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Packet Flow Monitoring on SONET/SDH Interfaces Overview


The Monitoring Services I and Monitoring Services II PICs are designed to enable IP services. If you have a Monitoring Services PIC and a SONET/SDH PIC installed in an M Series, MX Series, or T Series router, you can monitor IPv4 and IPv6 traffic from another router.

For information about enabling packet flow monitoring on SONET/SDH interfaces, see Enabling Packet Flow Monitoring on SONET/SDH Interfaces.

For the monitoring services interface, you can configure multiservice physical interface properties. For more information, see Configuring Multiservice Physical Interface Properties and the Junos OS Services Interfaces Library for Routing Devices.

To Monitor Packets with MPLS Labels

The Junos OS can forward only IPv4 packets to a Monitoring Services PIC. IPv4 packets with MPLS labels cannot be forwarded to a Monitoring Services PIC. By default, if packets with MPLS labels are forwarded to the Monitoring Services PIC, they are discarded. To monitor packets with MPLS labels, you must remove the MPLS labels as the packets arrive on the interface.

For information about removing MPLS labels from an incoming packet to a Monitoring Services PIC, see Enabling Packet Flow Monitoring on SONET/SDH Interfaces.


On T Series routers, the pop-all-labels command can remove up to five MPLS labels from incoming packets.


When you remove MPLS labels from incoming packets, note the following:

  • By default, the pop-all-labels statement takes effect for incoming packets with one or two labels.

  • The pop-all-labels statement has no effect on IP packets with three or more MPLS labels.

  • When you enable MPLS label removal, you must configure all ports on a PIC with the same label popping mode and required depth.

  • You use the pop-all-labels statement to enable passive monitoring applications, not active monitoring.

  • You cannot apply MPLS filters or accounting to the MPLS labels because the labels are removed as soon as the packet arrives on the interface.