Tunneling encapsulates the packets of a network protocol within the packets of a second network protocol and transfers them over a virtual point-to-point connection. The virtual connection is called a tunnel. Packets are encapsulated at the tunnel source and de-encapsulated at the tunnel destination.

Supported tunneling technologies

Tunneling supports the following technologies:

· ADVPN tunneling. For more information, see "Configuring ADVPN."

· GRE tunneling. For more information, see "Configuring GRE."

· MPLS TE tunneling. For more information, see MPLS Configuration Guide.

· IPsec tunneling. For more information, see Security Configuration Guide.

· VXLAN tunneling and VXLAN-DCI tunneling. For more information, see VXLAN Configuration Guide.

· IPv6 over IPv4 tunneling, IPv4 over IPv4 tunneling, and IPv4 over IPv6 tunneling.

Restrictions and guidelines: Tunnel interface configuration

Specifying the tunnel destination VPN instance is available only for the following cards:

Card category	Cards
CSPEX	CSPEX-1304X, CSPEX-1404X, CSPEX-1502X, CSPEX-1504X, CSPEX-1504XA, CSPEX-1602X, CSPEX-1602XA, CSPEX-1804X, CSPEX-1512X, CSPEX-1612X, CSPEX-1812X, CSPEX-1802X, CSPEX-1802XA, CSPEX-1812X-E, CSPEX-2304X-G, CSPEX-1502XA
SPE	RX-SPE200, RX-SPE200-E
CEPC	CEPC-XP4LX, CEPC-XP24LX, CEPC-XP48RX, CEPC-CP4RX, CEPC-CP4RXA, CEPC-CP4RX-L, CEPC-CQ8L, CEPC-CQ8LA, CEPC-CQ16L1

When an active/standby switchover occurs or the standby MPU is removed, the tunnel interfaces configured on the active or standby MPU still exist. To delete a tunnel interface, use the undo interface tunnel command.

You do not need to use the ip address or ipv6 address command to configure an IPv4 or IPv6 address for an IPv4 VXLAN, IPv6 VXLAN, IPv4 VXLAN-DCI, or IPv6 VXLAN-DCI tunnel interface. The IP address is meaningless.

Configuring a tunnel interface

About tunnel interface configuration

Configure a tunnel interface (Layer 3 virtual interface) at both ends of a tunnel. The devices use the tunnel interface to identify, process, and send packets for the tunnel.

Tunnel interface configuration tasks at a glance

To configure a tunnel interface, perform the following tasks:

1. Creating a tunnel interface

2. (Optional.) Specifying traffic processing slots for the tunnel interface

3. (Optional.) Configuring parameters for tunneled packets

4. (Optional.) Specifying the tunnel destination VPN instance

5. (Optional.) Restoring the default settings of the tunnel interface

6. (Optional.) Specifying an output interface for tunneled packets

7. (Optional.) Setting the statistics collection mode for tunneled traffic

Creating a tunnel interface

Restrictions and guidelines

An IPsec tunnel and a GRE over IPsec tunnel cannot use the same source IP address, the same destination IP address, or both.

Procedure

1. Enter system view.

system-view

2. Create a tunnel interface, specify the tunnel mode, and enter tunnel interface view.

interface tunnel number mode { advpn { gre | udp } [ ipv6 ] | ds-lite-aftr | gre [ ipv6 ] | ipsec [ ipv6 ] | ipv4-ipv4 | ipv4-ipv6 | ipv6-ipv4 [ 6to4 | isatap ] | mpls-te | { vxlan | vxlan-dci } [ ipv6 ] }

The mode vxlan ipv6 and mode vxlan-dci ipv6 modes are available only for the following cards in SDN-WAN system operating mode:

Card category	Cards
CSPEX	CSPEX-1304X, CSPEX-1404X, CSPEX-1502X, CSPEX-1504X, CSPEX-1504XA, CSPEX-1602X, CSPEX-1602XA, CSPEX-1804X, CSPEX-1512X, CSPEX-1612X, CSPEX-1812X
SPE	RX-SPE200
CEPC	CEPC-XP4LX, CEPC-XP24LX, CEPC-XP48RX, CEPC-CP4RX, CEPC-CP4RXA, CEPC-CP4RX-L

For more information about system operation modes, see device management in Fundamentals Configuration Guide.

ADVPN and IPsec settings can take effect only on the IM-SFMX card.

For packet tunneling to succeed, the two ends of a tunnel must use the same tunnel mode.

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

source { ipv4-address | ipv6-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 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.

4. Configure a destination address for the tunnel interface.

destination { ipv4-address | ipv6-address | dhcp-alloc interface-type interface-number }

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.

5. (Optional.) Configure a description for the interface.

description text

By default, the description for a tunnel interface is Tunnel number Interface.

6. (Optional.) Set the MTU of the tunnel interface.

mtu size

The default settings are as follows:

¡ If the tunnel interface has never been up, the MTU is 1500 bytes.

¡ If the tunnel interface is up, its MTU is identical to the outgoing interface's MTU minus the length of the tunnel headers. The outgoing interface is automatically obtained through routing table lookup based on the tunnel destination address.

As a best practice, set the MTU of a tunnel interface to a value larger than 1280 bytes if the device contains the following cards;

Card category	Cards
CEPC	CEPC-XP4LX, CEPC-XP24LX, CEPC-XP48RX, CEPC-CP4RX, CEPC-CP4RXA, CEPC-CP4RX-L, CEPC-CQ8L, CEPC-CQ8LA, CEPC-CQ16L1, CSPC-GE16XP4L-E, CSPC-GE24L-E, CSPC-GP24GE8XP2L-E
CSPEX	CSPEX-1304X, CSPEX-1404X, CSPEX-1502X, CSPEX-1504X, CSPEX-1504XA, CSPEX-1602X, CSPEX-1602XA, CSPEX-1804X, CSPEX-1512X, CSPEX-1612X, CSPEX-1812X, CSPEX-1802X, CSPEX-1802XA, CSPEX-1812X-E, CSPEX-2304X-G, CSPEX-1502XA, CSPEX-1104-E, CSPEX-1204
SPE	RX-SPE200, RX-SPE200-E

If the MTU of the tunnel interface is less than 1280 bytes, the tunnel interface uses the MTU of 1280 bytes to fragment packets received from those cards.

