

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IPv4 over IPv6 tunneling

Implementation

IPv4 over IPv6 tunneling adds an IPv6 header to IPv4 packets so that the IPv4 packets can pass an IPv6 network through a tunnel to realize interworking between isolated IPv4 networks.

Figure 5 IPv4 over IPv6 tunnel

Figure 5 shows the encapsulation and de-encapsulation processes.

· Encapsulation:

a. Upon receiving an IPv4 packet, Device A delivers it to the IPv4 protocol stack.

b. The IPv4 protocol stack uses the destination address of the packet to determine the egress interface. If the egress interface is the tunnel interface, the IPv4 protocol stack delivers the packet to the tunnel interface.

c. The tunnel interface adds an IPv6 header to the original IPv4 packet and delivers the packet to the IPv6 protocol stack.

d. The IPv6 protocol stack uses the destination IPv6 address of the packet to look up the routing table, and then sends it out.

· De-encapsulation:

a. Upon receiving the IPv6 packet from the attached IPv6 network, Device B delivers the packet to the IPv6 protocol stack to examine the protocol type encapsulated in the data portion of the packet.

b. If the protocol type is IPv4, the IPv6 protocol stack delivers the packet to the tunneling module.

c. The tunneling module removes the IPv6 header and delivers the remaining IPv4 packet to the IPv4 protocol stack.

d. The IPv4 protocol stack forwards the IPv4 packet.

Tunnel modes

IPv4 over IPv6 manual tunnel

An IPv4 over IPv6 manual tunnel is a point-to-point link and its source and destination IPv6 addresses are manually configured. You can establish an IPv4 over IPv6 manual tunnel to connect isolated IPv4 networks over an IPv6 network.

Configuring IPv6 over IPv4 tunneling

IPv6 over IPv4 tunneling tasks at a glance

To configure IPv6 over IPv4 tunneling, perform the following tasks:

1. Configuring an IPv6 over IPv4 tunnel

Choose one of the following tasks:

¡ Configuring an IPv6 over IPv4 manual tunnel

¡ Configuring an automatic IPv4-compatible IPv6 tunnel

¡ Configuring a 6to4 tunnel

¡ Configuring an ISATAP tunnel

2. (Optional.) Enabling dropping IPv6 packets that use IPv4-compatible IPv6 addresses

3. (Optional.) Enabling fragmentation check for packets to be tunneled

Configuring an IPv6 over IPv4 manual tunnel

Restrictions and guidelines

When you perform tasks in this section, follow these restrictions and guidelines:

· The tunnel destination address specified on the local device must be identical with the tunnel source address specified on the tunnel peer device.

· Do not specify the same tunnel source and destination addresses for the tunnel interfaces in the same mode on a device.

· To ensure correct packet forwarding, identify whether the destination IPv6 network and the IPv6 address of the local tunnel interface are on the same subnet. If they are not, configure a route reaching the destination IPv6 network through the tunnel interface. You can configure the route by using one of the following methods:

¡ Configure a static route, and specify the local tunnel interface as the outgoing interface or specify the IPv6 address of the peer tunnel interface as the next hop.

¡ Enable a dynamic routing protocol on both the local and remote tunnel interfaces.

For more information about route configuration, see Layer 3—IP Routing Configuration Guide.

· IPv6 over IPv4 manual tunnel configuration commands include the following common tunnel interface commands:

¡ interface tunnel.

¡ source.

¡ destination.

¡ tunnel dfbit enable.

For more information about these and more tunnel interface commands, see Interface Command Reference.

Procedure

1. Enter system view.

system-view

2. Enter IPv6 over IPv4 manual tunnel interface view.

interface tunnel number [ mode ipv6-ipv4 ]

3. Specify an IPv6 address for the tunnel interface.

See "Configuring basic IPv6 settings."

4. Configure a source address or source interface for the tunnel interface.

source { ipv4-address | interface-type interface-number }

By default, no source address or source interface is configured for the tunnel interface.

If you specify a source address, it is used as the source IP address of tunneled packets.

If you specify a source interface, the primary IP address of this interface is used as the source IP address of tunneled packets.

5. Configure a destination address for the tunnel interface.

destination ipv4-address

By default, no destination address is configured for the tunnel interface.

The tunnel destination address must be the IP address of the receiving interface on the tunnel peer. It is used as the destination IP address of tunneled packets.

6. (Optional.) Set the DF bit for tunneled packets.

tunnel dfbit enable

By default, the DF bit is not set for tunneled packets.

Example: Configuring an IPv6 over IPv4 manual tunnel

Network configuration

As shown in Figure 6, configure an IPv6 over IPv4 tunnel between Switch A and Switch B so the two IPv6 networks can reach each other over the IPv4 network. Because the tunnel destination IPv4 address cannot be automatically obtained from the destination IPv6 addresses, configure an IPv6 over IPv4 manual tunnel.

Figure 6 Network diagram

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Prerequisites

Make sure Switch A and Switch B have the corresponding VLAN interfaces created and can reach each other through IPv4.

Procedure

1. Configure Switch A:

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 100.

