Description

Starting from Junos OS Release 16.1R1, any changes to the configured size of the flow table does not require a reboot of the FPC (for earlier releases, changing the flow hash table size triggers the FPC to reboot), but the flow table size needs time to get programmed into PFE. Double check if all changes have been programed into PFE fully with the following PFE command:

Output before changing flow-table-size 

root@mx960> request pfe execute command "show jnh 0  inline-services  flow-table-info" target fpc3 
Sep 07 15:25:35
SENT: Ukern command: show jnh 0  inline-services  flow-table-info

 Configured IPv4 Flow Table in Unit: 3
 Configured IPv6 Flow Table in Unit: 3
 Configured BRIDGE Flow Table in Unit: 0
 Configured MPLS Flow Table in Unit: 0
 Programmed IPv4 Flow Table Size   : 825804
 Programmed IPv6 Flow Table Size   : 825804
 Programmed BRIDGE Flow Table Size   : 1024
 Programmed MPLS Flow Table Size   : 1024
<snip>

Change to flow table size from 3 to 5: 

{MASTER}[edit]
root@mx960# show | compare
Sep 07 15:27:19
[edit chassis fpc 3 inline-services flow-table-size]
-     ipv4-flow-table-size 3;
+     ipv4-flow-table-size 5;
-     ipv6-flow-table-size 3;
+     ipv6-flow-table-size 5;

{MASTER}[edit]
root@mx960# commit
Sep 07 15:27:22
re1:
configuration check succeeds
re0:
commit complete
re1:
commit complete

Output after changing the flow table size: 

{MASTER}
root@mx960> request pfe execute command "show jnh 0  inline-services  flow-table-info" target fpc3
Sep 07 15:32:02
SENT: Ukern command: show jnh 0  inline-services  flow-table-info

Configured IPv4 Flow Table in Unit: 5  
Configured IPv6 Flow Table in Unit: 5
Configured BRIDGE Flow Table in Unit: 0
Configured MPLS Flow Table in Unit: 0
Programmed IPv4 Flow Table Size   : 1376305   <-- Programed into PFE successully
Programmed IPv6 Flow Table Size   : 1376305   <-- Programed into PFE successully
Programmed BRIDGE Flow Table Size   : 1024
Programmed MPLS Flow Table Size   : 1024
IPv6 Extended Attribute   : 0

Symptoms

After changing flow-table size from 3 to 5, there seems to be no active flow. This inline Jflow worked fine before the size  change.

3 families of table-size 5 

root@mx960> show configuration groups INLINE-IPFIX chassis
Sep 02 15:17:39
fpc 4 {
    sampling-instance inline-jflow-instance;
    inline-services {
        flow-table-size {
            ipv4-flow-table-size 5;
            ipv6-flow-table-size 5;
            mpls-flow-table-size 5;
        }
    }
}
fpc 5 {
    sampling-instance inline-jflow-instance;
    inline-services {
        flow-table-size {
            ipv4-flow-table-size 5;
            ipv6-flow-table-size 5;
            mpls-flow-table-size 5;
        }
    }
}

Change to table-size 3 

{MASTER}[edit groups INLINE-IPFIX chassis]
root@mx960# set fpc 5 inline-services flow-table-size ipv4-flow-table-size 3 ipv6-flow-table-size 3 mpls-flow-table-size 3   
Sep 02 15:18:41
 
{MASTER}[edit groups INLINE-IPFIX chassis]
root@mx960# show
Sep 02 15:18:42
fpc 4 {
    sampling-instance inline-jflow-instance;
    inline-services {
        flow-table-size {
            ipv4-flow-table-size 3;
            ipv6-flow-table-size 3;
            mpls-flow-table-size 3;
        }
    }
}
fpc 5 {
    sampling-instance inline-jflow-instance;
    inline-services {
        flow-table-size {
            ipv4-flow-table-size 3;
            ipv6-flow-table-size 3;
            mpls-flow-table-size 3;
        }
    }
}

No more active flows: 

{MASTER}
root@mx960> show services accounting flow inline-jflow fpc-slot 4
Sep 02 15:18:57
  Flow information
    FPC Slot: 4
    Flow Packets: 2126, Flow Bytes: 2928370
    Active Flows: 0, Total Flows: 1404              <-- No active flow
    Flows Exported: 2709, Flow Packets Exported: 2697
    Flows Inactive Timed Out: 489, Flows Active Timed Out: 903
    Total Flow Insert Count: 501
 
    IPv4 Flows:
    IPv4 Flow Packets: 2126, IPv4 Flow Bytes: 2928370
    IPv4 Active Flows: 0, IPv4 Total Flows: 1404    <-- No active flow
    IPv4 Flows Exported: 2709, IPv4 Flow Packets exported: 2697
    IPv4 Flows Inactive Timed Out: 489, IPv4 Flows Active Timed Out: 903
    IPv4 Flow Insert Count: 501
 
    IPv6 Flows:
    IPv6 Flow Packets: 0, IPv6 Flow Bytes: 0
    IPv6 Active Flows: 0, IPv6 Total Flows: 0
    IPv6 Flows Exported: 0, IPv6 Flow Packets Exported: 0
    IPv6 Flows Inactive Timed Out: 0, IPv6 Flows Active Timed Out: 0
    IPv6 Flow Insert Count: 0
 
    MPLS Flows:
    MPLS Flow Packets: 0, MPLS Flow Bytes: 0
    MPLS Active Flows: 0, MPLS Total Flows: 0
    MPLS Flows Exported: 0, MPLS Flow Packets Exported: 0
    MPLS Flows Inactive Timed Out: 0, MPLS Flows Active Timed Out: 0
    MPLS Flow Insert Count: 0
 
{MASTER}
root@mx960> show services accounting flow inline-jflow fpc-slot 5   
Sep 02 15:18:59
  Flow information
    FPC Slot: 5
    Flow Packets: 246, Flow Bytes: 338988
    Active Flows: 0, Total Flows: 52          <-- No active flow
    Flows Exported: 117, Flow Packets Exported: 117
    Flows Inactive Timed Out: 7, Flows Active Timed Out: 39
    Total Flow Insert Count: 13
 
    IPv4 Flows:
    IPv4 Flow Packets: 246, IPv4 Flow Bytes: 338988
    IPv4 Active Flows: 0, IPv4 Total Flows: 52   <-- No active flow
    IPv4 Flows Exported: 117, IPv4 Flow Packets exported: 117
    IPv4 Flows Inactive Timed Out: 7, IPv4 Flows Active Timed Out: 39
    IPv4 Flow Insert Count: 13
 
    IPv6 Flows:
    IPv6 Flow Packets: 0, IPv6 Flow Bytes: 0
    IPv6 Active Flows: 0, IPv6 Total Flows: 0
    IPv6 Flows Exported: 0, IPv6 Flow Packets Exported: 0
    IPv6 Flows Inactive Timed Out: 0, IPv6 Flows Active Timed Out: 0
    IPv6 Flow Insert Count: 0
 
    MPLS Flows:
    MPLS Flow Packets: 0, MPLS Flow Bytes: 0
    MPLS Active Flows: 0, MPLS Total Flows: 0
    MPLS Flows Exported: 0, MPLS Flow Packets Exported: 0
    MPLS Flows Inactive Timed Out: 0, MPLS Flows Active Timed Out: 0
    MPLS Flow Insert Count: 0

Solution

Wait a few minutes to check if flow table size gets programmed into PFE fully after changing the flow table size for any family. Inline JFlow will also work as expected once it is programmed.

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