Deploying Tunnels

To properly deploy IP tunnels, you need to perform two main tasks. First, you create the tunnel link. Then, you configure an IP interface over the tunnel. This section briefly describes the requirements for creating tunnels and their corresponding IP interfaces.

Requirements for Creating Tunnels

To successfully create tunnels, you must observe the following requirements:

• If you use host names instead of literal IP addresses, these names must resolve to valid IP addresses that are compatible with the tunnel type.

• The IPv4 or IPv6 tunnel that you create must not share the same tunnel source address and tunnel destination address with another configured tunnel.

• The IPv4 or IPv6 tunnel that you create must not share the same tunnel source address with an existing 6to4 tunnel.

• If you create a 6to4 tunnel, that tunnel must not share the same tunnel source address with another configured tunnel.

For information about setting up tunnels in your network, refer to Planning for Tunnels in the Network Topology.

Requirements for Tunnels and IP Interfaces

Each tunnel type has specific IP address requirements on the IP interface that you configure over the tunnel. The requirements are summarized in the following table.

Table 7-1 Tunnels and IP Interface Requirements

You can override the default IPv6 interface address of 6to4 tunnels by specifying a different IPv6 address. Such additional IPv6 addresses can be included in the tunnel's hostname6.tunnel-name file. Otherwise, the file can remain empty.

Similarly, to override the link-local addresses that are automatically set for IPv6 interfaces over IPv4 or IPv6 tunnels, you can specify different source and destination addresses in the tunnel's host file.