<SwitchA> system-view

[SwitchA] vlan 100

[SwitchA-vlan100] port twenty-fivegige 1/0/2

[SwitchA-vlan100] quit

# Specify an IPv4 address for VLAN-interface 100.

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ip address 192.168.100.1 255.255.255.0

[SwitchA-Vlan-interface100] quit

# Add Twenty-FiveGigE 1/0/1 to VLAN 101.

[SwitchA] vlan 101

[SwitchA-vlan101] port twenty-fivegige 1/0/1

[SwitchA-vlan101] quit

# Specify an IPv6 address for VLAN-interface 101.

[SwitchA] interface vlan-interface 101

[SwitchA-Vlan-interface101] ipv6 address 3002::1 64

[SwitchA-Vlan-interface101] quit

# Create service loopback group 1, and specify its service type as tunnel.

[SwitchA] service-loopback group 1 type tunnel

# Add Twenty-FiveGigE 1/0/3 to service loopback group 1.

[SwitchA] interface twenty-fivegige 1/0/3

[SwitchA-Twenty-FiveGigE1/0/3] port service-loopback group 1

[SwitchA-Twenty-FiveGigE1/0/3] quit

# Create IPv6 over IPv4 manual tunnel interface Tunnel 0.

[SwitchA] interface tunnel 0 mode ipv6-ipv4

# Specify an IPv6 address for the tunnel interface.

[SwitchA-Tunnel0] ipv6 address 3001::1/64

# Specify VLAN-interface 100 as the source interface of the tunnel interface.

[SwitchA-Tunnel0] source vlan-interface 100

# Specify the destination address for the tunnel interface as the IP address of the VLAN-interface 100 on Switch B.

[SwitchA-Tunnel0] destination 192.168.50.1

[SwitchA-Tunnel0] quit

# Configure a static route destined for IPv6 network 2 through tunnel 0.

[SwitchA] ipv6 route-static 3003:: 64 tunnel 0

2. Configure Switch B:

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 100.

<SwitchB> system-view

[SwitchB] vlan 100

[SwitchB-vlan100] port twenty-fivegige 1/0/2

[SwitchB-vlan100] quit

# Specify an IPv4 address for VLAN-interface 100.

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ip address 192.168.50.1 255.255.255.0

[SwitchB-Vlan-interface100] quit

# Add Twenty-FiveGigE 1/0/1 to VLAN 101.

[SwitchB] vlan 101

[SwitchB-vlan101] port twenty-fivegige 1/0/1

[SwitchB-vlan101] quit

# Specify an IPv6 address for VLAN-interface 101.

[SwitchB] interface vlan-interface 101

[SwitchB-Vlan-interface101] ipv6 address 3003::1 64

[SwitchB-Vlan-interface101] quit

# Create service loopback group 1, and specify its service type as tunnel.

[SwitchB] service-loopback group 1 type tunnel

# Add Twenty-FiveGigE 1/0/3 to service loopback group 1.

[SwitchB] interface twenty-fivegige 1/0/3

[SwitchB-Twenty-FiveGigE1/0/3] port service-loopback group 1

[SwitchB-Twenty-FiveGigE1/0/3] quit

# Create IPv6 over IPv4 manual tunnel interface Tunnel 0.

[SwitchB] interface tunnel 0 mode ipv6-ipv4

# Specify an IPv6 address for the tunnel interface.

[SwitchB-Tunnel0] ipv6 address 3001::2/64

# Specify VLAN-interface 100 as the source interface of the tunnel interface.

[SwitchB-Tunnel0] source vlan-interface 100

# Specify the destination address for the tunnel interface as the IP address of VLAN-interface 100 of Switch A.

[SwitchB-Tunnel0] destination 192.168.100.1

[SwitchB-Tunnel0] quit

# Configure a static route destined for IPv6 network 1 through tunnel 0.

[SwitchB] ipv6 route-static 3002:: 64 tunnel 0

Verifying the configuration

# Use the display ipv6 interface command to display tunnel interface status on Switch A and Switch B. Verify that the interface tunnel 0 is up. (Details not shown.)

# Verify that Switch B and Switch A can ping the IPv6 address of VLAN-interface 101 of each other. This example uses Switch A.

[SwitchA] ping ipv6 3003::1

Ping6(56 data bytes) 3001::1 --> 3003::1, press CTRL_C to break

56 bytes from 3003::1, icmp_seq=0 hlim=64 time=45.000 ms

56 bytes from 3003::1, icmp_seq=1 hlim=64 time=10.000 ms

56 bytes from 3003::1, icmp_seq=2 hlim=64 time=4.000 ms

56 bytes from 3003::1, icmp_seq=3 hlim=64 time=10.000 ms

56 bytes from 3003::1, icmp_seq=4 hlim=64 time=11.000 ms

--- Ping6 statistics for 3003::1 ---

5 packet(s) transmitted, 5 packet(s) received, 0.0% packet loss

round-trip min/avg/max/std-dev = 4.000/16.000/45.000/14.711 ms

Configuring an automatic IPv4-compatible IPv6 tunnel

Restrictions and guidelines

Follow these guidelines when you configure an automatic IPv4-compatible IPv6 tunnel:

· You do not need to configure a destination address for an automatic IPv4-compatible IPv6 tunnel. The destination address of the tunnel is embedded in the destination IPv4-compatible IPv6 address.

