3Com 4007, Руководство по внедрению, Страница: 309 / 684

Key Concepts 309
Key Concepts
Before you use packet filters, review the following key concepts and
terms:
■
Standard Filters — Packet filters that are supplied with the
Switch 4007 that the hardware executes at wire speed. You can load
them from the Administration Console, or select them from the set of
predefined filters with the Filter Builder application. (Filter Builder is
part of the Web Management suite of applications. See Table 63 later
in this chapter.)
At present, one standard hardware filter is supported: the portGroup
(rejdiffportgrp) filter.
■
Custom Filters — Packet filters that are executed in software. You
create custom filters in any of these ways:
■
By writing a filter definition using the filter definition language.
■
By selecting from among the predefined custom filters provided by
the Filter Builder application
■
By using the Filter Builder’s wizards to construct a new filter. (See
Table 63 later in this chapter.)
■
Predefined filters — Hardware and software filters that are supplied
with the Filter Builder application. Filter Builder provides one standard
filter that is executed by the hardware; the others are custom filters
that are executed in software. (See Table 63 later in this chapter.)
■
Port Groups — A collection of ports that you can reference in a
packet filter. You create port groups from the Administration Console.
You can specify different filtering rules between various port groups.
Standard Packet
Filters
The Switch 4007 hardware supports standard packet filters. Standard
filters are implemented in the ASIC hardware to achieve the wirespeed
performance. To load them, use the Administration Console’s
bridge
packetfilter create
command.
At present, one standard hardware filter is supported: the portGroup
(rejdiffportgrp) filter.
Standard packet filter support in the hardware is limited to the receive all
and
transmit all
paths. Hardware filtering on the
receive multicast,
transmit multicast, and receive internal paths is not available; therefore, if
you assign a standard filter to one of these paths, the module implements
the filter in the software, which can affect performance.