Exam JN0-664 topic 1 question 14 discussion

More specific group range

I'm just wondering that the question is stating "for ALL groups". Now if you change the group range to be more specific on R2, it will certainly send multicast to R2 for matching groups, but IMHO it won't fulfill the requiremen of ALL groups. Thus, I would match the group subnets to /24 on both and then increase the priority on R2. Your thoughts?

Changing the bootstrap priority will only influence the bootstrap election. You need to chage the group range on R2 to be more specific.

1. Find all RPs with the most specific group range covering G. 2. From the subset in step 1, select all RPs with the highest priority (lowest priority value). 3. For the RPs that meet the requirements in steps 1 and 2, compute a hash value based on the group address G, the RP address, and the hask mask included in the Bootstrap messages. The RP with the highest hash value is the RP for the group. 4. In the case of a tie (that is, the same group address, priority and hash value), the RP with the highest IP address is the active RP.

A - Priority See the statement copied/pasted below from the information at this URL: https://www.juniper.net/documentation/us/en/software/junos/multicast/topics/topic-map/mcast-pim-bootstrap-router.html "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. A simple bootstrap configuration assigns a bootstrap priority value to a routing device."

D is correct, check this out https://higherlogicdownload.s3.amazonaws.com/JUNIPER/MigratedInlineFiles/9531b1e0a25c46edaaa976789ad6305e_697bd1d7acea48deb9bd00536487d7d4

When two RPs advertise the exact same groups then we will prefer the RP with the highest priority. Unlike the BSR selection, highest priority for RP selection means the lowest priority value (0 is the highest priority). The priority is a value we can configure on the RP. D is Correct

Absolutely priority. Group can exclude only. My R3 in lab is R3 in question. My R4 in lab is R2 in question root@R4# set rp bootstrap family inet priority 220 Output on other router directly connected to both address-family INET RP address Type Mode Holdtime Timeout Groups Group prefixes 192.168.0.3 bootstrap sparse 150 131 0 224.0.0.0/4 192.168.0.4 bootstrap sparse 150 131 2 224.0.0.0/4 <<<<<<<<<<< 2 GROUPS Group: 239.2.2.2 Source: * RP: 192.168.0.4 Flags: sparse,rptree,wildcard Upstream interface: ge-0/0/4.0 <<<<< To my R4 (R2 in question) Group: 239.1.1.1 Source: * RP: 192.168.0.4 Flags: sparse,rptree,wildcard Upstream interface: ge-0/0/4.0 <<<<<< To my R4 (R2 in question)

correct