· Do not specify the same source addresses for local tunnel interfaces in the same tunnel mode.

· Automatic IPv4-compatible IPv6 tunnel configuration commands include the following common tunnel interface commands:

¡ interface tunnel.

¡ source.

¡ tunnel dfbit enable.

For more information about these and more tunnel interface commands, see Interface Command Reference.

Procedure

1. Enter system view.

system-view

2. Enter automatic IPv4-compatible IPv6 tunnel interface view.

interface tunnel number [ mode ipv6-ipv4 auto-tunnel ]

3. Specify an IPv6 address for the tunnel interface.

See "Configuring basic IPv6 settings."

4. Configure a source address or source interface for the tunnel interface.

source { ipv4-address | interface-type interface-number }

By default, no source address or source interface is configured for the tunnel interface.

If you specify a source address, it is used as the source IP address of tunneled packets.

If you specify a source interface, the primary IP address of this interface is used as the source IP address of tunneled packets.

5. (Optional.) Set the DF bit for tunneled packets.

tunnel dfbit enable

By default, the DF bit is not set for tunneled packets.

Example: Configuring an automatic IPv4-compatible IPv6 tunnel

Network configuration

As shown in Figure 7, dual-stack switches Switch A and Switch B are connected over an IPv4 network. Configure an automatic IPv4-compatible IPv6 tunnel between the two switches to enable IPv6 communications over the IPv4 network.

Figure 7 Network diagram

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Prerequisites

Make sure Switch A and Switch B have the corresponding VLAN interfaces created and can reach each other through IPv4.

Procedure

1. Configure Switch A:

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 100.

<SwitchA> system-view

[SwitchA] vlan 100

[SwitchA-vlan100] port twenty-fivegige 1/0/2

[SwitchA-vlan100] quit

# Specify an IPv4 address for VLAN-interface 100.

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ip address 192.168.100.1 255.255.255.0

[SwitchA-Vlan-interface100] quit

# Create service loopback group 1, and specify its service type as tunnel.

[SwitchA] service-loopback group 1 type tunnel

# Assign Twenty-FiveGigE 1/0/3 to service loopback group 1.

[SwitchA] interface twenty-fivegige 1/0/3

[SwitchA-Twenty-FiveGigE1/0/3] port service-loopback group 1

[SwitchA-Twenty-FiveGigE1/0/3] quit

# Create automatic IPv4-compatible IPv6 tunnel interface Tunnel 0.

[SwitchA] interface tunnel 0 mode ipv6-ipv4 auto-tunnel

# Specify an IPv4-compatible IPv6 address for the tunnel interface.

[SwitchA-Tunnel0] ipv6 address ::192.168.100.1/96

# Specify VLAN-interface 100 as the source interface of the tunnel interface.

[SwitchA-Tunnel0] source vlan-interface 100

[SwitchA-Tunnel0] quit

2. Configure Switch B:

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 100.

<SwitchB> system-view

[SwitchB] vlan 100

[SwitchB-vlan100] port twenty-fivegige 1/0/2

[SwitchB-vlan100] quit

# Specify an IPv4 address for VLAN-interface 100.

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ip address 192.168.50.1 255.255.255.0

[SwitchB-Vlan-interface100] quit

# Create service loopback group 1, and specify its service type as tunnel.

[SwitchB] service-loopback group 1 type tunnel

# Assign Twenty-FiveGigE 1/0/3 to service loopback group 1.

[SwitchB] interface twenty-fivegige 1/0/3

[SwitchB-Twenty-FiveGigE1/0/3] port service-loopback group 1

[SwitchB-Twenty-FiveGigE1/0/3] quit

# Create automatic IPv4-compatible IPv6 tunnel interface Tunnel 0.

[SwitchB] interface tunnel 0 mode ipv6-ipv4 auto-tunnel

# Specify an IPv4-compatible IPv6 address for the tunnel interface.

[SwitchB-Tunnel0] ipv6 address ::192.168.50.1/96

# Specify VLAN-interface 100 as the source interface of the tunnel interface.

[SwitchB-Tunnel0] source vlan-interface 100

[SwitchB-Tunnel0] quit

Verifying the configuration

# Use the display ipv6 interface command to display tunnel interface status on Switch A and Switch B. Verify that the interface tunnel 0 is up. (Details not shown.)

