System information

BSR 64000 Configuration and Management Guide
5-10
Configuring Tunnels on an Interface
A tunnel interface is a logical interface that is used to encapsulate various packet
types and send them over a created a point-to-point link between two devices at
remote points over an IP internetwork. Multi-protocol packets are encapsulated using
either IP, GRE, or DVMRP tunnel encapsulation to traverse the link.
Tunneling is used for the following reasons:
• Allows multiprotocol LANs to connect over a single-protocol backbone.
• Solves problems for routed networks with restricted hop counts.
• Connects disjointed subnetworks.
• Permits virtual private networks (VPNs) across the internet.
Up to 255 tunnel interfaces can be configured on the BSR. A separate tunnel for each
link must be configured, since it is a point-to-point link.
When configuring tunnels on an interface, you must specify the tunnel source and
tunnel destination. You can optionally enable an ID key for a tunnel interface. You can
use Tunnel ID keys as a form of weak security to prevent misconfiguration or
injection of packets from a foreign source. Set the key to the same value on the tunnel
endpoints. The tunnel ID key is available with generic router encapsulation (GRE)
only.
Up to 255 tunnel interfaces can be configured on the BSR. Follow these steps to
define a tunnel address:
1. Use the interface tunnel command in Global Interface mode, to define a tunnel
interface, as shown below:
MOT(config)#interface tunnel <n>
where:
n is the number of the tunnel interface from 0 to 255
Note: When using GRE, the ID key is carried in each packet. We recommend
that you do not rely on this key for security purposes.