Description

This article explains the log message displayed when inline active flow monitoring (JFlow) is configured along with Routing Engine-based sampling (NetFlow v5), and inline sampling is enabled on 20 FPCs (MX2020 router).

Symptoms

When configuring inline active flow monitoring (JFlow sampling) on MX2020, if sampling is enabled on all 20 FPCs along with RE-based sampling, the following log messages are reported:

fpc10 PFEMAN_SVC_JFLOW:Failed to connect SRRD on RE
fpc10 PFEMAN_SVC_JFLOW: Socket to SRRD closed

When inline sampling is enabled on MX Series FPCs, the srrd (Sampling Route-Record Daemon) process is created to maintain, collect and export JFlow records. On regular time intervals, the srrd process scans through the sampling database for any update/change in the record.

Solution

In Junos OS 15.1F5 (14.2) and later, the maximum value for srrd clients is set to 20 (MX2020 max slot number) as part of the performance enhancement.

The configuration in which inline sampling (IPFIX) is configured on all 20 FPCs along with RE-based sampling (NetFlow v5) results in having 21 clients to srrd , i.e. 20 FPCs and the 'sampled' daemon (that does RE-based sampling). This results in the situation in which one of the FPCs will not get connected to the srrd process. The resulting impact is that the flow records from the unconnected FPC will not have route information.

Configuring inline active flow monitoring (JFlow) on all 20 FPCs makes RE-based sampling unusable since none of the packets sampled will be sent to the 'sampled' daemon on the RE.

The following considerations apply to the inline flow monitoring instance configuration:

  • User-defined sampling instance gets precedence over the global instance. When a user-defined sampling instance is attached to the FPC, the global instance is removed from the FPC and the user-defined sampling instance is applied to the FPC.
  • Assuming that the inline active flow monitoring (JFlow) is the required model for sampling, removing the RE-based sampling from the configuration will bring down the maximum clients of srrd to 20. This will allow successful connections from all 20 FPC clients to the srrd process.

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