Limiting the Number of Paths and Prefixes Accepted from CE Routers in Layer 3 VPNs
You can configure a maximum limit on the number of prefixes and paths that can be installed into the routing tables. Using prefix and path limits, you can curtail the number of prefixes and paths received from a CE router in a VPN. Prefix and path limits apply only to dynamic routing protocols, and are not applicable to static or interface routes.
To limit the number of paths accepted by a PE router from a CE router, include the maximum-paths statement:
For a list of hierarchy levels at which you can configure this statement, see the statement summary section for this statement.
To limit the number of prefixes accepted by a PE router from a CE router, include the maximum-prefixes statement:
For a list of hierarchy levels at which you can configure this statement, see the statement summary section for this statement.
A mandatory path or prefix limit, in addition to triggering a warning message, rejects any additional paths or prefixes once the limit is reached.
 | Note: Setting a path or prefix limit might result in unpredictable dynamic routing protocol behavior. |
You can also configure the following options for both the maximum-paths and maximum-prefixes statements:
- log-interval—Specify the interval at which log messages are sent.
- log-only—Generate warning messages only. No limit is placed on the number of paths or prefixes stored in the routing tables.
- threshold—Generate warning messages after the specified percentage of the maximum paths or prefixes has been reached.
