Classification; Policy Resources; Packet Mirroring - Juniper E320 Configuration Manual

Classification

Classification is the process of taking a single data stream in and sorting it into
multiple output substreams. The classifier engine on an E-series router is a
combination of PowerPC processors, working with a Field Programmable Gate
Array (FPGA) for a hardware assist.
In the Differentiated Services (DiffServ) architecture, two basic types of classifiers
exist. The first classifier type is a multifield (MF) classifier, which examines multiple
fields in the IP datagram header to determine the service class to which a packet
belongs. The second type of classifier is a behavior aggregate (BA) classifier, which
examines a single field in an IP datagram header and assigns the packet to a service
class based on what it finds.
There are two categories of hardware classifiers, depending on the type of line
module being used. OC48/STM16, GE-2, and GE-HDE line modules support
content-addressable memory (CAM) hardware classifiers—all other line modules
support FPGA hardware classifiers.

Policy Resources

The maximum number of policies that you can attach to interfaces on an E-series
router depends on the classifier entries that make up the policy and the number of
attachment resources available on the interface. JUNOSe software allocates
interface attachment resources when you attach policies to interfaces. E-series
routers support software and hardware classifiers. A policy can be made up of any
combination of software and hardware classifiers.

Packet Mirroring

Packet mirroring enables you to 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 enables you to mirror traffic traversing a specific interface or
traffic that is to or from a particular user. Packet mirroring is always transparent to
users and does not affect the delivery of the original traffic. In some cases, the
means and authority for conducting packet mirroring can depend on the
regulations of specific countries.
In the past, the most common method of packet mirroring was sometimes referred
to as interface mirroring or port mirroring because service providers used it to
replicate a particular interface's traffic. JUNOSe software supports both
interface-specific packet mirroring and a more robust, flexible, and secure
user-specific packet mirroring. It provides CLI-based and RADIUS-based methods
that you can use to configure and manage your packet mirroring environment.
Chapter 1: Policy Management Overview
Overview
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