Addendum

12
Miscellaneous Settings
This chapter contains several, diversified behavioral-changes and enhancements that apply to this
release.
• Default Host Name Change
• hostname (for Changes to Default)
Setting a Threshold for Switching to the SPT
The functionality to specify a threshold for switchover to the shortest path trees (SPTs) is available on S-
Series platforms. After a receiver receives traffic from the RP, PM-SM switches to SPT to forward multicast
traffic. Every multicast group has an RP and a unidirectional shared tree (group-specific shared tree).
The SPT-Threshold is zero, which means that the last-hop designated router (DR) joins the shortest path
tree (SPT) to the source upon receiving the first multicast packet.
Initially, a single PIM-SM tree called a shared tree to distribute traffic. It is called shared because all traffic
for the group, regardless of the source, or the location of the source, must pass through the RP. The
shared tree is unidirectional; that is, all multicast traffic flows only from the RP to the receivers. Once a
receiver receives traffic from the RP, PM-SM switches to shortest path trees (SPT) to forward multicast
traffic, which connects the receiver directly to the source.
You can configure PIM to switch over to the SPT when the router receives multicast packets at or beyond
a specified rate.
Table 4. Configuring PIM to Switch Over to the SPT
IPv4 Configure PIM to switch over to the SPT when
the multicast packet rate is at or beyond a
specified rate. The keyword infinity directs PIM
to never switch to the SPT.
ip pim spt-threshold
{value | infinity}
Default: 10 kbps
CONFIGURATION
IPv6 Configure PIM to switch over to the SPT when
the multicast packet rate is at or beyond a
specified rate. The keyword infinity directs PIM
to never switch to the SPT.
ip pim spt-threshold
{value | infinity}
Default: 10 kbps
CONFIGURATION
ip pim spt-threshold
To switch to the shortest path tree when the traffic reaches the specified threshold value, configure the
PIM router.
S6000
Syntax
ip pim spt-threshold value | infinity
To return to the default value, use the no ip pim spt-threshold command.
Miscellaneous Settings
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