7. (Optional.) Set the expected bandwidth for the tunnel interface.

bandwidth bandwidth-value

The default expected bandwidth (in kbps) is the interface maximum rate divided by 1000.

The expected bandwidth is an informational parameter used only by higher-layer protocols for calculation. You cannot adjust the actual bandwidth of an interface by using this command.

8. Bring up the tunnel interface.

undo shutdown

By default, a tunnel interface is not administratively down.

Specifying traffic processing slots for the tunnel interface

About this task

Specify a traffic processing slot if a feature (for example, IPsec antireplay) requires that all traffic on a tunnel interface be processed on the same slot.

For high availability, you can specify one primary and one backup traffic processing slot by using the service command and the service standby command, respectively.

If you specify both primary and backup slots for an interface, traffic on that interface is processed as follows:

· The backup slot takes over when the primary slot becomes unavailable. The backup slot continues to process traffic for the interface after the primary slot becomes available again. The switchover will not occur until the backup slot becomes unavailable.

· When no specified traffic processing slots are available, the traffic is processed on the slot at which it arrives. Then, the processing slot that first becomes available again takes over.

If you do not specify a primary or a backup traffic processing slot for an interface, traffic on that interface is processed on the slot at which the traffic arrives.

Restrictions and guidelines

You need to execute the service command on a tunnel interface only when an IPsec profile is applied to the tunnel interface. The traffic processing card specified by this command must be the IM-SFMX card.

Procedure

1. Enter system view.

system-view

2. Enter tunnel interface view.

interface tunnel number

3. Specify a primary traffic processing slot for the tunnel interface.

In standalone mode:

service slot slot-number

In IRF mode:

service chassis chassis-number slot slot-number

By default, no primary traffic processing slot is specified.

4. Specify a backup traffic processing slot for the tunnel interface.

In standalone mode:

service standby slot slot-number

In IRF mode:

service standby chassis chassis-number slot slot-number

By default, no backup traffic processing slot is specified.

Configuring parameters for tunneled packets

1. Enter system view.

system-view

2. Enter tunnel interface view.

interface tunnel number

3. Set the ToS for tunneled packets.

tunnel tos tos-value

By default, the ToS of tunneled packets is the same as the ToS of the original packets.

4. Set the TTL for tunneled packets.

tunnel ttl ttl-value

The default TTL for tunneled packets is 255.

Specifying the tunnel destination VPN instance

Hardware and feature compatibility

This feature is available only for the following cards:

Card category	Cards
CSPEX	CSPEX-1304X, CSPEX-1404X, CSPEX-1502X, CSPEX-1504X, CSPEX-1504XA, CSPEX-1602X, CSPEX-1602XA, CSPEX-1804X, CSPEX-1512X, CSPEX-1612X, CSPEX-1812X, CSPEX-1802X, CSPEX-1802XA, CSPEX-1812X-E, CSPEX-2304X-G, CSPEX-1502XA
SPE	RX-SPE200, RX-SPE200-E
CEPC	CEPC-XP4LX, CEPC-XP24LX, CEPC-XP48RX, CEPC-CP4RX, CEPC-CP4RXA, CEPC-CP4RX-L, CEPC-CQ8L, CEPC-CQ8LA, CEPC-CQ16L1

Restrictions and guidelines

For a tunnel interface to come up, the tunnel source and destination must belong to the same VPN instance. To specify a VPN instance for the tunnel source, use the ip binding vpn-instance command on the tunnel source interface. For more information about this command, see MPLS Command Reference.

Procedure

1. Enter system view.

system-view

2. Enter tunnel interface view.

interface tunnel number

3. Specify the VPN instance to which the tunnel destination belongs.

tunnel vpn-instance vpn-instance-name

By default, the tunnel destination belongs to the public network.

Restoring the default settings of the tunnel interface

Restrictions and guidelines

CAUTION:

This operation might interrupt ongoing network services. Make sure you are fully aware of the impact of this operation when you perform it on a live network.

This operation might fail to restore the default settings for some commands for reasons such as command dependencies or system restrictions. Use the display this command in interface view to identify these commands. Use their undo forms or follow the command reference to restore their default settings. If your restoration attempt still fails, follow the error message instructions to resolve the problem.

Procedure

1. Enter system view.

system-view

2. Enter tunnel interface view.

interface tunnel number

3. Restore the default settings of the tunnel interface.

default

Specifying an output interface for tunneled packets

About this task

If ECMP routes exist, the device randomly selects an output interface to forward tunneled packets. To forward tunneled packets over a specific path, perform this task to specify the output interface for the tunneled packets.

Hardware and feature compatibility

This feature is available only for the following cards:

Card category	Cards
CEPC	CEPC-XP4LX, CEPC-XP24LX, CEPC-XP48RX, CEPC-CP4RX, CEPC-CP4RXA, CEPC-CP4RX-L, CEPC-CQ8L, CEPC-CQ8LA, CEPC-CQ16L1
CSPEX	CSPEX-1304X, CSPEX-1404X, CSPEX-1502X, CSPEX-1504X, CSPEX-1504XA, CSPEX-1602X, CSPEX-1602XA, CSPEX-1804X, CSPEX-1512X, CSPEX-1612X, CSPEX-1812X, CSPEX-1802X, CSPEX-1802XA, CSPEX-1812X-E, CSPEX-2304X-G, CSPEX-1502XA
SPE	RX-SPE200, RX-SPE200-E

The CSPEX-1104-E card does not support this feature in standard operating mode and supports this feature in SDN-WAN operating mode only for GRE tunnel interfaces.

