Figure 20: Cli-Based Packet Mirroring; Chapter 10 Packet Mirroring Overview - Juniper POLICY MANAGEMENT - CONFIGURATION GUIDE V11.1.X Configuration Manual

Chapter 10
Packet Mirroring Overview
Packet Mirroring Overview
This chapter contains the following sections:
Packet Mirroring Overview on page 219
Comparing CLI-Based Mirroring and RADIUS-Based Mirroring on page 220
Packet-Mirroring Terms on page 222
Packet Mirroring Platform Considerations on page 222
Packet Mirroring References on page 223
Packet mirroring enables you to automatically send a copy of a packet to an external
host for analysis. Packet mirroring has many uses, including traffic debugging and
troubleshooting user networking problems.
The JUNOSe software provides two methods that you can use to configure and manage
your packet-mirroring environment CLI-based and RADIUS-based.
CLI-based packet mirroring An authorized operator uses the router's CLI
commands to configure and manage packet mirroring. You can mirror traffic
related to a specific IP, IPv6, or L2TP interface or traffic related to a particular
user. You also use CLI commands to create secure policies that identify the traffic
to be mirrored and specify how the mirrored traffic is treated.
RADIUS-based packet mirroring A RADIUS administrator uses RADIUS attributes
to configure packet mirroring of a particular user's traffic. The router creates
dynamic secure policies for the mirroring operation.
In both the CLI-based and the RADIUS-based packet mirroring methods, the original
traffic is sent to its intended destination and the mirrored traffic is sent to an analyzer
(the mediation device). The mirroring operations are transparent to the user whose
traffic is being mirrored.
NOTE: Packet-mirroring operations require some system resources. To avoid
performance degradation, limit the amount of mirrored traffic to a maximum of 5
percent of the E Series router's total traffic.
Packet mirroring is supported on ASIC-based modules. See ERX Module Guide,
Appendix A, Module Protocol Support for information about modules supported on
Packet Mirroring Overview
219