The router maintains a history of bandwidth measurements (H) for each mroute, up to
a maximum of M measurements. The actual rate, R, reported to the SRP is the maximum
rate measured in those H samples.
To minimize the IC to SRP traffic generated by the rate measurements, the IC reports a
bandwidth change only when a newly computed rate (R#) differs from the current rate
by a specified threshold. When R
s
is computed at time t = 5 seconds, R is set to R
1
. A rate
update occurs whenever a newly calculated rate (R) differs from R
1
by at least a threshold
value (specified as a percentage, P) of the measured peak bandwidth. This calculation
is as follows:
R = Rt, if and only if the absolute value of (R - Rt) > P * R.
Table 4 on page 13 lists values assigned to variables associated with this algorithm.
Table 4: Adaptive Mode Algorithm Values
DescriptionUnitsValueVariable
Sampling period; the time in which a sample is takenSeconds5T1
Sampling interval; zero (0) seconds indicates continuous
sampling
Seconds0T2
Number of history samples over which to compute
measurement
Samples12H
Maximum number of samples maintained in historySamples12M
Threshold value; percent difference by which a newly
calculated rate must differ from the measured peak
bandwidth before a rate update occurs
Percent1P
Multicast Bandwidth Map Example
The following example creates a multicast bandwidth map for both multicast traffic
admission control and QoS adjustment:
NOTE: In this example, you can replace the set admission-bandwidth command and
set qos-bandwidth command with their adaptive command counterparts.
1. Define a route-map using the set admission-bandwidth and set qos-bandwidth
commands. You can optionally issue the set priority command.
host1(config)#route-map mcast-bandwidths permit 10
host1(config-route-map)#match ip address sdtv
host1(config-route-map)#set admission-bandwidth 2000000
host1(config-route-map)#set qos-bandwidth 2000000
host1(config-route-map)#set priority 100
host1(config-route-map)#route-map mcast-bandwidths permit 20
host1(config-route-map)#match ip address hdtv
host1(config-route-map)#set admission-bandwidth 10000000
13Copyright © 2010, Juniper Networks, Inc.
Chapter 1: Configuring IPv4 Multicast
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