Edge-Core ECS4810-12M Layer 2 Management Manual page 1170

| Quality of Service Commands
C 38
HAPTER
mode the meter assumes that some preceding entity has pre-colored
the incoming packet stream so that each packet is either green, yellow,
or red. The marker (re)colors an IP packet according to the results of
the meter. The color is coded in the DS field [RFC 2474] of the packet.
The behavior of the meter is specified in terms of its mode and two
◆
token buckets, P and C, which are based on the rates PIR and CIR,
respectively. The maximum size of the token bucket P is BP and the
maximum size of the token bucket C is BC.
The token buckets P and C are initially (at time 0) full, that is, the token
◆
count Tp(0) = BP and the token count Tc(0) = BC. Thereafter, the token
count Tp is incremented by one PIR times per second up to BP and the
token count Tc is incremented by one CIR times per second up to BC.
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.
E
XAMPLE
This example creates a policy called "rd-policy," uses the
specify the previously defined "rd-class," uses the
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)#
– 1170 –
class command to
set phb command to