Configuring the AMT Protocol

To configure the AMT protocol, include the amt statement:

You can include this statement at the following hierarchy levels:

• [edit protocols]
• [edit logical-systems logical-system-name protocols]
• [edit routing-instances routing-instance-name protocols]
• [edit logical-systems logical-system-name routing-instances routing-instance-name protocols]

For an overview of logical systems and a detailed example of logical system configuration, see the Junos Logical Systems Feature Guide.

Note: In the following configuration examples, only the [edit protocols] hierarchy is identified.

1. To enable the MX Series router to create the UDP encapsulation (ud) logical interfaces, include the bandwidth statement and specify the bandwidth in gigabits per second.
   user@host# set chassis fpc 0 pic 1 tunnel-services bandwidth 1g
2. The minimum configuration to enable AMT is to specify the AMT local address and the AMT anycast prefix.

   Specify the local address by including the local-address statement at the [edit protocols amt relay family inet] hierarchy level.

   user@host# set protocols amt relay family inet local-address 192.168.7.1

   The local address is used as the IP source of AMT control messages and the source of AMT data tunnel encapsulation. The local address can be configured on any active interface. Typically, the IP address of the router’s lo0.0 loopback interface is used for configuring the AMT local address in the default routing instance, and the IP address of the router’s lo0.n loopback interface is used for configuring the AMT local address in VPN routing instances.

3. Specify the AMT anycast address by including the anycast-prefix statement at the [edit protocols amt relay family inet] hierarchy level.
   user@host# set protocols amt relay family inet anycast-prefix 192.168.0.0/16

   The AMT anycast prefix is advertised by unicast routing protocols to route AMT discovery messages to the router from nearby AMT gateways. Typically, the router’s lo0.0 loopback address is used for configuring the AMT anycast prefix in the default routing instance, and the router’s lo0.n loopback address is used for configuring the AMT anycast prefix in VPN routing instances. However, the anycast address can be either the primary or secondary lo0.0 loopback address.

   Ensure that your unicast routing protocol advertises the AMT anycast prefix in the route advertisements. For more information about configuring unicast routing protocols, see the Junos Routing Protocols Configuration Guide. If the AMT anycast prefix is advertised by BGP, ensure that the local autonomous system (AS) number for the AMT relay router is in the AS path leading to the AMT anycast prefix.

4. (Optional) You can specify the AMT secret key timeout. Specify the AMT secret key timeout by including the secret-key-timeout statement at the [edit protocols amt relay] hierarchy level. In the following example, the secret key timeout is configured to be 120 minutes.
   user@host# set protocols amt relay secret-key-timeout 120

   The secret key is used to generate the AMT Message Authentication Code (MAC). Setting the secret key timeout shorter might improve security, but it consumes more CPU resources. The default is 60 minutes.

5. (Optional) You can specify an AMT tunnel limit. Specify the AMT tunnel limit by including the tunnel-limit statement at the [edit protocols amt relay] hierarchy level. In the following example, the AMT tunnel limit is 12.
   user@host# set protocols amt relay tunnel-limit 12

   The tunnel limit configures the static upper limit to the number of AMT tunnels that can be established. When the limit is reached, new AMT relay discovery messages are ignored.

6. For troubleshooting the AMT protocol operation, you can trace AMT protocol traffic. To trace AMT protocol traffic, specify options to the traceoptions statement at the [edit protocols amt] hierarchy level. Options applied at the AMT protocol level trace only AMT traffic. In the following example, all AMT packets are logged to the file amt-log.
   user@host# set protocols amt traceoptions file amt-loguser@host# set protocols amt traceoptions flag packets

   Note: For AMT operation, configure the PIM rendezvous point address as the primary loopback address of the AMT relay.

   To trace the paths of multicast packets, use the mtrace command, as described in the Junos System Basics and Services Command Reference.

   For information about tracing and global tracing options, see the Junos Routing Protocols Configuration Guide.