Using a Destination Address to Demultiplex Traffic

The example in Figure 20 shows how you can use static subscriber interfaces to direct traffic toward special local content on the network, based on the traffic’s destination address. In this application, a local VoIP service is on network 10.11.0.0./16, and a local gaming service is on network 10.12.0.0/16.

Figure 20: Subscriber Interfaces Using a Destination Address to Demultiplex Traffic

To configure the static subscriber interfaces shown in Figure 20, perform the following steps:

1. Configure a primary IP interface on a supported layer 2 interface.
   1. Create a layer 2 interface.

      host1(config)#interface fastEthernet 3/1

   2. Create a primary IP interface.

      host1(config-if)#ip address 10.1.1.1 255.0.0.0

   3. Configure the primary interface to use a destination address to demultiplex traffic. (By default, a source address is used to demultiplex traffic.)

      host1(config-if)#ip demux-type da-prefix

   4. Exit Interface Configuration mode.

      host1(config-if)#exit

2. Configure subscriber interface IP1.
   1. Create the shared IP interface.

      host1(config)#interface ip ip1

   2. Associate the shared IP interface with the layer 2 interface by using one of the following methods:
      • Static

        host1(config-if)#ip share-interface fastEthernet 3/1

      • Dynamic

        host1:vr-a:vrf-1(config-if)#ip share-nexthop 10.1.1.2

   3. To fully configure the shared interface, assign an address or make it unnumbered.

      host1(config-if)#ip unnumbered loopback 0

   4. Specify the destination addresses for the subscriber interface to use to demultiplex traffic.

      host1(config-if)#ip destination-prefix 10.11.0.0 255.255.0.0

   5. Exit Interface Configuration mode.

      host1(config-if)#exit

3. Repeat Step 2 to configure subscriber interface IP2.

   host1(config)#interface ip ip2

   host1(config-if)#ip share-interface fastEthernet 3/1

   host1(config-if)#ip unnumbered loopback 0

   host1(config-if)#ip destination-prefix 10.12.0.0 255.255.0.0

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