Preferred Lifetime
The preferred lifetime for the prefixes in the router advertisement messages specifies how long the prefix generated by stateless autoconfiguration remains preferred. By default, the preferred lifetime is set to 604,800 seconds.
To configure the preferred lifetime, include the preferred-lifetime statement:
[edit protocols router-advertisement interface interface-name prefix prefix]
preferred-lifetime seconds;
If you set the preferred lifetime to 0xffffffff, the lifetime is infinite.
The preferred lifetime value must never exceed the valid lifetime value.
Valid Lifetime
The valid lifetime for the prefixes in the router advertisement messages specifies how long the prefix remains valid for on-link determination. By default, the valid lifetime is set to 2,592,000 seconds. To configure the valid lifetime, include the valid-lifetime statement:
[edit protocols router-advertisement interface interface-name prefix prefix]
valid-lifetime seconds;
If you set the valid lifetime to 0xffffffff, the lifetime is infinite.
The valid lifetime value must never be smaller than the preferred lifetime value.
Trace Options
To trace router advertisement traffic, you can specify options in the global traceoptions statement at the [edit routing-options] hierarchy level, and you can specify router advertisement options by including the traceoptions statement:
[edit protocols router-advertisement]
traceoptions {
file name <replace> <size size> <files number> <no-stamp>
<(world-readable | no-world-readable)>;
flag flag <flag-modifier> <disable>;
}
Note: Use the trace option flag detail with caution. These flags may cause the CPU to become very busy.
Timing and Configuring Router Advertisements
Default Lifetime
The default lifetime in router advertisement messages indicates the lifetime associated with the default router. To modify the default lifetime timer, include the default-lifetime statement:
[edit protocols router-advertisement interface interface-name]
default-lifetime seconds;
By default, the default router lifetime is three times the maximum advertisement interval.
Min/Max Advertisement Interval
The router sends router advertisements on each interface configured to transmit messages. The advertisements include route information and indicate to network hosts that the router is operational. The router sends these messages periodically, with a time range defined by minimum and maximum values.
To modify the router advertisement interval, include the min-advertisement-interval and maxadvertisement-interval statements:
[edit protocols router-advertisement interface interface-name]
min-advertisement-interval seconds;
max-advertisement-interval seconds;
By default, the maximum advertisement interval is 600 seconds and the minimum advertisement interval is one-third the maximum interval, or 200 seconds.
Reachable Time
After receiving a reachability confirmation from a neighbor, a node considers that neighbor reachable for a certain amount of time without receiving another confirmation. This mechanism is used for neighbor unreachability detection, a mechanism for finding link failures to a target node.
To modify the reachable time limit, include the reachable-time statement:
[edit protocols router-advertisement interface interface-name]
reachable-time milliseconds;
By default, the reachable time period is 0 milliseconds.
Current Hop Limit
The current-hop-limit field in the router advertisement messages indicates the default value placed in the hop count field of the IP header for outgoing packets. To configure the hop limit, include the current hop-limit statement:
[edit protocols router-advertisement interface interface-name]
current-hop-limit number;
The default hop limit is 64.
The default hop limit is 64.