Juniper JUNOSE 11.1.X MULTICAST ROUTING, Руководство по настройке

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period T
1
to yield the average rate. This process is repeated every sampling interval,
T
2
, to yield rates R1, R2, R3, and so on.
The first two sampling interval calculations are as follows:
R
1
= (N
5
- N
0
)/5
R
2
= (N
#+5
- N
#
)/5
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
Description Units Value Variable
Sampling period; the time in which a sample is taken Seconds 5 T1
Sampling interval; zero (0) seconds indicates continuous
sampling Seconds 0 T2
Number of history samples over which to compute
measurement Samples 12 H
Maximum number of samples maintained in history Samples 12 M
Threshold value; percent difference by which a newly
calculated rate must differ from the measured peak
bandwidth before a rate update occurs Percent 1 P
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.
Defining a Multicast Bandwidth Map
■ 13
Chapter 1: Configuring IPv4 Multicast