# Verify that Switch B and Switch A can ping the IPv4-compatible IPv6 address of each other. This example uses Switch A.

[SwitchA] ping ipv6 ::192.168.50.1

Ping6(56 data bytes) ::192.168.100.1 --> ::192.168.50.1, press CTRL_C to break

56 bytes from ::192.168.50.1, icmp_seq=0 hlim=64 time=17.000 ms

56 bytes from ::192.168.50.1, icmp_seq=1 hlim=64 time=9.000 ms

56 bytes from ::192.168.50.1, icmp_seq=2 hlim=64 time=11.000 ms

56 bytes from ::192.168.50.1, icmp_seq=3 hlim=64 time=9.000 ms

56 bytes from ::192.168.50.1, icmp_seq=4 hlim=64 time=11.000 ms

--- Ping6 statistics for ::192.168.50.1 ---

5 packet(s) transmitted, 5 packet(s) received, 0.0% packet loss

round-trip min/avg/max/std-dev = 9.000/11.400/17.000/2.939 ms

Configuring a 6to4 tunnel

Restrictions and guidelines

Follow these guidelines when you configure a 6to4 tunnel:

· You do not need to configure a destination address for a 6to4 tunnel, because the destination IPv4 address is embedded in the 6to4 IPv6 address.

· Do not specify the same source addresses for local tunnel interfaces in the same tunnel mode.

· Automatic tunnels do not support dynamic routing. You must configure a static route destined for the destination IPv6 network if the destination IPv6 network is not in the same subnet as the IPv6 address of the tunnel interface. You can specify the local tunnel interface as the egress interface of the route or specify the IPv6 address of the peer tunnel interface as the next hop of the route. For more information about route configuration, see Layer 3—IP Routing Configuration Guide.

· 6to4 tunnel configuration commands include the following common tunnel interface commands:

¡ interface tunnel.

¡ source.

¡ tunnel dfbit enable.

For more information about these and more tunnel interface commands, see Interface Command Reference.

Procedure

1. Enter system view.

system-view

2. Enter 6to4 tunnel interface view.

interface tunnel number [ mode ipv6-ipv4 6to4 ]

3. Specify an IPv6 address for the tunnel interface.

See "Configuring basic IPv6 settings."

4. Configure a source address or source interface for the tunnel interface.

source { ipv4-address | interface-type interface-number }

By default, no source address or source interface is configured for the tunnel interface.

If you specify a source address, it is used as the source IP address of tunneled packets.

If you specify a source interface, the primary IP address of this interface is used as the source IP address of tunneled packets.

5. (Optional.) Set the DF bit for tunneled packets.

tunnel dfbit enable

By default, the DF bit is not set for tunneled packets.

Example: Configuring a 6to4 tunnel

Network configuration

As shown in Figure 8, configure a 6to4 tunnel between 6to4 switches Switch A and Switch B so the two hosts can reach each other over the IPv4 network.

Figure 8 Network diagram

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Analysis

To enable communication between 6to4 networks, configure 6to4 addresses for 6to4 switches and hosts in the 6to4 networks.

· The IPv4 address of VLAN-interface 100 on Switch A is 2.1.1.1/24, and the corresponding 6to4 prefix is 2002:0201:0101::/48. Host A must use this prefix.

· The IPv4 address of VLAN-interface 100 on Switch B is 5.1.1.1/24, and the corresponding 6to4 prefix is 2002:0501:0101::/48. Host B must use this prefix.

Prerequisites

Make sure Switch A and Switch B have the corresponding VLAN interfaces created and can reach each other through IPv4.

Procedure

1. Configure Switch A:

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 100.

<SwitchA> system-view

[SwitchA] vlan 100

[SwitchA-vlan100] port twenty-fivegige 1/0/2

[SwitchA-vlan100] quit

# Specify an IPv4 address for VLAN-interface 100.

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ip address 2.1.1.1 24

[SwitchA-Vlan-interface100] quit

# Add Twenty-FiveGigE 1/0/1 to VLAN 101.

[SwitchA] vlan 101

[SwitchA-vlan101] port twenty-fivegige 1/0/1

[SwitchA-vlan101] quit

# Specify a 6to4 address for VLAN-interface 101.

[SwitchA] interface vlan-interface 101

[SwitchA-Vlan-interface101] ipv6 address 2002:0201:0101:1::1/64

[SwitchA-Vlan-interface101] quit

# Create service loopback group 1, and specify its service type as tunnel.

[SwitchA] service-loopback group 1 type tunnel

# Assign Twenty-FiveGigE 1/0/3 to service loopback group 1.

[SwitchA] interface twenty-fivegige 1/0/3

[SwitchA-Twenty-FiveGigE1/0/3] port service-loopback group 1

[SwitchA-Twenty-FiveGigE1/0/3] quit

# Create 6to4 tunnel interface Tunnel 0.

[SwitchA] interface tunnel 0 mode ipv6-ipv4 6to4

# Specify an IPv6 address for the tunnel interface.

[SwitchA-Tunnel0] ipv6 address 3001::1/64

# Specify the source interface as VLAN-interface 100 for the tunnel interface.

[SwitchA-Tunnel0] source vlan-interface 100

[SwitchA-Tunnel0] quit

# Configure a static route destined for 2002::/16 through the tunnel interface.

[SwitchA] ipv6 route-static 2002:: 16 tunnel 0

2. Configure Switch B:

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 100.

