Restrictions for IPv6 over IPv4 GRE Tunnels
This feature is not supported on the Cisco Catalyst 9600 Series Supervisor 2 Module.
The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.
This feature is not supported on the Cisco Catalyst 9600 Series Supervisor 2 Module.
The following sections provide information about configuring IPv6 over IPv4 GRE tunnels:
Overlay tunneling encapsulates IPv6 packets in IPv4 packets for delivery across an IPv4 infrastructure (a core network or the figure below). By using overlay tunnels, you can communicate with isolated IPv6 networks without upgrading the IPv4 infrastructure between them. Overlay tunnels can be configured between border devices or between a border device and a host; however, both tunnel endpoints must support both the IPv4 and IPv6 protocol stacks.
Note |
Overlay tunnels reduce the maximum transmission unit (MTU) of an interface by 20 octets (assuming that the basic IPv4 packet header does not contain optional fields). A network that uses overlay tunnels is difficult to troubleshoot. Therefore, overlay tunnels that connect isolated IPv6 networks should not be considered a final IPv6 network architecture. The use of overlay tunnels should be considered as a transition technique toward a network that supports both the IPv4 and IPv6 protocol stacks or just the IPv6 protocol stack. |
IPv6 supports GRE type of overlay tunneling. IPv6 over IPv4 GRE Tunnels can carry IPv6, Connectionless Network Service (CLNS), and many other types of packets.
IPv6 traffic can be carried over IPv4 GRE tunnels using the standard GRE tunneling technique that is designed to provide the services to implement any standard point-to-point encapsulation scheme. As in IPv6 manually configured tunnels, GRE tunnels are links between two points, with a separate tunnel for each link. The tunnels are not tied to a specific passenger or transport protocol but, in this case, carry IPv6 as the passenger protocol with the GRE as the carrier protocol and IPv4 or IPv6 as the transport protocol.
The primary use of GRE tunnels is for stable connections that require regular secure communication between two edge devices or between an edge device and an end system. The edge devices and the end systems must be dual-stack implementations.
Perform this task to configure a GRE tunnel on an IPv6 network. GRE tunnels can be configured to run over an IPv6 network layer and to transport IPv6 packets in IPv6 tunnels and IPv4 packets in IPv6 tunnels.
To configure GRE IPv6 tunnels, perform this procedure:
When GRE IPv6 tunnels are configured, IPv6 addresses are assigned to the tunnel source and the tunnel destination. The tunnel interface can have either IPv4 or IPv6 addresses assigned (this is not shown in the task). The host or router at each end of a configured tunnel must support both the IPv4 and IPv6 protocol stacks.
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 |
enable Example:
|
Enables privileged EXEC mode. Enter your password if prompted. |
||
Step 2 |
configure terminal Example:
|
Enters global configuration mode. |
||
Step 3 |
interface tunnel tunnel-number Example:
|
Specifies a tunnel interface and number, and enters interface configuration mode. |
||
Step 4 |
ipv6 address ipv6-prefix / prefix-length [eui-64 ] Example:
|
Specifies the IPv6 network assigned to the interface and enables IPv6 processing on the interface. |
||
Step 5 |
tunnel source {ip-address | ipv6-address | interface-type interface-number } Example:
|
Specifies the source IPv4 address or the source interface type and number for the tunnel interface.
|
||
Step 6 |
tunnel destination {host-name | ip-address | ipv6-address } Example:
|
Specifies the destination IPv6 address or hostname for the tunnel interface. |
||
Step 7 |
tunnel mode {aurp | cayman | dvmrp | eon | gre | gre multipoint | gre ipv6 | ipip [decapsulate-any ] | iptalk | ipv6 | mpls | nos Example:
|
Specifies a GRE IPv6 tunnel.
|
Device> enable
Device# configure terminal
Device(config)# interface Tunnel 0
Device(config-if)# ipv6 address 2001:1:1::1/48
Device(config-if)# tunnel source GigabitEthernet 0/0/0
Device(config-if)# tunnel destination 10.0.0.2
Device(config-if)# tunnel mode gre ipv6
Device(config-if)# exit
!
Device(config)# interface GigabitEthernet0/0/0
Device(config-if)# ip address 10.0.0.1 255.255.255.0
Device(config-if)# exit
!
Device(config)# ipv6 unicast-routing
Device(config)# router isis
Device(config-router)# net 49.0000.0000.000a.00
Related Topic | Document Title |
---|---|
For complete syntax and usage information for the commands used in this chapter. |
Command Reference (Catalyst 9600 Series Switches) |
This table provides release and related information for the features explained in this module.
These features are available in all the releases subsequent to the one they were introduced in, unless noted otherwise.
Release |
Feature |
Feature Information |
---|---|---|
Cisco IOS XE Gibraltar 16.11.1 |
IPv6 over IPv4 GRE Tunnels |
GRE tunnels are links between two points, with a separate tunnel for each link. The tunnels are not tied to a specific passenger or transport protocol, but in this case carry IPv6 as the passenger protocol with the GRE as the carrier protocol and IPv4 or IPv6 as the transport protocol. |
Use the Cisco Feature Navigator to find information about platform and software image support.