The CSPEX-1104-E, CSPC-GE16XP4L-E, CSPC-GE24L-E, and CSPC-GP24GE8XP2L-E cards support this feature in SDN-WAN operating mode only for GRE/IPv4 tunnel interfaces. The remaining cards support this feature for GRE/IPv4 and VXLAN tunnel interfaces.

Restrictions and guidelines

To ensure successful packet forwarding, the specified output interface must meet the following requirements:

· The interface is up.

· The interface has an IP address.

· The interface has a route to reach the destination.

Procedure

1. Enter system view.

system-view

2. Enter tunnel interface view.

interface tunnel number

3. Specify an output interface for tunneled packets.

tunnel out-interface interface-type interface-number

By default, no output interface is specified for tunneled packets. If ECMP routes exist, the device randomly selects an output interface to forward tunneled packets.

Setting the statistics collection mode for tunneled traffic

About this task

The device provides the following statistics collection mode for tunneled traffic:

· Payload—In this mode, the device counts bytes in packets before the packets are encapsulated.

· Encapsulation—In this mode, the device counts bytes in the entire packets after the packets are encapsulated.

Procedure

1. Enter system view.

system-view

2. Set the statistics collection mode for tunneled traffic.

tunnel statistics-mode { encapsulation | payload }

By default, the payload mode is used.

Display and maintenance commands for tunnel interface configuration

Execute display commands in any view and reset commands in user view.

Task	Command	Remarks
Display information about tunnel interfaces.	display interface [ tunnel [ number ] ] [ brief [ description \| down ] ]	N/A
Display IPv6 information on tunnel interfaces.	display ipv6 interface [ tunnel [ number ] ] [ brief ]	N/A
Clear statistics on tunnel interfaces.	reset counters interface [ tunnel [ number ] ]	N/A
Clear IPv6 statistics on tunnel interfaces.	In standalone mode: reset ipv6 statistics [ slot slot-number ] In IRF mode: reset ipv6 statistics [ chassis chassis-number slot slot-number ]	For more information about this command, see IPv6 basics in Layer 3—IP Services Command Reference.

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Troubleshooting tunnel interface configuration

Tunnel interface not up

Symptom

A tunnel interface configured with related parameters such as tunnel source address, tunnel destination address, and tunnel mode cannot come up.

Analysis

The physical interface of the tunnel does not come up, or the tunnel destination is unreachable.

Solution

1. To resolve the problem:

¡ Use the display interface or display ipv6 interface command to verify that the physical interface of the tunnel is up. If the physical interface is down, check the network connection.

¡ Use the display ipv6 routing-table or display ip routing-table command to verify that the tunnel destination is reachable. If the route is not available, configure a route to reach the tunnel destination.

2. If the problem persists, contact H3C Support.

IPv6 over IPv4 tunneling

About IPv6 over IPv4 tunneling

Implementation

IPv6 over IPv4 tunneling enables isolated IPv6 networks to communicate, as shown in Figure 1.

NOTE:

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

Figure 1 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.

6to4 tunneling

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

· 6to4 relay

6to4 relay connects a 6to4 network and an IPv6 network that uses an IP prefix other than 2002::/16. A 6to4 relay router is a gateway that forwards packets from a 6to4 network to an IPv6 network.

As shown in Figure 2, 6to4 network Site 1 communicates with IPv6 network Site 3 over a 6to4 tunnel. Configure a static route on the border router (Device A) in the 6to4 network. The next hop address must be the 6to4 address of the 6to4 relay router (Device C). Device A forwards all packets destined for the IPv6 network over the 6to4 tunnel, and Device C then forwards them to the IPv6 network.

Figure 2 Principle of 6to4 tunneling and 6to4 relay

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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 3 Principle of ISATAP tunneling

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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 a 6to4 tunnel

¡ Configuring an ISATAP tunnel

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

Configuring an IPv6 over IPv4 manual tunnel

Restrictions and guidelines

Follow these guidelines when you configure an IPv6 over IPv4 manual tunnel:

· 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 egress interface or specify the IPv6 address of the peer tunnel interface as the next hop.

¡ Enable a dynamic routing protocol on both tunnel interfaces to achieve the same purpose.

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

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.

Example: Configuring an IPv6 over IPv4 manual tunnel

Network configuration

As shown in Figure 4, configure an IPv6 over IPv4 tunnel between Router A and Router 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 4 Network diagram

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Prerequisites

Make sure Router A and Router B can reach each other through IPv4.

