User`s guide

Traffic Groupings and Creating a QoS Policy
7-12
IPQoS
Precedence
As previously mentioned, there are two types of IPQoS command
formats, a short form and a long form (also called a
flow
). A long form
multicast and unicast entry (flow) has higher precedence over a
matching short form multicast and unicast entry (non-flow). Also, as
indicated in Table 7-2, all forms of IPQoS have higher precedence
than destination MAC-based groupings.
Within the IPQoS short form, a higher granularity subnet mask takes
precedence over a subnet mask with less granularity. For example, of
the following two IPQoS policies:
config ipqos add 10.1.2.3/32 qp4
config ipqos add 10.1.2.0/24 qp3
All traffic containing
10.1.2.3
as the first 32 bits of the destination
IP address are assigned to the QoS profile
qp4
. All traffic containing
10.1.2 as the first 24 bits of the destination IP address, with the
exception of 10.1.2.3, are assigned to the profile
qp3
.
Within the IPQoS long form (flow), precedence is determined by the
traffic grouping information provided. For example, an IP QoS policy
that includes a specified source IP address has higher precedence
than an IP QoS policy that includes a layer 4 source port (but no
source IP address). An IP QoS policy containing a layer 4 destination
port (but no source IP or layer 4 port number) has the lowest
precedence.
As a further example, IPQoS commands that vary in the traffic
grouping information provided are listed below in order of
precedence from highest to lowest. A source IP address has the
highest precedence, followed by layer 4 source port, then by a layer
4 destination port. Assume the following precedes each command:
config ipqos add tcp 10.1.2.0/24
and is followed by one of the following (listed in highest to lowest
precedence):
❑
l4_dstport 80 11.12.0.0/16 l4_srcport 80
qosprofile qp3
❑
11.12.0.0/16 l4_srcport 80 qosprofile qp3
❑
l4_dstport 80 11.12.0.0/16 qosprofile qp3
❑
11.12.0.0/16 qosprofile qp3
❑
l4_srcport 80 qosprofile qp3
❑
l4_dstport 80 qosprofile qp3