Which two of these statements correctly describe classic PIM-SM? (Choose two.)
A.
The lOS default is for a last-hop router to trigger a switch to the shortest path tree as soon as a
new source is detected on the shared tree.
B.
The lOS default is for every one of the routers on the shared tree to trigger a switch to the
shortest path tree as soon as a new source is detected on the shared tree.
C.
The default behavior of switching to the shortest path tree as soon as a new source is detected
on the shared tree can be disabled by setting the value in the ip pirn spt-threshold command to
“infinity.
D.
The default behavior of switching to the shortest path tree as soon as a new source is detected
on the shared tree can be disabled by setting the value in the ip pirn spt-threshold command to
“zero.”
Explanation:
They are checking you for syntax ip pim spt-threshold command to “infinity” is the right answer.
same source as above:
IP pim spt-threshold [vrf vrf-name] spt-threshold {kbps | infinity} [group-list access-list]
To configure when a Protocol Independent Multicast (PIM) leaf router should join the shortest path
source tree for the specified group infinity Causes all sources for the specified group to use the
shared tree.http://www.cisco.com/en/US/docs/ios/12_2/ipmulti/command/reference/1rfmult2.html#wp1020111