Extreme Networks BlackDiamond 6800, Инструкция по установке и эксплуатации

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Asynchronous Transfer Mode (ATM) Module Installation and User Guide 3-35
Configuring QoS Functions
One potential use of the DSCP mapping capability is to reconcile varying DiffServ
policies at the boundary between autonomous systems, such as at the boundary
between two ISPs. The availability of different tables for the congested and
noncongested states is useful in marking operations that increase the probability of
packets being dropped during times of congestion, as discussed in the DiffServ Assured
Forwarding RFC (RFC 2597).
This command applies only to ATM ports with IP frames that are encapsulated
for bridged or routed protocols. You should also be aware that DSCP mapping is
performed even when the
diffserv examination
function is disabled on the
port.
To configure the mapping between an input DSCP and an associated output DSCP, use
the following command:
config diffserv dscp-mapping <input_codepoint>/<output_codepoint>
ports <portlist> {egress {no-congestion | congestion} | ingress}
where:
If you omit the
no-congestion
and
congestion
keywords, the command applies the
mapping to the tables for both states.
If you omit the
egress
and
ingress
keywords, the command applies the mapping to
the egress direction, and automatically configures a symmetrical mapping (with the
input_codepoint
and
output_codepoint
values reversed) in the ingress direction.
By default, all the tables are initialized such that DSCPs are not altered by the mapping
operations. For example, an input DSCP value of n is always mapped to an output
DSCP value of n.
input_codepoint
Specifies one of the 64 possible DiffServ code point values as the
input code point.
output_codepoint
Specifies one of the 64 possible DiffServ code point values as the
output code point.
egress
Applies the DSCP mapping to the egress direction.
no-congestion
Applies the DSCP mapping to the egress mapping table for the
non-congested state.
congestion
Applies the DSCP mapping to the egress mapping table for the
congested state.
ingress
Applies the DSCP mapping to the ingress direction.