Allied Telesis AT-S63 - Manual (Page 381)

AT-S63 Management Software Command Line User’s Guide
Section II: Advanced Operations 381
policies in the AT-S63 Management Software Features Guide before you
read this description.
Classifiers are an important component of Quality of Service policies
because they define the traffic flows of the policies. Classifiers have a host
of variables that you can choose from. You might, for instance, create
classifiers that define traffic flows based on source or destination IP
addresses, IP protocols, or Ethernet frame types.
To create policies with the other management interfaces, you have to
create the classifiers separately and afterwards add them to the flow
groups. For instance, to create classifiers from the standard command line
interface you use the CREATE CLASSIFIER command, described in
“CREATE CLASSIFIER” on page 336.
The AlliedWare Plus commands in the first group operate in the same
fashion in that the classifiers have to be created separately from the flow
groups. To use these commands, you first have to create the classifiers.
However, if you’ve read the description of the CREATE CLASSIFIER
command, you’ll see there isn’t an equivalent AlliedWare Plus command
that creates classifiers. So how do you create classifiers for use with the
commands in the first group?
You have two choices. First, you can use a different management
interface, such as the standard command line and the CREATE
CLASSIFIER command. After creating the classifiers, you can enter the
AlliedWare Plus command interface and create the flow groups, specifying
the classifiers created in the other management interface.
Another way is to use the AlliedWare Plus ACCESS-LIST command. You
use this command to create access control lists to control what packets a
port accepts or rejects. But access control lists also use classifiers. What
you can do is create access control lists using the AlliedWare Plus
commands and then add their classifiers to the flow groups. This is
demonstrated in Examples later in this section.
The flow group commands in the second group create the classifiers for
you. For instance, the MATCH TCP-FLAGS command creates a classifier
containing the specified TCP flag.
The AlliedWare Plus commands have other differences from the standard
commands. If you examine the syntax of “CREATE CLASSIFIER” on
page 336, you’ll see that there are a wide range of variables for defining
traffic flows. But the AlliedWare Plus commands support only a subset of
the possible variables. For instance, to create policies for packets
containing defined TCP or UDP port values, you’ have to use the standard
commands or another management interface, because the AlliedWare
Plus commands do not support those classifier criteria.
The same restrictions apply to the variables within the flow groups
themselves. If you examine the syntax of the standard CREATE QOS