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Configuring the Intermediate and Egress Routers for Static LSPs

Intermediate and egress routers perform similar functions—they modify the label that has been applied to a packet. An intermediate router can change the label. An egress router removes the label (if the packet still contains a label) and continues forwarding the packet to its destination.

To configure static LSPs on intermediate and egress routers, include the interface statement:




interface (interface-name | all) {

disable;

admin-group [ group-names ];



label-map in-label {

class-of-service cos-value; 

next-hop (address | interface-name | address/interface-name) | (discard | reject); 
(pop | swap <out-label>); 

preference preference; 

swap-push swap-label push-label;
}


}

You can include these statements at the following hierarchy levels:

[edit protocols mpls]
[edit logical-systems logical-system-name protocols mpls]

For the label-map statement configuration, the next-hop | (reject | discard) and pop | swap statements are required. The remaining statements are optional.

Each statement within the interface statement consists of the following parts:

Criteria to use to analyze the labeled packet. Two criteria are used: the interface on which the packet was received (specified in the opening interface statement itself) and the packet’s label (specified in the label-map statement).
The next-hop statement, which supplies the IP address of the next hop to the destination. The address is specified as the IP address of the next hop, or the interface name (for point-to-point interfaces only), or address and interface-name to specify an IP address on an operational interface. When the specified next hop is on a directly attached interface, this route is installed in the routing table. You cannot configure a LAN or NBMA interface as a next-hop interface.
Operation to perform on the labeled packet:
- For egress routers, remove the packet’s label altogether (pop).
- For intermediate routers only, exchange the label for another label (swap out-label).
- Discard the packet, sending an ICMP unreachable message to the packet’s originator (reject).
- Discard the packet without sending an ICMP unreachable message to the packet’s originator (discard).
Label properties to apply to the packet (all are optional):
- Preference value for this route (preference preference).
- For intermediate routers only, the CoS value to apply to the packet (class-of-service cos-value).

You can specify any number of label-map statements at the [edit protocols mpls interface interface-name] hierarchy level.

The static routes are installed in the default MPLS routing table, mpls.0, and the creating protocol is identified as static. To verify that a static route is properly installed, use the command show route table mpls.0 protocol static. The following is an example of the output:

1000123       *[Static/5] 00:00:38
> to 12.2.2.2 via so-5/0/0.0, swap 1000456

Example: Configuring an Intermediate Router

For packets labeled 1000123 arriving on interface so-0/0/0, assign the label 1000456, and transmit them to the next-hop router at 12.2.2.2:



[edit]
interfaces {


so-0/0/0 { 


unit 0 {
family mpls;
}


}


}
protocols {


mpls { 


interface so-0/0/0 {


label-map 1000123 {
next-hop 12.2.2.2;
swap 1000456;
}


}


}


}

To determine whether the static intermediate route is installed, use the following command:



user@host> show route table mpls.0 protocol
static

The following is a sample of the output. The swap 1000456 keyword identifies the route.

1000123       *[Static/5] 00:01:48
> to 12.2.2.2 via so-0/0/0, swap 1000456

Example: Configuring an Egress Router

For packets labeled 1000456 arriving on interface so-0/0/0, remove the label and transmit the packets to the next-hop router at 13.3.3.3:



[edit]
interfaces {


so-0/0/0 { 


unit 0 {
family mpls;
}


}


}
protocols {


mpls {


interface so-0/0/0 {


label-map 1000456 {
next-hop 13.3.3.3;
pop;
}


}


}


}

To determine whether the static egress route is installed, use the following command:



user@host> show route table mpls.0 protocol
static

The following is a sample of the output. The pop keyword identifies the egress route.

1000456        *[Static/5] 00:01:48
> to 13.3.3.3 via so-0/0/0, pop

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