Extreme Networks BlackDiamond 6800, Installation And User Manual

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3-34 Asynchronous Transfer Mode (ATM) Module Installation and User Guide
Configuring the ATM Module
To configure the mapping between a DiffServ code point and a specified QoS profile,
use the following command:
config diffserv examination code-point <code_point>
qosprofile <qosprofile> ports <portlist>
{low-drop-probability | high-drop-probability}
The mapping is applied in the ingress direction—for IP packets received from the ATM
link.
The optional
low-drop-probability
and
high-drop-probability
keywords apply
only to ATM ports. If you do not enter either of these keywords in the command, the
command uses
low-drop-probability
as the default.
The
low-drop-probability
and
high-drop-probability
keywords are useful in
conjunction with the Weighted RED (WRED) implementation provided by ATM ports.
This implementation supports two different drop probabilities: one for DiffServ code
points designated as having low drop-probability; another for DiffServ code points
designated as having high drop-probability. These keywords give you complete
flexibility in assigning DiffServ code points to these two drop-probability levels.
Configuring DiffServ Code Point Mapping Tables
You can use the
diffserv dscp-mapping
command to configure a mapped relationship
between an input DSCP and an associated output DSCP. Each ATM port supports three
DSCP mapping tables: one of the tables is used in the ingress direction; two are used for
egress flows (onto the ATM link). The two egress tables are for the congested and
noncongested states, as determined by the RED algorithm. If RED is not enabled on the
ATM port, the egress congested-state mapping table is not used.
In the ingress direction, the input DSCP of a packet received from the ATM link is
replaced by an output DSCP before the packet is forwarded. In the egress direction, the
operation is similar, except that the DSCP mapping occurs before the packet is
transmitted onto the ATM link.
40-47 Qp6
48-55 Qp7
56-63 Qp8
Table 3-9: Default Code Point-to-QoS Profile Mapping (continued)
Code Point QoS Profile