Juniper POLICY MANAGEMENT - CONFIGURATION GUIDE V11.1.X Configuration Manual page 281

Establish Resource Guidelines
Next, using the traffic loads that you determined for the line module, you can establish
guidelines for the amount of packet mirroring traffic for your router.
If you exceed these guidelines, regular (non-packet mirroring) packets from all
subscribers, including nonmirrored subscribers, will be dropped. If the fabric
bandwidth is not exceeded, then the performance penalties are contained within
the slot where the packet mirroring activity occurs. However, if the fabric bandwidth
is exceeded, traffic from other line modules might also be dropped.
NOTE: Packet mirroring can also affect the forwarding controller's packet handling
performance.
Logging Packet Mirroring Information
The JUNOSe software's packet mirroring feature provides two secure methods of
capturing and displaying packet mirroring-related information. Both methods ensure
security by requiring the mirror-enable command to be enabled.
(A + 2X + Y) must be less than the maximum fabric bandwidth supported from
this line module.
(2X + Y) must be less than 100Mbps (the enforced queue limit).
The 100 Mbps limit does not apply to the following line modules:
GE-2 line module (Juniper Networks ERX310 and ERX1440 Broadband
Services Routers)
GE-HDE line module (ERX310 and ERX1440 router)
OC48 Frame APS I/O module (ERX1440 router only)
ES2 4G LM (E120 router and E320 Broadband Services Routers)
ES2 10G LM (E120/E320)
(B + X ) must be less than the maximum supported egress bandwidth.
The number of mirrored interfaces per line module must be less than 1023 (the
configuration enforced for secure policy attachments).
The number of interfaces mirrored per chassis must be less than 2400 (the
configuration enforced for secure policy attachments).
Secure logging Captures packet mirroring information to a local secure log on
the router.
SNMP secure packet mirroring traps Captures and reports packet mirroring
information to an external device; you can then use the privileged show mirror
trap and show snmp traps CLI commands to view secure trap configuration
information.
Chapter 13: Managing Packet Mirroring
Logging Packet Mirroring Information
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