Information Technology Reference
In-Depth Information
Another method of marking packets is to use the
police
command, as shown in the following example:
policy-map
police-mark
class class-default
police
8000 1000 1000
conform-action
transmit
exceed-action
set-dscp-transmit 0
violate-action
drop
interface serial 1/0
service-policy output
police-mark
In the example, within the policy map called police-mark, the
class class-default
command matches all traffic, and the
police
bps
burst-normal burst-max
conform-action
action
exceed-action
action
violate-action
action
command then specifies that any traffic
that conforms to the rate limit will be transmitted unmodified, traffic that exceeds the rate limit will have its DSCP field set to zero,
and any traffic that violates the normal and maximum burst sizes will be dropped. Finally, the
service policy
command is used to
attach the policy map to interface serial 1/0 in an output direction.
You can find more information about the
police
command in the section, “Traffic Policing and Shaping,” later in this e-book.
The default QoS settings for Cisco IP phones (as set in CUCM Enterprise Parameters) are as follows:
■
Call signaling (SCCP or SIP):
CoS 3 and DSCP CS3 (DSCP 24)
■
Voice media (RTP):
CoS 5 and DSCP EF (DSCP 46)
Cisco has a set of recommendations with regard to classification, marking, and QoS configuration applicable to all types of traffic
(including voice media and call signaling traffic) crossing a network. This set of recommendations is called the Cisco QoS baseline,
and it is summarized in
Table 2-1.