Procedure

1. Configure Router A:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/2.

<RouterA> system-view

[RouterA] interface ten-gigabitethernet 3/1/2

[RouterA-Ten-GigabitEthernet3/1/2] ip address 192.168.100.1 255.255.255.0

[RouterA-Ten-GigabitEthernet3/1/2] quit

# Specify an IPv6 address for Ten-GigabitEthernet 3/1/1.

[RouterA] interface ten-gigabitethernet 3/1/1

[RouterA-Ten-GigabitEthernet3/1/1] ipv6 address 3002::1 64

[RouterA-Ten-GigabitEthernet3/1/1] quit

# Create IPv6 over IPv4 manual tunnel interface Tunnel 0.

[RouterA] interface tunnel 0 mode ipv6-ipv4

# Specify an IPv6 address for the tunnel interface.

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

# Specify Ten-GigabitEthernet 3/1/2 as the source interface of the tunnel interface.

[RouterA-Tunnel0] source ten-gigabitethernet 3/1/2

# Specify the destination address for the tunnel interface as the IP address of Ten-GigabitEthernet 3/1/2 on Router B.

[RouterA-Tunnel0] destination 192.168.50.1

[RouterA-Tunnel0] quit

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

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

2. Configure Router B:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/2.

<RouterB> system-view

[RouterB] interface ten-gigabitethernet 3/1/2

[RouterB-Ten-GigabitEthernet3/1/2] ip address 192.168.50.1 255.255.255.0

[RouterB-Ten-GigabitEthernet3/1/2] quit

# Specify an IPv6 address for Ten-GigabitEthernet 3/1/1.

[RouterB] interface ten-gigabitethernet 3/1/1

[RouterB-Ten-GigabitEthernet3/1/1] ipv6 address 3003::1 64

[RouterB-Ten-GigabitEthernet3/1/1] quit

# Create IPv6 over IPv4 manual tunnel interface Tunnel 0.

[RouterB] interface tunnel 0 mode ipv6-ipv4

# Specify an IPv6 address for the tunnel interface.

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

# Specify Ten-GigabitEthernet 3/1/2 as the source interface of the tunnel interface.

[RouterB-Tunnel0] source ten-gigabitethernet 3/1/2

# Specify the destination address for the tunnel interface as the IP address of Ten-GigabitEthernet 3/1/2 on Router A.

[RouterB-Tunnel0] destination 192.168.50.1

[RouterB-Tunnel0] quit

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

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

Verifying the configuration

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

# Verify that Router B and Router A can ping the IPv6 address of Ten-GigabitEthernet 3/1/1 of each other. This example uses Router A.

[RouterA] 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 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.

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.

Example: Configuring a 6to4 tunnel

Network configuration

As shown in Figure 5, configure a 6to4 tunnel between 6to4 routers Router A and Router B so the two hosts can reach each other over the IPv4 network.

Figure 5 Network diagram

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Analysis

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

· The IPv4 address of Ten-GigabitEthernet 3/1/2 on Router 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 Ten-GigabitEthernet 3/1/2 on Router 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 Router A and Router B can reach each other through IPv4.

Procedure

1. Configure Router A:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/2.

<RouterA> system-view

[RouterA] interface ten-gigabitethernet 3/1/2

[RouterA-Ten-GigabitEthernet3/1/2] ip address 2.1.1.1 24

[RouterA-Ten-GigabitEthernet3/1/2] quit

# Specify a 6to4 address for Ten-GigabitEthernet 3/1/1.

[RouterA] interface ten-gigabitethernet 3/1/1

[RouterA-Ten-GigabitEthernet3/1/1] ipv6 address 2002:0201:0101:1::1/64

[RouterA-Ten-GigabitEthernet3/1/1] quit

# Create 6to4 tunnel interface Tunnel 0.

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

# Specify an IPv6 address for the tunnel interface.

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

# Specify the source interface as Ten-GigabitEthernet 3/1/2 for the tunnel interface.

[RouterA-Tunnel0] source ten-gigabitethernet 3/1/2

[RouterA-Tunnel0] quit

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

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

2. Configure Router B:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/2.

<RouterB> system-view

[RouterB] interface ten-gigabitethernet 3/1/2

[RouterB-Ten-GigabitEthernet3/1/2] ip address 5.1.1.1 24

[RouterB-Ten-GigabitEthernet3/1/2] quit

# Specify a 6to4 address for Ten-GigabitEthernet 3/1/1.

[RouterB] interface ten-gigabitethernet 3/1/1

[RouterB-Ten-GigabitEthernet3/1/1] ipv6 address 2002:0501:0101:1::1/64

[RouterB-Ten-GigabitEthernet3/1/1] quit

# Create 6to4 tunnel interface Tunnel 0.

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

# Specify an IPv6 address for the tunnel interface.

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

# Specify the source interface as Ten-GigabitEthernet 3/1/2 for the tunnel interface.

[RouterB-Tunnel0] source ten-gigabitethernet 3/1/2

[RouterB-Tunnel0] quit

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

[RouterB] 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

Example: Configuring 6to4 relay

Network configuration

As shown in Figure 6, Router A is a 6to4 router, and 6to4 addresses are used on the connected IPv6 network. Router B acts as a 6to4 relay router and is connected to an IPv6 network (2001::/16). Configure a 6to4 tunnel between Router A and Router B to make Host A and Host B reachable to each other.

The configuration on a 6to4 relay router is similar to that on a 6to4 router. However, to enable communication between the 6to4 network and the IPv6 network, you must configure a route to the IPv6 network on the 6to4 router. The IPv4 address of Ten-GigabitEthernet 3/1/2 on the relay router is 6.1.1.1/24 and its corresponding 6to4 prefix is 2002:0601:0101::/48. The next hop of the static route must be an address using this prefix.

Figure 6 Network diagram

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Prerequisites

Make sure Router A and Router B can reach each other through IPv4.

Procedure

1. Configure Router A:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/2.

<RouterA> system-view

[RouterA] interface ten-gigabitethernet 3/1/2

[RouterA-Ten-GigabitEthernet3/1/2] ip address 2.1.1.1 255.255.255.0

[RouterA-Ten-GigabitEthernet3/1/2] quit

# Specify a 6to4 address for Ten-GigabitEthernet 3/1/1.

[RouterA] interface ten-gigabitethernet 3/1/1

[RouterA-Ten-GigabitEthernet3/1/1] ipv6 address 2002:0201:0101:1::1/64

[RouterA-Ten-GigabitEthernet3/1/1] quit

# Create 6to4 tunnel interface Tunnel 0.

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

# Specify an IPv6 address for the tunnel interface.

[RouterA-Tunnel0] ipv6 address 2002::1/64

# Specify Ten-GigabitEthernet 3/1/2 as the source interface of the tunnel interface.

[RouterA-Tunnel0] source ten-gigabitethernet 3/1/2

[RouterA-Tunnel0] quit

# Configure a static route to the 6to4 relay router.

[RouterA] ipv6 route-static 2002:0601:0101:: 64 tunnel 0

# Configure a default route to reach the IPv6 network, which specifies the next hop as the 6to4 address of the relay router.