<SwitchB> system-view

[SwitchB] vlan 100

[SwitchB-vlan100] port twenty-fivegige 1/0/2

[SwitchB-vlan100] quit

# Specify an IPv4 address for VLAN-interface 100.

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ip address 5.1.1.1 24

[SwitchB-Vlan-interface100] quit

# Add Twenty-FiveGigE 1/0/1 to VLAN 101.

[SwitchB] vlan 101

[SwitchB-vlan101] port twenty-fivegige 1/0/1

[SwitchB-vlan101] quit

# Specify a 6to4 address for VLAN-interface 101.

[SwitchB] interface vlan-interface 101

[SwitchB-Vlan-interface101] ipv6 address 2002:0501:0101:1::1/64

[SwitchB-Vlan-interface101] quit

# Create service loopback group 1, and specify its service type as tunnel.

[SwitchB] service-loopback group 1 type tunnel

# Assign Twenty-FiveGigE 1/0/3 to service loopback group 1.

[SwitchB] interface twenty-fivegige 1/0/3

[SwitchB-Twenty-FiveGigE1/0/3] port service-loopback group 1

[SwitchB-Twenty-FiveGigE1/0/3] quit

# Create 6to4 tunnel interface Tunnel 0.

[SwitchB] interface tunnel 0 mode ipv6-ipv4 6to4

# Specify an IPv6 address for the tunnel interface.

[SwitchA-Tunnel0] ipv6 address 3002::1/64

# Specify the source interface as VLAN-interface 100 for the tunnel interface.

[SwitchB-Tunnel0] source vlan-interface 100

[SwitchB-Tunnel0] quit

# Configure a static route destined for 2002::/16 through the tunnel interface.

[SwitchB] ipv6 route-static 2002:: 16 tunnel 0

Verifying the configuration

# Verify that Host A and Host B can ping each other.

D:\>ping6 -s 2002:201:101:1::2 2002:501:101:1::2

Pinging 2002:501:101:1::2

from 2002:201:101:1::2 with 32 bytes of data:

Reply from 2002:501:101:1::2: bytes=32 time=13ms

Reply from 2002:501:101:1::2: bytes=32 time=1ms

Reply from 2002:501:101:1::2: bytes=32 time<1ms

Ping statistics for 2002:501:101:1::2:

Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

Minimum = 0ms, Maximum = 13ms, Average = 3ms

Configuring an ISATAP tunnel

Restrictions and guidelines

Follow these guidelines when you configure an ISATAP tunnel:

· You do not need to configure a destination address for an ISATAP tunnel, because the destination IPv4 address is embedded in the ISATAP address.

· Do not specify the same source addresses for local tunnel interfaces in the same tunnel mode.

· Because automatic tunnels do not support dynamic routing, configure a static route destined for the destination IPv6 network at each tunnel end. You can specify the local tunnel interface as the egress interface of the route or specify the IPv6 address of the peer tunnel interface as the next hop of the route. For more information about route configuration, see Layer 3—IP Routing Configuration Guide.

· ISATAP tunnel configuration commands include the following common tunnel interface commands:

¡ interface tunnel.

¡ source.

¡ tunnel dfbit enable.

For more information about these and more tunnel interface commands, see Interface Command Reference.

Procedure

1. Enter system view.

system-view

2. Enter ISATAP tunnel interface view.

interface tunnel number [ mode ipv6-ipv4 isatap ]

3. Specify an IPv6 address for the tunnel interface.

See "Configuring basic IPv6 settings."

4. Configure a source address or source interface for the tunnel interface.

source { ipv4-address | interface-type interface-number }

By default, no source address or source interface is configured for the tunnel interface.

If you specify a source address, it is used as the source IP address of tunneled packets.

If you specify a source interface, the primary IP address of this interface is used as the source IP address of tunneled packets.

5. (Optional.) Set the DF bit for tunneled packets.

tunnel dfbit enable

By default, the DF bit is not set for tunneled packets.

Example: Configuring an ISATAP tunnel

Network configuration

As shown in Figure 9, configure an ISATAP tunnel between the switch and the ISATAP host so the ISATAP host in the IPv4 network can access the IPv6 network.

Figure 9 Network diagram

‌

Procedure

1. Configure the switch:

# Add Twenty-FiveGigE 1/0/1 to VLAN 100.

<Switch> system-view

[Switch] vlan 100

[Switch-vlan100] port twenty-fivegige 1/0/1

[Switch-vlan100] quit

# Specify an IPv6 address for VLAN-interface 100.

[Switch] interface vlan-interface 100

[Switch-Vlan-interface100] ipv6 address 3001::1/64

[Switch-Vlan-interface100] quit

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 101.

