Analyzer Overview; Statistical Analyzer Overview - Juniper EX9200 Features Manual

Port Mirroring Analyzers Feature Guide for EX9200 Switches
Understanding Port Mirroring Analyzers
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Port mirroring can be used for traffic analysis on routers and switches that, unlike hubs,
do not broadcast packets to every port on the destination device. Port mirroring sends
copies of all packets or policy-based sample packets to local or remote analyzers where
you can monitor and analyze the data.
In the context of port mirroring analyzers, we use the term switching device. The term
indicates that the device (including routers) is performing a switching function.
You can use analyzers on a packet level to help you:
Monitor network traffic
Enforce network usage policies
Enforce file sharing policies
Identify causes of problems
Identify stations or applications with heavy or abnormal bandwidth usage
You can configure an analyzer to mirror:
Bridged packets (Layer 2 packets)
Routed packets (Layer 3 packets)
Mirrored packets can be copied to either a local interface for local monitoring or a VLAN
or bridge domain for remote monitoring.
The following packets can be copied:
Packets entering or exiting a port—You can mirror packets entering or exiting ports,
in any combination, for up to 256 ports. For example, you can send copies of the packets
entering some ports and the packets exiting other ports to the same local analyzer
port or analyzer VLAN.
Packets entering or exiting a VLAN or bridge domain—You can mirror the packets
entering or exiting a VLAN or bridge domain to either a local analyzer port or to an
analyzer VLAN or bridge domain. You can configure multiple VLANs (up to 256 VLANs)
or bridge domains as ingress inputs to an analyzer, including a VLAN range and private
VLANs (PVLANs).
Policy-based sample packets—You can mirror a policy-based sample of packets that
are entering a port, VLAN, or bridge domain. You configure a firewall filter with a policy
to select the packets to be mirrored. You can send the sample to a port-mirroring
instance or to an analyzer VLAN or bridge domain.
This topic describes:
Analyzer Overview on page 5
Statistical Analyzer Overview on page 5
Copyright © 2016, Juniper Networks, Inc.