[RouterA] ipv6 route-static :: 0 2002:0601:0101::1

2. Configure Router B:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/2.

<RouterB> system-view

[RouterB] interface ten-gigabitethernet 3/1/2

[RouterB-Ten-GigabitEthernet3/1/2] ip address 6.1.1.1 255.255.255.0

[RouterB-Ten-GigabitEthernet3/1/2] quit

# Specify an IPv6 address for Ten-GigabitEthernet 3/1/1.

[RouterB] interface ten-gigabitethernet 3/1/1

[RouterB-Ten-GigabitEthernet3/1/1] ipv6 address 2001::1/16

[RouterB-Ten-GigabitEthernet3/1/1] quit

# Create 6to4 tunnel interface Tunnel 0.

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

# Specify an IPv6 address for the tunnel interface.

[RouterB-Tunnel0] ipv6 address 2003::1/64

# Specify Ten-GigabitEthernet 3/1/2 as the source interface of the tunnel interface.

[RouterB-Tunnel0] source ten-gigabitethernet 3/1/2

[RouterB-Tunnel0] quit

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

[RouterB] 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 2001::2

Pinging 2001::2

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

Reply from 2001::2: bytes=32 time=13ms

Reply from 2001::2: bytes=32 time=1ms

Reply from 2001::2: bytes=32 time<1ms

Ping statistics for 2001::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.

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.

Example: Configuring an ISATAP tunnel

Network configuration

As shown in Figure 7, configure an ISATAP tunnel between the router and the ISATAP host so the ISATAP host in the IPv4 network can access the IPv6 network.

Figure 7 Network diagram

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Procedure

1. Configure the router:

# Specify an IPv6 address for Ten-GigabitEthernet 3/1/2.

<Router> system-view

[Router] interface ten-gigabitethernet 3/1/2

[Router-Ten-GigabitEthernet3/1/2] ipv6 address 3001::1/64

[Router-Ten-GigabitEthernet3/1/2] quit

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/1.

[Router] interface ten-gigabitethernet 3/1/1

[Router-Ten-GigabitEthernet3/1/1] ip address 1.1.1.1 255.0.0.0

[Router-Ten-GigabitEthernet3/1/1] quit

# Create ISATAP tunnel interface Tunnel 0.

[Router] interface tunnel 0 mode ipv6-ipv4 isatap

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

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

# Specify Ten-GigabitEthernet 3/1/1 as the source interface of the tunnel interface.

[Router-Tunnel0] source ten-gigabitethernet 3/1/1

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

[Router-Tunnel0] undo ipv6 nd ra halt

[Router-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 router.

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 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 router.

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.

IPv4 over IPv4 tunneling

About IPv4 over IPv4 tunneling

IPv4 over IPv4 tunneling (RFC 1853) enables isolated IPv4 networks to communicate. For example, an IPv4 over IPv4 tunnel can connect isolated private IPv4 networks over a public IPv4 network.

Figure 8 IPv4 over IPv4 tunnel

Figure 8 shows the encapsulation and de-encapsulation processes.

· Encapsulation:

a. Device A receives an IP packet from an IPv4 host and submits it to the IP protocol stack.

b. The IPv4 protocol stack determines how to forward the packet according to the destination address in the IP header. If the packet is destined for the IPv4 host connected to Device B, Device A delivers the packet to the tunnel interface.

c. The tunnel interface adds a new IPv4 header to the IPv4 packet and submits it to the IP protocol stack.

In the new header, the source IP address specifies the tunnel source, and the destination IP address specifies the tunnel destination.

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

· De-encapsulation:

e. After receiving the packet, Device B delivers it to the IP protocol stack.

f. If the protocol number is 4 (indicating an IPv4 packet is encapsulated within the packet), the IP protocol stack delivers the packet to the tunnel module for de-encapsulation.

g. The tunnel module de-encapsulates the IP packet and sends it back to the IP protocol stack.

h. The protocol stack forwards the de-encapsulated packet.

Restrictions and guidelines: IPv4 over IPv4 tunnel configuration

Follow these guidelines when you configure an IPv4 over IPv4 tunnel:

· 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.

· The IPv4 address of the local tunnel interface cannot be on the same subnet as the destination address configured on the tunnel interface.

· 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 IPv4 address of the peer tunnel interface as the next hop.

¡ Enable a dynamic routing protocol on both tunnel interfaces to achieve the same purpose.

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

· The destination address of the route passing the tunnel interface cannot be on the same subnet as the destination address configured on the tunnel interface.

Configuring an IPv4 over IPv4 tunnel

1. Enter system view.

system-view

2. Enter IPv4 over IPv4 tunnel interface view.

interface tunnel number [ mode ipv4-ipv4 ]

3. Configure an IPv4 address for the tunnel interface.

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

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.

IPv4 over IPv4 tunnel configuration examples

Example: Configuring an IPv4 over IPv4 tunnel

Network configuration

As shown in Figure 9, the two subnets IPv4 group 1 and IPv4 group 2 use private IPv4 addresses. Configure an IPv4 over IPv4 tunnel between Router A and Router B to make the two subnets reachable to each other.

Figure 9 Network diagram

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Prerequisites

Make sure Router A and Router B can reach each other through IPv4.

