Juniper JUNOSE 11.2.X MULTICAST ROUTING User Manual

NOTE: When the mroute is first installed in the FC (at t = 0), R
0
is undetermined. For
multicast admission control no joins are admitted until the first bandwidth measurement
is computed (that is, for admission control, R
0
is considered to be infinite). Similarly, no
QoS adjustment occurs until the first bandwidth measurement is computed (that is,
for QoS adjustment, R
0
is considered to be zero [0]).
Using the earlier graph as a reference, the first bandwidth rate (R1
0
) and at time t
5
(N
5
)
and the bytes received values are subtracted and divided by the time 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 would look like the following:
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.
In order 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 would look like the following:
R = Rt, if and only if the absolute value of (R - Rt) > P * R.
The values assigned to variables associated with this algorithm are as shown in Table 9
on page 150.
Table 9: 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
Copyright © 2010, Juniper Networks, Inc.150
JunosE 11.2.x Multicast Routing Configuration Guide

Juniper JUNOSE 11.2.X MULTICAST ROUTING Specifications

General

Brand	Juniper
Model	JUNOSE 11.2.X MULTICAST ROUTING
Category	Software
Language	English