Set cos – Microsens MS453490M Management Guide User Manual

Page 843

HAPTER

| Quality of Service Commands

– 843 –

When a packet of size B bytes arrives at time t, the following happens if

trTCM is configured to operate in color-blind mode:

■

If Tp(t)-B < 0, the packet is red, else

■

if Tc(t)-B < 0, the packet is yellow and Tp is decremented by B, else

■

the packet is green and both Tp and Tc are decremented by B.

When a packet of size B bytes arrives at time t, the following happens if

trTCM is configured to operate in color-aware mode:

■

If the packet has been precolored as red or if Tp(t)-B < 0, the

packet is red, else

■

if the packet has been precolored as yellow or if Tc(t)-B < 0, the

packet is yellow and Tp is decremented by B, else

■

the packet is green and both Tp and Tc are decremented by B.

◆

The trTCM can be used to mark a IP packet stream in a service, where

different, decreasing levels of assurances (either absolute or relative)

are given to packets which are green, yellow, or red. Refer to RFC 2698

for more information on other aspects of trTCM.

XAMPLE

This example creates a policy called “rd-policy,” uses the

class

command to

specify the previously defined “rd-class,” uses the

set phb

command to

classify the service that incoming packets will receive, and then uses the

police trtcm-color-blind command to limit the average bandwidth to

100,000 Kbps, the committed burst rate to 4000 bytes, the peak

information rate to 1,000,000 kbps, the peak burst size to 6000, to remark

any packets exceeding the committed burst size, and to drop any packets

exceeding the peak information rate.

Console(config)#policy-map rd-policy

Console(config-pmap)#class rd-class

Console(config-pmap-c)#set phb 3

Console(config-pmap-c)#police trtcm-color-blind 100000 4000 100000 6000

conform-action transmit exceed-action 0 violate-action drop

Console(config-pmap-c)#

set cos

This command modifies the class of service (CoS) value for a matching

packet (as specified by the

match

command) in the packet’s VLAN tag. Use

the no form to remove this setting.

YNTAX

[no] set cos cos-value

cos-value - Class of Service value. (Range: 0-7)

EFAULT

ETTING

None

OMMAND

ODE

Policy Map Class Configuration