Procedure

1. Configure Router A:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/1.

<RouterA> system-view

[RouterA] interface ten-gigabitethernet 3/1/1

[RouterA-Ten-GigabitEthernet3/1/1] ip address 10.1.1.1 255.255.255.0

[RouterA-Ten-GigabitEthernet3/1/1] quit

# Specify an IPv4 address for Serial 3/1/1, which is the physical interface of the tunnel.

[RouterA] interface serial 3/1/1

[RouterA-Serial3/1/1] ip address 2.1.1.1 255.255.255.0

[RouterA-Serial3/1/1] quit

# Create IPv4 over IPv4 tunnel interface Tunnel 1.

[RouterA] interface tunnel 1 mode ipv4-ipv4

# Specify an IPv4 address for the tunnel interface.

[RouterA-Tunnel1] ip address 10.1.2.1 255.255.255.0

# Specify the IP address of Serial 3/1/1 as the source address for the tunnel interface.

[RouterA-Tunnel1] source 2.1.1.1

# Specify the IP address of Serial 3/1/2 on Router B as the destination address for the tunnel interface.

[RouterA-Tunnel1] destination 3.1.1.1

[RouterA-Tunnel1] quit

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

[RouterA] ip route-static 10.1.3.0 255.255.255.0 tunnel 1

2. Configure Router B:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/1.

<RouterB> system-view

[RouterB] interface ten-gigabitethernet 3/1/1

[RouterB-Ten-GigabitEthernet3/1/1] ip address 10.1.3.1 255.255.255.0

[RouterB-Ten-GigabitEthernet3/1/1] quit

# Specify an IPv4 address for Serial 3/1/2, which is the physical interface of the tunnel.

[RouterB] interface serial 3/1/2

[RouterB-Serial3/1/2] ip address 3.1.1.1 255.255.255.0

[RouterB-Serial3/1/2] quit

# Create IPv4 over IPv4 tunnel interface Tunnel 2.

[RouterB] interface tunnel 2 mode ipv4-ipv4

# Specify an IPv4 address for the tunnel interface.

[RouterB-Tunnel2] ip address 10.1.2.2 255.255.255.0

# Specify the IP address of Serial 3/1/2 as the source address for the tunnel interface.

[RouterB-Tunnel2] source 3.1.1.1

# Specify the IP address of Serial 3/1/1 on Router A as a destination address for the tunnel interface.

[RouterB-Tunnel2] destination 2.1.1.1

[RouterB-Tunnel2] quit

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

[RouterB] ip route-static 10.1.1.0 255.255.255.0 tunnel 2

Verifying the configuration

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

# Verify that Router A and Router B can ping the IPv4 address of the peer interface Ten-GigabitEthernet 3/1/1. This example uses Router A.

[RouterA] ping -a 10.1.1.1 10.1.3.1

Ping 10.1.3.1 (10.1.3.1) from 10.1.1.1: 56 data bytes, press CTRL_C to break

56 bytes from 10.1.3.1: icmp_seq=0 ttl=255 time=2.000 ms

56 bytes from 10.1.3.1: icmp_seq=1 ttl=255 time=1.000 ms

56 bytes from 10.1.3.1: icmp_seq=2 ttl=255 time=0.000 ms

56 bytes from 10.1.3.1: icmp_seq=3 ttl=255 time=1.000 ms

56 bytes from 10.1.3.1: icmp_seq=4 ttl=255 time=1.000 ms

--- Ping statistics for 10.1.3.1 ---

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

round-trip min/avg/max/std-dev = 0.000/1.000/2.000/0.632 ms

IPv4 over IPv6 tunneling

About 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 10 IPv4 over IPv6 tunnel

Figure 10 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 tunnels include IPv4 over IPv6 manual tunnels and DS-Lite tunnels.

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.

DS-Lite tunnel

Dual Stack Lite (DS-Lite) is a combination of the tunneling and NAT technologies. NAT translates the private IPv4 addresses of the IPv4 hosts before the hosts reach the IPv4 public network.

DS-Lite tunnel supports only an IPv4 host in a private network initiating communication with an IPv4 host on the Internet. It does not support an IPv4 host on the Internet initiating communication with an IPv4 host in a private network.

Figure 11 DS-Lite tunnel

As shown in Figure 11, the DS-Lite feature contains the following components:

· Basic Bridging BroadBand (B4) element

The B4 element is typically a CPE router that connects end hosts. IPv4 packets entering the B4 router are encapsulated into IPv6 packets and sent to the AFTR. IPv6 packets from the AFTR are de-encapsulated into IPv4 packets and sent to the subscriber's network.

Hosts that can act as the B4 router are referred to as DS-Lite hosts.

· Address Family Transition Router (AFTR)

An AFTR resides in the ISP network and terminates the tunnel from the B4 router. NAT is also implemented on the interface that is connected to the public IPv4 network.

An AFTR de-encapsulates the tunneled packet, translates the network address, and routes the packet to the destination IPv4 network. For IPv4 packets coming from the public IPv4 network, the AFTR performs reverse address translation and sends them to the B4 router by using the DS-Lite tunnel.

Figure 12 Packet forwarding process in DS-Lite

As shown in Figure 12, the packet forwarding process in DS-Lite is as follows:

1. Upon receiving a packet from the private IPv4 network, the B4 router adds an IPv6 header to the packet and sends the IPv6 packet to the AFTR through the tunnel.

2. The AFTR performs the following operations:

a. Removes the IPv6 header from the tunneled packet.

b. Assigns a tunnel ID for the B4 router.

c. Records the mapping between the IPv6 address of the B4 router (the source IPv6 address of the packet), and the tunnel ID.

3. After de-encapsulation, the AFTR translates the source private IPv4 address of the packet into a public IPv4 address and sends the packet to the destination IPv4 host. The AFTR also maps the NAT entries to the tunnel ID so that IPv4 networks connected to different B4 routers can use the same address space.

4. Upon receiving the response packet from the public network, the AFTR translates the destination public IPv4 address into the private IPv4 address. The AFTR performs the following operations:

a. Looks up the IPv6 address-tunnel ID mapping to obtain the IP address of the B4 router.

b. Uses the address as the destination address of the encapsulated IPv6 packet.

c. Forwards the packet to the B4 router.

