Configuring RTR Next-Hop Verification

To configure the next-hop verification example shown in Figure 12:

1. Configure a loopback interface, and assign an IP address and mask to the interface.

   host1(config)#interface loopback 0

   host1(config-if)#ip address 10.1.1.1 255.255.255.0

   host1(config-if)#exit

2. Configure Fast Ethernet port 4/0 with an unnumbered primary IP interface associated with the loopback interface configured in Step 1.

   host1(config)#interface fastEthernet 4/0

   host1(config-if)#ip unnumbered loopback 0

   host1(config-if)#exit

3. Repeat Step 2 for Fast Ethernet port 4/1.

   host1(config)#interface fastEthernet 4/1

   host1(config-if)#ip unnumbered loopback 0

   host1(config-if)#exit

4. Define probe RTR 10 for Fast Ethernet interface 4/0.
   1. Assign an operation number to the RTR probe, and access RTR Configuration mode. For information, see Configuring the Probe Type.

      host1(config)#rtr 10

      host1(config-rtr)#

   2. Configure the RTR probe as an echo type, and set the IP destination address and source interface.

      You must configure the RTR probe as an echo type to use next-hop verification. For information, see Configuring the Probe Type.

      host1(config-rtr)#type echo protocol ipIcmpEcho 10.1.1.2
      source fastEthernet 4/0

   3. Specify the interface on which the RTR probe expects to receive responses.

      You must set the receive-interface attribute when multiple RTR operations use the same target address. For information, see Setting the Receiving Interface.

      host1(config-rtr)#receive-interface fastEthernet 4/0

   4. (Optional) Configure optional probe characteristics, such as the frequency and samples-of-history kept. For information, see Configuring Optional Characteristics.

      host1(config-rtr)#frequency 1

      host1(config-rtr)#samples-of-history-kept 0

   5. Exit RTR Configuration mode.

      host1(config-rtr)#exit

   6. Enable the probe to react to the test-failure event and the test-completion event.

      You must configure both the test-failure and test-completion reaction conditions to use next-hop verification. For information, see Setting Reaction Conditions.

      host1(config)#rtr reaction-configuration 10   test-failure 3

      host1(config)#rtr reaction-configuration 10   test-completion

   7. Schedule the probe operation. For information, see Scheduling the Probe.

      host1(config)#rtr schedule 10 life 3

      host1(config)#rtr schedule 10 restart-time 1

      host1(config)#rtr schedule 10 start now

5. Repeat Step 4 to define RTR 11 for Fast Ethernet interface 4/1.

   host1(config)#rtr 11

   host1(config-rtr)#type echo protocol ipIcmpEcho 10.1.1.2
   source fastEthernet 4/1

   host1(config-rtr)#receive-interface fastEthernet 4/1

   host1(config-rtr)#frequency 1

   host1(config-rtr)#samples-of-history-kept 0

   host1(config-rtr)#exit

   host1(config)#rtr reaction-configuration 11 test-failure 3

   host1(config)#rtr reaction-configuration 11 test-completion

   host1(config)#rtr schedule 11 life 3

   host1(config)#rtr schedule 11 restart-time 1

   host1(config)#rtr schedule 11 start now

6. Establish a static route associated with RTR 10.

   This command creates a static route and installs it in the routing table only if RTR 10 is currently reachable or if no other static route to IP destination address 10.1.1.2 is usable.

   host1(config)#ip route 10.1.1.2 255.255.255.255 10.1.1.2 fastEthernet 4/0 verify rtr 10 last-resort

7. Establish a static route associated with RTR 11.

   This command creates a static route and installs it in the routing table only if RTR 11 is currently reachable or if no other static route to IP destination address 10.1.1.2 is usable.

   host1(config)#ip route 10.1.1.2 255.255.255.255 10.1.1.2 fastEthernet 4/1 verify rtr 11 last-resort

   When both RTR 10 and RTR 11 are unreachable, you can control which static route is installed in the routing table by including the last-resort keyword in the ip route verify rtr command only for the route that you want to install.

   Note: For detailed information about the commands for configuring RTR probes, see Response Time Reporter.

interface fastEthernet

• Use to select a Fast Ethernet (FE) interface on a line module or an SRP module.
• Example

  host1(config)#interface fastEthernet 1/0

• Use the no version to remove IP from an interface or subinterface. You must issue the no version from the highest level down; you cannot remove an interface or a subinterface if the one above it still exists.

  Note: For more details on use of this command, see the syntax description in the JUNOSe Command Reference Guide.

• See interface fastEthernet

interface loopback

• Use to access and configure a loopback interface.
• You can use a loopback interface to provide a stable IP address that can minimize the impact if a physical interface goes down.
• Example

  host1(config)#interface loopback 10

  host1(config-if)#ip address 100.20.32.1 255.255.255.0

• Use the no version to delete the loopback interface.
• See interface loopback

ip address

• Use to set an IP address for an interface or a subinterface.
• Specify the layer 2 encapsulation before you set the IP address.
• Example

  host1(config-subif)#ip address 192.0.2.50 255.255.255.0

• Use the no version to remove the IP address or to disable IP processing on the interface.
• See ip address

ip route verify rtr

• Use to establish a static route and associate it with a configured RTR operation.
• Use the verify rtr keywords to instruct the router to install the static route in the routing table only if the next hop to the specified destination address is resolved and if the specified RTR operation is currently reachable. When you use the verify rtr keywords, you must also specify the number of the associated RTR operation.
• Optionally, you can include the last-resort keyword when you use the verify rtr keywords to instruct the router to install the static route in the routing table even if the specified RTR operation is currently unreachable, provided that no other static route to the same network prefix is available.
• Example

  host1(config)#ip route 10.1.1.5 255.255.255.0 10.1.1.5 fastEthernet 1/0 verify rtr 5 last-resort

• Use the no version to remove a static route from the routing table.
• See ip route

ip unnumbered

• Use to configure an unnumbered IP interface.
• This command enables IP processing on an interface without assigning an explicit IP address to the interface.
• You must specify an interface location, which is the identifier of another interface on which the router has an assigned IP address. This interface cannot be another unnumbered interface.
• Example 1

  host1(config-if)#ip unnumbered fastEthernet 3/0

• Example 2

  host1(config-if)#ip unnumbered loopback 10

• Use the no version to disable IP processing on the interface.
• See ip unnumbered

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