Allied Telesis AT-S62 - Manual (Page 277)

AT-S62 Menus Interface User’s Guide
Section II: Advanced Operations 277
5 - DSCP value
Specifies a replacement value to write into the DSCP (TOS) field of
the packets. The range is 0 to 63.
A new DSCP value can be set at all three levels: flow group, traffic
class, and policy. A DSCP value specified in a flow group overrides
a DSCP value specified at the traffic class or policy level. A DSCP
value specified at the traffic class level is used only if no value has
been specified at the flow group level. It will override any value set
at the policy level.
6 - Max Bandwidth
Specifies the maximum bandwidth available to the traffic class.
This parameter determines the maximum rate at which the
ingress port accepts data belonging to this traffic class before
either dropping or remarking occurs, depending on option 3,
Exceed Action. If the sum of the maximum bandwidth for all traffic
classes on a policy exceeds the (ingress) bandwidth of the port to
which the policy is assigned, the bandwidth for the port takes
precedence and the port discards packets before they can be
classified. The range is 0 to 1016 Mbps.
The value for this parameter is rounded up to the nearest Mbps
value when this traffic class is assigned to a policy on a 10/100
port, and up to the nearest 8 Mbps value when assigned to a
policy on a gigabit port (for example, on a gigabit port, 1 Mbps is
rounded to 8 Mbps, and 9 is rounded to 16).
Note
If this option is set to 0 (zero), all traffic that matches that traffic class
is dropped. However, a access control list can be created to match
the traffic that is marked for dropping, or a subset of it, and given an
action of permit, to override this. This functionality can be used to
discard all but a certain type of traffic.
7 - Burst Size
Specifies the size of a token bucket for the traffic class. The range
is 4 to 512 Kbps.
The token bucket is used in situations where you set a maximum
bandwidth for a class, but where traffic activity may periodically
exceed the maximum. A token bucket can provide a buffer for
those periods where the maximum bandwidth is exceeded.
Tokens are added to the bucket at the same rate as the traffic
class’ maximum bandwidth, set with option 6, Max Bandwidth.
For example, a maximum bandwidth of 50 Mbps adds tokens to
the bucket at the same rate.