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Hierarchy Level


Configure the size of hash tables for inline services sampling.

Starting with Junos OS Release 15.1F2, by default, the software allocates one 1K IPv4 flow table. To allocate 15 256K IPv4 flow tables, the former default, you can enter this configuration from the [edit] hierarchy level:

The maximum supported flow table size for a combination of both IPv4 and IPv6 is 15. For example, you can set the flow table size for IPv4 to 10 and set the size for IPv6 to 5. Verify that you have sized the flow tables adequately for IPv4 and IPv6 flow sampling.


The recommended flow table size is 4 so that it can scale up to 4x256K flows, which is 1M. You can configure more; however, the system will issue a warning message.


We recommend that you configure this statement during a maintenance window:

  • Prior to Junos OS 16.1R1 and 15.1F2, the FPC reboots automatically after you commit this configuration change.
  • Starting from Junos OS Release 16.1R1 and 15.1F2, any changes in the configured size of the flow table do not require a reboot of the FPC.

The remaining statements are defined separately.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 12.1.

ipv6-extended-attrib option added in Junos OS Release 14.2 for MX Series routers.

vpls-flow-table-size option added in Junos OS Release 13.2 for MX Series routers.

bridge-flow-table-size option added in Junos OS Release 18.2R1 for MX Series routers, replacing the vpls-flow-table-size option, which has been deprecated.