interfaces tunnel <tunx> encapsulation <action>
Sets the encapsulation type for a tunnel interface.
GRE is the default encapsulation type.
- tunx
- The identifier of a tunnel interface. The identifier ranges from tun0 through tunx, where x is a non-negative integer.
- gre
- Uses GRE to encapsulate transported packets.
- gre-bridge
- Uses GRE to encapsulate transported packets. This encapsulation type is to be used only for bridging, that is, when the tunnel interface is to be added to a bridge group.
- gre-multipoint
- Uses multipoint GRE to encapsulate transported packets.
- ipip
- Uses IP-in-IP to encapsulate transported packets.
- ipip6
- Uses IP-in-IPv6 to encapsulate transported packets.
- ipip
- Uses IPv6-in-IPv6 to encapsulate transported packets.
- sit
- Uses SIT to encapsulate transported packets.
Configuration mode
interfaces {
tunnel tunx {
encapsulation {
gre
gre-bridge
gre-multipoint
ipip
ipip6
ip6ip6
sit
}
}The Generic Routing Encapsulation (GRE) protocol provides a simple-general purpose mechanism for encapsulating packets from a wide variety of network protocols to be forwarded over another protocol. The original packet (the "passenger" packet) can be one of many arbitrary network protocols-for example a multicast packet, an IPv6 packet, or a non-IP LAN protocol such as AppleTalk, Banyen VINES, or Novell IPX. The delivery protocol can be one of a number of routable IP protocols.
A limitations of a regular GRE encapsulated tunnel is that it cannot be added to a bridge group. GRE for Bridging (using the gre-bridge keyword) provides this ability. It should be used only in cases in which tunnel interfaces are to be included in a bridge group. Refer to Ciena Vyatta Network OS Bridging Configuration Guide for further information.
GRE for multipoint (by using the gre-multipoint keyword) is used as part of DMVPN network configurations. Refer to Ciena Vyatta Network OS DMVPN Configuration Guide for further information. The main difference between a standard GRE configuration and a GRE-for-multipoint configuration is that, when configuring GRE for multipoint, you do not specify a remote IP. Everything else remains the same.
The IP-in-IP encapsulation protocol is used to tunnel between networks that have different capabilities or policies. For example, an IP-in-IP tunnel can be used to forward multicast packets across a section of a network (such as an IPsec tunnel) that does not support multicast routing. An IP-in-IP tunnel can also be used to influence the routing of the packet, or to deliver a packet to a mobile device using Mobile IP.
The SIT encapsulation is used to tunnel IPv6 across an IPv4 network.
Use the set form of this command to set the encapsulation type for a tunnel interface.
Use the delete form of this command to delete restore the default encapsulation type, which is GRE, for a tunnel interface.
Use the show form of this command to display the encapsulation type for a tunnel interface.