User guide
9-18 E
XTREME
W
ARE
S
OFTWARE
U
SER
G
UIDE
Q
UALITY
OF
S
ERVICE
(Q
O
S)
You can change the QoS profile assignment for all 64 code points using the following
command:
config diffserv examination code-point <code_point> qosprofile
<qosprofile> ports [<portlist> | all]
Once assigned, the rest of the switches in the network prioritize the packet using the
characteristics specified by the QoS profile.
R
EPLACING
D
IFF
S
ERV
C
ODE
P
OINTS
The switch can be configured to change the DiffServ code point in the packet prior to
the packet being transmitted by the switch. This is done with no impact on switch
performance.
The DiffServ code point value used in overwriting a packet is determined by the 802.1p
priority value. The 802.1p priority value is, in turn, determined by the hardware queue
used when transmitting a packet, as described in the section “Replacing 802.1p Priority
Information.”
It is not necessary to receive or transmit 802.1Q tagged frames, only to understand that
the egress hardware queue, which also determines the 802.1p priority value, can also be
configured to determine the DiffServ code point value if you want to replace the
DiffServ code points.
To replace DiffServ code points you must enable both 802.1p replacement and DiffServ
replacement using the following commands:
enable dot1p replacement ports [<portlist> | all]
enable diffserv replacement ports [<portlist> | all]
The default 802.1p priority value to code point mapping is described in Tab le 9- 11.
32-39 Qp5
40-47 Qp6
48-55 Qp7
56-63 Qp8
Table 9-10: Default Code Point-to-QoS Profile Mapping (continued)
Code Point QoS Profile