Example: Configuring Active Flow Monitoring Version 9 for MPLS

Requirements

• Junos OS Release 9.2 or later
• One M Series Multiservice Edge Router, MX Series 3D Universal Edge Routers, or T Series Core Router
• One Adaptive Services PIC

Overview of Flow Monitoring

This example explains how to monitor MPLS flows.

The physical connections used in this example are shown in Figure 1.

Figure 1: Active Flow Monitoring Version 9 for MPLS Topology

Configuring Active Flow Monitoring Version 9 for MPLS

Step-by-Step Procedure

1. Enable the services PIC interface to process MPLS addresses by including the family statement and specifying the mpls option at the [edit interfaces sp-1/1/0 unit 0] hierarchy level.
   [edit interfaces]

   sp-1/1/0 {unit 0 {family mpls;}}
2. Configure the interface connected to the flow collector by including the address statement and specifying 100.1.1.1/24 as the IPv4 address of the interface at the [edit interfaces ge-1/1/3 unit 0 family inet] hierarchy level.
   [edit interfaces]

   ge-1/1/3 {description to-flow-collector;unit 0 {family inet {address 100.1.1.1/24;}}}
3. Create a version 9 template by including the template statement and specifying mpls as the name of the template at the [edit services flow-monitoring version9] hierarchy level.

   Enable the template for MPLS flows by including the mpls-template statement at the [edit services flow-monitoring version9 template mpls] hierarchy level. Also include the label-position statement and specify label positions 1 and 2 at the [edit services flow-monitoring version9 template mpls mpls-template] hierarchy level.

   Configure the flow active timeout by including the flow-active-timeout statement and specifying 600 seconds at the [edit services flow-monitoring version9 template mpls] hierarchy level. Configure the flow inactive timeout by including the flow-inactive-timeout statement and specifying 30 seconds at the [edit services flow-monitoring version9 template mpls] hierarchy level.

   [edit services]

   flow-monitoring {version9 {template mpls {flow-active-timeout 600;flow-inactive-timeout 30;mpls-template {label-position [ 1 2 ];}}}}
4. Configure the rate at which the router sends template definitions and options to the flow collector for MPLS.

   Since version 9 flow monitoring traffic is unidirectional from the monitor (router) to the flow collector, configure the monitor to send template definitions and options, such as sampling rate, to the collector.

   In this example, the template definitions and options are refreshed every 600 seconds or 480000 packets, whichever occurs first.

   Include the packets statement and specify 480000 packets at the [edit services flow-monitoring version9 template mpls template-refresh-rate] and [edit services flow-monitoring version9 template mpls option-refresh-rate] hierarchy levels. Include the seconds statement and specify 600 seconds at the [edit services flow-monitoring version9 template mpls template-refresh-rate] and [edit services flow-monitoring version9 template mpls option-refresh-rate] hierarchy levels.

   [edit services flow-monitoring version9 template mpls]

   template-refresh-rate {packets 480000;seconds 600;}

   option-refresh-rate {packets 480000;seconds 600;}
5. Configure the sampling rate and run length.

   The sampling rate determines the ratio of the number of packets to be sampled. For example, if you specify a rate of 10, 1 out of every 10 packets is sampled. In this example, the rate is 1 out of every 1 packets.

   Sampling can be configured as a global chassis configuration that is applicable to all Flexible PIC Concentrators (FPCs) and Dense Port Concentrators (DPCs) at the [edit forwarding-options sampling input] hierarchy level. Sampling can also be configured at the [edit forwarding-options sampling instance instance-name] hierarchy level and then applied to a single FPC.

   In this example two sampling categories are created. The global instance is configured to sample all packets matching a flow. Instance inst1 is configured to sample one in every 10 packets.

   To configure the global rate, include the rate statement and specify 1 as the rate at the [edit forwarding-options sampling input] hierarchy level. To configure the instance rate, include the rate statement and specify 10 as the rate at the [edit forwarding-options sampling instance ins1 input] hierarchy level.

   [edit forwarding-options]

   sampling {input {rate 1;}instance ins1 {input {rate 10;}}}
6. Apply the sampling instance to the desired FPC or DPC.

   The FPC number must match the FPC portion of the interface name for the interface on which sampling is enabled.

   To apply the sampling instance, include the sampling-instance statement and specify ins1 at the [edit chassis fpc 1] hierarchy level.

   [edit]

   chassis {fpc 1 {sampling-instance ins1;}}
7. Configure the flow collector and enable active flow monitoring using the version 9 template format.

   To configure the flow collector, include the flow-server statement and specify the IP address of the host system that is collecting traffic flows using version 9 at the [edit forwarding-options sampling instance ins1 family mpls output] hierarchy level. Also include the port statement and specify UDP port 2055 for use by the flow collector.

   To enable active flow monitoring using the version 9 template format, include the template statement and specify mpls as the name of the template to use at the [edit forwarding-options sampling instance ins1 family mpls output flow-server 100.1.1.2 version9] hierarchy level.

   [edit forwarding-options sampling instance ins1]

   family mpls {output {flow-server 100.1.1.2 {port 2055;version9 {template mpls;}}}}
8. Configure the IPv4 source address for the services PIC to be used in flow export.

   To configure the IPv4 source address for the sp-1/1/0 interface, include the source-address statement and specify 12.1.1.1 at the [edit forwarding-options sampling instance ins1 family mpls output interface sp-1/1/0] hierarchy level.

   [edit forwarding-options sampling instance ins1 family mpls output]

   interface sp-1/1/0 {source-address 12.1.1.1;}
9. Configure the firewall filter.

   The firewall filter identifies the traffic flows that need to be sampled and processed by the services PIC. Note that the implied “from” clause in the filter determines the packets that are matched and sampled according to the sampling rate.

   To configure the firewall filter, include the filter statement and specify mpls_sample_filter as the name of the filter at the [edit firewall family inet] hierarchy level. Include the term statement and specify 1 as the name of the term. For active monitoring using version 9, you must include the sample and accept action statements at the [edit firewall family mpls filter mpls_sample_filter term 1 then] hierarchy level.

   [edit firewall]

   family mpls {filter mpls_sample_filter {term 1 {then {sample;accept;}}}}
10. Apply the firewall filter to the set of media interfaces where traffic flow needs to be sampled.

    To apply the firewall filter to the ge-1/1/0 interface, include the input statement and specify mpls_sample_filter as the name of the filter at the [edit interfaces ge-1/1/0 unit 0 family mpls filter] hierarchy level.

    [edit]

    interfaces {ge-1/1/0 {unit 0 {family mpls {filter {input mpls_sample_filter;}}}}}

Results

For your reference, the relevant sample configuration for the MPLS flow collector follows.