Packet Mirroring Overview - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - POLICY MANAGEMENT CONFIGURATION GUIDE 2010-10-04 Configuration Manual

CHAPTER 10

Packet Mirroring Overview

Packet Mirroring Overview
Copyright © 2010, Juniper Networks, Inc.
This chapter contains the following sections:
Packet Mirroring Overview on page 213
Comparing CLI-Based Mirroring and RADIUS-Based Mirroring on page 214
Packet-Mirroring Terms on page 216
Packet Mirroring Platform Considerations on page 216
Packet Mirroring References on page 217
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.
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