Ipqos precedence, Ipqos precedence -12 – Allied Telesis AT-8550 User Manual
Page 118
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