router-preference maximum

Function

The router-preference maximum command configures a rule to match RA messages against the highest route preference in RA messages.

The undo router-preference maximum command deletes the rule used to match RA messages against the highest route preference in RA messages.

By default, no rule is configured to match RA messages against the highest route preference in RA messages.

Format

router-preference maximum { high | medium | low }

undo router-preference maximum

Parameters

Parameter	Description	Value
high	Sets the highest route preference in RA messages to high preference.	-
medium	Sets the highest route preference in RA messages to medium preference.	-
low	Sets the highest route preference in RA messages to low preference.	-

Views

IPv6 RA guard policy view

Default Level

2: Configuration level

Usage Guidelines

RA messages carry the route preference field. Route preferences are classified into high preference (with the value 1), medium preference (with the value 0), and low preference (with the value 3). After receiving an RA message, a host updates its default route list and selects a route in descending order of the route preference.

After a rule is configured in an IPv6 RA guard policy to match RA messages against the highest route preference in RA messages, the interface to which the policy is applied checks the route preference of the received RA messages and forwards the RA messages only when the route preference of the messages is lower than or equal to that configured in the rule. Otherwise, the interface discards the messages.

Example

# In the IPv6 RA guard policy p1, set the highest route preference used to match RA messages to medium preference.

<HUAWEI> system-view
[HUAWEI] nd raguard policy p1
[HUAWEI-nd-raguard-policy-p1] router-preference maximum medium