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Hierarchy Level


Set the maximum packet length to be used for port mirroring or traffic sampling. Packets longer than the maximum are truncated. This statement cannot be used with inline flow monitoring ([edit forwarding-options sampling instance instance-name family (inet | inet6) output inline-jflow] .


For MX Series routers with Modular Port Interface Concentrators (MPCs), when maximum-packet-length (clip length) is configured for port-mirrored packets and the mirror-destination interface is a next-hop-group, the clip length is effective only for the first member interface of the next-hop-group. The mirrored packet copy sent to the rest of the interfaces is not clipped.

In addition, native analyzer sessions (that is, the [edit forwarding-options analyzer analyzer-name input] hierarchy level for MX Series routers) can be configured without specifying input parameters. As such, these instances use the following input values by default: rate = 1, and maximum-packet-length = 0.


bytes—Maximum length (in bytes) of the mirrored packet or the sampled packet.

Set the maximum-packet-length value to zero to disable truncation; that is, to mirror or sample the entire packet. Otherwise, Juniper recommends that you configure the packet length to be equal to, or greater than, the IP header length. For IPv4, set the maximum length to at least 20, and for IPv6, set the maximum length to at least 40.

  • Range: 0 through 9216. For MX Series routers with MPCs, and for EX9200 switches, the range is 1 through 255 bytes.

  • Default: 0

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 9.6.

For MX Series routers except the MX 80, support at the [edit forwarding-options analyzer analyzer-name input] hierarchy level was introduced in Junos OS Release 14.1