Exam JN0-348 topic 1 question 73 discussion

answer is B because of highest local pref.

You can use the local-preference attribute to direct all outbound traffic through a specific peer. Before sending the traffic to the internal peers, the designated peer sets the local-preference value on all routes received. Then all the peers use those routes in their RIB-local tables. The local-preference attribute is a numeric value: higher values indicate a better metric. The Junos operating system (OS) enables you to set the local-preference value using BGP configuration or through routing policy. If you seta local-preference value through both configuration and routing policy, the system uses the value assigned through routing policy. Please check JNCIS practice exam Can an admin please correct the answer?

it's EBGP session , local preference is evaluated inside the AS only So AS path is the tie here , answer is D

answer B right: This is route received from other AS, it because local preference prefer than AS path, BGP chose this for best path.

Local Pref is an attribute for the best path LEAVING your network. AS Path is an attribute for routs ENTERING your network? Look at the diagram (which is there to help you and to explain what is going on). All 3 routers are in AS 65503, so this is IBGP. Look at the red arrows, R1 and R2 are pointing towards R3 which indicates the direction of traffic/packets. So these routes received from an EBGP peer towards an IBGP peer. If this is the case then AS Path is the answer. If the red arrows were from R3 towards R1 and R2, then Local Pref would be the answer On a side note, where R1 is showing AS 65530, I think this is a TYPO and should be 65503 as this would be a prepend configuration to make R2 the preferred route into the network.

Answer is D: This is for incoming advertisement. Local preference displayed is on local router R1 and R2.

https://networklessons.com/bgp/bgp-attributes-and-path-selection B is correct !

answer is D, the neighbor which received the prefix X would be in the AS 65530 (does not appear in the layout) R1 & R2 would advertise the ip prefix via EBGP despite IBGP so we have to apply this rule: "The LOCAL_PREF path attribute is never advertised to external BGP peers." In conclusion, we prefer the shortest AS-path length, in other words, ip prefix X received from R2.

B, Local preference is a metric for internal neighbors to reach external destinations .

The correct answer is B. Local preference is evaluated before AS Path and the HIGHER local preference will win out. Also, local preference is sent within the AS Path to steer exit points from the AS. (other values, such AS Path via prepend are used to steer traffic towards the AS). See the link for Local Pref discussion: https://www.juniper.net/documentation/en_US/junos/topics/topic-map/bgp-local-preference.html

should be B, local pref is not sent to ebgp neighbors, the question is implicating there's a policy map to add said local preferences when R1 and R2 are receiving the prefix.

It should be B as local preference does not work when traffic coming into the AS, it only works when traffic is exiting, it should be D

I also believe that there's a typo in the question. If you look at the arrows for R1 and R2, they're advertising the learned routes into IBGP. But the question says that R1 and R2 advertising into AS 65530. It's my belief that the AS in the exhibit should be labeled AS 65530 instead of 65503