Figure 12 shows an example of PAT translation for dynamic NAT. Typically, dynamic NAT is used. When you use static NAT for DS-Lite tunneling, make sure the IP addresses of private IPv4 networks connected to different B4 routers do not overlap. For more information about NAT, see NAT Configuration Guide.

Configuring an IPv4 over IPv6 manual tunnel

Hardware compatibility with IPv4 over IPv6 manual tunneling

This feature is available only for the following cards:

Card category	Cards
CEPC	CEPC-XP4LX, CEPC-XP24LX, CEPC-XP48RX, CEPC-CP4RX, CEPC-CP4RXA, CEPC-CP4RX-L, CEPC-CQ8L
CSPC	CSPC-GE16XP4L-E, CSPC-GE24L-E, CSPC-GP24GE8XP2L-E
CSPEX	CSPEX-1304X, CSPEX-1404X, CSPEX-1502X, CSPEX-1504X, CSPEX-1504XA, CSPEX-1602X, CSPEX-1602XA, CSPEX-1804X, CSPEX-1512X, CSPEX-1612X, CSPEX-1812X, CSPEX-1104-E, CSPEX-1204, CSPEX-1812X-E, CSPEX-2304X-G
SPE	RX-SPE200

Restrictions and guidelines

Follow these guidelines when you configure an IPv4 over IPv6 manual tunnel:

· 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.

¡ 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 tunnel interfaces to achieve the same purpose.

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

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 13, configure an IPv4 over IPv6 manual tunnel between Router A and Router B so the two networks can reach each other over the IPv6 network.

Figure 13 Network diagram

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Prerequisites

Make sure Router A and Router B can reach each other through IPv6.

Procedure

1. Configure Router A:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/1.

<RouterA> system-view

[RouterA] interface ten-gigabitethernet 3/1/1

[RouterA-Ten-GigabitEthernet3/1/1] ip address 30.1.1.1 255.255.255.0

[RouterA-Ten-GigabitEthernet3/1/1] quit

# Specify an IPv6 address for Serial 3/1/1, which is the physical interface of the tunnel.

[RouterA] interface serial 3/1/1

[RouterA-Serial3/1/1] ipv6 address 2001::1:1 64

[RouterA-Serial3/1/1] quit

# Create IPv6 tunnel interface Tunnel 1.

[RouterA] interface tunnel 1 mode ipv6

# Specify an IPv4 address for the tunnel interface.

[RouterA-Tunnel1] ip address 30.1.2.1 255.255.255.0

# Specify the IP address of Serial 3/1/1 as the source address for the tunnel interface.

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

# Specify the IP address of Serial 3/1/2 on Router B as the destination address for the tunnel interface.

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

[RouterA-Tunnel1] quit

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

[RouterA] ip route-static 30.1.3.0 255.255.255.0 tunnel 1

2. Configure Router B:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/1.

<RouterB> system-view

[RouterB] interface ten-gigabitethernet 3/1/1

[RouterB-Ten-GigabitEthernet3/1/1] ip address 30.1.3.1 255.255.255.0

[RouterB-Ten-GigabitEthernet3/1/1] quit

# Specify an IPv6 address for Serial 3/1/2, which is the physical interface of the tunnel.

[RouterB] interface serial 3/1/2

[RouterB-Serial3/1/2] ipv6 address 2002::2:1 64

[RouterB-Serial3/1/2] quit

# Create IPv6 tunnel interface Tunnel 2.

[RouterB] interface tunnel 2 mode ipv6

# Specify an IPv4 address for the tunnel interface.

[RouterB-Tunnel2] ip address 30.1.2.2 255.255.255.0

# Specify the IP address of Serial 3/1/2 as the source address for the tunnel interface.

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

# Specify the IP address of Serial 3/1/1 on Router A as the destination address for the tunnel interface.

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

[RouterB-Tunnel2] quit

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

[RouterB] 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 Router A and Router B. Verify that the tunnel interfaces are up. (Details not shown.)

# Verify that Router A and Router B can ping the IPv4 address of the peer interface Ten-GigabitEthernet 3/1/1. This example uses Router A.

[RouterA] 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

Configuring a DS-Lite tunnel

Restrictions and guidelines for DS-Lite tunnel configuration

An AFTR tunnel interface can establish tunnels with multiple B4 tunnel interfaces.

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

Follow these guidelines when you configure the AFTR of a DS-Lite tunnel:

· Enable NAT on the interface that is connected to the public IPv4 interface.

· The tunnel destination cannot be configured on the AFTR. The AFTR uses the address of the B4 router as the IPv6 address of the tunnel destination.

· It is not necessary to configure a route to the destination IPv4 address for forwarding packets through the tunnel interface.

The device cannot operate as the B4 router of a DS-Lite tunnel.

Configuring the AFTR of a DS-Lite tunnel

1. Enter system view.

system-view

2. Enter the view of the tunnel interface on the AFTR.

interface tunnel number [ mode ds-lite-aftr ]

3. Specify an IPv4 address for the tunnel interface.

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

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

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

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

The specified source address or the lowest IPv6 address of the specified source interface is used as the source IPv6 address of tunneled packets.

5. Return to system view.

quit

6. Enter the view of the interface that is connected to the IPv4 public network.

interface interface-type interface-number

7. Enable DS-Lite tunneling on the interface.

ds-lite enable

By default, DS-Lite tunneling is disabled.

Only after you use this command, the AFTR can tunnel IPv4 packets from the public IPv4 network to the B4 router.

8. Display information about the connected B4 routers on the AFTR.

In standalone mode:

display ds-lite b4 information [ slot slot-number ]

In IRF mode:

display ds-lite b4 information [ chassis chassis-number slot slot-number ]

Example: Configuring a DS-Lite tunnel

Network configuration

As shown in Figure 14, to enable hosts in the private IPv4 network to access the public IPv4 network over the IPv6 network, perform the following tasks:

· Configure a DS-Lite tunnel between Router A and Router B.