[Switch] vlan 101

[Switch-vlan101] port twenty-fivegige 1/0/2

[Switch-vlan101] quit

# Specify an IPv4 address for VLAN-interface 101.

[Switch] interface vlan-interface 101

[Switch-Vlan-interface101] ip address 1.1.1.1 255.0.0.0

[Switch-Vlan-interface101] quit

# Create service loopback group 1, and specify its service type as tunnel.

[Switch] service-loopback group 1 type tunnel

# Assign Twenty-FiveGigE 1/0/3 to service loopback group 1.

[Switch] interface twenty-fivegige 1/0/3

[Switch-Twenty-FiveGigE1/0/3] port service-loopback group 1

[Switch-Twenty-FiveGigE1/0/3] quit

# Create ISATAP tunnel interface Tunnel 0.

[Switch] interface tunnel 0 mode ipv6-ipv4 isatap

# Specify an EUI-64 IPv6 address for the tunnel interface.

[Switch-Tunnel0] ipv6 address 2001:: 64 eui-64

# Specify VLAN-interface 101 as the source interface of the tunnel interface.

[Switch-Tunnel0] source vlan-interface 101

# Disable RA suppression so that the ISATAP host can acquire information such as the address prefix from the RA message advertised by the ISATAP switch.

[Switch-Tunnel0] undo ipv6 nd ra halt

[Switch-Tunnel0] quit

2. Configure the ISATAP host:

Configurations on the ISATAP host vary by operating system. The following configuration is performed on Windows XP.

# Install IPv6.

C:\>ipv6 install

# On a host running Windows XP, the ISATAP interface is typically interface 2. Display information about the ISATAP interface.

C:\>ipv6 if 2

Interface 2: Automatic Tunneling Pseudo-Interface

Guid {48FCE3FC-EC30-E50E-F1A7-71172AEEE3AE}

does not use Neighbor Discovery

does not use Router Discovery

routing preference 1

EUI-64 embedded IPv4 address: 0.0.0.0

router link-layer address: 0.0.0.0

preferred link-local fe80::5efe:1.1.1.2, life infinite

link MTU 1280 (true link MTU 65515)

current hop limit 128

reachable time 42500ms (base 30000ms)

retransmission interval 1000ms

DAD transmits 0

default site prefix length 48

# Specify an IPv4 address for the ISATAP switch.

C:\>netsh interface ipv6 isatap set router 1.1.1.1

# Display information about the ISATAP interface.

C:\>ipv6 if 2

Interface 2: Automatic Tunneling Pseudo-Interface

Guid {48FCE3FC-EC30-E50E-F1A7-71172AEEE3AE}

does not use Neighbor Discovery

uses Router Discovery

routing preference 1

EUI-64 embedded IPv4 address: 1.1.1.2

router link-layer address: 1.1.1.1

preferred global 2001::5efe:1.1.1.2, life 29d23h59m46s/6d23h59m46s (public)

preferred link-local fe80::5efe:1.1.1.2, life infinite

link MTU 1500 (true link MTU 65515)

current hop limit 255

reachable time 42500ms (base 30000ms)

retransmission interval 1000ms

DAD transmits 0

default site prefix length 48

The host has obtained the address prefix 2001::/64 and has automatically generated the global unicast address 2001::5efe:1.1.1.2. The message "uses Router Discovery" indicates that the router discovery feature is enabled on the host.

# Display information about IPv6 routes on the host.

C:\>ipv6 rt

2001::/64 -> 2 pref 1if+8=9 life 29d23h59m43s (autoconf)

::/0 -> 2/fe80::5efe:1.1.1.1 pref 1if+256=257 life 29m43s (autoconf)

3. On the IPv6 host, configure a route to the ISATAP switch.

C:\>netsh interface ipv6 set route 2001::/64 5 3001::1

Verifying the configuration

# Verify that the ISATAP host can ping the IPv6 host.

C:\>ping 3001::2

Pinging 3001::2 with 32 bytes of data:

Reply from 3001::2: time=1ms

Ping statistics for 3001::2:

Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

Minimum = 1ms, Maximum = 1ms, Average = 1ms

Enabling dropping IPv6 packets that use IPv4-compatible IPv6 addresses

Restrictions and guidelines

Automatic IPv4-compatible IPv6 tunnels do not support this feature.

Procedure

1. Enter system view.

system-view

2. Enable dropping IPv6 packets that use IPv4-compatible IPv6 addresses.

tunnel discard ipv4-compatible-packet

By default, IPv6 packets that use IPv4-compatible IPv6 addresses are not dropped.

For more information about this command, see tunnel interface commands in Interface Command Reference.

Enabling fragmentation check for packets to be tunneled

1. Enter system view.

system-view

2. Enable fragmentation check for packets to be tunneled.

tunnel ipv6-fragmentation-check enable

By default, fragmentation check is disabled for packets to be tunneled.

Verifying and maintaining IPv6 over IPv4 tunneling

Displaying IPv6 over IPv4 tunnel interface information

Perform display tasks in any view.

· Display IPv6 over IPv4 tunnel interface information.

display tunnel-interface [ number ]

For more information about this command, see tunnel interface commands in Interface Command Reference.

· Display information about IPv6 over IPv4 tunnel interfaces.

display interface [ tunnel [ number ] ] [ brief [ description | down ] ]

For more information about this command, see tunnel interface commands in Interface Command Reference.

· Display IPv6 information about IPv6 over IPv4 tunnel interfaces.

display ipv6 interface [ tunnel [ number ] ] [ brief ]

For more information about this command, see IPv6 basics in Layer 3—IP Services Command Reference.

