Configuring Diffserv - Extreme Networks PoS Installation And User Manual

Configuring QoS Functions
If you enable on a PoS 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 BCP or IPCP 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 PoS ports. The syntax and description of the enhanced
command are given below.
config diffserv examination code-point
Also note that, in all cases, the 802.1p priority bits of ingress frames forwarded to the
switch backplane are set based on the ingress QoS profile classification. More
specifically, the 802.1p priority value is set to qp# – 1. For example, if the packet is
classified to qp5, then the 802.1p priority value is set to 4.
When you enable MPLSCP on a PoS port, classification for MPLS labeled packets is
done based only on the EXP bits in the label stack entry of the ingress frame. The EXP
bits are used to map an ingress frame to an 802.1p priority and assigned to the
corresponding ingress queue. Before the frame is forwarded to the switch backplane,
the 802.1p bits in the frame are set based on the exp-to-dot1p mapping. You can use the
command to configure the EXP to 802.1p
config mpls qos-mapping exp-to-dot1p
mapping. You can use the command to
config dot1p type dot1p_priority
configure the 802.1p to QoS mapping.
When you configure MPLSCP on a PoS port, other types of ingress commands such as
,
config diffserv examination code-point config ports <portlist>
, and are supported only for IPCP data
qosprofile config vlan <name> qosprofile
frames and not MPLS labeled frames. Similarly, egress replacement commands such as
and are supported only
enable dot1p replacement enable diffserv replacement
for IPCP data frame and not MPLS labeled frames.

Configuring DiffServ

All of the existing ExtremeWare DiffServ commands are supported by PoS ports with IP
frames that are encapsulated in BCP or IPCP, not MPLSCP (including the enhancements
to the command, described earlier in this
config diffserv examination code-point
chapter). PoS ports also support a DiffServ code point (DSCP) mapping function that
you configure using the command, which is
config diffserv dscp-mapping
described below. The DSCP is a 6-bit value in the IP-TOS byte of the IP packet header.
For more information on DSCPs, see "Configuring DiffServ" in the ExtremeWare Software
User Guide.
Packet Over SONET Module Installation and User Guide 3-47