Cisco Systems 78-11741-02 manual IPC-509

Configuring Unidirectional Link Routing

UDLR Tunnel Configuration Task List

•On the upstream router, where the UDL can only send, you must configure the tunnel to receive. When packets are received over the tunnel, the upper-layer protocols treat the packet as though it is received over the unidirectional, send-only interface.

•On the downstream router, where the UDL can only receive, you must configure the tunnel to send. When packets are sent by upper-layer protocols over the interface, they will be redirected and sent over this GRE tunnel.

To configure a UDLR tunnel on the upstream router, use the following commands beginning in global configuration mode:

	Command	Purpose
Step 1
	Router(config)# interface type number	Configures the unidirectional send-only interface.
Step 2
	Router(config-if)# interface tunnel number	Configures the receive-only tunnel interface.
Step 3
	Router(config-if)#tunnel udlr receive-only	Configures the UDLR tunnel. Use the same type and number
	type number	values as the unidirectional send-only interface type and number
		values specified with the interface type number command.
Step 4
	Router(config-if)# tunnel source	Configures the tunnel source.
	{ip-address type number}
Step 5
	Router(config-if)# tunnel destination	Configures the tunnel destination.
	{hostname ip-address}

To configure a UDLR tunnel on the downstream router, use the following commands beginning in global configuration mode:

	Command	Purpose
Step 1
	Router(config)# interface type number	Configures the unidirectional receive-only interface.
Step 2
	Router(config-if)# interface tunnel number	Configures the send-only tunnel interface.
Step 3
	Router(config-if)#tunnel udlr send-only	Configures the UDLR tunnel. Use the same type and number
	type number	values as the unidirectional receive-only interface type and
		number values specified with the interface type number
		command.
Step 4
	Router(config-if)# tunnel source	Configures the tunnel source.
	{ip-address type number}
Step 5
	Router(config-if)# tunnel destination	Configures the tunnel destination.
	{hostname ip-address}
Step 6
	Router(config-if)# tunnel udlr	Enables the forwarding of ARP and NHRP.
	address-resolution

See the “UDLR Tunnel Example” section later in this chapter for an example of how to configure a UDLR tunnel. See the “Integrated UDLR Tunnel, IGMP UDLR, and IGMP Proxy Example” section later in this chapter for an example of how to set up all three UDLR mechanisms in the same configuration.

Cisco IOS IP Configuration Guide

IPC-509