Extreme Networks BlackDiamond 6800 Installation And User Manual page 74

Configuring the ATM Module
configured ATM ports. Functions such as access list and destination MAC address QoS
policies are supported, as is the command.
enable diffserv replacement
Egress frames are always assigned to a QoS profile based on their 802.1p priority. Thus,
when an ATM port receives a frame from the switch fabric with a priority value n, that
frame is assigned to egress QoS profile qpn+1.
The existing and
enable diffserv examination ports disable diffserv
commands are used on ATM ports to control whether the DiffServ
examination ports
code point (DSCP) is examined for ingress classification purposes.
When you enable the LLC Encapsulation for Bridged Protocols on an ATM port, non-IP
frames that contain a VLAN tag are assigned to an ingress QoS profile based on their
802.1p priority value. You can configure this assignment using the
config dot1p type
command, which is used to specify the mappings between 802.1p priority values and
QoS profiles. However, if an ATM port receives a frame with a priority value n, for
which there is no mapping to one of the eight profiles (qp1-qp8), that frame is assigned
to ingress QoS profile qpn+1.
If is not enabled, then the preceding 802.1p priority
diffserv examination
classification rules are applied to tagged IP frames as well.
In both cases, untagged frames are assigned to a single ingress QoS profile (provided
that the port is an untagged member of a VLAN; if that is not the case, then untagged
frames are discarded). This QoS profile defaults to qp1, but you can assign it to another
profile using the command or
config ports <portlist> qosprofile <qosprofile>
the command (where the port-based
config vlan <name> qosprofile <qosprofile>
QoS configuration has higher precedence than VLAN-based QoS).
Additionally, if you enable the LLC Encapsulation for Routed Protocols on an ATM port
and do not enable on the port, then all ingress frames (received
diffserv examination
from the SONET link) are assigned to a single ingress QoS profile. The profile defaults
to qp1, but you can configure it to another profile using the
config ports <portlist>
command or the
qosprofile <qosprofile> config vlan <name> qosprofile
command.
<qosprofile>
If you enable on an ATM port, then ingress IP frames are
diffserv examination
assigned to a QoS profile based on the DiffServ code point (regardless of whether you
enabled either LLC Encapsulation for Bridged Protocols or LLC Encapsulation for
Routed Protocols on the port). The existing
config diffserv examination
command maps DiffServ code points to QoS profiles. This command has
code-point
been enhanced for use with ATM ports. The syntax and description of the enhanced
command are given below.
config diffserv examination code-point
3-32 Asynchronous Transfer Mode (ATM) Module Installation and User Guide