Clearing IPv6 over IPv4 tunnel interface information

Perform clear tasks in user view.

· Clear IPv6 over IPv4 tunnel interface statistics.

reset counters interface [ tunnel [ number ] ]

For more information about this command, see common interface commands in Interface Command Reference.

· Clear IPv6 statistics on IPv6 over IPv4 tunnel interfaces.

reset ipv6 statistics [ slot slot-number ]

For more information about this command, see IPv6 basics in Layer 3—IP Services Command Reference.

Configuring IPv4 over IPv6 tunneling

Configuring an IPv4 over IPv6 manual tunnel

Restrictions and guidelines

When you perform the tasks in this section, follow these restrictions and guidelines:

· The tunnel destination address specified on the local device must be identical with the tunnel source address specified on the tunnel peer device.

· Do not specify the same source and destination addresses for local tunnel interfaces in the same tunnel mode.

· To ensure correct packet forwarding, identify whether the destination IPv4 network and the IPv4 address of the local tunnel interface are on the same subnet. If they are not, configure a route reaching the destination IPv4 network through the tunnel interface. You can configure the route by using one of the following methods:

¡ Configure a static route, and specify the local tunnel interface as the egress interface or specify the IPv6 address of the peer tunnel interface as the next hop.

¡ Enable a dynamic routing protocol on both the local and remote tunnel interfaces.

For more information about route configuration, see Layer 3—IP Routing Configuration Guide.

· IPv4 over IPv6 tunnel configuration commands include the following common tunnel interface commands:

¡ interface tunnel.

¡ source.

¡ destination.

For more information about these and more tunnel interface commands, see Interface Command Reference.

Procedure

1. Enter system view.

system-view

2. Enter IPv4 over IPv6 tunnel interface view or IPv6 tunnel interface view.

interface tunnel number [ mode { ipv4-ipv6 | ipv6 } ]

3. Configure an IPv4 address for the tunnel interface.

ip address ip-address { mask | mask-length } [ sub ]

4. Configure the source address or interface for the tunnel interface.

source { ipv6-address | interface-type interface-number }

By default, no source address or interface is configured for the tunnel.

If you specify a source address, it is used as the source IPv6 address of tunneled packets.

If you specify a source interface, the lowest IPv6 address of this interface is used as the source IPv6 address of tunneled packets.

5. Configure the destination address for the tunnel interface.

destination ipv6-address

By default, no destination address is configured for the tunnel.

The tunnel destination address must be the IPv6 address of the receiving interface on the tunnel peer. It is used as the destination IPv6 address of tunneled packets.

Example: Configuring an IPv4 over IPv6 manual tunnel

Network configuration

As shown in Figure 10, configure an IPv4 over IPv6 tunnel between Switch A and Switch B so the two networks can reach each other over the IPv6 network.

Figure 10 Network diagram

‌

Prerequisites

Make sure Switch A and Switch B have the corresponding VLAN interfaces created and can reach each other through IPv6.

Procedure

1. Configure Switch A:

# Add Twenty-FiveGigE 1/0/1 to VLAN 100.

<SwitchA> system-view

[SwitchA] vlan 100

[SwitchA-vlan100] port twenty-fivegige 1/0/1

[SwitchA-vlan100] quit

# Specify an IPv4 address for VLAN-interface 100.

[SwitchA] interface vlan-interface 100

[SwitchA-Vlan-interface100] ip address 30.1.1.1 255.255.255.0

[SwitchA-Vlan-interface100] quit

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 101.

