Click the exhibit button.
[edit protocols pim]
user@R1# show
rp {
bootstrap {
family inet {
priority 250;
}
}
local {
address 10.220.1.1;
priority 1;
group-ranges {
224.1.1.11/32;
224.0.0.0/4;
}
}
}
interface all;
interface fxp0.0 {
disable;
}
[edit protocols pim]
user@R4# show
rp {
bootstrap {
family inet {
priority 249;
}
}
local {
address 10.220.1.4;
priority 5;
group-ranges {
224.1.1.12/32;
224.0.0.0/4;
}
}}
interface all;
interface fxp0.0 {
disable;
}
Referring to the exhibit, which router will be the RP?
A.
R4 for all groups
B.
R1 for group 224.1.1.11 and R4 for all other groups
C.
R1 for all groups
D.
R4 for group 224.1.1.12 and R1 for all other groups
Explanation:
A priority of 1 means the routing device has the least chance of becoming a designated router. Here R1 has
priority 1, while R4 has priority 5. R4 will be elected the designated router and the rendezvous point (RP) for
both address ranges.
Note: In a shared tree, the root of the distribution tree is a router, not a host, and is located somewhere in the
core of the network. In the primary sparse mode multicast routing protocol, Protocol Independent Multicast
sparse mode (PIM SM), the core router at the root of the shared tree is the rendezvous point (RP).
http://www.juniper.net/documentation/en_US/junos15.1/topics/example/ospf-designated-routerelection-configuring.html
I guess R1…any idea?
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0
I agree with you C. is Answer.
R1 is BSR, because priority is 250.
R1 is RP for all groups, because RP priority is 1 (lower value is higher priority). R1 priority is cover for 224.1.1.11/32 and 224.0.0.0/4(Class D – All multicast groups).
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0
But, this leaves out 224.1.1.12? Do you mean that R1 is RP for that group too?
0
0
yes C
0
0
I think the answer is D, but for the 224.1.1.12/32 the R4 is more specific, for the rest is R1 is RP
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priority number;
number—Priority for becoming an RP. A lower value corresponds to a higher priority.
https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/priority-edit-protocols-pim-local.html
bootstrap priority.
By default, each routing device has a bootstrap priority of 0, which means the routing device can never be the bootstrap router.
The routing device with the highest priority value is elected to be the bootstrap router. In the case of a tie, the routing device with the highest IP address is elected to be the bootstrap router.
https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/mcast-bootstrap-ipv4.html
RP election consider the lowest priority or the lowest IP address as a primary RP.
However, BSP election considers the highest priority or the highest IP address as primary BSR.
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0