(Optional) Configuring a Limit on the Number of PIM-SM Entries

IPv6 PIM-SM allows you to limit the number of (S, G) and (*, G) entries separately. After a specified limit is reached, new entries of the corresponding type cannot be created.

Context

Limit the number of PIM-SM entries to prevent a device from generating excessive multicast routing entries when attackers send numerous multicast data or MLD/PIM protocol messages. Therefore, this function helps prevent high memory and CPU usage and improve multicast service security.

Procedure

In a public network scenario, configure a limit on the number of PIM-SM entries and alarm thresholds.
1. Run system-view
  The system view is displayed.
2. Run
  A limit on the maximum number of PIM-SM entries and alarm thresholds are configured.
  
  star-group-number indicates that the configuration takes effect for (*, G) entries. source-group-number indicates that the configuration takes effect for (S, G) entries. After the command is run:
  - After the specified limit is reached, new entries cannot be created, and the alarm PIM_1.3.6.1.4.1.2011.5.25.149.4.0.23 routeExceed is generated.
  - If threshold-alarm upper-limit upper-limit-value is set, the alarm PIM_1.3.6.1.4.1.2011.5.25.149.4.0.21 routeThresholdExceed is generated when the percentage ratio of created PIM-SM entries to the specified limit reaches upper-limit-value.
  After the specified limit is reached, new (*, G) and (S, G) entries can be manually added, and ASM share-group entries for Rosen MVPN can be created.
3. Run commit
  The configuration is committed.
In a VPN instance, configure a limit on the number of PIM-SM entries and alarm thresholds.
1. Run system-view
  The system view is displayed.
2. Run ip vpn-instance vpn-instance-name
  The VPN instance view is displayed.
3. Run ipv6-family
  The VPN instance IPv6 address family view is displayed.
4. Run route-distinguisher route-distinguisher
  An RD is configured for the VPN instance's IPv6 address family.
5. Run multicast ipv6 routing-enable
  IPv6 multicast routing is enabled.
6. Run multicast ipv6 limit pim sm { star-group-number | source-group-number } limit-count [ threshold-alarm upper-limit upper-limit-value lower-limit lower-limit-value ]
  A limit on the number of PIM-SM entries and alarm thresholds are set. star-group-number indicates that the configuration takes effect for (*, G) entries. source-group-number indicates that the configuration takes effect for (S, G) entries. After the command is run:
  - If the number of PIM-SM entries in the IPv6 address family of a VPN instance reaches a configured limit, new entries fail to be created and the alarm PIM_1.3.6.1.4.1.2011.5.25.149.4.0.32 hwPimVrfTypeSGExceed is triggered.
  - If upper-limit upper-limit-value is specified and the number of PIM-SM entries in the IPv6 address family of a VPN instance reaches the configured alarm trigger threshold, the alarm PIM_1.3.6.1.4.1.2011.5.25.149.4.0.30 hwPimVrfTypeSGThresholdExceed is triggered.
  Manually created (*, G) and (S, G) entries are not affected by a limit on the maximum number of PIM-SM entries in the IPv6 address family of a VPN instance. The limit takes effect only on dynamic (*, G) and (S, G) entries.
7. Run commit
  The configuration is committed.