[SwitchA] vlan 101

[SwitchA-vlan101] port twenty-fivegige 1/0/2

[SwitchA-vlan101] quit

# Specify an IPv6 address for VLAN-interface 101.

[SwitchA] interface vlan-interface 101

[SwitchA-Vlan-interface101] ipv6 address 2001::1:1 64

[SwitchA-Vlan-interface101] quit

# Create service loopback group 1, and specify its service type as tunnel.

[SwitchA] service-loopback group 1 type tunnel

# Assign Twenty-FiveGigE 1/0/3 to service loopback group 1.

[SwitchA] interface twenty-fivegige 1/0/3

[SwitchA-Twenty-FiveGigE1/0/3] port service-loopback group 1

[SwitchA-Twenty-FiveGigE1/0/3] quit

# Create IPv6 tunnel interface Tunnel 1.

[SwitchA] interface tunnel 1 mode ipv6

# Specify an IPv4 address for the tunnel interface.

[SwitchA-Tunnel1] ip address 30.1.2.1 255.255.255.0

# Specify the IP address of VLAN-interface 101 as the source address for the tunnel interface.

[SwitchA-Tunnel1] source 2001::1:1

# Specify the IP address of VLAN-interface 101 on Switch B as the destination address for the tunnel interface.

[SwitchA-Tunnel1] destination 2002::2:1

[SwitchA-Tunnel1] quit

# Configure a static route destined for IPv4 network 2 through the tunnel interface.

[SwitchA] ip route-static 30.1.3.0 255.255.255.0 tunnel 1

2. Configure Switch B:

# Add Twenty-FiveGigE 1/0/1 to VLAN 100.

<SwitchB> system-view

[SwitchB] vlan 100

[SwitchB-vlan100] port twenty-fivegige 1/0/1

[SwitchB-vlan100] quit

# Specify an IPv4 address for VLAN-interface 100.

[SwitchB] interface vlan-interface 100

[SwitchB-Vlan-interface100] ip address 30.1.3.1 255.255.255.0

[SwitchB-Vlan-interface100] quit

# Add Twenty-FiveGigE 1/0/2 (the physical interface of the tunnel) to VLAN 101.

[SwitchB] vlan 101

[SwitchB-vlan101] port twenty-fivegige 1/0/2

[SwitchB-vlan101] quit

# Specify an IPv6 address for VLAN-interface 101.

[SwitchB] interface vlan-interface 101

[SwitchB-Vlan-interface101] ipv6 address 2002::2:1 64

[SwitchB-Vlan-interface101] quit

# Create service loopback group 1, and specify its service type as tunnel.

[SwitchB] service-loopback group 1 type tunnel

# Assign Twenty-FiveGigE 1/0/3 to service loopback group 1.

[SwitchB] interface twenty-fivegige 1/0/3

[SwitchB-Twenty-FiveGigE1/0/3] port service-loopback group 1

[SwitchB-Twenty-FiveGigE1/0/3] quit

# Create IPv6 tunnel interface Tunnel 2.

[SwitchB] interface tunnel 2 mode ipv6

# Specify an IPv4 address for the tunnel interface.

[SwitchB-Tunnel2] ip address 30.1.2.2 255.255.255.0

# Specify the IP address of VLAN-interface 101 as the source address for the tunnel interface (IP address of VLAN-interface 101).

[SwitchB-Tunnel2] source 2002::2:1

# Specify the IP address of VLAN-interface 101 on Switch A as the destination address for the tunnel interface.

[SwitchB-Tunnel2] destination 2001::1:1

[SwitchB-Tunnel2] quit

# Configure a static route destined for IPv4 network 1 through the tunnel interface.

[SwitchB] ip route-static 30.1.1.0 255.255.255.0 tunnel 2

Verifying the configuration

# Use the display interface tunnel command to display the status of the tunnel interfaces on Switch A and Switch B. Verify that the tunnel interfaces are up. (Details not shown.)

# Verify that Switch A and Switch B can ping the IPv4 address of the peer interface. This example uses Switch A.

[SwitchA] ping -a 30.1.1.1 30.1.3.1

Ping 30.1.3.1 (30.1.3.1) from 30.1.1.1: 56 data bytes, press CTRL_C to break

56 bytes from 30.1.3.1: icmp_seq=0 ttl=255 time=3.000 ms

56 bytes from 30.1.3.1: icmp_seq=1 ttl=255 time=1.000 ms

56 bytes from 30.1.3.1: icmp_seq=2 ttl=255 time=0.000 ms

56 bytes from 30.1.3.1: icmp_seq=3 ttl=255 time=1.000 ms

56 bytes from 30.1.3.1: icmp_seq=4 ttl=255 time=1.000 ms

--- Ping statistics for 30.1.3.1 ---

5 packet(s) transmitted, 5 packet(s) received, 0.0% packet loss

round-trip min/avg/max/std-dev = 0.000/1.200/3.000/0.980 ms

Verifying and maintaining IPv4 over IPv6 tunneling

Displaying IPv4 over IPv6 tunnel interface information

This section only lists commands available for displaying IPv4 over IPv6 tunnel interface information. For more information about the commands, see tunnel interface commands in Interface Command Reference.

Perform display tasks in any view.

· Display IPv4 over IPv6 tunnel interface information.

display tunnel-interface [ number ]

· Display information about IPv4 over IPv6 tunnel interfaces.

display interface [ tunnel [ number ] ] [ brief [ description | down ] ]

Clearing IPv4 over IPv6 tunnel interface information

To clear IPv4 over IPv6 tunnel interface statistics, execute the following command in user view:

reset counters interface [ tunnel [ number ] ]

For more information about this command, see common interface commands in Interface Command Reference.

05-Layer 3—IP Services Configuration Guide

About IPv6 transition technologies

Dual stack

NAT-PT

6PE

Tunneling

IPv6 over IPv4 manual tunneling

Automatic IPv4-compatible IPv6 tunneling

6to4 tunneling

ISATAP tunneling

IPv4 over IPv6 manual tunnel

Configuring IPv6 over IPv4 tunneling

Configuring an IPv6 over IPv4 manual tunnel

Network configuration

Prerequisites

Procedure

Verifying the configuration

Network configuration

Prerequisites

Procedure

Verifying the configuration

Configuring a 6to4 tunnel

Network configuration

Analysis

Prerequisites

Procedure

Verifying the configuration

Network configuration

Procedure

Verifying the configuration

Restrictions and guidelines

Procedure

Configuring an IPv4 over IPv6 manual tunnel

Network configuration

Prerequisites

Procedure

Verifying the configuration

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