· Configure NAT on Ten-GigabitEthernet 3/1/1 on the AFTR.

Figure 14 Network diagram

‌

Prerequisites

Make sure Router A and Router B can reach each other through IPv6.

The CGN card is installed in slot 4 on Router B.

Procedure

1. Configure Router A:

IMPORTANT:

The device cannot act as a B4 router. The following information is only for illustration.

‌

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/1.

<RouterA> system-view

[RouterA] interface ten-gigabitethernet 3/1/1

[RouterA-Ten-GigabitEthernet3/1/1] ip address 10.0.0.2 255.255.255.0

[RouterA-Ten-GigabitEthernet3/1/1] quit

# Specify an IPv6 address for Ten-GigabitEthernet 3/1/2, which is the physical interface of the tunnel.

[RouterA] interface ten-gigabitethernet 3/1/2

[RouterA-Ten-GigabitEthernet3/1/2] ipv6 address 1::1 64

[RouterA-Ten-GigabitEthernet3/1/2] quit

# Create IPv6 tunnel interface Tunnel 1.

[RouterA] interface tunnel 1 mode ipv6

# Specify an IPv4 address for the tunnel interface.

[RouterA-Tunnel1] ip address 30.1.2.1 255.255.255.0

# Specify the IP address of Ten-GigabitEthernet 3/1/2 as the source address for the tunnel interface.

[RouterA-Tunnel1] source 1::1

# Specify IP address of Ten-GigabitEthernet 3/1/2 on Router B as the destination address for the tunnel interface.

[RouterA-Tunnel1] destination 2::2

[RouterA-Tunnel1] quit

# Configure a static route to the public IPv4 network through the tunnel interface.

[RouterA] ip route-static 20.1.1.0 255.255.255.0 tunnel 1

2. Configure Router B:

# Specify an IPv4 address for Ten-GigabitEthernet 3/1/1.

<RouterB> system-view

[RouterB] interface ten-gigabitethernet 3/1/1

[RouterB-Ten-GigabitEthernet3/1/1] ip address 20.1.1.1 24

[RouterB-Ten-GigabitEthernet3/1/1] quit

# Specify an IPv6 address for Ten-GigabitEthernet 3/1/2, which is the physical interface of the tunnel.

[RouterB] interface ten-gigabitethernet 3/1/2

[RouterB-Ten-GigabitEthernet3/1/2] ipv6 address 2::2 64

[RouterB-Ten-GigabitEthernet3/1/2] quit

# Create DS-Lite tunnel interface Tunnel 2.

[RouterB] interface tunnel 2 mode ds-lite-aftr

# Configure an IPv4 address for the tunnel interface.

[RouterB-Tunnel2] ip address 30.1.2.2 255.255.255.0

# Specify Ten-GigabitEthernet 3/1/2 as the source interface of the tunnel interface.

[RouterB-Tunnel2] source ten-gigabitethernet 3/1/2

[RouterB-Tunnel2] quit

# Enable DS-Lite tunneling on Ten-GigabitEthernet 3/1/1.

[RouterB] interface ten-gigabitethernet 3/1/1

[RouterB-Ten-GigabitEthernet3/1/1] ds-lite enable

# Enable NAT on Ten-GigabitEthernet 3/1/1 and use the IP address of Ten-GigabitEthernet 3/1/1 as the translated address.

[RouterB-Ten-GigabitEthernet3/1/1] nat outbound

[RouterB-Ten-GigabitEthernet3/1/1] quit

3. On host A, specify the IP address for the host as 10.0.0.1 and configure a static route to 20.1.1.0/24 with next hop 10.0.0.2. (Details not shown.)

4. On host B, specify the IP address for the host as 20.1.1.2. (Details not shown.)

Verifying the configuration

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

# Verify that host A can ping host B.

C:\> ping 20.1.1.2

Pinging 20.1.1.2 with 32 bytes of data:

Reply from 20.1.1.2: bytes=32 time=51ms TTL=255

Reply from 20.1.1.2: bytes=32 time=44ms TTL=255

Reply from 20.1.1.2: bytes=32 time=1ms TTL=255

Ping statistics for 20.1.1.2:

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

Approximate round trip times in milli-seconds:

Minimum = 1ms, Maximum = 51ms, Average = 24ms

06-Layer 3—IP Services Configuration Guide

About tunneling

Restrictions and guidelines

Procedure

About this task

Restrictions and guidelines

Procedure

Hardware and feature compatibility

Restrictions and guidelines

Procedure

Restrictions and guidelines

Procedure

About this task

Hardware and feature compatibility

Restrictions and guidelines

Procedure

Setting the statistics collection mode for tunneled traffic

About this task

Procedure

Display and maintenance commands for tunnel interface configuration

Symptom

Analysis

Solution

IPv6 over IPv4 tunneling

IPv6 over IPv4 manual tunneling

6to4 tunneling

ISATAP tunneling

Configuring an IPv6 over IPv4 manual tunnel

Network configuration

Prerequisites

Procedure

Verifying the configuration

Configuring a 6to4 tunnel

Network configuration

Analysis

Prerequisites

Procedure

Verifying the configuration

Network configuration

Prerequisites

Procedure

Verifying the configuration

Configuring an ISATAP tunnel

Network configuration

Procedure

Verifying the configuration

Enabling dropping IPv6 packets that use IPv4-compatible IPv6 addresses

Restrictions and guidelines

Procedure

Network configuration

Prerequisites

Procedure

Verifying the configuration

IPv4 over IPv6 manual tunnel

DS-Lite tunnel

Configuring an IPv4 over IPv6 manual tunnel

Network configuration

Prerequisites

Procedure

Verifying the configuration

Configuring a DS-Lite tunnel

Network configuration

Prerequisites

Procedure

Verifying the configuration

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